低排放情景下未来极端降水特征分析——以嘉陵江流域为例

Analysis of extreme precipitation characteristics under future low-emission scenarios.Case study of Jialing River basin

一场极端降水事件所造成的灾难性后果除与总量、峰值有关外,还与其时间分布模式有关。本文基于实测和全球气候模式降水数据,改进了三分段偏差校正方法,分析了嘉陵江流域基于时间分布模式的极端降水事件(包括日极端降水与其前后降水两部分)频次、降水量、持续时间及集中度的历史分布特征及未来演变规律。结果表明:改进的三分段偏差校正法比传统的三分段偏差校正法校正效果明显,能更有效地减小实测值与模拟值间的误差;与历史期相比,未来情景下两种主要降水类型降水量增加,持续时间延长,集中度下降;未来预估期内,两种主要降水类型的频次、降水量、持续时间和集中度总体呈现先增长后减少的趋势。

Disastrous consequences following an extreme event of precipitation are related not only to its total volume and peak value,but also to its time distribution pattern.Based on the daily precipitation data of in-situ measurements and global climate model projections,this paper improves the three-segment deviation correction method,and examines the extreme precipitation events(daily extreme precipitation and the preceding and succeeding precipitation)in the Jialing River basin using a time distribution model,focusing on their historical distribution characteristics and the future trends in the frequency,volume,duration,and concentrating patterns of precipitation.The results show that the new improved method generates a more significant correction effect than that of the three-segment method,and a more effective reduction of the simulation errors against measurements.Compared with the historical period,the volumes of precipitation of two major types show an increasing trend and their durations are prolonged,while their concentration ratios take a decreasing trend.In the future projection period,the frequency,volume,duration,and concentration of extreme precipitation events all present an increasing trend followed by a decreasing trend.