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United States Department of Agriculture

Agricultural Research Service

Title: Estimation of Surface Roughness in a Semiarid Region from C-Band Ers-1 Synthetic Aperture Radar Data

Authors
item Sano, E - EMBRAPA/CPAC BRAZIL
item Huete, A - UNIV OF ARIZONA
item Troufleau, D - INST GEOGRAPHY DENMAKR
item Moran, Mary
item Vidal, A - CEMAGREG-ENGREF

Submitted to: Revista Brasileira de Entomologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 10, 2000
Publication Date: N/A

Interpretive Summary: Studies in the past indicated that surface roughness plays a key role in water runoff, interception, and evaporation. If the surface is rough, less water will run off and more water will go into the soil for plant use. Therefore, it is important to develop a technique to measure surface roughness. In the past, this was done manually at limited locations, which is very labor intensive. In this study, we investigated how remote sensing imagery could be used to map surface roughness. It was found that microwave data can be used for this purpose if the surface is dry and void of vegetative cover. When the surface is wet and vegetation is present, further research is required to take into account the soil moisture and vegetative effects. Ultimately, this research will provide farmers with a new tool to evaluate their precision farming practices.

Technical Abstract: In this study, we investigated the feasibility of using the C-band European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) data to estimate surface soil roughness in a semiarid rangeland. Radar backscattering coefficients were extracted from both a dry- and a wet- season SAR image and were compared with 47 in situ soil roughness measurements obtained in the rocky soils of the Walnut Gulch Experimental Watershed, southeastern Arizona, USA. Both the dry and the wet season SAR data showed exponential relationships with root mean square (RMS) height measurements. The dry C-band ERS-1 SAR data were strongly correlated (r2=0.80), while the wet season SAR data have somewhat higher secondary variation (r2=0.59). This lower correlation was probably provoked by the stronger influence of both soil moisture and vegetation, which may not be negligible in the wet season SAR data. We concluded that the single configuration C-band SAR data are useful to estimate surface roughness of rocky soils in semiarid rangeland.

Last Modified: 8/29/2014
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