Projected Future Changes Of Extreme Precipitation Climate Events Over China By A High Resolution Regional Climate Model (RegCM3)

RegCM3, a high resolution regional climate model, is employed to simulate two sets of multi-decadal experiments at a horizontal grid spacing of 20 km, one for present climate (1961~1990) and the other for future climate (2071~2100, under SRES A2 scenario emission). The model domain encompasses the whole China and adjacent areas. It is nested in one-way mode within the NASA/NCAR finite volume element AGCM (FvGCM).For the simulation results, Author used International Common definition for the extreme precipation index (Frich et al., 2002) at first, and then referred to Xie(2007) high resolution precipitation observation materials, and finally analyzed the simulation accuracy of the models on extreme climate events over China. Author analyzed that extreme climate events indictors most suit for China mainly from the researching the precipitation.Based on the 2071-2100 simulation result, Author analyzed the changes of the future extreme precipitation climate events with the variation of China climate and under IPCC SRES A2 scenarioThis article mainly focus on four conclusions:(1) The result of FvGCM have better effect in simulating every extreme precipation index over China, and it is very close to observation (Xie). The results basically reproduced the symptom of yearly and quarterly indicators of extreme precipitation events in the region. It proved that this mode can simulate the current extreme precipitation events in China, and the result can be used for the initial and boundary conditions during the RegCM simulation.(2) Comparing to FvGCM, proved by control experiment result, with higher resolution and better physical process, RegCM provides more detail and real simulation for extreme precipitation events. Extreme precipitation index deviations for most of regions are smaller than FvGCM, and it also simulated the changes caused by small topography. Results prove that RegCM is very good in simulating extreme precipitation events over China. Author concluded that for four seasons RegCM is better for simulating summer and the next is for winter; for regions, it is better for Northwest, and autumn season Southeast region has the awful simulation result. In summary, like other models, RegCM simulated more on small precipitation days, but less on big precipitation days. But RegCM3 to extreme precipitation events indicators is better than FvGCM..(3) Compares FvGCM A2 experiment result with RF experiment result, we can get the future change percentage of every extreme precipitation events indicator over China. From the result, by the end of 21 st century, under the A2 scenario, every indicator of yearly average extreme precipitation events over China is increasing. The change of Quarterly average will has small difference.(4) Compares RegCM A2 experiment result with RF experiment result, we may draw a conclusion that by the end of 21st century and under the A2 scenario, yearly and quarterly results are similar to FvGCM.So we may deduce that under the IPCC SRES A2 scenario, the frequency of Northwest extreme precipitation events will increase in the future.