Reading a Snowy Landscape

January 25, 2024

This image of a winter landscape in central Asia was taken by an astronaut aboard the International Space Station. Where surfaces are covered with snow, textures are more useful than colors for interpreting landscapes from orbit.

The featureless area at the top left is the smooth water surface of Bositeng Lake, a large lake in the far northwest of China. The slightly curved sand spit offers one indication that the monotonous area is a lake. Spits such as these are common features near lake shores and are produced by waves and longshore currents.

In contrast to the smooth surface of the lake is the intricate pattern of a dune field on its south side. This pattern is indicative of barchan dunes that have coalesced. These crescent-shaped sand dunes form where the wind blows in one direction across level terrain. Darker surfaces next to and between some of the dunes are wet, saline soils where snow has partly melted.

Alluvial fans are visible between the mountainous topography (lower right) and the lake. Water flowing out of the higher terrain branches into numerous streams upon reaching a flat expanse. Agricultural fields appear as rectangular shapes in the center and lower left of the image.

The wider setting of Bositeng Lake was captured in an oblique east-looking astronaut image in 2018. The lake is faintly visible in the center of the photo above the snowy mountains.

Astronaut photograph ISS070-E-80513 was acquired on January 25, 2024, with a Nikon D5 digital camera using a focal length of 400 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 70 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Justin Wilkinson, Texas State University, JETS Contract at NASA-JSC.