Cambodia Experiences Rapid Rate of Forest Loss March 22, 2017
When it comes to forest loss on a global scale, Cambodia is notable for how rapidly its forests are being cleared.
Among countries with accelerated rates of deforestation—Sierra Leone, Madagascar, Uruguay, and Paraguay among them—Cambodia ranks above them all with an annual loss of 14.4 percent of its forests between 2001 and 2014, according to researchers at the University of Maryland, who used Landsat data to track their rates. In that time period, Cambodia lost 5,560 square miles of forests.
That loss is easily seen in these Landsat images. The Landsat 5 image captured in 1999 (left) shows vast dark green forest among a mountainous area of Cambodia. The 2017 image acquired by Landsat 8 (right) reveals areas where forest has been clear-cut. The bright green landscapes in the lower left interspersed with darker blocks are crops. The pinkish-tan areas are old, small-plot agricultural areas, and the bright green rectangles (top left) are agroforestry areas where rubber or oil palm plantations have emerged.
Working with Landsat data and other economic datasets, researchers at the University of Maryland have demonstrated that changes in global rubber prices and a surge in land-concession deals have helped accelerate Cambodia’s rate of deforestation. The Cambodian government leases concession lands to domestic and foreign investors for agriculture, timber production, and other uses.
Landsat Detects Eruptions at Ethiopian Volcano March 10, 2017
Landsat 8’s shortwave infrared (SWIR) band is useful in viewing recent eruptions at Erta Ale volcano in northern Ethiopia near the Eritrea border. The volcano’s name means “smoking mountain,” and its southernmost vent is referred to as “the gateway to hell.” Both names acknowledge its long-term volcanic activity since the early 1900s, and the persistent filling and draining of lava lakes within its main crater rim. The lava lakes have been filled most recently since the 1960s.
Like other shield volcanoes, Erta Ale has gentle slopes and a wide base of about 25 miles in diameter. Shield volcanoes do not erupt explosively. Instead, the basaltic lava is very fluid and erupts like fountains in the lava lakes and along fissures, flowing like streams down the sides. Darker streaks in these recently acquired Landsat images are some of the previously erupted, cooled, and solidified lava flows.
The elliptical summit crater contains several smaller pit craters, and the current lava lake is in one of these. The red spot in the January 10 image is a SWIR signal associated with the location of the most recent lava lake. The February 11 image, however, shows out-gassing of that lava lake and other hot spots on the southeastern slope of the volcano. According to the Global Volcanism Program, new fissures opened on January 21. Landsat’s SWIR signal infers increased temperatures where new lava is either at very shallow depths below the surface or gurgling to the surface.
Wildfires Ravage Central, South-Central Chile February 17, 2017
Wildfires fueled by dry conditions, high temperatures, and strong winds are scorching central Chile at a level Chilean officials say they haven’t seen in decades. Landsat 8 Operational Land Imager (OLI) mosaics on the left from January 24 and February 2 show multiple fire scars growing across the Chilean landscape.
The fires, which had consumed roughly 1,060 square miles as of late January, include a large burn area that threatened the city of Empedrado. The two images to the right capture the explosive growth of the fire around the city.
On January 24, the burned land can be seen primarily south of Empedrado, with blue smoke and orange flames visible from an active fire on the periphery of the scar. By February 2, the burn scar expanded to completely surround the city, and extends north all the way to and beyond the Maule River.
Satellite data have shown smoke from the Chile fires traveling hundreds of miles, reaching areas in the Central South Pacific. As of February 2, 123 active forest fires were registered in Chile by the National Forest Corporation (CONAF). In all, more than 20,000 people, including firefighters and experts from over a dozen countries, helped battle the wildfires, CONAF officials said.
January Rain, Snow Refills California Reservoirs February 10, 2017
A decade of drought in California has eased after the first month of 2017 thanks to heavy rains and snow, a fact that Landsat images are helping to confirm.
For the first time in three years, the U.S. Drought Monitor reported in late January 2017 that not a single area in California is considered in “exceptional drought,” the most severe category. A year ago, about 40 percent of the state was under the most severe designation. Landsat 8’s Operational Land Imager captures the dramatic reversal in these false-color views of Lake Nacimiento and Lake San Antonio along the coast in central California between Los Angeles and San Francisco.
Drought left Lake Nacimiento at only 22 percent full as of late 2016. Since 2014, Lake San Antonio had been emptied to critical levels to help recharge the groundwater in the Salinas Valley. At only 3 percent full, the lake was closed to public use on July 1, 2015. The red burn scar from the Chimney Fire in August 2016 is a vivid reminder of the drought’s impact on the area.
Today, however, the January 30, 2017, image shows how the recent precipitation has transformed the water levels in these two lakes. Lake Nacimiento is now at 81 percent full, while Lake San Antonio—virtually dry before—sits at 26 percent full.
All told, more than 48 percent of California was drought free as of February 1, 2017, compared to only 5 percent a year ago, according to the Drought Monitor.
Argentina Flooding Has Major Impact on Soybean Production February 3, 2017
Heavy rains in late December 2016 and early January 2017 are affecting soybean production in Argentina’s bread-basket provinces while impacting soy prices worldwide.
Landsat 8’s Operational Land Imager is a valuable tool for confirming weather’s impact on crop production. While rainfall is common in northeastern Argentina from December through February each year, the flooding of soybean fields in that area is dramatic in the January 2017 Landsat image, compared to a similar period in January 2015, when no such inundation covers the landscape.
The flooding in the world’s third largest soybean-exporting country caused soybean and soymeal prices to hit six-month highs in mid-January on the Chicago Board of Trade, commodity analysts said. Argentina’s Rosario Grains Exchange has reported that almost 4 million acres of soybeans in that country were damaged by this recent flooding. This image shows a portion of that inundation.
As the longest-running satellite system covering the Earth, Landsat is vital to national and international food production. The Landsat imagery not only helps verify crop damage, as it did in this case, but is also valuable to agencies like the U.S. Department of Agriculture for formulating reports on crop production, condition, progress, and projecting yields.
West Africa Atlas Details Efforts to Manage, Preserve Okomu Forest January 24, 2017
A new atlas named Landscapes of West Africa: A Window on a Changing World tells the story of transformations and trends across many lands in West Africa, including this look at the threat of human activities in the Okomu Forest Reserve in southern Nigeria.
Closed-canopy tropical moist forest once covered large parts of this Nigerian landscape. Since the 1940s, however, systematic rotational logging and farming have caused major losses of natural forest.
In the 1984 Landsat 5 image, parts of the reserve have already been converted to plantations of oil palm and rubber trees, as seen in shades of magenta. In 1985, a wildlife sanctuary of 44 square miles was carved out of the most intact area of the forest reserve to protect a small population of forest elephants and several species of threatened primates.
The sanctuary was designated the Okomu National Park in 1999 to give it more protection from plantation and farm development, as well as human settlement expansion. The visible impact of large-scale rubber and oil palm plantation expansion in the northern half of the forest reserve is easily seen in the 2017 Landsat 8 image. However, the Okomu National Park remains largely protected within the reserve and stands out against its surroundings.
The atlas and its accompanying datasets are valuable tools to Nigerian forest managers in their effort to protect Okomu from further ecosystem degradation.
Wildfires Scorch Pampas Region of Argentina January 17, 2017
Since mid-December 2016, roughly two dozen wildfires in the Pampas region of Argentina have consumed almost 2.5 million acres while unleashing giant plumes of dense smoke above the rural landscapes.
Likely caused by thunderstorms that followed a stretch of severe drought in the winter and spring of 2016, the first fires started southwest of the city of Bahía Blanca. A scene from Landsat 8’s Operational Land Imager (OLI) on December 22, 2016, shows smaller red burn scars from those initial blazes—an area of approximately 100,000 acres.
Despite rain in the final days of December, a handful of hot spots persisted, and the fires spread. When it passed overhead on January 7, 2017, OLI captured dramatic imagery of large red burn scars across the landscape of Argentina’s central province of La Pampa, and its southern province of Rio Negro.
On January 5, 2017, the International Charter “Space and Major Disasters,” of which USGS is a member, granted Argentina’s request for Charter members’ available satellite data to help in rapidly assessing the extent of damage and determining a disaster response.
Marree Man Geoglyph in Australia Does Reappearing Act January 10, 2017
In June 1998, a pilot discovered a strange sight in the Australian outback that wasn’t there before—a huge outline of what appeared to be an Aboriginal man throwing either a boomerang or a stick. It turned out to be a geoglyph, which is a design on the ground typically made of natural elements and best viewed from above. This geoglyph was distinctive and large enough to be clearly visible in Landsat images.
Its origin remains a mystery, as no credible source has claimed responsibility. Over the years, the “Marree Man” faded because of rain and wind. In July 2000, Landsat 7 shows an outline with far fewer details.
In August 2016, the Marree Man was re-etched. A grader and GPS were used to re-create the outline, and this time the geoglyph is expected to last longer. The lines created are wind grooves that will trap water, so over time the outline should turn green.
Now clearly visible again in the November 2016 Landsat 8 image, Marree Man is among the biggest geoglyphs on Earth. It stretches 3.5 kilometers from the tip of his stick to his toes. From an airplane, a person would need to be at around 3,000 feet to view it in its entirety.
Rare Snow Falls at the Edge of Sahara Desert January 4, 2017
In mid-December 2016, a rarity occurred on the edge of the Sahara Desert in northwest Africa. It snowed.
Landsat 7’s Enhanced Thematic Mapper Plus (ETM+) sensor captured the image that shows the white covering on the caramel-colored landscape southwest of the Algerian community of Ain Sefra, a town sometimes referred to as “the gateway to the desert.” All the snow except that at the highest elevations melted soon after, a fact Landsat 8 confirmed when it passed overhead on December 27.
Ain Sefra’s last snowfall occurred on February 18, 1979. While snow does collect in Africa at higher elevations—Mount Kilimanjaro in Tanzania has long been crowned by a cap of snow and ice—snow on the edge of the Sahara Desert seldom falls.
The average summertime temperature at Ain Sefra is 99 degrees Fahrenheit. Though winter temperatures are known to drop into the 30s, snow is as rare as the cool temperatures given that just a few centimeters of precipitation fall there annually.
Expansion at the Port of Rotterdam December 21, 2016
A large infrastructure project has changed the shape of the coastline of the Netherlands while increasing the cargo capacity at Europe’s largest port. This pair of Landsat images spanning 15 years shows the Maasvlakte 2 project, which is an expansion of the Port of Rotterdam. The port provides accessibility for the transportation of cargo from Rotterdam to the rest of Europe.
Land building at Maasvlakte 2 began in 2008. About 230 million cubic meters of sand were dredged from the North Sea to create about 5,000 acres of new land. In addition, 7 million metric tons of stone were used to construct new seawalls.
Commercial cargo operations at the new Maasvlakte 2 facility began in December 2014. Its terminals currently can hold 2.7 million individual 20-foot shipping containers. There is more space for terminals to be built on the new land once demand increases, which would increase the port’s cargo handling capacity even more.
The expansion of land resulted in some loss of permanently flooded sandbanks that affected the availability of food for some protected bird species, such as the common scoter, the sandwich tern, and the common tern. However, this loss was compensated for by establishing a protected seabed area south of the Maasvlakte 2 in the Voordelta. Also, three bird resting areas in the seabed were established where boat traffic is restricted. Landsat can help monitor this coast to ensure the positive impact of these protected areas as compensation for the land expansion.
A Landsat Mosaic for Indiana’s Bicentennial December 12, 2016
Throughout 2016, Indiana has been celebrating its 200th anniversary of statehood. Joining the Union on December 11, 1816, as the 19th state, Indiana was the second state admitted from what was once known as the Northwest Territory.
This satellite mosaic of the Hoosier State was created from several Landsat scenes stitched together to create one seamless image. Data from the National Elevation Dataset (NED) is also incorporated into the image. The names of major cities and county boundaries have been added.
The Landsat images used for this mosaic were from summer months, so it shows the state at the height of the growing season. Since farmland makes up about 70% of the state’s land, much of the state appears green. By contrast, urban areas appear in shades of lavender. The large spot in the middle of the state marks the location of Indiana’s capital and largest city, Indianapolis.
The Wabash River, the official state river, flows west across the northern part of the state and turns south to form part of the border with Illinois.
As Glaciers Worldwide Are Retreating, One Defies the Trend December 6, 2016
Many glaciers around the world are losing ice mass and retreating. One such area is the Southern Patagonia Icefield (SPI) in Chile. However, one glacier in the SPI is actually defying the worldwide trend. The Pio XI Glacier is advancing, and based on scientific studies, there is no clear reason why.
Pio XI flows from the SPI toward the west then splits into two fronts. From 1998 to 2014, the southern front advanced 593 meters. The northern front, which flows into Lake Greve, advanced 107 meters in the same time period. This pair of Landsat images shows that all of the other glaciers that flow down from the SPI into Lake Greve are retreating.
The complex behavior of glaciers involves more than just measuring where the ice ends. Scientists theorize that something is happening inside or beneath Pio XI to make it advance, rather than an external factor like climate. The glacier flows from a wide accumulation area into a narrow outlet, and the depth of the lakes it flows into, along with the speed of the glacier’s flow, may also be factors.
Whatever the cause, glaciers continue to be closely monitored, and in the remote region of the SPI, that monitoring needs to be done with remote sensing. Landsat offers several observations per year in these areas and will help scientists understand the glacier’s future behavior.
Landsat Chronicles Deforestation in Colombia November 28, 2016
Deforestation has long been a fact of life in the Amazon, Andean, and Caribbean regions of Colombia, South America, something that Landsat satellite data have thoroughly chronicled through the years.
Landsat images used by Colombia’s Institute of Hydrology, Meteorology and Environmental Studies (IDEAM) determined that total forest land cover in the country has dropped from 56.8 percent in 1990 to 52.6 percent by 2012, or almost 5 million hectares.
Driven by logging, mining, and conversion to agricultural uses, Colombia lost 140,356 hectares of forest cover in 2014 alone, according to IDEAM, and 120,934 hectares in 2013. These scenes from Landsat 4 in 1989 and Landsat 8 in 2016 reveal the dramatic change over time. Dark green depicts rain forest in both images. The pink, yellow, and lighter green indicate the removal of healthy forest.
Colombia has committed to zero net deforestation in the Amazon by 2020, to allow no overall loss of forest area or forest quality while allowing some flexibility to meet local needs. Satellite images, including those from Landsat, will continue to be an important component in monitoring this goal.
Saudi Wheat Experiment Relied on Fossil Water November 21, 2016
In the mid-1980s, Saudi Arabia embarked on an ambitious agricultural plan to grow crops in its desert areas using ancient fossil water deep beneath the sand, and installed center-pivot irrigation systems in the barren Wadi As-Sirhan basin in the northwest part of the country. The water, which was once used to grow fruit, vegetables and wheat, was buried deep underground for thousands of years.
These Landsat images show the remarkable transformation of desert sand in 1986 into green, circular fields—some as large as 1 kilometer across—by 2016.
The drawback with center-pivot irrigation lies in the fact that water in these aquifers is not recharged. Rainfall here only averages 100 to 200 millimeters per year, making groundwater in the area a nonrenewable resource. Hydrologists predict it will only be feasible to pump the groundwater for another 50 years, so domestic wheat production will be phased out. Local farmers are being encouraged to engage in alternative sustainable agricultural activities, such as greenhouse farming using advance drip irrigation techniques, to produce fruits and vegetables.
Future Landsat data acquisitions will be useful in monitoring and seeing how the changes in farming techniques affect the landscape.
Three Gorges Dam Brings Power, Concerns to Central China November 14, 2016
The construction of the Three Gorges Dam on the Yangtze River in central China offers an interesting glimpse into the balancing act borne from humanity’s changing of the natural landscape.
Images from Landsat 5 in 1993 and Landsat 8 in 2016 show a river transformed after the completion of the largest hydroelectric power plant in the world in 2012. The Yangtze appears light blue in these scenes because of heavy sedimentation in the water as it passes through the Qutang, Wu, and Xiling gorges in this mountainous region. Tributaries with less sediment appear darker blue. Forested areas are red because of Landsat’s near-infrared imaging capability.
Hydropower as an alternative energy source to coal is a valuable output from the dam. Three Gorges’ power plant has a generating capacity of 22,500 megawatts, over 3 times that of the Grand Coulee Dam and 20 times that of Hoover Dam. Besides hydropower, the dam has also made river navigation easier, eased flooding, and provided an ample water supply for irrigation.
