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Shiran Havivi Doron Amir Ilan Schvartzman Yitzhak August Shimrit Maman Stanley R. Rotman Dan G. Blumberg 《地球表面变化过程与地形》2018,43(6):1229-1240
It is generally held that subtle changes in sandy environments are very difficult to detect in imagery. Nonetheless, this study demonstrates how synthetic aperture radar (SAR) interferometric decorrelation can be used to identify changes in individual sand dunes. The use of coherence maps over time facilitates the analysis of dune dynamics, both temporally and spatially. The Ashdod‐Nizzanim coastal dunes, along the southern coastal plain of Israel, were chosen as an illustrative example of the analysis of dune dynamics. High‐resolution TerraSAR‐X (TSX) radar images covering the entire research area were acquired for the period February to July 2012, together with meteorology data (wind and rain) for the area. The coherence results enabled the stability of individual dunes to be described as a function of time. It was found that the dune crests were more stable than the windward slopes and that the degree of stability was dependent on the distance of the dune from the sea. The results of this study show the potential of using interferometric synthetic aperture radar (InSAR) decorrelation for aeolian studies, even in areas characterized by low coherence. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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S. Maman L. OrlovskyD.G. Blumberg P. BerlinerB. Mamedov 《Journal of Arid Environments》2011,75(9):842-850
The shortage of fresh water in Turkmenistan may be partially alleviated by runoff water from takyrs. However, anthropogenic degradation of takyrs over the past few decades has reduced their efficacy as catchment areas. The main goal of this study was to map the spatial extent of takyrs and their change over time. Digital image processing of Landsat MSS and Landsat 7 ETM+ images were used to identify, map and classify the takyrs and estimate their overall area and degradation rates. Thereafter, a change detection procedure was applied. Results retrieved from Landsat MSS images of southern Turkmenistan (1972-1975) showed a total area of non-degraded takyr surfaces of ∼20,000 km2, whereas those from Landsat 7 ETM+ images (2002-2003) showed a total non-degraded takyr area of ∼16,000 km2. These include ∼8000 km2 which were degraded and ∼4000 km2 that were only detected by the ETM+ due to its improved spectral resolution. Accuracy was assessed by comparing the Landsat results with higher spatial resolution images of QuickBird. Additional ground points located with GPS measurements validated the classification results. We were thus able to assess the takyr areas degraded over the past decades, and find ∼16,000 km2 of non-degraded takyrs suitable for water harvesting. 相似文献
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