西南地区持续性气候事件的未来变化预估

利用RegCM4.0区域气候模式单向嵌套BCC_CSM1.1模式输出资料进行连续积分获得的模拟预估数据，对西南地区未来2025-2055年在两种温室气体排放情景下持续性干期和持续湿期事件的特征及其相对于历史基准期的变化进行了预估分析。结果表明，最长持续干期和湿期在RCP4.5和RCP8.5两种情景下的变化趋势不一致，RCP8.5情景下的最长湿期和持续湿期事件的发生频次相较RCP4.5并没有大幅增加，而是比RCP4.5情景具有更高的年际变率特征。相对于历史基准期，两种情景下的最长持续性气候事件的日数和发生频次在西南地区的东南部区域显著性增加，而在川西高原地区显著减少。对于持续干期发生的频次FCDD和最长持续湿期而言，四川中部以及四川、云南和贵州三省邻接处在RCP4.5情景下表现为显著增加的区域在RCP8.5情景下转变为显著减少。未来几十年西南地区持续性湿期和干期的分布特征可能更加趋于不均匀。

Prediction of future change of persistent climate event in Southwest China

The future consecutive precipitation events and consecutive dry events under two greenhouse gas emission scenarios (RCP) and the change in comparison with historical periods in the Southwest China have been investigated by using the continuously integrate simulation data from the RegCM4.0 regional climate model one-way nested BCC_CSM1.1 model output. The results show that:the variation trends of the greatest consecutive dry and precipitation days are inconsistent with RCP4.5 and RCP8.5 scenarios. The greatest precipitation days and the frequency of consecutive precipitation events with RCP8.5 scenario are not significantly increase in comparison with RCP4.5, but has higher inter-annual variability characteristics than RCP4.5 scenario. In comparison with the historical base period, the number of days and frequency of the greatest consecutive climate events with the two scenarios increased significantly in the southeast part of the southwest region, but decreased significantly in the western Sichuan Plateau. As for the frequency of consecutive dry and the number of days with the greatest consecutive rainfall, the areas in central Sichuan, Yunnan and Guizhou Provinces, which shows a significant decrease with the RCP4.5 scenario to change a significant increase with the RCP8.5 scenario. The distribution characteristics of consecutive precipitation and drought in the southwest region probably become more uneven in the future.