On the downside, the project forced the relocation of more than 1.2 million people. A 2010 study by the China Earthquake Administration found that Three Gorges Dam had triggered about 3,400 earthquakes from mid-2003 to the end of 2009, as well as numerous landslides, representing a 30-fold increase in seismicity. Environmentalists worry as well that large amounts of silt are congregating in the Three Gorges’ region because of a change in the river’s flow, that biodiversity in the river downstream from the dam has been lost, and that important archaeological sites and ancient monuments were inundated as the reservoir filled.
Landsat Monitors Gypsy Moth Damage November 7, 2016
Massive defoliation caused by a severe outbreak of the European gypsy moth caterpillar during the spring and summer of 2016 across southern New England and the Mid-Atlantic was easily captured by the Landsat 8 Operational Land Imager sensor from 438 miles in space.
Frequent monitoring to assess gypsy moth impacts is a valuable area of Landsat time-series research. In the past, traditional monitoring of gypsy moth damage to vegetation was done with aerial surveys that took hundreds of hours by pilots in planes crisscrossing the region once per season. Today, Landsat 8 imagery is acquired every 16 days, and automated algorithms are available for extracting change information. If used with Landsat 7 imagery, monitoring can take place every 8 days.
In these 2015 and 2016 Landsat images of the forested countryside surrounding Providence, RI, during July, defoliation is easily discernible. In the 2015 image, healthy forest appears light green. Almost exactly a year later, after the caterpillars have hatched and had an opportunity to feed, defoliation of the hardwood forests is captured by wide swaths of dull peach landscape through the middle of the image.
While gypsy moths are a constant presence in the northeastern United States, their populations swell certain years because of several environmental factors. In 2016, forest managers and biologists are blaming two successive dry springs and the accompanying drought on the outbreak. Drought in turn weakens a second factor that keeps the gypsy moth population in check—a fungus found on the ground that can infect and ultimately kill gypsy moth caterpillars.
Hurricane Sandy Slammed Eastern U.S. Four Years Ago October 31, 2016
On October 29, 2012, Hurricane Sandy barreled across the shorelines of New Jersey, New York, and Connecticut, impacting lives across two dozen states that fell within its destructive path.
High Resolution Orthoimagery archived at the USGS EROS Center and inset into the larger image show the New Jersey coastal town of Mantoloking five years before Sandy made landfall, as well as the slow recovery three years after the storm. Entire blocks of houses visible in the 2007 image were damaged or completely washed away by the storm surge and wind, replaced by empty patches of sand in the 2015 image.
The larger background image acquired by the Remote Sensing Division of the National Oceanic and Atmospheric Administration in the days after the storm in 2012 shows the immediate devastation, including a breach cut across the island and connecting the Atlantic Ocean to Barnegat Bay.
The Mantoloking Bridge was covered in water, sand, and debris from houses after the storm. Built for roughly $25 million and opened in 2005, it was closed after Sandy went through because county officials considered it unstable, and didn’t reopen until the first week of January 2013.
Hurricane Matthew Exacts Heavy Toll on Haiti October 21, 2016
A week after Hurricane Matthew slammed through southwestern Haiti on October 4, 2016, Landsat 8’s Operational Land Imager sensor provided dramatic documentation of the scope of destruction in the Caribbean country.
In Haiti, land is often managed in small patches. A household may have subsistence crops in a number of locations, often on steep slopes. Data acquired on September 26 shows the landscape green with vegetation. On October 12, eight days after the storm, the hillsides are denuded after the Category 4 storm washed away crops and fallows.
Also evident in the post-storm image is a surge of sediment in the coastal waters at the mouth of the Ravine du Sud River near the seaport town of Les Cayes after Matthew went through. Geologists say the sediment likely comes from slopes that lacked protective tree cover.
The slow-moving storm dropped upwards of 30 inches of rain across parts of the impoverished nation. Hundreds of thousands of homes were damaged or destroyed. Meanwhile, public health authorities fear that the rush of rain will worsen a cholera epidemic that was already present.
Beauty of Earth Science Revealed Within Great Smoky Mountains October 17, 2016
Earth Science reminds us that the study of Earth and its biological processes can occur anywhere—whether we realize it or not. An easy way to appreciate science is illustrated in these images vividly portraying the life cycle of vegetation and displaying seasonal change at an area within the Great Smoky Mountains National Park along the Tennessee–North Carolina border.
Earth’s constant biological changing resonates in a revolving gallery of seasonal brushstrokes across the park’s landscape. The vibrant green of forest life explodes as trees still dormant in April awaken and reach full bloom by the time summer stretches into September in these false-color images from Landsat 8’s Operational Land Imager.
By late October, senescence has begun—trees brushed in autumn colors start to shed their leaves. While the dark green of coniferous forests remains constant, as it does all year, the start of winter in December ushers back the pink hues of nature in slumber, surrounded by leafless, dormant deciduous trees.
Cedar River Surges to Second-Highest Level in Eastern Iowa October 5, 2016
On September 27, 2016, the Cedar River surged to a crest of 22 feet at Cedar Rapids, Iowa—6 feet above the river’s major flood stage designation. This inundation was a result of quick-moving storms that dropped about 10 inches of rain in the eastern part of the state recently.
Images from Landsat 8’s Operational Land Imager sensor show the dramatic transformation of the river as it flows toward Cedar Rapids. On July 8, 2016, the shallow river meanders into the city, surrounded by green crops in the heart of the growing season. The September 26 image shows the overflowing river at a time when magenta tones around it speak to a countryside preparing for the harvest.
Emergency crews erected nearly 10 miles of temporary flood barricades and laid 250,000 sandbags in Cedar Rapids to prepare for rising waters in the city. Authorities advised as many as 10,000 residents to evacuate as the Cedar River surged to levels exceeded only by the flood of 2008, when the water crested at a record 31.12 feet.
Landsat Confirms Spatial Extent of Wind Tower Sediment Plumes September 27, 2016
Earth observation satellites help researchers confirm the presence of large plumes containing suspended sediments extending from hundreds of wind towers in the coastal waters of the North Sea southeast of England.
Images acquired by both the Operational Land Imager (OLI) on Landsat 8, as well as the MultiSpectral Instrument (MSI) on the European Space Agency’s Sentinel-2A, show the turbid wakes of individual wind turbines. The wakes are 30 meters to 150 meters wide, several kilometers in length, and change direction depending on tidal currents. The wakes from two boats are evident at the left of the Landsat image. A large cloud is part of the left side of the Sentinel image. The improved radiometric quality of Landsat 8 and Sentinel-2A are valuable in this kind of application.
These waters can be highly productive and provide nursery grounds for fish. A study in Remote Sensing of Environment says researchers are studying how the plumes of suspended sediment may impact substrate fauna, seabirds, and marine mammal environments. The source of the suspended sediment remains unclear.
Landslide Spreads 6 Miles Across Glacier Bay National Park September 14, 2016
On June 28, 2016, a 4,000-foot-high mountainside in Glacier Bay National Park and Preserve collapsed, sending rocky debris equivalent to 60 million mid-size SUVs tumbling onto nearby Lamplugh Glacier.
Almost 6 weeks later, on August 7, the Operational Land Imager sensor aboard Landsat 8 captured the black stain of the landslide in the image on the right. No such discoloration is evident in the Landsat image to the left, acquired on September 13 of the previous year. Seismologists analyzed the seismic waves created by the event and estimated that the slide accelerated for almost a minute as it tumbled over a mile down the mountain and continued to slide along the glacier for another 6 miles.
As we celebrate the 100th anniversary year of the National Park Service, this timely event is a powerful reminder of how unstable mountains are in the southeast corner of Alaska. The region is geologically active, with mountains being pushed up as tectonic plates move, and is considered a global hotspot for such landslides.
Glacier Bay became a national monument on February 25, 1925, and was established as a national park and preserve on December 2, 1980. The park now covers 3.3 million acres. Landsat sensors will continue to monitor landslide activity in this remote region as they have for the past 44 years.
Landsat Records Aftermath of Historic World Trade Center Attack September 8, 2016
Landsat’s role in monitoring land use and land cover changes on Earth gives it a spectacular view of the planet’s most historic events. Such was the case with the September 11, 2001, attacks on New York City’s World Trade Center.
This true-color image was taken by the Enhanced Thematic Mapper Plus (ETM+) sensor aboard the Landsat 7 satellite on September 12, 2001, at roughly 11:30 a.m. Eastern Daylight Savings Time. A day after the attack, smoke continues to billow out of the collapsed Twin Towers.
The inset moves in closer on the same Landsat 7 image, but uses infrared bands to reveal burning that continues in the footprints of the towers.
Since it began acquiring imagery of Earth from space in 1972, Landsat has captured numerous other significant world events, such as the Chernobyl nuclear power plant disaster, Mount St. Helens volcanic eruption, and Hurricane Katrina.
Landsat Monitors 1,800-Year-Old Redwoods September 1, 2016
Redwood National and State Parks in northern California are the embodiment of America’s ongoing challenge to balance the country’s economic interests against preserving its natural wilderness, protecting some forested lands while allowing for resource extraction elsewhere.
When gold was discovered in 1849, hundreds of thousands of people poured into California, and redwoods were logged extensively to meet the demand for lumber and other resources. Today only 4 percent of the old-growth forest and its 1,800-year-old trees remain, primarily along the coast. To stem that ongoing loss, Interior Secretary Stewart Udall successfully pushed to establish Redwood National Park in October 1968.
These Landsat images show logging’s influence around the dark green protected forests. Many of the small pink spots in the lower left corner and across the right side of the 1984 scene are logging sites revealed through Landsat 5’s Thematic Mapper sensor. In the 2016 Landsat 8 image, logging seems to have lessened overall, particularly as areas on the right side of the scene experience regrowth.
Today the majestic trees in Redwood Parks—some soaring as high as 30-story skyscrapers—are under the protection of the National Park Service (NPS), which celebrated its centennial in August 2016. The NPS’s mandate is to help preserve the future of the trees. Landsat’s continuous monitoring will help ensure it.
Landsat Shows Spread of Soberanes Fire August 23, 2016
A wildfire near Soberanes Creek along the Pacific coast of California started July 22, 2016, and spread to over 86,000 acres one month later.
California Department of Forest and Fire Protection officials say the blaze began after an illegal campfire was abandoned. By mid-August, it had destroyed 57 homes and was threatening 410 more structures in an area hugging the coast northwest of Big Sur.
Landsat images from July 13, July 29, and August 14 show the dramatic progression as active fire burns orange in the latter two scenes, and smoke appears as a blue haze. Landsat 8’s Operational Land Imager sensor using shortwave infrared, near infrared, and red spectral bands reveals the growing red burn scar from a fire that was only 60 percent contained by mid-August.
The Soberanes Fire is one of the largest blazes in California’s 2016 fire season, with more than 4,100 firefighters battling it at various times.
Crater Lake Image Shows Potential of Sentinel-2A August 16, 2016
This image from the European Space Agency’s Sentinel-2A satellite offers a breathtaking view of Crater Lake National Park in southern Oregon. It offers something equally important to park managers, scientists, and anyone else interested in land cover change—a view that is highly similar and complementary to Landsat acquisitions.
In this 100th anniversary year of the National Park Service, land managers and scientists tasked with overseeing parks and other government-owned lands typically rely on frequent remote imaging to monitor changes to forests, vegetation, hydrology, and more. Frequent imagery means observers can detect change quicker, and address or manage the effects of change in a more timely fashion.
With its potential repeat coverage of every 10 days, Sentinel-2A should eventually provide additional revisit opportunities to the 8-day coverage from Landsats 7 and 8 combined. Sentinel-2A has spectral bands similar to Landsat 8, with a higher spatial resolution in several bands. So at Crater Lake, for example, a hydrologist seeking information on the amount of snow cover in the high country around the lake, and the subsequent snowmelt, should benefit in the future from more potential images.
Beyond scientific use, Sentinel-2A, like the Landsat satellites, offers a stunning view of the national park, which was established in 1902—14 years before the National Park Service came into being. Crater Lake formed 7,700 years ago when the volcano Mount Mazama erupted and collapsed into itself, creating the deepest lake in the United States. A burn scar visible just north of the lake in this image was caused by a wildfire in August 2015.
Sentinel-2A imagery is free and can be downloaded through EarthExplorer or GloVis, online search and order tools available through USGS.
Landsat Reveals Scar of ‘Good Burn’ at Guadalupe Mountains August 9, 2016
Wildfires in wilderness areas like Guadalupe Mountains National Park in west Texas are always a danger, but they can produce what land managers call a “good burn,” too. The Coyote Fire that scorched parts of Guadalupe Mountains from May 7, 2016, until June 17 is a prime example of that.
Pre- and post-fire images acquired with shortwave infrared (SWIR), near infrared (NIR), and red bands on Landsat 8’s Operational Land Imager sensor reveal a significant, 14,442-acre burn scar within the park’s high country. The burn scar appears red in the June 23 image. Lightning started the wildfire, and strong winds drove it to the Texas-New Mexico border.
As many as 300 firefighters worked to keep the blaze from encroaching on private lands or reaching park structures, while officials decided to let portions of the fire simply burn. The Guadalupe Mountains’ rugged backcountry makes firefighting dangerous. On top of that, areas of the densely wooded park hadn’t burned in almost a century. Unharnessed, the Coyote Fire consumed dead wood and saplings that could have fueled future catastrophic blazes. Land managers also avoided drenching the wilderness in retardants and scarring the landscape with lines dug by firefighters trying to cut off the fire.
In this 100th anniversary year of the National Park Service, new grass growing on charred ground at Guadalupe Mountains National Park is an important reminder that sometimes fire can be a good thing.
Kilauea, Mauna Loa Volcanoes Shape the Face of Hawaii August 1, 2016
Hawaii’s Volcanoes National Park reminds humanity that no matter how much it alters the face of the Earth to meet its needs, it has no control when nature decides to unleash its awesome, eruptive powers.
Though the park celebrates its 100th anniversary on August 1, 2016, its main attractions—Kilauea and Mauna Loa volcanoes—have been adding to the land mass of Hawaii’s “Big Island” for at least 400,000 years. That expansion continues today as bright molten lava from Kilauea flows downslope across the coastal plain on its south flank, spilling over a cliff on its way to a steamy transformation to hard rock in the Pacific Ocean.
The Operational Land Imager from Landsat 8, as well as NASA’s Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, show that volcanic influence in several ways. MODIS captures the 1,700-mile stretch of the Hawaiian Islands that began to emerge from volcanic eruptions during the Quaternary Period beginning 2.588 million years ago. A mosaic of Landsat images from October 2015 and February 2016 reveals the extent of Kilauea’s and Mauna Loa’s presence on the big island of Hawaii, and ASTER zooms in even closer on the lava flows and tubes that channel descending lavas from the summit craters and fissure vents.
Even now, in this year of centennial celebrations for both Hawaii Volcanoes National Park and the National Park Service, imagery from sensors such as these will continue to show change with time. Kilauea and Mauna Loa are two of the world’s most active volcanoes. They will be adding land mass to the “Big Island" for years to come.
Water, Gravity Carve Out Magnificent Canyonlands July 26, 2016
In September 1964, Interior Secretary Stewart Udall successfully shepherded some of the most remote and rugged terrain within the continental United States into the jurisdiction of the National Park Service (NPS) with the creation of Canyonlands National Park in southeastern Utah.
In this 100th anniversary year of the NPS, the Operational Land Imager (OLI) on Landsat 8 has acquired a stunning, false-color image that enhances the park’s irregular topography. No paved roads exist to join together the park’s three main districts—Island in the Sky, the Needles, and the Maze. The Horseshoe Canyon Unit is the detached part of the park in the upper left corner of the image.
In the high desert of the Colorado Plateau, countless canyons, mesas, and buttes have emerged over millennia from the eroding forces of water and gravity across the park’s 1,365 square kilometers (527.5 square miles). Perhaps the most accessible district is Island in the Sky, a relatively flat mesa that rises 600 meters above the Green River to the west and the Colorado River to the east.
The Needles District in the southeast corner of Canyonlands takes its name from the colorful spires of Cedar Mesa Sandstone that dominate the area. The least accessible district, the Maze, is a remote labyrinth of deep canyons set against a landscape of standing rocks above it.
But Canyonlands’ colorful beauty doesn’t end there. Landsat imagery captures the deeply cut meanders and oxbows carved out by ancestral rivers in the national park. It also reveals the distinct, circular Upheaval Dome on the northern border of Canyonlands, a formation that geologists say was either created by a meteorite impact or by the movement of salt layers deep underground.
Fire and Rebirth: Landsat Tells Yellowstone’s Story July 19, 2016
In the summer of 1988, a wildfire ravaged the world’s first national park, consuming 1.2 million acres in and around the Greater Yellowstone Park ecosystem. Landsat imagery became an important record of the burn severity and recovery.
