Dunes on the north-eastern Tibetan Plateau as influenced by climate change: a remote sensing study of the past 5 decades

Dunes react quickly to climatic changes, with the main drivers being the dominating wind regime (e.g. magnitude and direction), precipitation, and temperature. Further, human impact can alter dune movement by fixation of active dunes through greening projects, or reactivation of stationary ones through overgrazing by animals. The north-eastern Tibetan Plateau shows a high variability of climatic parameters like wind, temperature, and precipitation within a high elevation environment, situated between the mid-latitude westerlies and the East Asian Summer monsoon. The presented studies asses active barchan dunes in different climatic settings, from the arid southern margins of the Badain Jaran Desert, to the humid Zoige Basin.

Since climate stations on the Tibetan Plateau are rare and their measurements often cover only a short time span, climatic changes were studied from ERA-5 reanalysis data, dating back to the 1950s. These metrics were processed via cloud computing, using Google Earth Engine, and were then compared to dune migration rates, which were deduced from optical satellite imagery. Here, the CORONA KH-4B images from the late 1960s, the Landsat archives, and up-to-date high resolution data (GeoEye and WorldView) were used. The Normalized Difference Vegetation Index (NDVI) was implemented to observe changes in vegetation. As a newly tested metric, dune field density changes were calculated, in order to investigate dynamics of dense dune field setting.

Over 500 dunes were mapped and analyzed in total within four focus-areas for comparative purposes. The results highlight a wide range of different behavioral patterns of dunes within the environment of the north-eastern Tibetan Plateau. This showcases how dunes can be influenced by and linked to climatic changes.