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Vulfson L.,Bar - Ilan University | Vulfson L.,Katif Research Center for the Development of Coastal Deserts | Genis A.,Ben - Gurion University of the Negev | Genis A.,Katif Research Center for the Development of Coastal Deserts | And 6 more authors.
Journal of Arid Environments | Year: 2012

The objective of this study was to develop a method to determine root mean square (RMS) height h of the surface roughness using single-channel data from the European remote-sensing satellite-2 (ERS-2) synthetic aperture radar (SAR) for known soil texture and water content. Accordingly, a new equation for the determination of h was obtained, which required combining two models: a semi-empirical model of vertically co-polarized mode backscattering coefficient σvv0 for bare soil; a semi-empirical model for the real part of dielectric constant ε and the empirical equation deriving the roughness correlation length l from h. The equation allowed calculating h for ERS-2 SAR data on natural bare smooth flat sandy and loessy areas of the Negev desert (Israel) for the dry, wet and artificially wetted conditions. It was found that the roughness of soil was typically small (h < 0.5 cm) and remained constant throughout the whole annual wetting cycle. Corresponding formulas were developed and applied for the determination of absolute and relative errors of retrieved h. It was shown that the relative error in retrieving of h was almost independent of its value. The values of h obtained from ERS-2 SAR data showed acceptable correlation with the ground measurements. © 2012 Elsevier Ltd. Source


Genis A.,Ben - Gurion University of the Negev | Genis A.,Katif Research Center for the Development of Coastal Deserts | Vulfson L.,Katif Research Center for the Development of Coastal Deserts | Vulfson L.,Bar - Ilan University | And 6 more authors.
International Journal of Remote Sensing | Year: 2013

Evaluation of the environmental and agricultural potential of arid lands is often limited by the lack of information on soil surface roughness and water content. The current study proposes an efficient method to retrieve these parameters of bare soil from single-channel ERS-1, -2 synthetic aperture radar (SAR) data. New equations were derived by combining the model for vertically co-polarized mode backscattering coefficient the model for the real part of dielectric constant and the empirical equation interrelating parameters of roughness. These equations allowed for calculation of the root mean square (RMS) height h of small surface roughness (h ≤ 1 cm) for naturally sandy, flat areas of the Negev desert (Israel) during dry periods when is extremely low and generally known. As soil roughness was found to be sufficiently constant under the arid environment, this study showed that calculated h could be reliably used to retrieve during the wet period. Statistical analysis of the relative errors of retrieved h and showed their high independence on the absolute values. Retrieved values of h and obtained from ERS-2 SAR data showed acceptable correlation with the direct ground measurements. Therefore, the effectiveness of the proposed methodology for h and retrieval was proved. © 2013 Copyright Taylor and Francis Group, LLC. Source

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