As we celebrate the 100th anniversary of the National Park Service, which was established to better manage Yellowstone and other national parks within the Department of Interior, Landsat continues to prove the outstanding value of its land-monitoring mission. The June 2016 image, captured by Landsat 8, portrays the widespread recovery of tree cover and other vegetation within the 28-year-old burn scar.
The national park’s western border is easily evident in images acquired shortly before and after the fire, on Sept. 22, 1987, and again on Oct. 10, 1988. A prohibition on logging in the national park is revealed in a dividing line of land use that shows dark green forests to the right of the park boundary, and the pink and light green hues of forest clearcuts to the left.
Yellowstone’s healing since the fire is obvious in the time-series views as well. Landsat 5’s shortwave infrared, near-infrared, and red bands combine in the October 1988 image to reveal vibrant red burn scars above and below Yellowstone Lake. In 2016, the scars have faded beneath the lush, green forest canopies and resurgent grasslands.
Landsat, ASTER Work Together on Russian Wildfires July 14, 2016
Remotely sensed imagery of wildfires burning in the Siberia region of Russia shows the complementary possibilities of Landsat 8 and NASA’s ASTER sensor aboard its Terra satellite.
Lightning triggered dozens of forest fires in remote Siberia in late June 2016, burning as much as 7,400 acres, according to Russia’s TASS news agency. Imagery acquired from Terra ASTER on June 29 shows smoke billowing from a small and a large fire, as well as some older burn scars. A day later, when Landsat 8 passed overhead, there was almost no smoke coming from the smaller fire, and a more pronounced scar. Vegetation appears red in the false-color imagery because near infrared (NIR) spectral bands used by both sensors are sensitive to vegetation greenness and were placed in the red position of Red-Green-Blue (RGB) composite images. Burn scars appear a dark brown to black with this band combination.
Though the Terra satellite images the entire Earth every 1 to 2 days, its ASTER instrument with its three separate telescopes only collects data when it is remotely programmed to do so over requested areas of land. That makes it valuable for monitoring disasters. Because Terra’s orbit is similar to that of Landsats 7 and 8—though timed differently—they prove quite complementary when it comes to identifying the impacts of wildfire, flooding, and other events.
Though there is little population in the wildfire area, Russia’s Roscosmos State Corporation for Space Activities asked the International Charter “Space and Major Disasters,” of which USGS and EROS are members, for assistance. That request was granted July 2, giving Russia rapid access to satellite data for assessing the extent of damage and helping with disaster response.
Landsat Reveals Industrial Growth in Powder River Basin July 1, 2016
The expanding coal fields in Wyoming’s Powder River Basin serve as prime examples of Landsat’s ability to monitor land cover change related to industrial growth across the American landscape.
In imagery acquired more than three decades apart, Landsat time-series data illustrate what USGS scientists call a central reality of industrial growth in this country—changing the use of land to increase its economic output. Agriculture remained the main occupation in the basin into the 1970s, until the coal boom took off. The largest U.S. coal mine, the North Antelope Rochelle Mine south of Gillette, WY, opened late in 1983.
The influence of mining is readily apparent in these Landsat images. In 1984, the Landsat 5 scene is largely devoid of open-pit mining signatures. But 32 years later, in 2016, Landsat 8 captures how the Black Thunder Mine and the North Antelope Rochelle Complex have expanded over the last few decades. In 2014, the two mines produced 22 percent of the nation’s coal supply.
USGS officials estimate that mines in the Powder River Basin generally have less than 20 years of economically recoverable coal remaining. Once they end operations, coal mining companies are required by law to reclaim the land, a requirement that Landsat can help verify in the decades to come.
New Delhi Among Fastest Growing Urban Areas in the World June 28, 2016
In a world becoming increasingly urbanized, few cities have seen growth as dramatic as that occurring in India’s capital of New Delhi.
These Landsat images from March 1991 and March 2016 show the city and its adjacent suburban areas—known collectively as Delhi. The area’s population ballooned from 9.4 million to 25 million during that period. Only Tokyo is more populated today with a population of 38 million. The United Nation’s Report on World Urbanization projects that Delhi will be at 37 million residents by 2030.
Landsat can be a valuable tool in monitoring urban growth and its impact on the environment. Adjacent forests and agricultural fields converted to streets, parking lots, and rooftops can affect wildlife habitat. Rainfall blocked by impervious surfaces from soaking into the soil can pool and increase local flooding. Chemicals present on the pavement at the time of rain can be carried away with runoff, reducing water quality and threatening aquatic ecosystems downstream.
All are important considerations—in Delhi or any area undergoing significant growth—when it comes to discussions about urban planning. From a regional standpoint at least, and from an environmental one, Landsat is an important part of that conversation.
Large Wildfire Consumes Boreal Forest in Eastern Russia June 22, 2016
A massive wildfire on the Kamchatka Peninsula in far eastern Russia has consumed nearly 600,000 acres of boreal forest and tundra since late May 2016.
Shortwave infrared bands on Landsat 7 used in combination with the visible red band revealed a large, brown burn scar on June 10, 2016, compared to 11 months earlier—on July 18, 2015—when Landsat 8 captured an image showing healthy, growing forest vegetation. Fires appear orange in the 2016 image, and smoke from the fires is light blue.
The Siberian Times reported that smoke from the Russian wildfire was “producing exceptional sunsets” in the western United States and Canada. The newspaper attributed the Kamchatka fire and others this spring in eastern Russia in part to an unusually warm and dry winter, and faster than normal snowmelt.
The Kamchatka Peninsula occupies an area of roughly 100,000 square miles, with the Pacific Ocean to the east of the peninsula and the Sea of Okhotsk to the west. Most of the fire has been on the western side of the peninsula, north of the Kharyryuzova River.
Beaufort Sea Ice Experiences Unusually Early Breakup June 13, 2016
Ice covering Beaufort Sea near the Arctic Ocean typically reaches full-blown breakup by late May each year as air and water temperatures warm, and as daylight turns longer. But 2016 has been dramatically different.
This year, significant breakup and fracturing of the sea ice had occurred by mid-April, as seen in these Landsat 8 images acquired almost exactly a year apart. On April 13, 2015, the ice is largely intact, though fracturing has begun. A year later, on April 15, 2016, much more open water is visible.
Ice specialists with NASA say this year’s breakup is attributable to unusually warm air temperatures during the first months of the year, and to strong winds caused by a stalled high-pressure system over the area. The same warmth that fueled the massive Fort McMurray wildfire in northern Alberta earlier in May is part of the weather pattern affecting the Beaufort Sea.
Though the region was once covered by thicker, multi-year ice, it now has largely seasonal, first-year ice that is thinner, weaker, and more easily broken up by strong winds. While the early breakup hints to the possibility that 2016 could ultimately witness the lowest sea ice extent in the history of satellite recording, that, of course, will depend on the weather conditions in the coming months. Future Landsat acquisitions will help scientists monitor the area and visualize changes.
The surface level of Lake Mead in Nevada and Arizona has fallen to a historic low as 16 years of ongoing drought in the American Southwest continue to impact the Colorado River Basin.
Landsat imagery captures the decline of the country’s largest reservoir. In a May 1984 Landsat 5 acquisition, Lake Mead is almost full. But 32 years later, in May 2016, Landsat 8 data show the reservoir when it was 37 percent full. The drop in lake level isn’t even as apparent as it might otherwise be because of the steep topography in the region, but the surface area reduction is still quite noticeable.
Today, Lake Mead supplies water to 25 million people. Virtually all of nearby Las Vegas, NV, with its 2 million residents and 40 million tourists a year, gets its drinking water from the shrinking reservoir. Lake Mead also serves farms, tribes, and businesses in Arizona, California, Nevada, and northern Mexico.
According to the U.S. Bureau of Reclamation, Lake Mead reached a historic low in May 2016 of 1,074 feet above sea level. It has not been this low since the reservoir began filling in the 1930s.
Rain-Swollen Brazos River Floods Suburban Houston June 2, 2016
Heavy rains that began falling during Memorial Day weekend in late May 2016 pushed the Brazos River, 30 miles southwest of Houston, Texas, toward a near-record flooding stage that hasn’t been seen since 1913, according to the National Weather Service (NWS).
Shortwave infrared and red bands on Landsat 8’s Operational Land Imager (OLI) sensor reveal the river’s dramatic flooding extent on May 28, compared to two months earlier, on March 25, when the Brazos ran much more sedately past the nation’s fourth most-populous city. Just two years earlier, in 2014, the 840-mile-long river snaking through the center of Texas had gone dry in places because of drought conditions, the NWS said.
As of June 1, more than 120 high-water boat rescues from buildings and cars had been reported near Houston by Fort Bend County first responders. The International Charter “Space and Major Disasters,” of which USGS and EROS are members, was activated May 31 to provide Texas Emergency Management rapid access to Landsat and other satellite data for assessing the extent of damage and helping with disaster response.
With the rain expected to continue, future Landsat acquisitions will be important for that response. After almost 20 inches had fallen over parts of Texas since late May, NWS forecasters predicted up to 10 additional inches of precipitation by June 3, which would exacerbate flooding conditions along the flat, low-lying landscape of suburban Houston.
Landsat 8 Imagery Reveals Heavy Flooding in Sri Lanka May 24, 2016
On May 18, 2016, a Landsat 8 acquisition of flood-ravaged Sri Lanka produced impressive imagery of swollen waterways.
A pattern of torrential rain that began May 15 in the island country just off the southern tip of India has caused massive landslides and flooding, the latter of which is evident when compared to a March 31, 2016, satellite image. Both of the images resulted from data acquired by the shortwave, near-infrared, and red bands (6,5,4) on Landsat 8’s Operational Land Imager.
Officials in Sri Lanka’s national Disaster Management Center say the heaviest rains in a quarter century forced 200,000 people out of the low-lying parts of the country’s capital in Colombo, sent 400,000 fleeing to state-run relief camps, and covered entire villages in walls of mud. A history of clearing forests for agricultural use in Sri Lanka is a potential contributor to the destruction caused by the heavy rains and ensuing flooding.
The International Charter on Space and Major Disasters, of which USGS and EROS are members, was activated May 17 to provide Sri Lanka’s government rapid access to Landsat and other satellite data for assessing the extent of damage and helping with disaster response. Future Landsat acquisitions will be part of this response.
Landsat 8 Shows Burn Extent, Active Fire at Fort McMurray May 13, 2016
Eleven days after a wildfire first sparked south of Fort McMurray in northern Alberta, Landsat 8’s Operational Land Imager (OLI) captured imagery of one of the most destructive infernos in Canadian history. The fire has burned an area approaching 600,000 acres.
The May 12, 2016, false-color image relies on shortwave infrared, near infrared, and red light (OLI bands 7-5-4) to show hazy blue smoke, bright orange active burning spots, and a reddish-brown burn scar that surrounds Fort McMurray as it extends east and south toward the Saskatchewan border. It is a stark contrast from the pre-fire image acquired by Landsat 8 on October 17, 2015.
Alberta officials report that nearly 10 percent of Fort McMurray was destroyed by the fire, which started May 1 south of the city. Hot weather, dry vegetation, and strong winds spread the fire quickly. The cause has yet to be determined.
So far, over 2,400 structures have been destroyed in and around Fort McMurray. At least another 500 were damaged in the city, and many of the structures still standing suffered smoke damage.
Staff from the U.S. Geological Survey are assisting the Provincial Operations Centre in Edmonton, Alberta, Canada, by providing Landsat imagery that shows the fire’s progress, and post-fire burn severity assessments that are expected to provide information of value during post-fire mitigation activities.
Wildfire Forces Evacuations in Fort McMurray, Alberta May 6, 2016
A massive wildfire burning near Fort McMurray in Alberta, Canada, fueled by dry conditions and high winds, has destroyed 1,600 structures and forced more than 88,000 people to evacuate the area so far.
On May 3, 2016, Landsat 8 acquired data of the inferno, which razed neighborhoods within Fort McMurray. Using shortwave infrared (SWIR) and near infrared (NIR) bands to help penetrate clouds and smoke and create false-color imagery, Landsat shows the active fires’ hot spots, which appear orange. Burned area is dark red, and smoke is hazy blue.
Two weeks before the fire started, on April 17, Landsat captured a much quieter scene of Fort McMurray and its surrounding landscape—home to the Athabasca oil sands, the largest known reservoir of crude bitumen in the world.
By May 5, the wildfires had consumed almost 210,000 acres, and forced the largest evacuation on record in Canada.
Forest and fire management officials in Alberta can turn to Landsat for help with post-fire mitigation activities once the blaze is out. Landsat’s infrared sensors are valuable for producing burn-severity maps and other products quickly after images are acquired.
Lake Levels in Hispaniola Rise Dramatically May 4, 2016
Landsat imagery shows a dramatic change in lakes Azuéi and Enriquillo, inland saltwater lakes on the Caribbean island of Hispaniola that are known for their crocodiles and iguanas.
A Landsat 7 image acquired in March 2002 showed Lake Enriquillo in the Dominican Republic at half the size it is now. In March 2016, Landsat 8 found a growing lake that has engulfed 40,000 acres of farmland and displaced thousands of families. Similarly in Haiti, Lake Azuéi grew 40 percent in that time period, and now stretches even farther across the border into the Dominican Republic.
Lake levels were high 30 years ago, and have fluctuated depending on rainfall and weather patterns. But a consortium of scientists from the United States and Dominican Republic studying this latest phenomenon call a dramatic rise between 2004 and 2009 unprecedented. The Dominican government believes water from the Rio Yaque del Sur, the nation’s second-longest river, is channeling into Lake Enriquillo through agricultural canals after heavy rain events.
Dominican leaders hope damming the Yaque will stymie the growing lakes. Otherwise, they fear the lakes will continue to swallow more farmland as they threaten a fragile ecosystem.
A single Landsat satellite images this area—and any area around the globe—every 16 days, giving scientists a continuous ability to monitor and perhaps mitigate the situation. With the Hispaniola economy already suffering, with Cao Cao and other bird species continuing to lose their nesting habitat, and with crocodiles and endangered iguanas being forced to higher ground to compete with humans and other wildlife, a solution can’t come soon enough.
Landsat Played Role in Confirming 1986 Chernobyl Disaster April 25, 2016
When the Chernobyl Nuclear Power Plant exploded 30 years ago, on April 26, 1986, Landsat 5 was the first civilian satellite to confirm the disaster near Pripyat, Ukraine, in the agricultural heartland of the Soviet Union.
Soviet officials initially denied the explosion in the plant’s Reactor Number 4, which destroyed part of the reactor containment building, ignited graphite in the core, and spewed radioactivity into the atmosphere for 10 days. Three days after the explosion, data from Landsat 5’s near-infrared band 7 confirmed a bright red spot within the plant complex—the exposed burning graphite of the damaged reactor shown immediately at right.
Landsat revealed more than that. Images acquired before the explosion show heated water being pumped from the plant into the adjacent cooling pond and circulating counter-clockwise. Under normal circumstances, Landsat 5’s thermal infrared band 6 would confirm that the heated water—orange in the image—gradually turns yellow and then blue as it cools. But the image from April 29 indicates all the water in the pond is the same temperature, evidence the plant was not operating.
Pressed by growing evidence from Landsat and other satellite imagery, reticent Soviet officials only slowly confirmed the facts. General Secretary Mikhail Gorbachev did not speak publicly about the disaster until May 14, 1986. Pripyat was abandoned, its people relocated.
At present, the natural environment in the 18-mile exclusion zone around Chernobyl continues to recover. These Landsat images show the change from a previously vibrant agricultural and forestry economy in April 1986 to October 2015, when crops have been replaced by thick grasslands. Today, nearby farm fields are excluded from use by government officials—a prohibition expected to remain for a long time.
Wildfires Scorch Large Swaths Along Oklahoma-Kansas Border April 18, 2016
Grasslands made lush by summer rains in 2015 have turned into a tinderbox along the Kansas-Oklahoma border after a dry winter and gusty spring winds transformed the withering vegetation into fire fuel.
The latest in a season of wildfires is the 350 Complex Fire near Freedom, OK, just south of the Kansas border and south of the Cimarron River. On April 5, 2016, four fires sparked by downed power lines merged into one and burned almost 57,500 acres in three days. In late March, the Anderson Creek Fire—the largest blaze ever in Kansas—started in Oklahoma and spread into Kansas, burning almost 400,000 acres.
Using shortwave infrared, near infrared, and visible bands, these Landsat images provide a before and after look at the 350 Complex and Anderson Creek fires. In the March 14 image acquired by Landsat 8, a minor scar from an earlier fire appears orange in the lower left corner. The fan-shaped blue and black object at the center right edge of the image is the Great Salt Plains Lake and Salt Plains National Wildlife Refuge in Oklahoma.
