NASA’s Advanced Microwave Scanning Radiometer
The Advanced Microwave Scanning Radiometer (AMSR-E), carried aboard NASA’s Aqua satellite, is also being used to measure important factors relating to the changing global climate such as snow depth, precipitation, oceanic water vapor, cloud-borne water, wind speed near the surface, temperature of the sea’s surface, sea ice and soil moisture. Because of the importance of snow depth in the Arctic to the study of climate changes in the region and the importance of snow cover to wildlife such as polar bears and Arctic foxes, a mission to the Arctic that is funded by NASA, is intended to check the accuracy of measurements made by satellite observations.
The Arctic expedition is using new airborne radar developed by Prasad Gogineni, an engineer from the University of Kansas, which measures snow depth from an airplane. Known as ultra wide-band snow radar, this system will be able to confirm data developed by the satellite. A radar pulse is transmitted which penetrates the snow covering the ice, and measurements are taken of the time necessary for the reflection to return from the top of the snow and the time required for the return of the signal from the top of the ice. The difference in the return times are used to calculate the depth of the snow.
Measuring the depth of snow accumulation on top of sea ice has always been difficult, as the measuring was done from ships, often endangered by the harsh conditions, with results not always accurate. Satellite technology has given researchers an invaluable tool to make the accurate measurements necessary for this important work.
Accurately measuring the depth of snow covering the polar ice will give researchers more insight into the amount of water and ice on Mars or other planets which may have some form of life, as compared to climate changes in polar regions as well as provide information to wildlife biologists about the amount of snow available for polar animals. Polar bears, for example, require adequate snow depths to provide shelter from blizzards and cold temperatures. The bears dig out dens in which the temperature will not fall below freezing to give birth or provide shelter for their cubs. Arctic foxes and even sled dogs utilize the insulating properties of the snow as well. Also benefitting from snow cover are smaller animals such as field mice which are able to move around beneath the snow in networks of tunnels to locate food.
Information obtained by AMSR-E and confirmed by the Arctic mission has confirmed findings obtained from other scientific sources that the Arctic has experienced significant changes, especially the decrease in the amount of sea ice in the polar regions.
This entry was posted on Monday, July 16th, 2007 at 12:30 am and is filed under Space Agency News, Technical Concerns. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
