Variations In The Start,end,and Length Of Extreme Precipitation Period Across China

In the backdrop of the global climate change,extreme precipitation events bring a serious threat to natural environment,socio-economic development,humanlife and property security,which has attracted wide attention from the public,the government and the academia.The research on extreme precipitation event has become one of the current main and important hotspots of applied climatology.Using the daily precipitation records during 1961~2013 from 686 meteorological stations across China,CMIP5 multimodel ensemble data and the atmospheric circulation indexes,this study investigates the spatio-temporal changes in the occurrence time and length of the extreme precipitation period(EPP)in the past and future,as well as their influencing factors.The results show the following aspects:(1)In the last 53 years,the start dates of the extreme precipitation period(EPPS)generally advanced.The end dates of the extreme precipitation period(EPPE)are delayed,which show an increasing trend.The lengths of the extreme precipitation period(EPPL)in most of the China meteorological stations increased.The extreme precipitation at the Gongshan station is the first to occur,starting on the 62 nd day(March 3).The Qionghai station in SEC is the last station with active extreme precipitation,which ended on the 300 th day(October 27).The station with the longest EPPL is Gongshan station,with a value of 226 days(from March 2 to October 14).(2)The spatial patterns of the trends in the occurrence timeand length of the extreme precipitation period are similar and show obvious clustering.In southeastern China,the average EPPS is earlier,EPPE is later than those in other regions,and their EPPL is prolonged.The EPP in northeastern China begins later and ends earlier,and its EPPL is shorter than that in other regions.To the east of 110o regions,the spatial gradient of EPP is significant,and its spatial distribution is consistent with the migration characteristic of rain belt in East of China.Compared with other sub-regions,the decrease trend of EPPS and the increase trend of EPPE and EPPL exist more remarkable differences.(3)For the numerical characteristics under the future scenario,the EPP begins earlier,the ends more late and EPPLs are longer in the future.And the high emission scenarios than the low emission scenarios are more sensitive to the influence of the EPP indices.The spatial distribution pattern of EPP indices under three different emission scnarios is same as the spatial distribution of historical measured values.Namely,increasing trend of EPPS and decreasing trend of EPPE and EPPL from southeast to northwest.To the east of 110o regions,which is still exist the movement law of the rain belt in eastern China.The occurrence time variation of extreme precipitation events in northwestern China sub-region,Qinghai-Tibetan Plateausub-region and eastern China sub-region is more sensitive to the response of climate warming.(4)For the trend characteristics under the future scenario,the EPPEs are delayed and the EPPLs are prolong under three different RCPs scenarios,which is same as the result of trend historical measured values.Specifically,only the EPPS under RCP8.5 emission scnariois earlier,which is same as the result of historical measured values.While the EPPS under the RCP2.6 scenarios and RCP4.5 scenarios are later.The increase trend of EPPE and EPPL under high emission scenariosis larger than low emission scnario,while the EPPS is contrary.Spatially,compared with the result of historical measured value,the result under different emission scenarios,the trend of meteorological station from negative trend in the past to positive trend in the future.The trend of EPP indice in northwestern China sub-region and Qinghai-Tibetan Plateau sub-region is more sensitive to the response of climate warming.(5)The western Pacific subtropical high,Northern Hemisphere polar vortex,Antarctic Oscillation,and western Pacific warm pool have significant effects on the occurrence time and length of EPP,and different regions show different effects.There are negative correlations among the western Pacific subtropical high index,Antarctic Oscillation,western Pacific warm pool and EPPSs in most of Chinese meteorological stations,while EPPEs are opposite.While there are positive correlations between the EPPS,EPPE and Northern Hemisphere polar vortex.