Media Information

 
 
 
collection:
nasa new
mediatype:
image
collection:
nasa
collection:
nasaimageofthedaygal lery
title:
Lena River Delta, Russia: Image of the Day
description:
After a 4,400-kilometer (2,734-mile) journey north from the mountains of south-central Russia, the Lena River fractures into myriad streams that fan out across the tundra and empty into the Arctic Ocean via the Laptev Sea. Its far northern location keeps the Lena River Delta frozen for as long as seven months of the year, but during the short summer, it thaws into a wetland of tremendous ecological importance. Climate scientists are also interested in the area because changes in the volume of water emptying into the sea as well as the depth of the permafrost (soil that remains frozen year round) are indicators of Arctic climate change. This image of part of the Lena Delta was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer asterweb.jpl.nasa.go v (ASTER) on NASA's terra.nasa.gov Terra satellite on July 16, 2005, during the area's short summer. Just beyond the lower left corner of the image is where the main channel begins to fan out. The two largest streams bend back to the east (along the bottom of the image) and northeast, and then they themselves split into additional streams, which meander across the tundra. Vegetation-covered areas are green, while bright white areas are probably places that were scoured by the annual spring floods. Mudflats and other areas covered by shallow water appear light blue. The hundreds of lakes and ponds that dot the tundra occur because each summer, only 20-40 centimeters (about 8-16 inches) of the ground thaws. The permafrost below acts like the cement bottom of a swimming pool, keeping the lakes from draining. In 2005, earthobservatory.nas a.gov/Newsroom/NewIm ages/images.php3? img_id=16986 scientists made a survey of northern Siberia's lakes and determined that 11 percent of them disappeared between 1970 and 2002. The culprit appears to be thawing permafrost. As the permafrost melts, it cracks open under the lakes, allowing the water to drain deeper into the ground.
subject:
Where -- Russia
subject:
What -- Terra
subject:
What -- ASTER
subject:
What -- Advanced Spaceborne Thermal Emission and Reflection Radiometer
subject:
What -- Advanced Communication Technology Satellite (ACTS)
subject:
Where -- Arctic Ocean
subject:
Where -- Laptev Sea
what:
Terra
what:
ASTER
what:
Advanced Spaceborne Thermal Emission and Reflection Radiometer
what:
Advanced Communication Technology Satellite (ACTS)
where:
Russia
where:
Arctic Ocean
where:
Laptev Sea
identifier:
ge_07343
uploader:
gwilliam@archive.org
addeddate:
2011-07-07 10:00:08
publicdate:
2011-07-07 10:00:08
creator:
NASA -- Image courtesy of NASA/GSFC/MITI/ERSDA C/JAROS, and the U.S./Japan asterweb.jpl.nasa.go v/ ASTER Science Team.
ImageUID:
file:/home/lunaadmin /Source_download/201 107/1/ge_07343/lena_ ast_16jul05_geo.tif
ImageUID:
file:/home/lunaadmin /Source_download/201 107/1/ge_07343/lena_ ast_2005197_lrg.jpg
filename:
lena_ast_2005197_lrg .jpg
date:
2005-07-16
rights:
Public Domain
source:
year:
2005
language:
eng

Lena River Delta, Russia: Image of the Day