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United States Department of Agriculture

Agricultural Research Service

Title: Sensitivity Analysis of Ers-1 Synthetic Aperture Radar Data to the Surface Moisture Content of Rocky Soils in a Semiarid Rangeland

Authors
item Sano, E - BRAZILIAN AG RES ORG
item Huete, A - UNIVERSITY OF ARIZONA
item Troufleau, D - INST GEOGRAPHY DENMARK
item Moran, Mary
item Vidal, A - CEMAGREF FRANCE

Submitted to: Water Resources Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 1997
Publication Date: N/A

Interpretive Summary: Information about the soil moisture content is important to agricultural resource managers to improve yield forecasting, schedule irrigations, and monitor general plant health. Conventional methods to measure soil moisture are both labor intensive and limited to a single point within the region. Images acquired from sensors aboard orbiting satellites could provide repetitive estimates of soil moisture over large areas. The work presented here addresses the estimation of soil moisture in a semiarid region using measurements made with a radar device aboard an earth-observation satellite. The results of this work showed an improvement in soil moisture estimation over conventional methods in hilly terrain with rocky soils. This approach has potential for operational application because it is based on proven radar theory and the radar measurements are currently available to the community.

Technical Abstract: This study was conducted to analyze the sensitivity of the European Remote Sensing Satellite (ERS-1) C-band synthetic aperture radar (SAR) data to the surface moisture content of rocky soils in a semiarid rangeland in southeast Arizona. A dry season and a wet season SAR images were corrected for topographic effects. Soil moisture content and soil roughness were obtained from 47 sampling sites. An intensive soil moisture sampling campaign was also conducted at three sites to determine the number of samples necessary to estimate soil moisture content with 10% accuracy. Soil roughness was found to be a dominant factor affecting the backscattering coefficients. A general trend between soil moisture content and SAR data was seen only after the correction of SAR data for soil roughness effects. The number of soil moisture samples were a crucial factor in obtaining representative soil moisture values. In the study area, at least seven samples per acre were needed to obtain soil moisture estimates with 10% accuracy.

Last Modified: 9/2/2014
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