基于CMIP5的中国区域气溶胶变化及其对降水的影响

Variation of Aerosol and Its Effects on Precipitation in China Based on CMIP5 Models

基于第5次国际耦合模式比较计划(CMIP5)提供的气溶胶光学厚度(AOD)数据和气溶胶单因子历史试验降水数据,采用线性趋势分析、相关分析、经验正交分解(EOF)方法,从时间和空间维度上分析了自工业革命以来中国AOD的变化及其对降水的影响。1860-2000年,中国区域的AOD整体呈显著增加的趋势(P<0.001),AOD的增加趋势以胡焕庸线为界呈现出"东高西低"的空间分布格局,并在1945年以后AOD的增加趋势〔0.3807·(100a)^-1〕显著大于1945年以前的趋势〔0.0290·(100a)^-1〕。在气溶胶单因子驱动试验中,中国有89.1%区域的降水呈显著减少的趋势(P<0.001),其中东南部、四川盆地以及青藏高原东南部是降水减少最明显的区域,西北地区降水减少趋势较弱,并在1962年以后降水的减少趋势〔118.04mm·(100a)^-1〕显著大于1962年以前的趋势〔26.67mm·(100a)^-1〕。气溶胶主要通过抑制弱降水显著降低了降水事件发生的频率与降水强度,降低速率分别为3.160d·(100a)^-1、0.1624mm·d^-1·(100a)^-1。研究工业革命以来气溶胶对降水的气候效应,为更好的应对区域气候变化问题提供科学依据。

Aerosol plays an important role in the physical and chemical processes in the atmosphere. As more and more aerosols are discharged into the atmosphere due to the enhancement of human activities,the climate problems caused by aerosol emissions have also attracted wide attention. The purposes of this study were to analyze the change of aerosol optical thickness (AOD) and its effects on precipitation by applying the linear trend analysis,correlation analysis and empirical orthogonal function (EOF). The spatiotemporal variation of aerosol and its effects on precipitation since the industrial revolution in China was also approached based on the multi-mode experimental data provided by the Phase Five of the Coupled Model Intercomparison Project (CMIP5). The result showed that the variation of AOD in China was in an increase trend from 1860 to 2000 (P < 0. 001),the increase trend was more significant in the area east of the"Hu’s Line"than that in the area west of it and after 1945. The increase rate after 1945〔0. 380 7·(100a)^-1〕was significantly higher than that before 1945〔0. 029 0·(100a)^-1〕. In the experiments in which the aerosol change was considered only,as the aerosol emissions were increased,precipitation was obviously decreased in 89. 1% area of China (P < 0. 001). Precipitation was reduced predominantly in most of the southeast China,Sichuan Basin and southeast of Qinghai-Tibet Plateau,while the trend of precipitation reduction in northwest China was moderate. The decrease trend of precipitation was more significant after 1962 than that before it. The decrease rates were 118. 04 mm·(100a)^-1 in period after 1962 and 26. 67 mm·(100a)^-1 in period before 1962. The increase of aerosol emission served a role in the lessening of rainfall events’ frequency and precipitation intensity by inhibiting the light precipitation,and their reduction rates were 3. 16 d·(100a)^-1,0. 162 4 mm·d^-1·(100a)^-1,respectively. It provides an important scientific basis to study the climatic effects of AOD’s change on precipitation since the industrial revolution for better response to regional climate change in the future.