An astronaut aboard the International Space Station took this photo of glaciers in the high-elevation valleys of the Pamir Mountains of Central Asia. The upper portion of Fedchenko Glacier crosses the center of the scene. Fedchenko is among the planet’s longest glaciers outside of the polar regions.
Fedchenko originates in an ice field (left side of the image) at an elevation of 5,200 meters (17,000 feet) above sea level. The ice flows north, gathering more ice from tributary glaciers as Fedchenko bends west. The glacier exits this scene (top center) at a much lower elevation of 4,350 meters (14,250 feet), where annual temperatures are higher than those of the mountain peaks. A cloud casts a shadow on the ice, visible as a dark spot near the center of the image.
Most of the larger glaciers show a prominent pattern of light- and dark-brown parallel lines. The darker “streamlines,” known as medial moraines, give a sense of the direction of flow of the ice down the valleys. These are concentrations of debris that has been eroded by the glacier from the adjacent mountainsides or a rocky outcrop. An astronaut image of the nearby Siachen Glacier shows these parallel lines in even more detail.
Numerous short glaciers, originating at the summits of the various mountain ridges, appear bright white. The larger glaciers, however, show a clear pattern of color change, starting with the brilliant white of fresh snow and ice near the mountain peaks and turning dusty brown down lower.
Farther from the peaks, at lower, warmer elevation, the snow and ice have melted enough for the moraine lines to become visible. This is a common pattern seen in large mountain glaciers. One small glacier at the top-left of the image appears entirely brown near its lower end. This glacier continues to flow downslope, but its ice lies mostly out of sight below a layer of debris.
Research has shown that glaciers in many parts of the world, including in Central Asia, are losing mass. Many are melting from the top as well as from the end—what has been termed ice-front retreat.
Astronaut photograph ISS069-E-60332 was acquired on August 15, 2023, 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 at Johnson Space Center. The image was taken by a member of the Expedition 69 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, Amentum JETS II Contract at NASA-JSC.