On April 7, Landsat 7 captured the large, brilliant red burn scars caused by the fires.
As of April 8, the National Interagency Fire Center in Boise, ID, reported that 817,480 acres had burned year-to-date across the country, the largest tally in that time frame since 2006.
In the United States, barrier beaches and spits line up along nearly a quarter of the country’s coasts, mostly facing the Atlantic Ocean and Gulf of Mexico. Spits are like islands that connect to a mainland at one end.
These barrier systems protect their adjacent mainlands from the full fury of ocean wind and wave energy. They promote critical marsh and wetland habitats. They are living landscapes that grow, shrink, and migrate over time.
These images of the southeastern elbow of Cape Cod capture the impact of natural forces that have raised up, shifted, and torn down the Nauset-Monomoy coastal barrier system. In the June 1984 scene acquired by Landsat 5, an unbroken barrier spit protects the Atlantic-facing coast of Chatham, MA, and its harbor. South of the mainland, North and South Monomoy Islands stand apart from each other and the coast.
Thirty-one years later, Landsat 8 reveals a landscape reshaped by the natural ebb and flow of waves, currents, winds, and tides. The changes are both subtle and substantial. Storms have breached the barrier spit in several places. By September 2015, the Monomoy islands have grown together. At the same time, waters around North Monomoy are shallower with sandbars and shoals closer to the water surface.
Time and the forces of nature will continue this reshaping of the barrier system. As they do, Landsat’s continuous monitoring will be there to document it.
Landsat Helps Battle Pine Beetle Hordes April 4, 2016
At the size of a grain of rice, the mountain pine beetle’s subtle assault on America’s forests isn’t always obvious to the naked eye. Yet over time, their armies of thousands can ravage entire mountainsides. That’s why the continuous monitoring abilities of Landsat satellites have become so important in fighting the insect hordes.
The U.S. Geological Survey’s (USGS) decision in 2008 to make what is now 44 years of archived satellite data free for distribution gave rise to time-series imagery that has become a powerful tool in revealing forest change. Landsat’s no-cost access gives forest managers an important and economical asset in discerning where outbreaks are happening as they occur. That knowledge in turn enables them to make more informed decisions on thinning tree stands affected by beetles, thus minimizing the potential fire threat they pose.
The value of continuous monitoring is readily apparent in these images. In August 1992, Landsat 5 focused on a swath of the Uinta Mountains just east of Salt Lake City, Utah. The shades of dark green indicate areas of healthier undisturbed forest. Almost exactly 18 years later, Landsat 5 found something much different—dark red stains readily visible throughout the image that tell a story of widespread pine beetle destruction.
Because they only measure field plots once a decade, Forest Service crews may have a harder time grasping the enormity of the assault. With Landsat’s continuous monitoring, the size and timing of infestations become much clearer.
Mississippi River Floods Deep South March 29, 2016
Late winter storms March 10–12, 2016, drenched areas of Louisiana, eastern Texas, Mississippi, and Arkansas with up to 20 inches of rain, causing significant damage and evacuations.
Louisiana officials say the resulting flooding there is among the most widespread for any non-hurricane event ever seen. These images acquired by Landsat 8 clearly capture the scope of that historical inundation.
Though earlier storms in January had already pushed the Lower Mississippi River toward the top of its banks, the meandering waterway appears largely contained in the image on the left, acquired March 4, 2016. Sixteen days later, however, the satellite’s sensors reveal something much more dramatic.
In the center of the March 20 image, the deep blue floodwaters spill on to the landscape surrounding Vicksburg, MS. At the bottom center, the river is engorged just south of Natchez, MS, as it flows off the image on its way to Baton Rouge, LA.
Smaller tributaries west across the border in Louisiana show the impact of the drenching rains as well, testifying to the most widespread flooding in the region since Hurricanes Isaac (August 2012) and Katrina (August 2005).
When the Earth shook Alaska 52 years ago—on Good Friday, March 27, 1964—tsunamis wiped out entire villages. Landslides swept Anchorage neighborhoods into Cook Inlet. A collision of tectonic plates comprising the planet’s outermost layer had caused a 9.2 magnitude earthquake, the largest in U.S. history, and killed 131 people.
Aerial photographs archived at the USGS Earth Resources Observation and Science (EROS) Center capture the quake’s dramatic impact on Anchorage’s coastal boundaries. In the 1953 image, the Turnagain neighborhood west of the city’s downtown area is only beginning to emerge from the trees along the inlet. Eight years after the disaster, in 1972, the wooded shoreline has vanished, the bluffs now submerged in a sediment band created by the cataclysmic actions of the temblor. Yet extensive new development shows that Anchorage continued to expand in this area.
These are just two of the 6.5 million aerial photographs that span the last 80 years and are available on the USGS EarthExplorer Web site. Along with millions of other data files in the EROS archive that have been acquired from satellites, airborne radar, and the U.S. space program, these aerial photographs tell an important and compelling story about land cover that is ever changing, both in the United States and around the globe.
Landsat Reveals Water Use Dynamics in the San Joaquin Valley March 14, 2016
California’s San Joaquin Valley is one of the world’s most productive agricultural regions. Much of that productivity depends on the availability of water for irrigation. Recent prolonged droughts in California have underscored the importance of accurately monitoring changes and trends in water use in order to make well-informed water management decisions.
Scientists with the USGS Earth Resources Observation and Science (EROS) Center used Landsat images to quantify water use in the San Joaquin Valley over a 30-year period. A first step was to determine evapotranspiration (ET), which is water transpired by plants into the atmosphere as well as water that evaporates from the surrounding soil. ET can be used as a measure of water usage across a landscape. The scientists employed a computer model that incorporates Landsat imagery, including the Landsat 8 thermal band, along with climate data to estimate ET for every Landsat scene of the Valley from 1984 to 2014.
The team then integrated the ET results with precipitation and runoff data to create maps that reveal historical trends in water use and availability on irrigated basins in the Valley over the 30-year time period. Detailed enough to show individual fields, the maps depict water use (in millimeters) for a given day or an entire growing season, and, when combined with crop data, can also reveal which crops are using the most, or least, water.
The two maps above show seasonal water use in the San Joaquin Valley in 1990 (left) and 2014 (right). Color coding indicates how irrigation patterns changed over time. Notice, for example, that water use intensified in many places (increase in blue areas) and some irrigated lands (green in 1990) transitioned out of agricultural production (reddish brown) by 2014.
Landsat data are free and easily accessible at http://earthexplorer.usgs.gov/. This research approach can be replicated to produce similar water use maps for other locations across the United States. These maps can help farmers, water management agencies, and rural development planners balance irrigation practices and crop choices with precious water resources.
Sometimes the destructive nature of wildland fires lies beyond the flames. It reveals itself in what is left behind—scorched mountainsides with no trees to stop rain-driven mudslides or dangerous debris flows. When such potential exists, the Shortwave Infrared (SWIR) bands on the sensors aboard the Landsat satellites help to identify those possibilities quickly.
The SWIR bands measure diminished moisture content in soil and vegetation. When SWIR band 7 is paired with Landsat’s Near-Infrared (NIR) band 5, which is highly sensitive to growing vegetation, the two produce vivid, accurate images of burn scars. That information is useful to post-fire responders who must act quickly to stabilize burn areas and address potential risks to people, property, and communities nearby.
Landsat 8 helped map destruction caused by the Cougar Creek fire 75 miles northeast of Portland, Oregon, in mid-August 2015. At left is a pre-fire image of Mount Adams in Washington. Snow appears cyan on its peak. In the middle is a post-fire image where the previous green vegetation south and east of the mountain is now charred and appears in shades of red. The burn severity map at right was produced with Landsat’s infrared imaging, including a SWIR band that is found on few other satellites. Within the fire perimeter, dark green is non-burned, light blue is low burn severity, yellow is moderate severity, and red is high.
Clouds can be a real headache when it comes to satellite imaging. Thin, almost transparent cirrus clouds are often difficult to spot, leaving scientists scratching their heads when data from pixels beneath them come out slightly skewed.
But Landsat 8 has an answer for that.
The newest spacecraft in the Landsat family – which has been acquiring data since February 2013 – contains a spectral band on its Operational Land Imager (OLI) that identifies the high-altitude clouds that are not otherwise apparent in other bands.
These images show that well. On the left, cirrus formations drift above the landscape. On the other hand, cirrus clouds are difficult to discern in the natural-color composite Landsat 8 image on the right, looking down on Columbia, S.C., and across the border north to Charlotte, N.C.
Scientists are using the cirrus band to flag images that are heavy with cirrus cloud contamination. Landsat’s newest band makes that easy to detect, thus allowing for the most accurate data possible.
Great Salt Lake North Arm Reaches Record Low February 19, 2016
The water level of the north arm of Great Salt Lake, Utah, has reached a record low elevation of 4,191.6 feet, 1 foot below the previous record. Lower snowpack in recent years has lessened the spring runoff flowing into the lake. These Landsat images show the change in water levels between 2011 and 2015.
Great Salt Lake is a closed lake, with no outlet. Since water leaves the lake only through evaporation, it leaves behind its dissolved minerals, making the lake up to 8 times as salty as seawater.
On the right side of these images are evaporation ponds. Water from the north arm is pumped to these ponds. The water evaporates and salt, potassium, and other minerals are extracted.
The lake’s north and south arms are separated by a railroad causeway, the straight line cutting across the images. Limited water circulates between the lake’s north and south arms through the Union Pacific Railroad Causeway breach, but because of the low water levels, the breach is now dry. The result is even saltier water in the north arm.
A USGS article published in late 2015 provides more information about Great Salt Lake.
Measuring Water Use with Landsat February 11, 2016
As drought conditions continue in the western United States, there is more demand for water for irrigation purposes. Increasing population also increases water demand.
Scientists at the USGS Earth Resources Observation and Science (EROS) Center developed a method to use remote sensing data to quantify water use in the Colorado River Basin. Using Landsat and other ancillary data, including Landsat’s thermal infrared data, scientists created the first ever evapotranspiration (ET) map for the entire basin. ET is water that transpires from plants and evaporates from the ground. It can be used as a measure of water usage. Landsat’s 30-meter resolution allows scientists to estimate ET at the field level.
The annual water use map on the left is based on Landsat data collected during 2010. The colors correspond to millimeters (mm) of water lost to the atmosphere through ET. Fields that are green and blue show the highest ET values. Relatively more water has been used on those irrigated fields. Orange hues are areas that have very little ET, such as sparsely vegetated desert. The Landsat 8 image on the right from September 28, 2015, shows many irrigated crop fields just south of Phoenix, Arizona. The image shows the same area as the water use map for comparison.
With the ET map, water managers get information not seen in just the natural color image. This method can be used to create annual water use maps of other regions or even nationwide. Accurate information on water availability and usage is necessary for planning sustainable use of water, particularly in an arid region like the southwestern United States.
On January 22–24, 2016, a major winter storm dropped 2 or more feet of snow on much of the U.S. East Coast. Landsat 8 images acquired before and after the storm offer a dramatic view of the Washington, DC, area. Before the storm, there was no snow on the ground; however, on January 24 the landscape had become blanketed in white.
In both of these natural color images, the Washington Monument casts a shadow, but the shadow shows up more clearly when the ground is white.
In the lower right part of the image, Andrews Field at Joint Base Andrews becomes a large swath of bright white in the January image. Ronald Reagan Washington National Airport, just south of DC, also exhibits this extra brightness. At Reagan, the main runway appears to have been cleared.
Warm temperatures in December meant the Potomac River was not frozen in the December image. By mid-January, parts of the Potomac froze, so some of the river is covered in white in the January image.
These Landsat images show the land use changes of the Liaodong Bay area in northeastern China. The Shuangtaizi River and the Daliao River carry large amounts of sediment from the loess plains and agricultural soil erosion upstream. The salt marshes on the river delta have been affected by an expanding aquaculture industry, visible as the dark geometrical shapes that have clearly expanded in the 2015 image. Also visible is the expanding city of Yingkou and ports extending into Liaodong Bay.
Salt marshes in this region decreased during the 1980s and early 2000s. Aquaculture ponds, and rice paddy and reed fields replaced the salt marsh; however, from 2004 to 2009, salt marshes showed a slow recovery. Researchers use Landsat imagery to monitor the recovery as well as human uses of this land to track salt marsh extent from year to year and how those changes affect habitats and wildlife.
Satellite images are necessary for this monitoring because large areas can be mapped relatively quickly where it is difficult to conduct field surveys. The 30-meter resolution of Landsat provides enough detail for remote sensing scientists to observe and quantify such changes.
Lithium Mining in Salar de Atacama, Chile January 19, 2016
The Salar de Atacama in Chile is a large, dry salt flat surrounded by mountain ranges and is one of the driest places on Earth. Parts of the Atacama Desert have gone without rain for as long as people have been keeping track, but water rich in dissolved salts lies beneath this flat surface. The Salar is particularly rich in lithium salts.
Lithium is used in rechargeable batteries. With increased use of smartphones, mobile computers, and electric cars, there is higher demand for the soft, silvery metal.
Brines from beneath the salty crust are pumped to evaporation ponds, visible as the blue rectangles in these Landsat images. The extremely dry and windy conditions here result in an efficient process. The concentrated salts are left behind after evaporation from which lithium carbonate and other materials can be extracted.
The lithium mining activities in the Salar de Atacama have expanded over the years, as can be seen in these Landsat images acquired in 1993 and 2015. Landsat imagery can help study worldwide land change effects from a variety of mining types.
New Year’s Flooding in the Midwest January 6, 2016
At the end of 2015, a series of storms dropped 6–10 inches of rain in a few days over the central part of the United States. Missouri and Illinois were particularly hard hit, with many waterways overflowing their banks.
Water has receded in most places, but a Landsat 7 image acquired January 1, 2016, clearly shows an example of the extent of the flooding. Flowing north to south at the top center of the image is the Wabash River, which forms the border between Illinois and Indiana. The Wabash flows into the Ohio River.
Water is blue in these images. The December 8, 2015, image shows the rivers at normal water levels. The January 1 image shows the swollen Wabash and Ohio Rivers, each of them submerging the floodplains. Smaller tributaries have also overflowed their banks.
USGS collects streamflow data at streamgages throughout the region, and throughout the United States. These gages measure water levels, streamflow, and rainfall. Along with satellite images, these data help monitor the flooding, and help project the severity of flooding effects downstream.
The Selenga River begins in Mongolia and flows north into Russia where it empties into Lake Baikal, the world’s deepest lake. The river slows as it approaches the lake, dropping large amounts of sediment in a wide alluvial plain. The braided river flows past farm fields—the blocky shapes in the images—and to the lake.
The river forms a unique delta as it carries sediment to Lake Baikal. These Landsat images show the delta in 1989 and 2015. While the overall shape of the delta has not changed significantly, a halo of sand bars surrounds the edge of the delta in the 2015 image. Varying lake levels and the river’s sediment load influence the changing shape of the delta and its sand bars.
Landsat data are freely available to anyone interested in researching and monitoring changes happening to the Earth’s surface.
Brazilian Mining Disaster, Doce River December 16, 2015
On November 5, 2015, a tailings pond dam failed at an iron mine in southeastern Brazil, sending contaminated water sediment through the nearby village of Bento Rodrigues and into tributaries of the Rio Doce (Sweet River). (See http://eros.usgs.gov/imagegallery/image-week-2#Brazil_Images) The sediment from that disaster has since moved downstream to the mouth of the Doce River.
The Landsat 8 image from September 11, 2015, shows what the mouth of the Doce River looks like under normal conditions. A Landsat 8 image acquired on November 30 shows a plume of sediment flowing into the Atlantic Ocean. This may be contaminated sediment from the dam breach. Advanced Landsat 8 capabilities, including the new coastal aerosol band and superior instrument performance, may improve monitoring the extent of sediment flow in the river.
Near-surface permafrost in Alaska is in danger of degrading with projected warmer conditions. Detailed information is needed to adequately monitor permafrost, but previous modeling of permafrost properties has typically been done at coarse resolution. A new study, led by the USGS Earth Resources Observation and Science (EROS) Center, developed the first medium-resolution (30-m) map of near-surface (within 1 m) permafrost for all of mainland Alaska.
Researchers used models to project permafrost degradation in the future based on various climate scenarios described in the Intergovernmental Panel on Climate Change (IPCC). Projections indicate that climate impacts (excluding fire impacts) will cause a decrease in near-surface permafrost of 16 to 24 percent by the end of the 21st century. Predictions of permafrost degradation were most pronounced for central Alaska, where permafrost temperatures typically hover around the melting point of 0°C.
The colors on this map indicate the probability that there is near-surface permafrost currently. Red and orange shades are areas with a low probability of permafrost, and blue shades are areas with a high probability of permafrost. When comparing the current map to future scenarios, the expectation of degraded permafrost is evident.
