Landsat 7 imagery acquired on November 22, 2009, defines a series of ancient walls developed to capture wild animals. The study sites are in the deserts of modern Israel, Jordan, and Egypt. The low walls, called desert kites, are roughly one meter high and some are as long as 60 kilometers. Constructed to channel herds of animals, the walls led them to what some believe were killing pits. Studies indicate the walls were common 2,300 years ago and later abandoned, replaced by other means of capturing animals.
Image of the Week
Images found during the week that show change from our past that correlate to current events.
Mar Chiquita is the largest of the naturally occurring saline lakes in Argentina. The feeder systems for the lake include the Dulce River from the north, and the Primero/Suquia and Segundo/Xanaes Rivers from the south.
The Dulce River, as the principle feeder, has a heavy saline content, and increased drawing of the river upstream for irrigation has affected the levels of the lake. Additionally, long drought periods have diminished recharge capabilities.
These Landsat 5 images show how record-breaking rainfall from severe storms on May 1 and 2, 2010 affected the Mississippi River along the state borders of Tennessee, Kentucky, Arkansas, and Missouri.
The water has receded from the populated areas of Memphis, which is just south of the image, but some families are still living in shelters due to health hazards that resulted from the flooding.
Lightning caused a forest fire in early June in the Big Mountain, Alaska, region near the Canadian border. Within days, over 10,800 acres of black spruce trees had been destroyed by the fire.
Alaska and Canadian Forest Service employees routinely use Landsat satellite data, acquired, processed, and distributed by the U.S. Geological Survey, to identify and monitor forest fires in relatively isolated regions.
Landsat imagery can capture changes in lake surface water extents. This sequence of images illustrates changes occurring in the Yukon River Basin in Alaska.
Twelve Mile Lake, located southwest of Fort Yukon in interior Alaska, decreased in surface size more than 60% between 1979 and 2009. Drying has also been noted in other northern latitude water bodies around the globe. Landsat can be used to quantify the magnitude of the phenomena. These hydrologic changes have local and global influences on carbon dioxide, methane, heat, and water fluxes.
On June 20, 2010, a forest fire, caused by an improperly extinguished camp fire, started near Flagstaff, Arizona. By June 30, over 15,000 acres of scenic forest land were affected. Over 1,000 residents were evacuated as a precaution; however, no lives were lost nor were any major structures destroyed. 800 firefighters worked to contain the fire and the fire was largely contained by early July. Estimated damage and cost of fighting the fire is $8 million.
Landsat imagery, acquired and processed by the U.S. Geological Survey, illustrate fires along the Volga River near Nizhniy Novgorod, the third largest city in Russia.
The Landsat 7 image acquired on June 27 shows conditions before the fires. The green tones represent vegetation, the medium colors represent crops, and the darker tones represent marshy land. The Landsat 5 image acquired on July 5 shows the burned areas, and smoke from continuing fires. The burned areas shown in shades of red, cover approximately 3,000 acres.
An extreme drought on the Kamchatka Peninsula in eastern Siberia has led to a series of major fires. Landsat satellite data, collected and processed by the U.S. Geological Survey, are being used by regional resource managers and fire fighting officials to monitor the extent of the fires and conditions of affected vegetation.
Landsat 7 data, acquired by the U.S. Geological Survey, show the break of a large ice unit in the Petermann Glacier in northwestern Greenland.
Massive flooding in Pakistan has been triggered by the annual monsoon. Rains fell in the northeast of Pakistan for over a month, and the floodwaters have flowed south through the country along the Indus River floodplain. Hundreds of thousands of people have been displaced, and the floodwaters will take weeks or months to recede.