A pioneering study led by Prof. AN Zhisheng and Prof. ZHOU Weijian from the Institute of Earth Environment of the Chinese Academy of Sciences, with contributions from scientists from the University of Maine, South China Normal University, Xi’an Institute of Earth Environment Innovation, University of Science and Technology of China, Beijing Normal University, and the University of Oslo, presents an innovative approach to examining the contrasting hydroclimate impacts of the summer monsoons and westerly circulation in the hyper-arid Asian interior since the middle Holocene.

The Tarim Basin, home to the Taklamakan Desert—the second-largest shifting sandy desert in the world—has long been characterized by extremely arid conditions, with annual precipitation of less than 50 mm, concentrated primarily in the summer months. 

Using high-precision dating techniques and analyzing multiple climate proxies—such as grain size, geochemical elements, and isotopes—from the high-resolution loess records in the central Kunlun Mountains, the researchers conducted a comprehensive study of the hydrological and climatic changes in the Tarim Basin over the past 8,000 years. 

They found that during the mid-Holocene (8.2–4.2 ka BP), precipitation in the region sharply decreased, influenced by the poleward shift of the subtropical westerly jet. This shift reduced precipitation in the surrounding mountain ranges, subsequently lowering downstream runoff. At the same time, the northward movement of the westerly jet allowed more tropical moisture to enter the Tarim Basin, leading to an increase in summer rainfall events. However, despite these increases, the overall climate during this period remained relatively dry.

This study suggests that a meridional shift in the westerly jet, along with its interaction with the Asian summer monsoon, driven by changes in the mid- and high-latitude temperature gradients during the boreal summer, plays a crucial role in regulating average water availability in the region (Fig. 3). These findings offer valuable insights into the past climatic dynamics of arid regions and provide trend-based projections for future hydrological and climatic changes under warming scenarios.

This work, published on Communications Earth & Environment, was funded by the National Natural Science Foundation of China, and the Chinese Academy of Sciences' Strategic Priority Research Program (B) among other research initiatives.