Katif Research Center for the Development of Coastal Deserts

Katif, Israel

Katif Research Center for the Development of Coastal Deserts

Katif, Israel
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Genis A.,Ben - Gurion University of the Negev | Vulfson L.,Katif Research Center for the Development of Coastal Deserts | Vulfson L.,Bar - Ilan University | Blumberg D.G.,Ben - Gurion University of the Negev | And 4 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.


Vulfson L.,Bar - Ilan University | Genis A.,Katif Research Center for the Development of Coastal Deserts | Genis A.,Ben - Gurion University of the Negev | Blumberg D.G.,Ben - Gurion University of the Negev | And 4 more authors.
International Journal of Remote Sensing | Year: 2013

Knowledge of vertical distribution of the soil water content in the root zone W plays a key role in the optimization of irrigation and, hence, for water saving. Therefore, in this study, synergistic use of the frequency modulated continuous-wave P-band (λ = 68 cm) scatterometer (SC) and the gamma-ray radiometer (GR) for the range of 50-3000 keV, both low in sensitivity to soil surface roughness and vegetation, was proposed. This combination allowed the determination of W at the three depth ranges: 0-5, 0-30, and 5-30 cm. This considerably specified the vertical distribution of W. Both instruments were developed as an integrated remote-sensing system that was installed onboard a light aircraft and tested on an irrigated agricultural region of the Negev desert, Israel. For processing and analysing the results, analytical models for both reflection coefficient (Ṙ) and intensity of the natural gamma radiation (Is) were developed for various types of soils and vertical distributions of W. Using these models, the problem of the inverse retrieval of W was solved, and the depth of sampling z was evaluated. SC allowed the measurement of average W for the depth of 0.5-5.0 cm depending on W and dW/dz at the soil surface. For GR, the sampling depth varied from 20 to 30 cm depending on the mean value of W in the top soil layer. Field experiments showed that W retrieved by the developed system was in good agreement (r2 ≥ 0.9) with ground measurements, thus indicating sufficient accuracy of both instruments. © 2013 Copyright Taylor and Francis Group, LLC.

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