一个RCM及其驱动GCM对21世纪中国气候变化的预估

摘要

为得到中国地区未来气候变化更为全面的图像,需要进行多全球模式驱动下多区域模式在不同温室气体排放情景下的预估模拟.作为这一工作的一部分,本文使用CSIRO-Mk3.6.0全球气候模式(CSIRO)结果,驱动RegCM4区域模式(CdR),进行CORDEX-东亚区域21世纪气候变化的预估并进行了分析.结果表明两个模式都模拟出未来将显著变暖、DJF升温比JJA更高以及RCP8.5比RCP4.5升温更高等共同特征.但CSIRO和CdR所预估变暖的空间分布型不同,变暖的数值也有一定差异.降水变化表现为DJF总体增加,JJA则呈增加-减少的混合分布.JJA中两个模式的降水变化存在很大区别.本文进一步强调了气候变化预估在该地区的不确定性.%A regional climate model (RegCM4) is used to project climate change over China in the twenty-first century under the RCP4.5 and RCP8.5 pathways.The driving GCM is CSIRO Mk3.6.0 (hereafter referred to simply as CSIRO),and the simulation (hereafter referred to as CdR) is run at a grid spacing of 25 km.The focus of the present paper is on the changes in mean surface air temperature and precipitation in December-January-February (DJF) and June-July-August (JJA) over China.Validation of the model performances is provided first,followed by a comparison of future changes projected by CSIRO and CdR.Substantial warming in the future is simulated by both models,being more pronounced in DJF compared to JJA,and under RCP8.5 compared to RCP4.5.The warming shows different spatial patterns and,to a less extent,magnitude between CSIRO and CdR.Precipitation change shows a general increase in DJF and a mixture of increase and decrease in JJA.Substantial differences between the two models are found in for precipitation change in JJA.The paper further emphasizes the uncertainties in climate change projection over the region.