Temporal Stability of Soil Moisture and Radar Backscatter Observed by the Advanced Synthetic Aperture Radar (ASAR)

Sensors

Wolfgang Wagner³  Carsten Pathe³  Marcela Doubkova³  Daniel Sabel³  Annett Bartsch³  Stefan Hasenauer³  Günter Blöschl⁴  Klaus Scipal¹  José Martínez-Fernández² 

[1] European Centre for Medium Range Weather Forecasting, Shinfield Park, Reading RG2 9AX, United Kingdom E-mail:;Department of Geography, University of Salamanca, Cervantes 3, 37002 Salamanca, Spain E-mail:;Vienna University of Technology, Institute of Photogrammetry and Remote Sensing, Guβhausstraβe 27-29, 1040 Vienna, Austria. E-mails:;Vienna University of Technology, Institut für Wasserbau und Ingenieurhydrologie, Karlsplatz 13/222, A-1040 Wien, Vienna, Austria E-mail:

关键词: Soil moisture;    SAR;    backscatter;    scaling;    temporal stability;   

DOI  :  10.3390/s80201174

来源: mdpi

【 摘 要 】

The high spatio-temporal variability of soil moisture is the result of atmospheric forcing and redistribution processes related to terrain, soil, and vegetation characteristics. Despite this high variability, many field studies have shown that in the temporal domain soil moisture measured at specific locations is correlated to the mean soil moisture content over an area. Since the measurements taken by Synthetic Aperture Radar (SAR) instruments are very sensitive to soil moisture it is hypothesized that the temporally stable soil moisture patterns are reflected in the radar backscatter measurements. To verify this hypothesis 73 Wide Swath (WS) images have been acquired by the ENVISAT Advanced Synthetic Aperture Radar (ASAR) over the REMEDHUS soil moisture network located in the Duero basin, Spain. It is found that a time-invariant linear relationship is well suited for relating local scale (pixel) and regional scale (50 km) backscatter. The observed linear model coefficients can be estimated by considering the scattering properties of the terrain and vegetation and the soil moisture scaling properties. For both linear model coefficients, the relative error between observed and modelled values is less than 5 % and the coefficient of determination (R²) is 86 %. The results are of relevance for interpreting and downscaling coarse resolution soil moisture data retrieved from active (METOP ASCAT) and passive (SMOS, AMSR-E) instruments.

【 授权许可】

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