The mapping of permafrost distribution across Alaska is important for land-use planning, environmental assessments, and predicting future vegetation and carbon stocks. For more information, see the research article in Remote Sensing of Environment.
Two dams at an iron ore mine in southeastern Brazil broke on November 5, 2015, sending mine waste cascading into nearby valleys. The muddy floodwaters destroyed hundreds of homes in the village of Bento Rodrigues, which lies in a valley below the mining area. Natural color images from Landsat 8 compare how the area looked before the breach in the dams to how it looked one week after the incident.
The orange colors along the left side of the images are open pit iron ore mines. The dams burst from the tailings ponds, which hold mine waste. The November 12 image shows the orange sediment flowing down a valley through the dark green rain forest. This sediment may contain mining chemicals that could affect the fertility of downstream farmland. Researchers are still testing the water to get a better idea about the contents of the mine waste.
Death Valley 1,000-year Flood Event October 29, 2015
This October, a system of storms caused significant flooding in most of Death Valley National Park, California. Collectively, the area only received 1–2 inches (2.5–5 centimeters) of rain, but the annual average in Death Valley is about 2 inches (5 centimeters). The largest of the storms occurred on October 18. Flash floods from the storm destroyed roads and utilities, and damaged several historical structures. This was the largest flood event in the recorded history of the area.
In this image pair Landsat 8 images contrast October 2014 (a year with typical precipitation) to October 2015. The false color images highlight hydrogeology; the areas in green to blue are the locations with moisture content. Especially striking is the Badwater Basin, normally a dry lake bed. In the 2015 image, it is full of water.
Landsat imagery acquired before and after the flood event will help with monitoring and evaluation of landscape response and impacts.
Landsat 7, which launched on April 15, 1999, has been continuing to acquire land images worldwide for 16 years. Landsat 5 may hold the Guinness World Record for longest Earth-observing satellite at 28+ years, but Landsat 7 also has an impressive track record. In fact, Landsat 7 has now acquired over 2 million images. They are all freely available online at USGS GloVis or EarthExplorer.
Landsat 7 and Landsat 8 acquire over 1,200 new images per day. This is more data than at any other time in the history of the Landsat program.
The 2 millionth Landsat 7 scene includes a portion of northwestern Madagascar, acquired on September 11, 2015. The dark region in the lower left is the Ankarafantsika Nature Reserve. This large area of deciduous forest, savannah, and wetland is protected as a national park. On the left edge of the scene is Mahajamba Bay. This shallow bay contains Madagascar’s largest mangrove ecosystem, with tidal mudflats along the edges of the mangroves.
Vredefort Impact Structure, South Africa October 14 ,2015
The Vredefort Impact Structure is the oldest and largest known impact crater on Earth. The entire crater is believed to have been about 300 kilometers (186 miles) across and was formed when an asteroid struck the Earth over 2 billion years ago. The asteroid that produced the crater is thought to have been about 5–10 kilometers (3–6 miles) in diameter.
The crater’s outline is now mostly hidden because of weathering and erosion. The only remaining visible feature is the crescent-shaped Vredefort Dome, shown in the center of this Landsat 8 image. The remnant dome is thought to have formed as a direct result of the impact. The southeastern portion of the dome has been covered over time by features that were formed later.
The Vaal River cuts across the dome remnant and its different rock layers. The city of Parys sits along the Vaal River near the dome. The multicolored geometric shapes to the left and right of the dome are related to agricultural land use.
The Landsat 8 optical sensor includes numerous spectral bands that can be used in various combinations, allowing users to accentuate and study specific features on the Earth's surface. This false color image uses a combination of visible and invisible (shortwave infrared) wavelengths to highlight the geological features of the area, in contrast to the surrounding agricultural and urban land use.
Nauru is the world’s smallest island country, with only 21 square kilometers (8 square miles) of land area. Since the early 1900s, the tiny island has been mined for its rich phosphate reserves. By 2000, most of the phosphate deposits had been exhausted, and the strip mining and associated activities had denuded up to 80% of Nauru’s surface. The mining left extensive damage to Nauru’s surface and ecology, but in recent years there have been efforts to rehabilitate the affected areas.
These two Landsat images are false-color composites. The red tones indicate a strong signal from Landsat's near-infrared (NIR) band, which is used by landscape scientists to monitor the presence and condition of vegetation and forested areas. In this type of image, a deep red color indicates actively growing vegetation and forest, while non-vegetated or poorly vegetated areas will have less red tone.
The 1999 Landsat image (left) shows the bright mine scars along with dull, mixed color tones across the landscape, indicating a generally poor condition for the island’s vegetation. The deep red colors throughout the 2015 image (right) suggest an overall increase in vegetation and forest cover.
Landsat imagery can be a valuable tool to help document the history of the mining impacts and track the progress of restoration activities as Nauru works to revitalize their island nation.
Old Name, New Elevation for North America’s Highest Peak September 2, 2015
Secretary of the Interior Sally Jewell recently announced that the highest point in North America, formerly known as Mount McKinley, will be designated by the name Denali in all federal records. Later, U.S. Geological Survey acting Director Suzette Kimball announced that the Denali summit has a new, official elevation of 20,310 feet.
Using the latest methods of satellite-based surveying technology (GPS), a team of mountaineering surveyors under the direction of the U.S. Geological Survey, NOAA’s National Geodetic Survey (NGS), the National Park Service, and the University of Alaska Fairbanks Geophysical Institute re-measured the height of the mountain this summer. The last official survey of the summit had been conducted in 1953.
Scientists from NOAA’s NGS, Dewberry, CompassData, the University of Alaska Fairbanks, and the USGS carefully analyzed the raw data acquired by the survey party to arrive at the final elevation number. The exceptional circumstances for this surveying challenge, such as making allowances for the variable depth of the snow pack and establishing the appropriate surface that coincides with mean sea level, were judiciously considered before the new apex elevation was finally determined.
The Landsat 8 image from June 15, 2015, shows a clear view of the perennially snow-covered summit. Glaciers stream down the mountain to lower elevations.
Burned Area Analysis for the Soda Fire, Idaho August 28, 2015
On August 10, 2015, the Soda Fire began burning about 8 miles northeast of Jordan Valley, OR. It spread rapidly because of high winds, parched fuels, triple digit heat, and low humidity. Over 283,000 acres had burned by August 20.
On the morning of August 22, Landsat 7 captured a postfire image (left) of the Soda Fire burn scar. This image was used along with a prefire image from Landsat 8 to derive a Burned Area Reflectance Classification (BARC) map.
The BARC map (right) was created using digital image analysis techniques developed by USGS, USFS, and other scientists, and it allows a synoptic view of fire extent and severity. The map is preliminary and has not yet been field-validated.
This type of detailed information would be difficult to obtain in a timely manner based on ground observations alone. Reflecting the amount of vegetation loss caused by the fire, the colors on this map show that the Soda Fire was mostly classified as low and moderate severity (light green and yellow), with few high severity areas (red).
EROS scientists respond to dozens of requests for burn mapping support each year. It would not be possible to obtain a rapid and complete assessment without satellite imagery, and Landsat’s 30-meter resolution provides the detail needed for rapid landscape-scale wildland fire mapping.
Expansion of the Suez Canal, Egypt August 20, 2015
The Suez Canal is a man-made waterway connecting the Mediterranean Sea and the Red Sea. It is one of the world's most important waterways for trade, but the main channel was previously too narrow to allow ships to travel and pass in opposite directions.
A massive expansion project was started in 2014 to increase the depth of the existing channels and create a separate shipping lane along a major portion of the Suez Canal. The project took one year to complete and included 22 miles (35 kilometers) of new channel near Ismailia, Egypt. This new shipping lane will dramatically shorten the travel times for ships traveling in both directions.
This series of Landsat 8 images shows the area before, during, and after construction. The first image (August 2014) shows the Suez Canal near the time construction began. The new route is faintly visible in the second image (December 2014) while construction was in progress. The third image (August 2015) shows the completed and operational canal project, with the new shipping lane filled with water and clearly visible.
The 40+ year archive of Landsat imagery is a valuable resource for monitoring land use changes over time.
Island-Building in the South Pacific August 4, 2015
An undersea volcano between the two small islands of Hunga Tonga (right) and Hunga Ha’apai (left) began erupting in early December 2014. After about a month of eruptive activity, a new landmass had formed, nearly joining the two islands.
This series of Landsat 8 images shows the two islands in October 2014 (before eruptions), in December 2014 (during the eruptions), and in July 2015 (after the eruptions).
Along with creating new landmass, the volcanic activity has also radically changed the islands’ ecology. The first panel shows vegetation cover (green) on both of the original islands. The predominantly gray and brown colors in the third image now indicate bare land surface, especially on the southeastern island.
Landsat images are often useful for mapping changes to the Earth’s land surface. Future images will also allow scientists to monitor any changes and long-term recovery of vegetation and land cover
Laguna Pastos Grandes is a shallow salt lake located in Bolivia’s Pastos Grandes volcanic caldera. Fed by intermittent rivers and springs, the lake contains high concentrations of lithium, potassium, and boron. These three images show how Landsat 8’s extended spectral capabilities can be used to highlight various surface features, often with vibrant results.
The left image uses the three visible bands from Landsat (red, green, and blue) to create a natural color representation. In this image, the ground features appear in colors very similar to what would be seen by the human eye. Non-vegetated ground is brown, and water appears dark. The bright areas indicate salt and other evaporated deposits in dry or very shallow areas of the lake.
Along with the visible wavelengths, Landsat 8’s extended spectral bands show additional details that cannot be seen by the human eye. The middle image uses two infrared bands that can be used to highlight the water bodies (red), salt and evaporated deposits (yellow, gold), and varying composition of other materials (green, tan) within the basin. The right image also uses infrared bands, but in a different combination which accentuates the salt and evaporated deposits (light blue) and the geologic features within the surrounding volcanic region (brown, green).
The many spectral bands available on Landsat provide an important set of tools for scientists, geologists, and others to study and map features on the Earth’s landscape. These features cannot always be seen by the human eye alone.
Near the western edge of the Sahara Desert is a feature that resembles a large eye when viewed from space. The Eye of the Sahara, also known as the Richat Structure or Guelb er Richat, is a symmetrical dome of eroded sedimentary and volcanic rock. The outermost rings measure approximately 40 km (25 miles) across. Persistent northeasterly winds keep much of the dome free from sand, exposing the various layers of rock. The circular feature was initially interpreted to be an asteroid impact structure, but most scientists have now concluded that it was caused by geologic uplift.
This Landsat mosaic of four different scenes shows the geologic feature in false color. By blending visible and infrared wavelengths (bands), scientists can enhance the visibility of the various rock layers in contrast to the surrounding sand (yellow to white).
The largest mud volcano in the world is located in Porong, Sidoarjo in Indonesia, where it is locally called the Lusi Mud Volcano. Mud volcanoes are created when hot mud (rather than lava) erupts from a vent on the Earth’s surface. This type of eruption typically includes a mixture of steam and gas, groundwater, and mud-based slurry.
Lusi first erupted in May 2006, and is expected to continue erupting for decades. So far, enough mud has erupted to cover nearly 27,000 football fields in a meter of mud. These two Landsat images were acquired by Landsat 7 on April 28, 2006 (left) and June 24, 2015 (right). The round feature in the center of the right-hand image shows the current extent of the mudflow. This second image also shows a series of levee structures that were built in 2008 to surround and contain the ongoing mudflows.
The Landsat sensors include numerous spectral bands that can be used in various combinations, allowing users to accentuate and study specific features on the Earth’s surface. These two images used a combination of shortwave and near-infrared wavelengths to highlight the mudflow area, in contrast to the surrounding urban and agricultural areas.
The afternoon of Sunday June 14, Alaskan authorities were notified of a 40-acre fire in Willow, AK. Named the Sockeye Fire for the street where the fire began, the fire moved quickly through the black spruce forested area due to flat topography and hot, dry, windy weather. In only 48 hours, the burned area grew to about 6,500–7,000 acres. Strong north winds are expected to drive the fires to the south, threatening populated areas. Smoke could affect Anchorage, 80 miles to the south.
These two Landsat images were acquired by Landsat 8 on May 30, 2015 (left) and June 15, 2015 (right). Bright red indicates where the fire is burning. Burned areas are dark shades, and smoke from the fire forms a hazy trail toward the south. The Susitna River, to the west of the burned area, acts as a natural firebreak.
Landsat imagery assists with response planning and identification of areas at further burn risk. Future Landsat imagery will be useful for mapping and measuring burned areas and monitoring vegetation recovery.
Heavy rains fell over Texas, Oklahoma, Arkansas, and Louisiana in late May 2015. Many lakes and rivers filled and overflowed their banks, causing widespread flooding in both urban and rural areas. These rains provided much-needed moisture for this area of the southern Plains, and may help to suspend a multiyear drought in the region. However, the rapid rate of the rainfall has been excessive for many areas.
These images show the Trinity River southeast of Dallas, Texas. In the May image, the river can hardly be seen because of the vegetation along its banks. The June image shows Trinity River and flooded regions in bright blue and dark tones.
As the water moves downstream, continued flooding is affecting many homes, businesses, and cropland within Texas and its neighboring states. Future Landsat images will help with the monitoring and evaluation of impacts, as the waters crest and begin to recede.
2015 Earthquake and Landslides, Nepal May 27, 2015
A magnitude 7.8 earthquake struck Nepal on April 25, 2015. Along with damage due to shaking, the earthquake and its aftershocks triggered many large and small landslides throughout the region. As of early May, over 3,000 individual landslides had been identified, based on analysis of hundreds of satellite images collected after the earthquake.
The background image above is a Landsat 8 mosaic of the entire region, produced by stitching together Landsat images acquired from 2013–2014.
The insets show an image pair acquired by WorldView-2 and WorldView-3 over one example location near the town of Namrung, Nepal. Comparing the image acquired shortly after the earthquake with an image from a previous date allows scientists to map the exact locations and extent of local changes caused by the landslides. Here, the post-event (May 8) WorldView-2 image shows one major landslide, as well as many smaller-scale slides that also occurred along the Buri Gandaki river valley after the earthquake. The image also shows a new lake that formed behind the largest landslide, as a result of damming of the Tom Khola River.
This inset image pair shows just one location, and these changes have occurred across the landscape, especially in the mountainous regions.
Scientists will continue to monitor the region with various satellite data. As post-event images become available, earthquake damage and landslide maps are being created and updated. For more information (including earthquake damage assessments and a landslide inventory map) see the International Charter ‘Space and Major Disasters’ home page: https://www.disasterscharter.org.
35th Anniversary of Mount St. Helens Eruption May 20, 2015
The violent eruption of Mount St. Helens 35 years ago permanently changed the mountain and surrounding forest. The volcanic blast on May 18, 1980, devastated more than 150 square miles of forest within a few minutes. In these Landsat false-color images, forest appears as bright red interspersed with patches of logging. Snow appears white, and ash is gray.
Before the eruption, Mount St. Helens towered about a mile above its base, but when the volcano erupted, its top slid away in an avalanche of rock and debris. When measured on July 1, 1980, the mountain’s height had been reduced from 9,677 feet to 8,364 feet—a difference of about 1,300 feet.
The 2014 Landsat image shows vegetation regrowth, as light red and pink, in the devastated area. However, the gray around the mountain is still evident, and the volcanic crater is still prominent as an “amphitheater,” where the peak of the mountain slid away.
Scientists are using this opportunity to witness the recovery process, both with satellites and on the ground. With its 40-plus years of consistent imagery, the Landsat archive is perfect for studying the landscape changes caused by natural disasters and the gradual recovery process.
Haruj is the large volcanic field that dominates this Landsat image mosaic acquired over central Libya. The plateau was built from basaltic lava flows that erupted over time from approximately 150 separate volcanoes. The volcanic craters and lava flows are all evidence of a previous active period, well preserved in the dry Sahara Desert.
The geologic evolution of this landscape is not fully understood, but some scientists have used the texture and color differences revealed in satellite images to try to interpret the relative ages and sequence of different volcanic events. The numerous spectral bands and band combinations available from Landsat mean that the color variation of individual lava flows can be especially helpful for interpreting different phases of volcanic activity.
Many of the bright spots within the darker colored basalt flows are sand-filled craters associated with individual volcanoes. Other light-colored areas are depressions covered with silt and fine sand.
This image mosaic consists of numerous Landsat 8 scenes acquired in early 2015. Landsat images can be useful to support geologic mapping and studies of large and remote features such as this.
Lake Urmia, located in northwestern Iran, was once one of the largest saltwater lakes in the Middle East. It supports an important seasonal habitat for many species of migrating birds.
