气候变化下浙江省极端降水时空变化研究

基于CMIP5的18个GCMs模型,通过LARS-WG降尺度模型获得降雨数据,计算了2041-2070年在RCP4.5和RCP8.5两个情景下的11个极端降雨指数,并通过贝叶斯平均法获得两个情景下的集合值,分别与浙江省1971-2000年实测数据的极端指数计算结果进行对比分析,最后探讨了浙江省2041-2070年极端降水时空变化特征,结论如下:(1)浙江省的降雨量在2041-2070年间趋于集中化,整体向极端降雨量和降雨日数增加的方向发展。其中强降雨量R95pTOT和极强降雨量R99pTOT相对基准期的变化最具代表性,上升幅度最大;中雨日数R20 mm和大雨日数R30 mm上升幅度明显高于小雨日数R10 mm。(2)全省降雨在空间分布上趋于极端化,极端降雨由东部沿海向西部递减,东部沿海地区未来极端降雨强度和频率相对其他地区增加明显;(3)RCP4.5和RCP8.5排放情景下极端降雨指数相对基准期的变化相似,相较之下,RCP4.5排放情景下降雨强度和频率增加更为明显,说明该情景下发生极端降雨事件的概率更大。

Research on the Spatial-temporal Changes of Extreme Precipitation in Zhejiang Province under Climate Changes

Based on 18 GCMs of CMIP5,precipitation data is generated by the LARS-WG downscaling model,and 11 extreme precipitation indices are calculated under the two emission scenarios of RCP4.5 and RCP8.5 from 2041 to 2070,which are averaged by the Bayesian model averaging method and compared with the historical data in Zhejiang Province during the baseline period from 1971 to 2000.This study explores the spatial-temporal variations of extreme precipitation in Zhejiang Province.The results are as follows:①The precipitation in Zhejiang Province tends to be more concentrated,which has an overall trend for increase in extreme precipitation amount and number of rainfall days.The change of R95pTOT and R99pTOT is the most representative with the largest increase related to the reference period.R20 mm and R30 mm increase obviously higher than R10 mm.②The spatial distribution of precipitation tends to be extreme,and extreme precipitation decreases from the eastern coast to the west.The eastern coast will experience more and stronger precipitation in the future than other regions.③The extreme precipitation indices have similar changes under RCP4.5 and RCP8.5 emission scenarios compared with the baseline period.In comparison,the increase in extreme precipitation intensity and frequency under RCP4.5 emission scenario is more obvious,which means the probability of the occurrence of extreme precipitation events is higher under RCP4.5 emission scenario.