Fine Structure And Sensitive Areas In China Under 1.5/2.0℃ Warming As Indicated By Extreme Climate Events

The Paris Agreement aims to keep global surface mean temperature rise well below 2℃ and better to limit the temperature increase no more than 1.5℃ above pre-industrial levels by the end of this century.Community Earth System Model(hereafter CESM)low-warming experiment data are downscaled by a regional model WRF.Using the CESM low-warming experiment data and dynamic downscaling WRF data,we investigated the difference in extreme climate indices associated with temperature and precipitation,and analyzed the highly sensitive areas in China between 1.5℃ and 2℃ scenarios at a finer resolution.Our results show that WRF has a cold bias in historical simulation,but the WRF data with bias correction method is closer to the observed condition than original CESM result unless TR,ID and FD are considered.CESM results show that 0.5℃ bias in the temperature affects Northeast,Northwest,North China and Qinghai-Tibet Plateau region most.North China region experiences higher extreme high temperature event that is also be more frequent.Northwest China and Qinghai-Tibet plateau are mainly affected by the extreme low temperature events.While North,Northwest,Northeast,East and Central China in WRF simulations is more sensitive between 1.5℃ and 2℃scenarios.Stronger and more frequent summer’s extreme high temperature event may happen in North China and extreme low temperature event is also stronger.Northwest China is mainly affected by the extreme temperature in summer and Northeast China is mainly affected by the extreme low temperature events.East and Central China are newly emerging sensitive areas in the WRF simulation with stronger intensity and longer duration of extreme temperature in summer.Both WRF and CESM simulation results show a worse performance on precipitation than temperature,but WRF results are greatly improved.WRF data is closer to the observation in the extreme precipitation index of Prcptot,R10mm and R20mm.However,it has a larger RMS error than CESM in Rxlday and Rx5day.This is mainly because WRF overestimated the extreme precipitation in southern China and eastern China,but WRF results have a larger spatial correlation coeffici.ent with the observation.By analzing CESM results,we can find East,Southwest China and Qinghai-Tibet Plateau region are mostly exposure to extreme precipation under 2.0℃warming.In East China,the intensity of extreme precipitation increases significantly,the number of heavy precipitation increases,and the continuous precipitation also increases.Tibetan Plateau and Southwest China experience stronger and more frequent extreme precipitation.For WRF results,we can conclude that Tibetan Plateau,Southwest China and Northeast China are most sensitive areas when the global temperature rise from 1.50℃ to 2.0℃.Large increase in precipitation intensity,heavy precipitation frequency and more continuous extreme precipitation in Southwest China and the Qinghai-Tibet Plateau.The intensity of extreme precipitation in Northeast China will reach a higher level,and be more frequent.However,Extreme precipitation events between 1.5℃ and 2.0℃ warming target largely failed to pass the test of significance.