期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2008
卷号：XXXVII Part B7
页码：75-82
出版社：Copernicus Publications
摘要：Due to the accelerating global warming, droughts which cause severe damages especially in the agriculture became a very recurrent phenomenon in all over the world. Monitoring the characteristics of soil moisture is very important in Turkey because the major impact of the global warming on our country appears to be climate changes. In this respect, drought has become a serious threat for the country where the agriculture is one of the major income sources. Therefore, monitoring of draughts has the highest priority among the other strategies. Although the sensitivity of microwaves towards the soil moisture is well understood, retrieving soil moisture with Synthetic Aperture radar (SAR) measurements still has difficulties due to the major impact of soil texture, surface roughness and vegetation cover. In this study, SAR data gathered by different sensors for the same area in closer dates were used to estimate the relative soil moisture. The relation between the ground soil moisture and the sigma nought/backscatter values of SAR images were investigated. Sigma nought values of C band HH polarized Radarsat Fine Beam image and C Band VV polarized ENVISAT (ASAR) images as well as backscatter values of an L band HH polarized ALOS (PALSAR) satellite images were used. RADARSAT, ASAR and PALSAR images were gathered on the 28th of May, 8th of June, and 10th of June in 2006 respectively for the alluvial lands of Menemen Town, Izmir. Ground soil moisture measurements taken using gravimetric methods showed a good agreement with the backscatter values of the images obtained from different types of SAR data. A comparison among the spatial distribution of retrieved soil moisture changes from SAR images was done. The correlations between the soil moisture content and backscattering of ASAR, RADARSAT-1 and PALSAR images were found 76%, 81% and 86 % respectively. Although the resolution of RADARSAT-1 fine beam image (6.25m × 6.25m) is closer to the resolution of PALSAR image (6.25m × 6.25m), PALSAR gives better correlation than RADARSAT-1 image. Although the resolution of RADARSAT-1 and PALSAR images is far more higher than that of the ASAR image (30m × 30m), the significance of the results produced is almost similar in such flat areas