In recent years, the lake has diminished dramatically. Water enters Lake Urmia primarily from rainfall and inflowing rivers. The diversion of water from local rivers for agricultural use is one likely cause of Lake Urmia’s decline. Since 1996, drought has further contributed to the lower lake levels. The lake now covers about 10 percent of the area it covered in the 1970s.
These Landsat images show the changes to Lake Urmia’s surface area over the past fourteen years. Each image was created by mosaicking several individual Landsat scenes to show the full lake area. From 2000 to 2010, some changes can be seen. In the final image (2014), the entire southern portion of the salty lakebed is now exposed.
Future Landsat imagery will continue to be a useful tool for mapping and monitoring of further changes to Lake Urmia and its surrounding areas.
These two Landsat images show the urban area around Cape Town, South Africa. The more recent image (right) reveals scars from several fires that broke out in early March 2015, and were intensified by strong winds and hot summer temperatures.
The dark fire scar on the left side of the March 11 image is from a fire that had started ten days earlier and burned more than 5,000 hectares (12,000 acres). The dark scar on the right side of the same image is from the Jonkershoek Fire, which started March 9 and was still active at the time this image was collected. About 4,000 hectares (10,000 acres) were burned before this second fire was contained.
Landsat imagery is a valuable tool for the mapping and measurement of burned extent and lost vegetation due to wildfires. As the landscape begins to recover, Landsat will also be useful for monitoring the area’s regrowth and restoration.
Agricultural Land Use along the Chira River, Peru March 20, 2015
These two Landsat images show the expansion of agricultural fields along the Chira River in northern Peru. The green of irrigated fields contrasts against the arid background of the land in this coastal region. The main crops in this region include rice, cotton, maize, mangoes, and lemons.
The new agricultural areas in the second image (2014) are supported by irrigation from the Chira River and Poechos Reservoir in the upper right portion of the images. The reservoir and its system of dams were developed to generate electricity, control flooding, and support local irrigation needs.
Landsat imagery is often used to monitor the status and changes of agricultural land use and water resources over time.
New Land Forming in the Atchafalaya Basin March 6, 2015
Most of the Mississippi River Delta in southern Louisiana is sinking. An area almost the size of Delaware has been lost to subsidence over the past 80 years. However, further west along the coastline is an area of delta buildup.
These two Landsat images show changes to the coastline along the Atchafalaya River outlets between 1984 and 2014. Sediments carried by the Atchafalaya River, a distributary of the Mississippi, are responsible for the growth of two new river deltas seen in the 2014 image. These two deltas are from the main Atchafalaya River (right) and its associated Wax Lake Outlet (left). Both of these channels were used for flood control during the Mississippi River floods of 2012, when water was diverted from the Mississippi through the Atchafalaya River Basin into the Gulf of Mexico.
The slow-moving waters of the Atchafalaya River allow suspended sediments to settle near shore. This creates an optimal land- and marsh-building environment. In contrast, the lower Mississippi River’s waters flow quickly through a narrow channel, carrying most of its suspended sediments far offshore. The coastal marshland that has now been built in the Atchafalaya region gives planners hope that other areas of the Mississippi Delta could be similarly rebuilt or preserved through land and water management.
The continuous acquisition of Landsat imagery now spans more than four decades, providing a valuable historical record that can help researchers and scientists monitor and understand landform changes on the Earth’s surface.
These two Landsat images show several of Iceland’s ice caps as they appeared in September 1986 and 2014.
The largest white area is the Mýrdalsjökull Ice Cap. Underneath this massive mound of ice sits the active Katla volcano. Katla erupts every 40–80 years and is accompanied by high-volume glacial outburst floods (jökulhlaups). The smaller ice cap to the west is Eyjafjallajökull. This ice cap also covers an active volcano, which last erupted in 2010 and disrupted air travel for several weeks.
The brown areas on both ice caps consist of accumulated volcanic ash and other deposits from past volcanic eruptions. The dark cover of volcanic ash from the 2010 eruption is especially prominent on the 2014 image of Eyjafjallajökull.
At first glance, there appears to be remarkable shrinkage of the ice caps by 2014, the situation for most of Iceland’s ice cover. However, the bright white areas in the 1986 image represent fresh snow cover, which is not present in the 2014 image. To monitor the actual changes in the extent of an ice cap, scientists measure changes in the position of the terminus of outlet glaciers.
Landsat is one of several important remote sensing tools being used by glaciologists to map and monitor changes in the Earth’s ice cover over time.
Chesapeake Bay: A Landsat 8 Surface Reflectance Mosaic February 12, 2015
Chesapeake Bay is the Nation’s largest estuary and its restoration and protection is a priority. The USGS provides scientific information to help manage this vital ecosystem. As part of that role, staff at the USGS Earth Resources Observation and Science (EROS) Center created this true color composite image. The image was created using Provisional Surface Reflectance data from five Landsat 8 scenes, acquired in October and November 2014.
Provisional Surface Reflectance processing includes atmospheric correction to reduce haze, aerosol, water vapor, and ozone effects from Landsat Level 1 processed data. The enhanced processing makes this seamless mosaic possible and provides a sharper view of the Earth’s surface, as if there were no atmosphere interrupting the view between the satellite and ground.
Chesapeake Bay is the dark shape stretching up through the center of the image. Sediment in the water appears either light blue or green. Baltimore, Maryland, and Washington, DC, are the two bright areas near the upper left. The peninsula across the Chesapeake from these cities is a patchwork of farm, forest, and protected areas.
Moving water holds potential for generating electricity, and hydroelectric power currently generates over 16 percent of the world’s electricity.
These Landsat images show the site of the Three Gorges Dam in China, which is the largest hydroelectric dam in the world. The dam is over 2,300 meters (1.4 miles) long and forms the straight line across the river in the second image. The project became fully operational in 2012 and has a power generation capacity of 22,500 megawatts. The reservoir created behind the dam stretches 600 kilometers (373 miles) along the Yangtze River and provides water storage for downstream flood control along with electric power.
The Landsat image from 1993 (left) shows the area one year before construction began. The 2013 image (right) was acquired one year after the power plant became fully operational. The second image shows the reservoir created by the dam and the higher water level that now extends into many side valleys. Also visible in the 2013 image is a lock system that supports shipping traffic, as the increased depth and width of the river now permit larger ships to travel this area.
As hydroelectric power continues to expand around the world, Landsat imagery can help monitor the land surface changes and impacts caused by these projects.
The Topaz Solar Farm is one of the largest solar farms in the United States. Located in central California, the 550-megawatt power station consists of 9 million solar panels across 9.5 square miles (24.6 square kilometers). Construction began in 2012 and was completed in late 2014, and the site can now produce enough electricity to power 160,000 homes.
These images, acquired by Landsat 7 and Landsat 8, show the area of the solar farm development. The 2011 image was acquired before construction started and shows that the previous land use was agriculture. The 2015 image shows the completed project. In the second image, the agricultural land use (green blocks) has been replaced by the solar installation (dark blocks). This second image also shows less overall greenness, due to seasonal change.
Landsat images such as these can help document changes to the landscape, as alternative power sources are being developed to provide renewable energy for the Earth’s growing population.
Wind Power in Texas, United States January 20, 2015
Wind power is produced by using large generators to harness the kinetic energy of wind. It is gaining importance as a large-scale source of renewable energy, and new wind farms are being developed worldwide.
In the Texas Panhandle of the United States, an area previously known for fossil fuel production is undergoing a rapid surge in wind energy development. One example is the Longhorn North Wind Project, which was initiated in late 2013 and expected to be fully operational in 2015. When completed, the installation will provide approximately 200 megawatts of power from 100 wind turbines. The area covers almost 57 square kilometers (22 square miles), and is only one of many new wind farms that are being developed in this region of Texas.
These two images show the Longhorn North Wind Project area in December 2013 and one year later in December 2014. The irregular white lines in the later image are access roadways that support construction of the new wind turbines and connection to major transmission networks in the area. The small bright dots on those roadways represent individual turbine locations.
Another change in the later image is an increased number of green fields and small lakes filled with water. In September 2014, remnants from a tropical storm brought heavy rain to this part of Texas, which had been in a drought since 2011.
As wind energy sources continue to expand in the United States and worldwide, Landsat imagery will be useful for monitoring the land changes associated with this development. The consistent, repetitive images from Landsat can also provide a valuable record of the weather- and climate-induced influences as they occur on the Earth’s landscape.
The Sampson Flat Fire started on January 2, 2015 near Adelaide, Australia. Hot, windy weather during the Australian summer caused the bushfire to spread quickly and move erratically. By January 7, it had burned over 120 square kilometers (46 square miles) of woodland and grassland within the steep and inaccessible terrain of the Mount Lofty Ranges.
In the Landsat 8 image acquired on January 4, the burned areas are brown. Active fire appears red with white-blue smoke rising from it. The urban area of Adelaide can be seen in the lower left.
As of January 9, the fire has been contained, but firefighters continue to monitor the unburned pockets of vegetation for flare-ups. Falling trees and limbs have become a hazard for crews working in the area.
Multiple Storms along the Vietnam Coastline December 23, 2014
In July 2014, rains from Typhoon Rammasun triggered heavy flooding as it made landfall in northern Vietnam. Only two months later, Typhoon Kalmaegi made landfall along the same section of coast. While the rainfall was not as strong as it was from Rammasun, rivers were still swollen from the previous storm.
The first two Landsat images show the shoreline along the Gulf of Tonkin after each of these major storms. In the July image, the dark shades across the landscape indicate the extent of flooded land and potential crop damage due to Typhoon Rammasun. Increased flows of river sediment into the gulf are prominent in this image; bright shades of blue contrast with the surrounding waters.
The second image was acquired several days after Typhoon Kalmaegi made landfall. This image shows a less pronounced flood impact across the landscape, but sediment flows are still clearly visible from this storm. The October image shows the area in continued recovery after both typhoons, with normalized sediment flows into the gulf.
Landsat data provide an important source of pre- and post-event images that are often used to support disaster and recovery monitoring worldwide.
Ohio’s capital city, Columbus, is situated along the Scioto River and is one of the fastest growing cities in the state. In 1986, the municipal population was estimated at 600,000. The latest population estimate for Columbus from the U.S. Census Bureau is over 820,000.
These two images show Columbus and surrounding areas in 1986 and again in 2014. The second image shows the gray urban areas expanding into previous agricultural land, which is indicated by green patchy areas. The bright areas throughout the city are retail and industrial centers. The dark blue spots along the river in the southern part of the city are wastewater treatment ponds and other ponds associated with local sand and gravel quarries.
The historical record provided by Landsat images can be a useful tool for city managers, planners, and scientists who are monitoring and documenting the changes to Earth’s land cover caused by urban expansion.
A volcanic eruption that started on August 31 in Iceland shows no sign of weakening. This eruption is occurring at the Bardarbunga volcano, which lies north of the Vatnajökull glacier in south-central Iceland. Lava has been flowing spectacularly from the Holuhraun lava field, and the eruptive fissure has now spread lava across more than 70 square kilometers (27 square miles).
These Landsat 8 images show different spectral bands and band combinations acquired on September 6, 2014. These images provide examples of the type of information being used by scientists to monitor and map the eruption.
The first image is a false-color composite that combines information from the shortwave infrared, near-infrared, and green wavelengths of light. In this image, the recently erupted lava glows bright orange and red. The areas covered by snow and ice within the neighboring glacier can also be seen in shades of blue-green. The second image is a natural color representation, based on the visible wavelengths of light. In this image, the location of active volcanic fissures can be seen as small bright features, and the plumes and trajectory of ash and steam can also be clearly seen. The surface of the cooling lava flows (where visible) are black. The third image is a thermal infrared representation. This image shows relative surface temperature over the region, with the hottest areas (erupted lava) shown in bright hues and colder areas (glacial ice and water bodies) shown in dark tones.
The combined information available in Landsat images can provide an important complement to ground sensors. These images are important for scientists and decision makers engaged in mapping and monitoring the eruption.
As 2014 comes to an end, so does the growing season in the northern U.S. heartland. Millions of acres of corn, soybeans, alfalfa, and small grains have been harvested from the land in recent weeks.
These two Landsat images show the harvest activity and seasonal vegetation changes along the Platte River in south-central Nebraska. The river flows from the northwest corner of the images and then to the east, and its associated basin provides an important corridor for agriculture. The first image was acquired in early September. This image shows many actively growing fields (green blocks) across the landscape, especially within the Platte River basin. The second image (late October) is dominated by shades of tan, pink, and gray. These colors indicate bare ground, and only a small number of green fields remain.
Landsat data are often used for agriculture monitoring and management. This imagery can help users monitor local and regional conditions of the world’s croplands—within a growing season, from year to year, and from one decade to another.
Over 20 Million Landsat Scenes Downloaded October 29, 2014
Since 2008, all Landsat data—archived and newly acquired—have been available for free download. On September 16, 2014, users worldwide downloaded over 14,000 scenes from the servers at the USGS Earth Resources Observation and Science (EROS) Center. These downloads brought the total number of Landsat data downloads to more than 20 million.
This Landsat 8 scene was one of the many downloaded on September 16. It shows the area around Juneau, Alaska. Water is dark and includes Lynn Canal, the long water body in the middle of the image. Green is vegetation and forested mountain areas.
This image also provides a clear view of the Juneau Icefield. Several glaciers flow from this icefield, and glaciologists are using the 42-year Landsat archive to monitor the advance and retreat of the glaciers over time. Since Landsat 7 and Landsat 8 together provide an 8-day repeat cycle, Landsat can be an important supplement to ground-based glacier monitoring.
Scientists, students, city planners, environmental engineers, and many others have been able to use the vast archive of Landsat data free of charge to support and enhance their research. The free availability of Landsat data enables scientists to conduct large-scale global studies that would otherwise be too costly.
Urban Growth of Maracaibo, Venezuela October 22, 2014
The city of Maracaibo, Venezuela, is located on the western shore of a strait that connects Lake Maracaibo to the Gulf of Venezuela. The region is an important source of oil production for Venezuela, and Maracaibo serves as a major port for shipments of oil. This area is also known for its commercial fisheries, shrimp farming, and salt production.
These two Landsat images show the urban expansion of the city of Maracaibo between 1986 and 2014. Cities along the lake to the east and south have also grown.
The 40-year archive of Landsat data is useful for studying many types of change across the Earth’s surface, including changes due to urban growth, agricultural activities, and coastal land use.
The Huang He (Yellow) River in China is the most sediment-filled river on Earth. It flows from the Bayan Har Mountains to the Bohai Sea. Along the way, it crosses a soft plateau that is covered with fine, wind-blown soil. The river carries away millions of tons of this delta-building material every year. Over time, the river carries its sediment load farther outward into the sea. These Landsat images provide a view of the dramatic changes to the shoreline.
Besides changes to the delta, aquaculture has significantly expanded along the coastline near the river delta, as well as farther south along Laizhou Bay. The dark geometric shapes along the coast were built on what were once tidal flats. These ponds hold shrimp and other types of seafood.
Landsat imagery is useful in providing historical records of the changes taking place on the Earth’s surface, and future acquisitions will allow scientists to help in protecting the delta’s natural wetlands, while meeting the demands of development along the shoreline.
As a 3-year drought continues in the western United States, water levels have been dropping in many California reservoirs, leading to emergency water use restrictions across the state.
These two Landsat images show the changing shoreline of Shasta Lake reservoir in northern California over the past three years. The first image was collected in September 2011 and shows the shoreline when the reservoir’s water levels were at 77 percent of total capacity. The tan colors in the September 2014 image show the change in shoreline. Even though snowmelt slightly increased the lake level earlier in 2014, the reservoir was still at only 27 percent capacity when this more recent image was acquired.
The lower right portion of the second image also shows a recent burn scar from the Gulch Fire. This fire was officially contained one day before the September 17 image was collected.
The images collected by Landsat are an important tool for monitoring changes to the earth’s surface, and can help support analysis related to water resources and other environmental conditions for affected communities.
Mapping Biodiverse Highlands with Satellite Imagery and Advanced Elevation Data September 23, 2014
A team from the USGS Earth Resources Observation and Science (EROS) Center produced a detailed land use/land cover map using Landsat satellite and 30-meter elevation data from the Shuttle Radar Topography Mission (SRTM) of the highlands along the Senegal-Guinea border. The Dindefelo Nature Reserve was created to protect the high biodiversity of this area, including chimpanzee habitat, which is closely correlated with topography. The map helps scientists visualize the resources within the reserve and the mounting human pressure on the natural landscapes that surround it.
