澜沧江上游极端降水变化特征及未来预估研究

The Changing Characteristics and Future Prediction of Extreme Precipitation in the Upper Lancang River Basin

为探究澜沧江上游极端降水变化特征,基于中国区域地面气象要素驱动数据集(CMFD)再分析数据,对第六次国际耦合模拟比较计划(CMIP6)的10个气候模式降水数据进行了极端降水模拟评估,基于年降水总量对CMIP6多模式降水数据进行了偏差纠正,预估了未来时期(近期:2020—2049年、远期:2060—2089年)极端降水的变化趋势,并探讨了其趋势变化的驱动因素。结果表明:(1)偏差纠正后CMIP6多模式极端降水指数的不确定性减小,多模式集合平均的模拟效果优于多数单一模式。(2)未来研究区的降水总量增加,年内降水日数增多,降水频率上升。未来近期,研究区各极端降水指数的变化趋势并不明显,极端降水事件呈减少趋势;未来远期,尤其是高辐射强迫下,研究区极端降水的强度和频率都呈现显著的增加趋势。(3)气候变暖导致的空气含水量增加可能是极端降水增强的原因。

In order to explore the changing characteristics of extreme precipitation in the upper Lancang River Basin(ULRB),based on the reanalysis data of China Meteorological Forcing Dataset(CMFD),this study evaluated extreme precipitation simulation by 10 GCMs′data of the Coupled Model Intercomparison Project Phase Six(CMIP6),correcting the deviation of CMIP6 multi⁃modal precipitation data based on the total annual precipitation,and on this basis,the changing trend of extreme precipitation in the future periods(recently 2020—2049,forward 2060—2089)was estimated,discussing the reason of its changing trend.The re⁃sults indicate that:(1)the uncertainty of CMIP6 multimodal extreme precipitation indices decreases after the deviation correction,and the R95p simulation effect of the multi-model ensemble mean is better than that of most single model.(2)In the future,the total precipitation of the research area will increase,with an increase in precipitation days within the year and an increase in pre⁃cipitation frequency.In 2020—2049,the changing trend of extreme precipitation indices is not significant,and extreme precipita⁃tion events are showing a decreasing trend;in 2060—2089,especially under high radiation forcing,the intensity and frequency of extreme precipitation will show a significant increasing trend.(3)Climate warming leading to regional humidification could be the reason for the increase of extreme precipitation.