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.