基于高分辨率动力降尺度方法的中国西部干旱区极端气候变化及机理研究

在全球变暖的背景下，中国西部干旱区气候发生了明显的变化，该地区气温增暖速率接近全球平均的三倍，降水总体增多但变率增大，极端气候事件频发。然而，已有的研究对干旱区关注较少，对极端气候变化特征机理及未来变化趋势研究不足。模式模拟是研究气候变化的首要途径，但全球模式水平分辨率较粗且陆面过程较为简化，对沙漠绿洲交替分布的西部干旱区模拟能力有限。因此，本项目拟利用高分辨率动力降尺度方法进行中国西部干旱区极端气候变化及机理研究。本项目主要关注极端降水，首先利用多种观测及再分析资料研究过去几十年极端降水的变化事实及特征；进而系统地评估模式的性能，在此基础上开展高分辨率动力降尺度模拟，研究未来极端降水变化，并初步研究植被变化反馈这一关键的陆面过程的影响。研究结果有助于加深对全球变暖背景下干旱区极端气候响应这一科学问题的认识，也可为西部干旱区应对气候变化战略决策提供科学依据。

The climate over the arid regions in the western China (ARWC) has changed obviously under the global warming background, for example, the temperature of ARWC increases at the rate of about three times of that of the global mean, the precipitation increases with large variability, and the extreme climate happens more frequently. However, the researchers always pay little attention on ARWC, and the research on the cause, process and mechanism of extreme climate is insufficient. Numerical simulations are important in the climate change research, however, the resolution of global climate models(GCMs) is relatively coarse, and the land surface model in the GCMs is simplified, as a result, the performance of the GCMs is poor over ARWC. In this project, we will study the extreme climate change over ARWC using high-resolution dynamical downscaling simulations. First, we will study the facts of the extreme climate change during the last several decades; then we will conduct high-resolution simulations based on systematic model evaluation, and analyze the extreme climate change and the corresponding atmospheric circulation change; finally, we will investigate the possible influence of vegetation feedback on future extreme climate change over ARWC. This project will deepen our understanding of the responds and feedback to the global climate change over ARWC, and provide scientific support for the adaptation decisions.