Remote Sensing of Permafrost
Passive Microwave Sensing
SSMI
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The Special Sensor Microwave Imager (SSMI) is a seven channel, four frequency, linearly-polarized, passive microwave radiometric system which measures atmospheric, ocean, and terrain microwave brightness temperatures at 19.35, 22.24, 37.00, and 85.80. NOAA's National Climatic Data Center (NCDC) has undertaken the task of recovering SSMI data starting from the first successful launch of the F-8 platform in 1987.
Data from the Special Sensor Microwave Imager (SSMI) instrument is collected under the Defense Meteorological Satellite Program (DMSP), which is a Department of Defense (DoD) program responsible for designing, building, launching, and operating polar-orbiting environmental satellites.
Source: NOAA
AMSR-E
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The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is a twelve-channel, six-frequency, passive-microwave radiometer system. It measures horizontally and vertically polarized brightness temperatures at 6.9 GHz, 10.7 GHz, 18.7 GHz, 23.8 GHz, 36.5 GHz, and 89.0 GHz. Spatial resolution of the individual measurements varies from 5.4 km at 89 GHz to 56 km at 6.9 GHz.
The AMSR-E instrument measures geophysical variables related to the earth's water cycle, including: precipitation rate, cloud water, water vapor, sea surface winds, sea surface temperature, sea ice concentration, snow water equivalent, and soil moisture.
Source: NSIDC
Remote sensors can be either passive or active. Passive sensors respond to external stimuli, such as microwave energy emitted from the earth's surface, as is the case in remote sensing of permafrost.
Source: NOAA