image: High-resolution model simulated changes during mid-Holocene summer. (a) Precipitation, (b) Diabatic heating rate, (c) Moisture transport.
Credit: ©Science China Press
This study is led by Dr. Sha Yingying, Dr. Shi Zhengguo, and their colleagues from the State Key Laboratory of Loess Science at the Institute of Earth Environment, Chinese Academy of Sciences. The researchers found a pronounced north–south dipole pattern in mid-Holocene summer precipitation over arid central Asia, driven by an amplified heat source over the Tianshan Mountains.
Arid central Asia, the world's largest non-zonal arid area, has recently exhibited complex hydrological changes under global warming. However, the mechanisms behind this spatial heterogeneity remain poorly understood and difficult for most global climate models to simulate. Through a combination of high-resolution and CMIP6 model simulations and paleoclimate proxy records, researchers revealed a pronounced north–south dipole pattern during the warmer mid-Holocene summer. This pattern was characterized by significant wetter conditions in the Tarim Basin contrasting with drier conditions the north of the Tianshan Mountains, including the Altai Mountains.
The study demonstrates that the enhanced Tianshan heat source functioned as a thermal pump during the warmer mid-Holocene boreal summers. This mechanism strengthened the cyclonic circulation, drawing moisture from the intensified Asian summer monsoon further westward into the Tarim Basin and enhancing rainfall. Concurrently, it contributed to adjusted wave trains along the northward-shifted and weakened mid-latitude westerlies, which promoted large-scale subsidence and drying north of the Tianshan Mountains.
Given this mechanism, the poor representation of the Tianshan Mountains and their heating effects in current climate models introduces significant uncertainty into future hydroclimate projections for central Asia, underscoring an urgent need for model improvement.
See the article:
Sha Y, Shi Z, Zhang X, Shang K, Zhou P, Shu P, Lei J, Li X, Cheng H, An Z. 2025. Tianshan topographic heating and a Central Asian dipole precipitation anomaly in the mid-Holocene. Science China Earth Sciences, 68(11): 3653–3664, https://doi.org/10.1007/s11430-025-1704-x
Journal
Science China Earth Sciences