基于CMIP6-HiCPC数据集的青藏高原东北部未来降水预估OA

The northeastern Qinghai-Xizang Plateau is located in the core arid and semi-arid region of the plateau.Its precipitation change is crucial for the region′s fragile ecosystem and water resource security.Against the backdrop of global warming,it is essential to accurately project future precipitation trends in this area.This region,forming a critical transition zone from humid to arid climates and encompassing the vast Qaidam Basin and Qilian Mountains,is one of the most sensitive areas on the plateau to climate change.Therefore,understanding its future hydroclimate evolution has profound implications for regional ecological stability and water management.This study systematically evaluated 19 Coupled Model Intercomparison Project Phase 6(CMIP6)models from the recently developed HiCPC high-resolution(0.1°)downscaled dataset,assessing their ability to simulate annual and seasonal mean precipitation over the northeastern Qinghai-Xizang Plateau against the China Meteorological Forcing Dataset(CMFD)for the 1979-2014 baseline period.Based on a multi-model ensemble(MME),we projected future precipitation changes under multiple scenarios and analyzed the associated uncertainties.The evaluation results indicate that the MME can effectively simulate the spatial distribution pattern of precipitation decreasing from southeast to northwest.However,general biases exist in the model simulations;the annual mean precipitation simulated by all models is lower than the observations,with an average relative bias of approximately 28%.Notably,while capturing the annual cycle′s peak in July,the MME systematically underestimates precipitation,particularly during the wet season in summer,where the largest absolute biases are observed.Based on the shared socioeconomic pathways(SSPs),this study projected precipitation changes for the near-term(2021-2040),mid-term(2041-2060),and long-term(2081-2100)period.The results show that future annual mean precipitation in the study area is projected to increase with fluctuations under all scenarios.The increase is most significant under the high-emission scenario(SSP5-8.5),with annual precipitation expected to increase by 25.6%by the end of the 21st century.Seasonally,precipitation in winter shows the largest increase,while in summer,the increase is the smallest.The relative increase in precipitation in winter is particularly stark,projected to rise by up to 75.1%by the late 21st century under the SSP5-8.5 scenario,highlighting a profound shift in seasonal water availability.Spatially,the most significant increases are concentrated in arid northwestern areas like the Qaidam Basin,whereas the southern regions exhibit the smallest increase.Signal-to-noise ratio analysis further reveals that the projected signals for annual and winter precipitation changes are highly credible in most areas,while the uncertainty in projections of summer is the greatest.The high uncertainty in projections of summer underscores the persistent challenges that climate models face in accurately simulating the complex interactions between the East Asian summer monsoon and the plateau′s unique topography.The study indicates a fluctuating increasing trend in future precipitation over the northeastern Qinghai-Xizang Plateau,providing scientific support for water resource and ecological adaptation decisions in this vulnerable region.This projected trend of increased precipitation in arid regions suggests a significant shift in the regional water cycle.The findings imply that while increased water availability could alleviate drought,it may also elevate the risks of floods and geohazards,necessitating the development of robust and nuanced adaptation strategies.