NEX-GDDP-CMIP6模式对东北地区极端降水的模拟性能评估和预估OA

Extreme precipitation is a major climate-related hazard affecting water resources,ecosystems,agricul-ture,and urban safety.Northeast China is a climatically sensitive region characterized by complex topography,a concentrated population,and significant agricultural importance.Under a warming climate,changes in extreme precipitation are expected to increase the risk of flooding and associated socioeconomic losses.Therefore,a sys-tematic assessment of the spatiotemporal characteristics of extreme precipitation,climate model performance,and future changes in exposure is of considerable importance for regional disaster mitigation and climate adaptation.Based on CN05.1 observational data,CMIP6 global climate model outputs,and high-resolution down-scaled NEX-GDDP-CMIP6 data,this study investigates the spatiotemporal distribution of extreme precipitation in North-east China and compares the ability of these datasets to reproduce observed characteristics.To improve the relia-bility of multi-model projections,the Climate Model Weighting by Independence and Performance(ClimWIP)approach is applied to construct weighted ensembles that account for both model performance and inter-model de-pendence.In addition,the generalized extreme value(GEV)distribution is used to estimate return levels of Rx1day,including 10-year and 20-year return periods.On this basis,future changes in extreme precipitation and population exposure are analyzed using the weighted ensemble mean of NEX-GDDP-CMIP6.The results show that,during 1961-2014,extreme precipitation in Northeast China exhibits a clear spatial pattern,decreasing from the southeast to the northwest,with high-value centers located mainly in southern coastal areas and the Changbai Mountain region.Significant regional differences are observed in long-term trends.Extreme precipitation decreases markedly in central regions,whereas in northern mountainous areas total precipitation declines while ex-treme precipitation increases significantly.In parts of southeastern Northeast China,both total and extreme precip-itation exhibit significant upward trends.Model evaluation indicates that both the ClimWIP-weighted CMIP6 and NEX-GDDP-CMIP6 ensembles can reasonably reproduce the observed spatial pattern of extreme precipitation,al-though systematic biases remain.NEX-GDDP-CMIP6 generally underestimates precipitation,while CMIP6 tends to overestimate it.Compared with the original CMIP6 outputs,the downscaled NEX-GDDP-CMIP6 data show clear improvements in simulating regional extreme precipitation.Moreover,the weighted NEX-GDDP-CMIP6 en-semble reduces inter-model uncertainty and provides a more robust basis for future projections.Future projections based on the weighted NEX-GDDP-CMIP6 ensemble indicate significant increases in both total and extreme pre-cipitation across most of Northeast China.The intensity of Rx1day events associated with 10-year and 20-year re-turn periods is also projected to increase.As the frequency of extreme precipitation event rises,population expo-sure is expected to increase substantially.Under the SSP2-4.5 scenario,population exposure to 10-year(20-year)Rx1day events is projected to increase by 139.0%(298.6%),165.6%(251.6%),and 102.1%(182.3%)in the near term,mid-term,and late 21st century,respectively,relative to the historical period.Even larger increases are projected under the high-emission scenario.Overall,Northeast China is expected to experience intensified ex-treme precipitation and increased population exposure in the future.These findings provide a scientific basis for flood risk management,climate adaptation,and regional planning.