为更好地应对长江上游地区未来气候变化导致的暴雨事件， 本文利用1990 -2014年长江上游地区687个气象观测站日降水资料及第六次耦合模式比较计划（Coupled Model Intercomparison Project Phase 6， CMIP6）中的24个全球气候模式的模拟结果， 研究了该地区2021 -2099年的年平均暴雨量、 暴雨天数和暴雨强度在不同共享社会经济路径（Shared Socioeconomic Pathways， SSPs）情景下的时空变化特征及其不确定性。研究结果表明： （1）相对参考时段（1995 -2014年）， 长江上游地区预估总时段（2021 -2099年）及21世纪末期（2080 -2099年）的年平均暴雨量、 暴雨天数和暴雨强度在SSP1-2.6、 SSP2-4.5和SSP5-8.5情景下都以增多增强为主， 在SSP5-8.5情景下的增幅最大， 且模式间预估方向的一致性及预估值的确定性都随排放的增加而增加。预估总时段的暴雨量、 暴雨天数和暴雨强度在SSP1-2.6和SSP2-4.5情景下的分布相似， 但与SSP5-8.5情景下的分布有所不同。21世纪末期暴雨量及天数在三种情景下的分布相似， 暴雨强度变化的分布在SSP5-8.5情景下不同于SSP1-2.6及SSP2-4.5情景； （2）相对参考时段， 三种情景下长江上游的暴雨量在预估总时段分别以3.5 mm·（10a）^-1， 5.4 mm·（10a）^-1， 14.7 mm·（10a）^-1的速率增加， 暴雨天数分别以0.045 d·（10a）^-1， 0.07 d·（10a）^-1， 0.18 d·（10a）^-1的速率增加， 暴雨强度则分别以0.37 mm·d^-1·（10a）^-1， 0.78 mm·d^-1·（10a）^-1， 1.94 mm·d^-1·（10a）^-1的速率增强， 都通过99%信度检验及同号率检验， 预估值确定性较高的时期都出现在21世纪末期SSP5-8.5情景下； （3）三种情景下， 预估总时段的暴雨量、 暴雨天数和暴雨强度在空间上都主要呈增加趋势， 其中藏东南地区的暴雨量及暴雨天数的增速最大。暴雨强度增速最大的地区在SSP1-2.6情景下出现在四川北部， 而SSP2-4.5和SSP5-8.5情景下出现在云南北部； （4）三种情景下21世纪前期（2021 -2040年）暴雨量、 暴雨天数和暴雨强度相对参考时段的变化幅度不明显， 中期（2041-2060年）及后期暴雨量、 暴雨天数和暴雨强度在SSP2-4.5及SSP5-8.5情景下显著增多增强， 尤其在21世纪后期SSP5-8.5情景下的增幅最大， 模式间预估方向一致性最高。

To prepare for the heavy rainfall resulting from future climate change in the upper reaches of the Yangtze River， this paper analyzed daily precipitation data from 687 meteorological stations in the region between 1990 and 2014， as well as simulation results from 24 global climate models （GCMs） provided by the Coupled Model Intercomparison Project Phase 6 （CMIP6）.The spatio-temporal characteristics and uncertainties of the mean annual rainstorm volume， rainstorm days and rainstorm intensity in the upper reaches of the Yangtze River during 2021 -2099 under different Shared Socioeconomic Pathways （SSPs） scenarios are studied.The results show： （1） Compared to the reference period of 1995 -2014， the mean annual volume， days and intensity of rainstorm in the upper reaches of the Yangtze River are projected to increase and strengthen during the whole projection period of 2021 -2099 and the end of the 21st century （2080 -2099） under the SSP1-2.6， SSP2-4.5， and SSP5-8.5 scenarios.The largest increase is observed under the SSP5-8.5 scenario.The predicted direction is consistent and the certainty of the projection among models increases with higher emissions.The distribution of rainstorm volume， days and intensity during 2021 -2099 is similar under SSP1-2.6 and SSP2-4.5 scenarios， but differs from that of the SSP5-8.5 scenario.By the end of the 21st century， the distribution of volume and days of rainstorm is similar under the three scenarios.However， the distribution of rainstorm intensity under the SSP5-8.5 scenario differs from that under the SSP1-2.6 and SSP2-4.5 scenarios.（2） Relative to the reference period， the rainstorm volume in the upper reaches of the Yangtze River increases by 3.5 mm·（10a）^-1， 5.4 mm·（10a）^-1 and 14.7 mm·（10a）^-1 under SSP1-2.6， SSP2-4.5， SSP5-8.5， respectively.The rainstorm days increases by 0.045 d·（10a）^-1， 0.07 d·（10a）^-1 and 0.18 d·（10a）^-1 under the three scenarios， respectively.The rainstorm intensity increases by 0.37 mm·d^-1·（10a）^-1， 0.78 mm·d^-1·（10a）^-1 and 1.94 mm·d^-1·（10a）^-1 under the three scenarios， respectively.All of the trends pass the 99% confidence test and the same-sign rate test.The period with a high level of prediction certainty is expected to occur in the late 21st century under the SSP5-8.5 scenario.（3） The analysis of the three scenarios indicates an increasing trend in the volume， days and intensity of rainstorm throughout the whole prediction period.The region of southeast Tibet has experienced the highest growth rate in terms of volume and days of rainstorms.The region with the largest increasing trend of rainstorm intensity under the SSP1-2.6 scenario is in northern Sichuan， while under the SSP2-4.5 and SSP5-8.5 scenarios， it is in northern Yunnan.（4） During the early 21st century（2021 -2040）， there is no significant change in the volume， days or intensity of rainstorm in the upper reaches of the Yangtze River， as compared to the reference period， under the three scenarios.While during the middle（2041 -2060）and the end of the 21st century， the volume， days and intensity of rainstorm increase significantly under the SSP2-4.5 and SSP5-8.5 scenarios.This effect is particularly pronounced during the end period of the 21st century under the SSP5-8.5 scenario， as well as the consistency of predicted direction among modes is the highest.