Increased southerly and easterly water vapor transport contributed to the dry-to-wet transition of summer precipitation over the Three-River Headwaters in the Tibetan Plateau  

作　　者：Xuan LIU Ming-Xiang YANG Ning-Peng DONG Wei-Ning XIE Hong-Gang LI Zhen GUAN Fan WEN Hao WANG Deliang CHEN 

机构地区：[1]College of Civil Engineering,Tianjin University,Tianjin 300354,China [2]State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China [3]Cooperative Innovation Center for Water Safety&Hydro Science,Hohai University,Nanjing 210098,China [4]State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China [5]Hydrology and Water Resources Survey Bureau of Hainan Province,Hainan 571126,China [6]Huaneng Lancang River Hydropower INC.,Kunming 650214,China [7]Regional Climate Group,Department of Earth Sciences,University of Gothenburg,Gothenburg S-40530,Sweden

出　　处：《Advances in Climate Change Research》2023年第4期502-510,共9页气候变化研究进展（英文版）

基　　金：supported by Science and Technology Project of China Huaneng Research on Integrated Meteorology and Hydrology Forecasting System in Lancang River Basin(HNKJ21-HF241);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0207-02);the Research Programme of the Kunming Engineering Corporation Limited(DJ-HXGG-2021-04);the Key Research and Development Programme of Yunnan(202203AA080010)as part of the Science and Technology Plan Project of Yunnan Provincial Department of Science and Technology.Support from Swedish STINT(CH 2019-8377 and CH 2020-8767)is also acknowledged.

摘　　要：The Three-River Headwaters(TRH)region in the Tibetan Plateau is vulnerable to climate change;changes in summer(June–August)precipitation have a significant impact on water security and sustainability in both local and downstream areas.However,the changes in summer precipitation of different intensities over the TRH region,along with their influencing factors,remain unclear.In this study,we used observational and ERA5 reanalysis data and employed a precipitation categorization and water vapor budget analysis to quantify the categorized precipitation variations and investigate their possible linkages with the water vapor budget.Our results showed an increasing trend in summer precipitation at a rate of 0.9 per year(p<0.1)during 1979–2020,with a significant dry-to-wet transition in 2002.The category‘very heavy precipitation’(10 mm d−1)contributed 65.1%of the increased summer precipitation,which occurred frequently in the northern TRH region.The dry-to-wet transition was caused by the effects of varied atmospheric circulations in each subregion.Southwesterly water vapor transport through the southern boundary was responsible for the increased net water vapor flux in the western TRH region(158.2%),while southeasterly water vapor transport through the eastern boundary was responsible for the increased net water vapor flux in the central TRH(155.2%)and eastern TRH(229.2%)regions.Therefore,we inferred that the dry-to-wet transition of summer precipitation and the increased‘very heavy precipitation’over the TRH was caused by increased easterly and southerly water vapor transport.

关 键 词：Summer precipitation Three-river headwaters region Precipitation intensity Water vapor budget 

分 类 号：P426[天文地球—大气科学及气象学]