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United States Department of Agriculture

Agricultural Research Service


item Njoku, Eni
item Jackson, Thomas
item Lakshimi, Venkat

Submitted to: Sring Meeting American Geographical Union Washington DC
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: None.

Technical Abstract: The Advanced Scanning Microwave Radiometer (AMSR) is a multichannel passive microwave sensor developed by the Japanese Space Agency (NASDA). The AMSR is currently planned for launch on NASA's EOS-Aqua satellite (1:30 pm orbit) in December 2000 and on NASDA's ADEOS-II satellite (10:30 am orbit) in November 2001. Each AMSR will provide observations at 6.9 to 89 GHz (dual-polarized) with spatial resolution of about 60 km at the lowest frequency and with global coverage every two days. A significant level of effort involving the hydrology community needs to be undertaken to ensure that maximum benefit is derived from AMSR data for hydroclimatology applications. This paper describes the current status of algorithms for retrieving soil moisture and associated land parameters from AMSR data. It describes the unique sampling characteristics of the sensor as they impact the retrieval problem. Two critical aspects of the retrieval are: 1) understanding how vegetation, topography, and other land features affec the estimated average soil moisture over the 60-km footprint, and 2) estimating the percent of global land cover over which successful soil moisture retrievals may be obtained. In this regard, the AMSR should be considered as a useful step toward a future dedicated soil moisture mission that would more optimally use a lower frequency sensor (1.4 GHz or L-band). An L-band sensor would provide more accurate retrievals over a larger percentage of global land area. The sensor sampling characteristics and spatial resolution impose significant challenges for validating satellite-retrieved soil moisture. The use of scaling approaches in well-designed field experiments will be crucial in interpreting and utilizing the satellite results.

Last Modified: 06/24/2017
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