Study of paleolakes in Tibetan Plateau based on SIR-C/X-SAR and other data sets: implication to paleo-climatic changes

The Qinghai-Tibet Plateau of Western China exists mostly elevated and densely distributed lakes in the world. Having undergone the uplifting of Qinghai-Tibet plateau, the paleolakes had 8-10 schemes of retreat, indicating that the climate at that time had 8-10 comparatively arid periods on the plateau. Many ancient shorelines are well preserved on the lake basins in this area. The highest shoreline is 60 m above the present lake level of Tianshuihai Lake. During the highest lake level epoch, the biggest ancient Tianshuihai Lake combined with ancient Aksayqin Lake and formed a united big lake, which is 7 to 8 times in area as large as the present two lakes. While at the foot of the Kunlun Mountains, the famous lake Lop Nur also presents several ancient shorelines. These shorelines´ features can be clearly depicted from SIR-C/X-SAR and Radarsat images. This paper presents the radar backscatter characteristics at different wavelength and polarizations, and analyzes SAR imaging mechanisms. The results have shown that like-polarization images are better than cross-polarization images for characterizing the shoreline features. Based on SAR image and literature, the paleo-environment of Qinghai-Tibet area is analyzed