江淮流域梅雨期气候对全球气候变暖的响应

Response of climate during the Meiyu period over the Yangtze-Huai River Valley to global warming

在全球气候变暖背景下,中国江淮流域梅雨期的气候响应趋于复杂,给江淮流域梅雨期的气候预测带来了更多的不确定因素。研究江淮梅雨期气候对全球变暖的响应,对于认识江淮梅雨变化新趋势、提高新气候背景下的汛期预报及制定防灾减灾政策均有深远意义。采用中国地面气温和降水日值数据集对近几十年来江淮地区梅雨期的气温和降水变化进行了深入分析,基于观测结果,评估了国际耦合模式比较计划第5阶段(CMIP5)的22个模式结果,并对CMIP5模式预估的21世纪中排放(RCP4.5)和高排放(RCP8.5)情景下中国江淮流域梅雨期的气温和降水变化进行了分析,并对梅雨期气候变化的机理进行了探讨。研究结果表明,在全球变暖背景下,江淮地区梅雨期气候亦发生了相应的变化,气温呈现出显著的升高趋势,降水亦发生了相应调整,在较暖年降水偏多,较冷年降水偏少。在未来全球进一步变暖的背景下,江淮地区梅雨期平均气温进一步升高,降水进一步增多,且随着排放量的增加,降水的空间分布不均匀性也在加剧。

In the context of global warming,the climate over the Yangtze-Huai River Valley(YHRV,28°-34°N,110°-122°E)of China tends to be more complicated.The climate prediction during the Meiyu period over the YHRV is a scientific issue that needs to be solved urgently.We investigate the response of the climate during the Meiyu period over the YHRV in recent decades in this study.Through assessing the performance of the Coupled Model Intercomparison Project Phase 5(CMIP5)models over the YHRV Region,the surface air temperature and precipitation over this region during the 21 century are predicted under the RCP4.5 and the RCP8.5 scenarios basing on simulations of 22 CMIP5 models.The related mechanism is studied as well.The result shows that under the background of global warming,climate in the YHRV during the Meiyu period has been undergoing corresponding changes.The surface air temperature during the Meiyu period over the YHRV shows an increasing trend at the rate of 0.40℃/(10 a),and the precipitation adjusts correspondingly at the same time.The precipitation becomes relatively more in the warm years but less in the cold years.With global warming in the future,averaged temperature and precipitation during the Meiyu period over the YHRV would further increase,and the spatial distribution of precipitation would become more inhomogeneous.