The Landsat 8 image (left) of the study area coupled with the SRTM 30-meter data (center) provides a specialized view of the topography. The land cover map (right) shows the diverse habitats, including the locations of gallery forests. These narrow ribbons of dense trees follow watercourses and are indicated as purple shades on the land cover map. Gallery forests provide critical refuge for many species of plants and animals during the long, hot dry season. The maps are being used in a proposal by the Jane Goodall Institute to Senegal and Guinea to extend the Dindefelo Nature Reserve south into the Guinea highlands.
Mapping these biodiverse highlands is one example that demonstrates the advantage of the more accurate elevation data from SRTM. For more information, see the USGS Top Story here.
Detailed Elevation Data—Niger River Delta September 23, 2014
Shuttle Radar Topography Mission (SRTM) data had previously only been available worldwide at 90-meter resolution. The National Geospatial-Intelligence Agency (NGA), NASA, and USGS are now releasing a newly processed, global SRTM 30-meter dataset.
The above images show an example of the difference between the 90-meter and 30-meter data of the Niger River Delta in western Africa. The Landsat image, also at 30-meter resolution, of the same area shows the extensive coastal estuaries, tidal flats, mangrove forests, and lowland rainforests of this part of southern Nigeria. More detailed elevation data are especially critical in such coastal settings that have small elevation changes.
For more information on the new SRTM elevation product, see the USGS Top Story here.
Coastal Flooding near Semarang City, Indonesia September 19, 2014
Coastal inundation is an ongoing concern for the region near Semarang, Indonesia. This area faces several different types of flood risk, due to the potential combination of high tides, seasonal rainfall events, and river flooding. Much of this low-lying area is only 0–25 meters above sea level, and in some areas, land subsidence has also been occurring for many years. All of these factors lead to a risk of coastal flooding for local populations.
These Landsat images indicate changes in the area near Semarang City over the past 20 years. Semarang City is located at the bottom center of these images, and the differences along the coastline are particularly visible northeast of the city. In particular, the 2014 image shows coastal inundation that is encroaching on populated areas, roads, and structures.
Disaster managers and risk reduction personnel rely on satellite imagery such as Landsat to help document and mitigate flood threats as effectively as possible. The 42-year archive of Landsat imagery also provides a historical record that can be used to indicate long-term changes as they occur in coastal areas. This can help scientists and engineers understand and analyze historical trends, and assist with future planning for flood management and mitigation.
The Zapata Peninsula is located in western Cuba. Most of this sparsely populated area lies within the Ciénaga de Zapata National Park and UNESCO-designated Biosphere Reserve.
The region is covered by large areas of open swamp and marshes intermixed with dense woodlands. It is also home to one of the largest coastal wetlands in the Caribbean region. The extensive and fragile ecosystem is protected for its biodiversity and high concentration of migratory birds, mangrove forests, seagrass beds, and coral reefs.
This Landsat 8 image shows the peninsula and neighboring region. The dense forests are dark green, while the open swamps and marshlands are shown in brighter green and yellow tones. This image also shows the surrounding deep ocean water and channels (dark blue and black), along with shallow water and coral reefs (bright blue).
Landsat images provide a valuable record of the earth’s surface and are useful for space-based mapping and classifications of vegetation, ecosystems, and coastal habitats.
Mount Tavurvur erupted on August 29, 2014, sending ash over surrounding areas on Papua New Guinea’s New Britain Island. The stratovolcano is located along the eastern edge of the Rabaul Volcanic Complex, and its last major eruption was in 1994.
These two Landsat images were acquired in April and September 2014. In both images, Mount Tavurvur can be seen to the east side of Simpson Harbor. This harbor forms part of the much larger (mostly submerged) Rabaul Caldera.
The second image was acquired a few days after the August 2014 eruption. This image shows the extent of ashfall (gray-brown), while the forested areas that were less affected by ash remain green.
Images acquired by the Landsat satellites are useful for monitoring land changes and recovery after natural disasters such as volcanoes.
Oil Production near Tioga, North Dakota August 28, 2014
These Landsat images show the area around Tioga, North Dakota, in 2002 and again in 2014. Oil was first discovered near Tioga in 1951, and the town has experienced several episodes of rapid growth due to its location over the Williston Basin, a major North American geologic source of oil, natural gas, and other energy resources. The recent development of advanced drilling techniques has led to a new surge of production, particularly within the Bakken Formation, which has become an important source of oil within the United States.
These two Landsat images show the dramatic changes to the landscape near Tioga in recent years. Many new oil wells and related facilities (small bright features) are visible in the 2014 image compared to the earlier image. The rapid expansion of the town of Tioga can also be seen, as the town has grown to support an expanding workforce. The 2014 image also shows the development of new oil processing and transportation facilities along the western and eastern edges of Tioga.
The images from the Landsat archive span four decades and provide a consistent worldwide record of land use and land cover changes as they occur across the Earth’s surface.
Urban Expansion of Shenyang, China August 22, 2014
The city of Shenyang is one of the largest cities in northeastern China. Situated along the Hun River, the city is a major transportation hub. It is also an important industrial center, representing the core city of the Shenyang Economic Zone. Its urban and outlying areas are home to over 8 million people.
These images show the city of Shenyang in 1984, and again in 2014. The expansion of Shenyang’s urban area over the past 30 years is striking, as the urban developed area (shades of silver and gray) has expanded into the previous farmland and forested areas (green shades) surrounding the city. The large green feature in the north-central part of the urban area is Beiling Park, the largest park in the city.
The 40+ year archive of Landsat imagery provides a valuable tool for recording urban growth and other types of land cover change over time. The information in these images can also be useful for monitoring the effects of urban growth on the surrounding landscape and ecosystems.
Dam Breach at Mount Polley Mine, Canada August 13, 2014
On August 4, 2014, an earthen dam failed at the Mount Polley Mine in central British Columbia, Canada. The dam had been built to hold a tailings pond that contained water and waste materials from local gold and copper mining operations.
The tailings pond covered over 4 square kilometers and within a few days, millions of cubic meters of wastewater and slurry had flowed from the pond into neighboring Polley Lake, Hazeltine Creek, and Quesnel Lake.
These two Landsat images show the area of active mining and associated tailings pond. In both images, the dark areas indicate clear water. The suspended materials within the tailings pond (first image) are more reflective, so this water appears brighter. In the August 6 image, the waste materials from the tailings pond can be seen (blue, green, and silver) flowing down Hazeltine Creek and into the two nearby lakes.
Algae blooms commonly happen in summer on Lake Erie, but the blooms have been increasing in recent years. This year, north winds pushed the algae toward the water intake system for Toledo, Ohio, the urban area visible in the lower left of these Landsat 8 images.
Certain types of freshwater algae produce a toxin that can be harmful to people. Whether harmful or not, algae blooms are often large enough to appear in satellite images. This Lake Erie bloom shows up as green swirls on the surface of the water in the August 1 image. The white spots above the land and water are clouds. The June 14 image is displayed for comparison.
Scientists often use satellite imagery (such as Landsat) along with aerial imagery and water-based sensors to monitor the algae blooms each summer. The information helps them determine the type and distribution of the algae. Furthermore, comparing the annual extent of the blooms helps scientists monitor long-term trends and predict the impacts and movement of future algae bloom events.
Heavy rains starting in June have brought the worst flooding the country of Paraguay has ever seen. Thousands of residents have been displaced due to flooding of the urban and rural areas along the Paraguay River in this central South American country.
These images, acquired by Landsat 8 on April 14, 2014, and July 19, 2014, show the Paraguay River, north of the city of Asuncion. The April image shows the area before the flooding began. The July image shows the dramatic change due to the flooding.
Future Landsat data acquisitions will be useful in monitoring the affected areas.
The Bone Valley region in Central Florida contains the largest known deposits of phosphate in the United States. These deposits were formed within layers of fossil-rich sediments that developed millions of years ago when the area was underwater. The rocks in this region contain phosphate minerals that are broken down for phosphorus, which is used to produce agricultural fertilizer and other applications.
These Landsat images show an area with phosphate mining activity in 1986 and again in 2014. The two images show numerous changes to the landscape during this time interval. The surface mining process involves removal of the vegetation and top layers. The exposed phosphate ore is removed and scooped into a pit, then mixed with water to create “slurry”. The slurry is pumped to a processing plant where the phosphate is extracted. After processing, the remaining waste by-products are pumped into settling ponds, and the land undergoes a reclamation process.
The multiple stages of this process are apparent in these Landsat images. The bright areas indicate exposed rock and land surface. The black, blue, and purple tones indicate water combined with other components in varying compositions, within the slurry and settling ponds. The green shapes with geometric outlines (particularly toward the center of the second image) indicate reclaimed areas with new vegetation.
Dry conditions have made this year another busy one for wildfires in the western United States. For example, responders in east-central Oregon are currently fighting several separate fires that were started by lightning near Malheur Lake on July 14, 2014. The combination of high winds, low humidity, and high temperatures has been making the firefighting work difficult.
These Landsat images were acquired on July 1, 2014 (left), and again on July 17, 2014. Malheur Lake is in the center of both images. The large fire scars visible in the second image show the area burned within the Buzzard Complex as of July 17. The bright orange areas also show where the fires were continuing to burn at the time the second image was collected.
Landsat imagery can be an important tool to help evaluate the areas damaged and destroyed by fire, and can assist in response planning and identifying areas of further risk. Future images from Landsat will also be helpful for monitoring the land recovery after major fires such as this.
2014 World Cup—Rio de Janeiro, Brazil July 11, 2014
The 2014 Fédération Internationale de Football Association (FIFA) World Cup began on June 12, 2014, and has been taking place at numerous venues across Brazil. The final match is on Sunday, July 13, at the Maracanã Stadium in Rio de Janeiro.
This Landsat 7 image was acquired on June 26, 2014. The main image shows the spectacular setting of the city of Rio, with its high mountains, islands, and famous long beaches that follow the coastline. The smaller image shows the location of the stadium (white circle) where the 2014 World Cup final match will take place.
These “pan-sharpened” images use Landsat’s panchromatic band (15-m resolution) in combination with the 3-band multispectral information (30-meter resolution). This technique is often used by scientists and analysts when it is necessary to show more details within the Landsat image than would be visible using the multispectral information alone.
These Landsat image products were created using hundreds of individual Landsat scenes. The images have been mosaicked and “draped” over elevation data to show the topography and landscapes across the United States.
The main image shows the Rocky Mountains and other mountain ranges that dominate the western United States. The central portion of the image consists mainly of rolling plains and farmland. The right portion of the main image shows the mountain ranges and coastal plains that make up the eastern U.S. seaboard. The Alaska and Hawaii mosaics show the predominant features of those landscapes as well.
An individual Landsat state mosaic has been prepared for every one of the 50 U.S. states plus Puerto Rico. All of the Landsat image mosaics are available in poster-ready format and may be viewed and downloaded via the USGS Earth Resources Observation and Science (EROS) Center Image Gallery (http://eros.usgs.gov/imagegallery/landsat-state-mosaics).
The imagery that is collected by the Landsat satellites can be useful for general visualization of large areas and landscapes, and is often used in combination with other datasets (such as elevation) to create image products such as these.
Flooding in Southeastern South Dakota June 27, 2014
In June 2014, southeastern South Dakota received record amounts of rainfall, and parts of neighboring states also received excessive rainfall due to a series of severe storms. As rivers overran their banks, many roadways became impassable and the rising waters damaged many homes and businesses. This area is an important agricultural region, and the heavy rainfall and accompanying hail damaged many of the recently planted corn and soybean crops.
The second image clearly shows the Vermillion River and the Big Sioux River flooded over their banks. The lower right corner of the second image also has darker tones mixed throughout the agricultural areas (bright green). These darker tones suggest potential flood damage to the crops in this region.
Landsat images such as these can be an important tool for evaluating the damage to local crops and for monitoring the agricultural recovery and replanting efforts on a regional scale. The Landsat imagery will also be useful for monitoring the overall distribution oft floodwaters as they recede and move downstream.
28 Years of Landscape Change in Texas, USA June 23, 2014
These images show a portion of the Texas Panhandle where it meets the western border of Oklahoma. The area is part of the “Granite Wash” region, which contains over 3,600 wells that mine oil and natural gas from as deep as 17,000 feet (5,182 meters) underground.
When comparing Landsat imagery from 1986 (left) and 2014 (right), many changes can be seen on the landscape. The large number of white spots in the second image indicates an overall increase in the number of oil wells. The reduced overall greenness (vegetation) in the second image was caused by several recent years of drought. Other visible changes include additional center-pivot irrigation systems (dark circles). There are also several new burn scars from wildfires that occurred in March 2014.
As the Landsat archive grows, its imagery can be used to record and monitor many different types of landscape changes through time.
The Funny River Fire was first discovered on May 19, 2014. By early June, it had burned almost 200,000 acres in south-central Alaska, including much of the Kenai National Wildlife Refuge.
The Landsat 8 image on May 4 shows the area before the fire began. Heavy smoke covers the Kenai Peninsula in the May 20 image, and this image also shows some of the areas of active burning (bright orange) along the edges of the wildfire area. On June 5, Landsat 8 captured the total extent of the burned area.
A series of wildfires erupted along the coastal region north of San Diego, California, in mid-May 2014. The first wildfire (Bernardo Fire) began on May 13, followed by several additional fires that occurred over the following days. At one point, firefighters were battling at least eight active wildfires and over 175,000 evacuation notices were issued.
The Landsat 8 image (left) was acquired on May 9, 2014, and shows the area before the fires began. The Landsat 7 image (right) was acquired eight days later. The red tones show numerous areas that were burned as of May 17, 2014.
The repetitive imagery provided by the Landsat satellites allows officials to evaluate the destructive impacts and monitor future recovery after disaster events such as these wildfires.
A tornado that touched down in central Arkansas on April 27, 2014, proved devastating and deadly.
These Landsat images show the area northwest of Little Rock, Arkansas, before and after the storm. The path of the tornado can be seen in the May 1, 2014 image. The tornado began southwest of Lake Maumelle, before crossing the Arkansas River and moving through the town of Mayflower. It then continued to the northeast through the town of Vilonia.
Landsat image acquisitions will be useful for monitoring the current impacts and future recovery of vegetation destroyed in the storm.
Winter Ice Cover, Lake Superior (USA/Canada) May 8, 2014
The extreme cold of the 2013-2014 winter season created historic ice cover on the North American Great Lakes and much slower than normal spring melt. The persistent and widespread ice has affected shipping transportation throughout the Great Lakes region. At one point, the Lake Superior ice cover was estimated to be nearly 95% with an average thickness of 22.6 centimeters (8.9 inches). Pressure ridges and ice motion can also cause plates of ice to buckle and stack, creating local ridges up to 1.5 meters (5 feet) thick in some places. Even though the ice has now started to melt, some areas of this year’s ice cover could last into June.
The abnormal thickness and extent of this year’s ice cover caused challenges to the ice breakers that allow shipping to and from ports such as Duluth Harbor. When cutting through very thick ice, it can take many hours to go a very short distance. At one point, as many as 70 ships were awaiting entry into Lake Superior, and the ships were being grouped together as escorted convoys to maximize ice-breaking efforts and allow safe passage.
These three Landsat 8 ”natural-color” (3-band composite) images show the Lake Superior area north of Duluth, Minnesota, in February and April 2014. The first image (February 16) shows the ice cover near its maximum. The second image (April 5) shows reduced ice coverage, along with an ice breaker channel that was created to allow ships to enter Duluth Harbor. The third image shows the remaining ice cover as of April 21.
Landsat imagery provides a consistent and repetitive view of the Earth’s surface and can be used to help monitor changing conditions over time.
Drought Conditions in California, USA April 24, 2014
After several consecutive years of below-normal precipitation, the U.S. state of California is preparing for its most severe drought emergency in decades. The current drought is due in part to decreased rainfall along with reduced winter snowpack in the Sierra Nevada mountain range. In 2013, California received less precipitation than any other year since it became a state in 1850. Water conservation efforts are already in place for many locations. For 2014, there is potential for major agricultural impacts, and the wildfire danger is expected to be unusually high.
These three images show a portion of California’s Central Valley (left side of the images) and the neighboring Sierra Nevada mountains as viewed by Landsat in February 2011, 2013, and 2014.
The decrease of winter snow cover can be seen in this progression of images. The reduction of available water supplies in the Central Valley is also indicated by the changing outlines of Folsom Lake, Camanche Reservoir, and other lakes and reservoirs in the images.
The 40-year archive of Landsat imagery is useful for monitoring the changing conditions of Earth’s surface areas through time.
Urban and Agricultural Change in Cairo, Egypt April 11, 2014
Egypt’s capital city of Cairo lies in the fertile Nile River Valley. Historically, Cairo and its agricultural areas have been geographically limited by natural desert borders, but these patterns are changing due to recent reclamation of surrounding desert land.
