全球变暖情景下中国东部地区不同等级降水变化特征分析

Analysis of Changes in Different-Class Precipitation over Eastern China under Global Warming

利用日本东京大学气候系统研究中心、日本环境研究所和日本地球环境研究中心联合研制的全球海气耦合气候模式MIROC_Hires输出的逐日降水资料,分析了全球变暖背景下中国东部地区不同等级降水的变化特征。为了检验模式模拟未来中国不同地区降水变化趋势的可信程度,首先评估该模式对1971—2000年夏季降水的模拟能力,结果表明,该模式无论从空间分布还是时间变化上均可以较好地模拟中国1971—2000年的降水情况。在此基础上,将中国东部地区划分为华南、江淮、华北、东北4个区域,分析在全球变暖情景下未来（2071—2100年）较近期（1971—2000年）各个地区不同等级的降水量和降水频数的变化特征,发现华南地区无降水和强降水（≥24 mm·d^-1）的频数增加幅度均较大,分别达到13.8 d·a^-1和4.2 d·a^-1,弱降水（1～12 mm·d^-1）的频数减少;江淮地区年降水量增加,强降水的频数增加了3.6 d·a^-1,弱降水的频数减少;华北地区年降水量增加幅度在4个地区中最大,达到30.5%,无降水频数减少,8 mm·d^-1以上的降水频数增加;东北地区的降水强度和频数均增加。即中国东部地区降水变化趋势呈现华南地区暴雨频数增加，江淮、华北和东北地区降水量增多，降水强度也增加的情形，因此，4个地区极端降水事件发生的频数增加。

Daily precipitation data simulated by high-resolution version of MIROC（MIROC_Hires, Model for Interdisciplinary Research On Climate） is used to analyze changes in different-class precipitation characteristics over eastern China under global warming. The results show that the MIROC model can well reproduce not only the spatial distribution but also the seasonal changes of precipitation over eastern China in 1971-2000. Since in the whole eastern China, the precipitation intensity differs much from south to north, characteristics of precipitation in South China, Yangtze-Huaihe Basin, North China and Northeast China are analyzed, respectively. Comparing with the quantity and frequency of different-class precipitation between the period of 1971-2000 and 2071-2100, there are siginficant changes in the four regions. In South China, increase in frequencies of non-precipitation and heavy （≥24 mm · d^-1） rainfall days is significant, up to 13.8 d · a^-1 and 4.2 d · a^-1 , respectively, and those of relatively weak （1～12 mm · d^-1 ） rainfall days decrease. In Yantze-Huaihe Basin, the mean annual precipitation averaged over the region increases while frequencies of heavy rainfall days increase by 3.6 d · a^-1 and those of relatively weak rainfall days decrease. In North China, the increase of mean annual precipitation is the most significant in the four regions, up to 30. 5%, while frequencies of non-precipitation increase. In Northeast China, though the rainfall intensity in present days is not so much as in the other three regions, the frequencies of rainfall days increase either. As the rainfall intensity increases in the four regions, events of the extreme rainfall days are supposed to increase.