SAR data for subsurface saline lacustrine deposits detection and primary interpretation on the evolution of the vanished Lop Nur Lake

Abstract

Lop Nur was a huge lake located at the eastern end of the Tarim Basin, northwest of China, which dried up prior to 1970. Using synthetic aperture radar (SAR), which has the advantage of penetration capability and sensitivity to moist saline materials, the subsurface lacustrine deposits were revealed. SAR also delineated the partially buried shorelines and detailed a complete picture of Lop Nur Lake that led to three important scientific findings. Based on the interpretation of the scattering mechanism of polarimetric and multiple frequency SAR data, field investigation, and sample analysis, it was found that the total area of the vanished Lop Nur Lake was more than 10 000 km2, which is much larger than earlier reports. The relatively young West Lake was superposed on top of the lacustrine deposits of East Lake, making the well known “Ear” feature of Lop Nur, so the western part of the shoreline was buried and not visible on optical remote sensing images. Therefore the Lop Nur Lake actually has near circular, closed shorelines. The drying-up process of East Lop Nur Lake went through six phases according to the shorelines interpreted from multiple SAR data. The shrinking phases of Lop Nur Lake indicate the climate changes between wet and dry environmental conditions.