These two images were acquired by the Landsat satellites in 1987 and 2014. During this time period, Cairo’s population has increased from an estimated 6 million in 1986 to over 15 million in 2014.
The recent population growth has caused the city and its associated urban areas to expand into the surrounding desert, as seen in the second image. Within the main Nile River Valley, these two images also show an overall increase in developed urban area (grey/brown) versus previous agricultural land use (green).
As new urban and agricultural areas are being developed in the desert, they require diversion of water supplies from the main Nile River Valley. This expanded irrigation is indicated by the numerous bright green areas throughout the second image.
The Landsat data archive spans more than 40 years and provides a valuable record of changes on the Earth’s surface, including urbanization and agricultural land use change.
On March 22, 2014, a massive landslide occurred in the Cascade Mountains near Oso, Washington. Triggered by heavy rains, the slide covered the North Fork of the Stillaguamish River and destroyed numerous homes. After a week of intensive search and rescue efforts, at least 20 deaths had been reported and many others were still reported missing. The muddy debris also created a dam that blocked the river, causing concerns for flooding and flash flooding as the water filled behind and moved around the dam.
These images were acquired by Landsat 8 on January 18, 2014, and again on March 23, 2014. Along with the landslide, the barrier lake caused by the blocked river channel can also be seen in the later image.
Landsat imagery will be useful (along with other datasets) as the efforts to recover, reclaim, and restore this area are implemented.
These Landsat images show the Sesan River (Tonlé San), which runs through the boundary region between northeast Cambodia and Vietnam. The river forms an important tributary to the Mekong River, which lies to the west (not shown). The two images were acquired in 1989 (left) and again in 2014 (right).
These images are “false-color composites.” The red tones are due to a strong signal from Landsat’s near-infrared (NIR) band, which is often used by landscape scientists to monitor the presence and condition of vegetation and forested areas. The lighter tones in the 2014 image show where vegetation has been cleared for logging, mining, or other land use purposes.
The Yali (Yaly) Falls Dam was built in 1993–1996, and its associated reservoir can be seen on the right side of the 2014 image.
The information contained in images such as these can be used to understand the landscape conditions at any location worldwide, and the 40-year record of Landsat allows scientists and others to monitor changes to this landscape over time.
Yarki Island and Lake Baikal, Russia March 14, 2014
Located in southern Siberia in Russia, Lake Baikal is the deepest lake in the world (1,700 m) and contains 20 percent of the fresh surface water on the planet. Because of its geologic age and geographic isolation, more than 80 percent of the lake’s freshwater species are found only at Lake Baikal.
A narrow sand spit stretches across the lake’s north end to form Yarki Island, which separates the northernmost shoreline from the open water. This long, discontinuous land surface is the result of accumulated sediments from several rivers flowing in from the north, combined with the interaction of these sediments with incoming waves, wind, and storms from the main lake to the south. The shallow lagoon that is created behind Yarki Island is filled with relatively warm waters and peat deposits, and forms an important bird sanctuary.
This Landsat image shows the area around Yarki Island and northernmost Lake Baikal. The green tones in the lagoon area depict vegetative sediments. The mouth of the Verkhnaya Angara River can be seen on the right side of the image.
The vast archive of Landsat images helps researchers and scientists monitor the Earth’s ecosystems, and provides unbiased evidence of how changes can affect these ecosystems worldwide.
Near the southernmost tip of Africa lies the Sundays River Valley, an agricultural area rich in citrus fruit production. Urban settlements and orchards in the subtropical climate are aided by a well-developed irrigation system that was established in the early 1920s with the construction of a dam upstream of the area shown in these images.
These Landsat images show the Sundays River Valley area in November 1986, and again the same month in 2013. Orchards can be seen expanding along both sides of this stretch of river. The bright green colors indicate orchards and agricultural lands, and pinkish hues indicate unused parcels.
Landsat imagery is valuable for measuring and monitoring land use and land use changes across the Earth’s landscape.
These Landsat images show portions of the Cordoba and San Luis provinces in central Argentina. The urban area to the right of image center is Villa Dolores. To the north and east of the urban area, the Embalse Allende (“Vineyard Dam”) can be seen in the two images.
This region has been long noted as an important center for potato production. In this semiarid climate, a double crop is possible when the potatoes are given enough moisture through irrigation. Other important local crops include wine grapes, olives, tobacco, walnuts, and jojoba.
These two images show 20 years of change to the agricultural landscape. The first image was acquired in January 1994 and shows areas of active cropland (bright green and lighter tones). The second image, from January 2014, shows apparent conversion of additional areas to agricultural use. The bright green circles indicate center pivot irrigation systems, which have been installed over the past two decades.
Since both images were acquired during the same time of year (mid-January) the overall difference in color tones also suggests a difference in weather conditions between the two years. The 1994 image (green) was likely a year of higher precipitation, compared to the 2014 image (brown) which has been relatively dry.
Landsat imagery is an important tool for monitoring change to the Earth’s landscape over time.
32 Years of Change: Incheon, South Korea February 25, 2014
The shoreline area of Incheon, South Korea, has been changing dramatically over the past 32 years, as depicted by these Landsat images acquired in 1981 and again in 2013. Previous marsh areas have been turned into usable land through land reclamation. Urban growth has also expanded.
In the center of these images, previously separate islands have been joined together as reclaimed land to become home to Incheon International Airport. The airport opened in 2001 and is now one of the largest and busiest in the world. The new Incheon Bridge (also called the Incheon Grand Bridge) can also be seen in the second image; it opened in October 2009.
The Landsat archive contains 40 years of data, which allows users to see changes as they are occurring throughout the Earth’s landscape.
On January 15, 2014, lightning sparked a brushfire in Grampians National Park in the State of Victoria in southeastern Australia. The combination of dry, hot weather and strong winds contributed to a rapidly spreading complex. The fire became so intense it created a 12-km (7.5-mi) wide convection column that created its own weather, generated lightning strikes, and sparked many smaller spot fires.
Residents of the town of Halls Gap, just south of the burned area, were evacuated. The fire claimed at least one life and scorched over 53,000 hectares (131,000 acres) before it was contained on January 21.
These two Landsat 8 images show the area on January 12, 2014 (before the start of the fires) and again on January 28, 2014. The dark tones in the later image depict the burned areas.
The information contained in Landsat images is useful for mapping wildfires, along with many other types of land cover change.
Effects of Flooding: Hyères, France February 7, 2014
In mid-January 2014, unusually heavy rains in southeast France led to flooding, landslides, and evacuations. In some areas, up to 20 centimeters (8 inches) of rainfall occurred over three days, far exceeding the typical monthly totals.
These Landsat 8 images show the area around Hyères, along with the Giens Peninsula (Presqu’île de Giens) and nearby islands.
The two images were acquired on January 15, 2014 (one day before the rains began) and again on January 31, 2014. The bright blue colors in the right image show the flow of the sediment-rich floodwaters as they moved out into the Mediterranean Sea.
Gaborone is the capital and largest city in Botswana. Its current residential population is estimated at 250,000 within the city limits (450,000 when including the outlying areas).
Almost all of this urban development has occurred within the last 50 years. Development of initial infrastructure began in 1963, and the city was formally established in 1966 on the eve of Botswana’s independence. Since that time, Gaborone has experienced rapid urban growth. This expansion is expected to continue as economic and commercial entities become further established there.
The Gaborone Dam, south of the city, was completed in 1964 and provides critical water supply for the growing city. Within the last decade, the water levels have dropped significantly due to increasing water usage along with climate factors. In the early 2000s, the reservoir was estimated to be 80 percent full; as of December 2013, the water level of the reservoir reached its lowest point since the dam was built, at approximately 13 percent full.
These Landsat images show the city of Gaborone and the surrounding area in 2001 and again in 2013. These images show the urban growth (gray) extending into the landscape in the later image. The images also show the reduction in size of the reservoir over the past 12 years.
As urban populations continue to grow, the changing landscape and water resource management become important issues for community leaders. Landsat imagery provides repetitive views of the Earth’s surface which can help monitor urban growth patterns and other changes to Earth’s resources.
Cuesta del Viento Reservoir, Argentina January 24, 2014
The Cuesta del Viento (Wind Slope) Reservoir formed behind a large dam that was constructed on the Jáchal River in 1997–1998 in the San Juan Province of Argentina.
Surrounded by spectacular mountains, the reservoir controls the flow of streams from snowmelt of the Andes Mountains and provides a source of irrigation for fruit plantations and other crops. The reservoir has also become a popular destination for windsurfing and kitesurfing because of the consistent afternoon winds that reach 30–40 knots (55–74 km/hour; 34–46 mi/hour). These powerful winds are caused by the daily flow of air currents that travel out of the eastern Andes Mountains and converge in the river valley.
These Landsat images show the area in November 1996 (before the dam was built) and December 2013. The inclusion of Landsat’s shortwave infrared band information for this image pair also highlights the geologic features of the area.
Landsat images provide an unbiased view of features on the Earth’s surface and the changes that take place on the landscape.
Bear Glacier is located on the Kenai Peninsula near Seward, Alaska.
This glacier represents one of over 30 glacial outflows for the nearby Harding Icefield, which covers over 700 square miles (1,800 square km).
Bear Glacier has been receding dramatically over recent decades, as shown in this series of images. The black and white aerial photograph mosaic was collected in 1950 and shows the glacier extending almost fully across the highlighted region (red outline). The satellite images (color) were acquired by Landsat 4 (1989), Landsat 7 (2001), and Landsat 8 (2013). Taken together, these images show an overall trend of glacial retreat in this area for the 63-year time period.
There are millions of aerial and satellite images held in the USGS archives, which provide important historical and current views of Earth’s changing landscape. These images are public and available for download by anyone for any location worldwide. This glacier represents one of over 30 glacial outflows for the nearby Harding Icefield, which covers over 700 square miles (1,800 square km). Bear Glacier has been receding dramatically over recent decades, as shown in this series of images. The black and white aerial photograph mosaic was collected in 1950 and shows the glacier covering almost the entire area within the highlighted region (red outline). The satellite images (color) were acquired by Landsat 4 (1989), Landsat 7 (2001), and Landsat 8 (2013). Taken together, these images show an overall trend of glacial retreat in this area for the 63-year time period. There are millions of aerial and satellite images held in the USGS archives, which provide important historical and current views of Earth’s changing landscape. These images are public and available for download by anyone for any location worldwide.
Lake Chilwa is a shallow, enclosed saline lake located along the East African Rift Valley in southern Malawi, near its border with Mozambique.
This lake experiences high water level fluctuation, as it is strongly influenced by rainfall and summer evaporation patterns. In recent years, Lake Chilwa has been shrinking. Because the basin is an important source of local rice and fish production, the current drying trend is a potential food security concern.
These Landsat images show the net reduction of lake area between October 1990 and November 2013. The two images also show changes to the extensive wetlands (bright green) that surround Lake Chilwa. These wetlands are internationally recognized as an important seasonal hosting location for migratory birds from the Northern Hemisphere.
Landsat data are extremely useful for scientists and authorities to monitor water resources and land cover changes over time.
Auckland is on the North Island of New Zealand along the Hauraki Gulf. The urban area (purple hues) can be seen on the left side of this image. The round island north of the city that appears darker than the others is a volcanic island (Rangitoto Island) within the Auckland volcanic field.
As one of the few cities in the world to have two harbors on two separate bodies of water, the city has grown to become the largest and most populous in the country. Manukau Harbor is to the southwest of the city and opens into the Tasman Sea. Waitemata Harbor, along the city’s north shores, opens into the Pacific Ocean. On the right side of this image is the Firth of Thames, a bay important for habitat and wetland conservation.
The Landsat 8 Operational Land Imager (OLI) captured this image on September 2, 2013.
The Niigata Prefecture is on the northwest coast of Honshu, Japan’s largest island. Multiple rivers along the shoreline form a fertile coastal plain that supports abundant fields of rice and flowers, both of which are major industries of the area.
The city of Niigata, situated along the coast of the Sea of Japan, is the capital and the most populous city. Due to the low elevation and high annual rainfall, numerous wetlands can be found within the city limits. In fact, Niigata is sometimes called the “City of Water” due to the shoreline location, wetlands, and rivers that flow through it.
Landsat imagery supplies an unbiased view of the Earth’s surface over the past four decades and provides a record of land use, land cover, and change over time.
The city of La Rioja is located on the eastern foothills of the Sierra de Velasco mountain range in northwestern Argentina. The Los Sauces Reservoir and Dam can also be seen to the west of the city.
These Landsat images, acquired in 1984 and 2013, display the urban growth and other changes in the local landscape. With growing population, the city has expanded into the surrounding landscape. Agricultural land use has also increased, as shown in the green and light tan blocks east of the city. The arid climate makes irrigation systems vital to the region’s crops.
The information contained in Landsat imagery helps land managers observe land use and manage hydrological resources.
The large Landsat 8 image shows the full extent of Bangong Lake, which means “long neck swan” in Tibetan. It is located partly in China and partly in the region of Kashmir that is controlled by India. The lake is approximately 155 kilometers (96.3 miles) long from east to west. It reaches only 5 meters (16 feet) wide at its narrowest point.
This lake is unique in that the eastern portion has fresh water, while the waters to the west are saline.
The two smaller Landsat images show the easternmost portion of Bangong Lake. Changes to the local shoreline can be seen by comparing the two images, acquired in 1998 and 2013. During this time period, changing conditions have expanded the lake area, particularly along the marshy southwest and northern shorelines. These shoreline changes can affect the local salinity levels, which in turn may affect the vegetation and biological balance of the area.
The 40-year archive of Landsat imagery is useful in documenting change to the Earth’s landscape.
This image of the Grand Canyon in the southwestern United States is a mosaic of two Landsat 8 scenes acquired October 31 and November 9, 2013. Designated as a national park in 1919, the Grand Canyon has breathtaking views and unique geological formations that attract over 5 million visitors each year. Archaeological artifacts have been found in the park that are nearly 12,000 years old.
Recent high-flow releases of water from the Glen Canyon Dam (northeast of this image) have moved sand along the Colorado River and into the canyon. These sediments are helping to establish sandbars for fish and wildlife habitat and to protect archaeological resources.
The Landsat 8 satellite, launched in February 2013, is providing high-quality worldwide images of the landscape on a daily basis. Landsat serves as a valuable tool for all interested in monitoring the characteristics of the earth’s surface.
Forest Change Portrayed by Landsat Imagery November 22, 2013
On November 15, 2013, a new Global Forest Change survey was released. This online tool shows the forest change that has occurred worldwide from 2000 to 2012, and is based on the global repetitive observations by Landsat satellites during this time period.
These example images show the observed changes in forest cover north and east of Tuscaloosa, Alabama. They also show the change after an EF5 tornado caused massive destruction on April 27, 2011.
The two Landsat images show the forested areas in 2000 and 2011. The tornado path can be clearly seen in the second image.
The derived Global Forest Change map for the same area (right) is based on repeated Landsat observations from 2000 to 2012. Red indicates net forest loss, and blue indicates net forest gain. Magenta indicates mixed activity (gain and loss) within this time interval. Green indicates no change to the forest cover, and black indicates nonforest.
The overall mixed colors in the Global Forest Change map help to record the dynamic nature of the local forest land cover. The red streak clearly shows the forest loss caused by the 2011 tornado.
Agno River Valley flooding, Philippines November 14, 2013
The Agno River is located on the island of Luzon and is the fifth largest river system in the Philippines. Over 2 million people live in the Agno River Valley. The first image was acquired by Landsat 8 in June 2013. The second image (Landsat 7) shows the November 2013 flooding caused by Typhoon Haiyan (Yolanda).
The Landsat satellites collect imagery worldwide on a daily basis, and can help measure and monitor the landscape changes caused by devastating storms.
Boundary Dam Power Station, Saskatchewan November 8, 2013
The coal-fired Boundary Dam Power Station began operations in the early 1960s along the Souris River near Estavan, in Saskatchewan, Canada.
These three Landsat images were acquired in 1972, 1986, and 2013 and show how the landscape has been changing over the years.
The Boundary Dam and Reservoir (near the left-center of the first image) was constructed in 1957 to provide coolant for the coal-fired power station operations. The 1986 image shows expansion of coal mining operations into the surrounding area. The 2013 image shows the Rafferty Dam (upper left), which was developed in the late 1980s and early 1990s to provide additional water for the area and reduce downstream flooding along the Souris River. This image also shows further expansion of the coal mining operations, as well as the emergence of many temporary lakes which began to develop during the wet spring of 2011.
The Landsat archive contains more than 40 years of data that are useful for land change analysis, covering all areas of the globe. Landsat provides scientists and project engineers with invaluable imagery to conduct their research on how the changes affect the landscape.