CMIP6模式对我国西南地区降水分布的评估和预估

Evaluation and Projection of Precipitation in Southwestern China Using CMIP6 Models

摘要: 利用第六次国际耦合模式比较计划(CMIP6)的模式模拟结果和全国降水观测资料评估了20个全球模式对1961~2014年我国西南地区夏季降水以及夏季极端降水的模拟能力，并选取模拟性能较好的7个模式进行集合平均，预估了SSP126和SSP585两种情景下2015~2100年西南地区夏季降水的变化趋势。得到如下主要结论：1) 20个模式模拟的西南地区夏季降水都偏多，半数模式模拟的降水偏差超过50%，大部分模式相对于观测值的标准差之比在1~1.5之间，空间相关系数相差较大。2) 对西南地区夏季极端降水的模拟能力优于对夏季降水模拟能力，模式模拟的主要降水中心基本与观测数据一致。3) 在SSP126情景下，未来西南地区大部分地区夏季降水增多，四川西北部、川西高原增多明显；在SSP585情景下，未来西南地区夏季降水整体呈增多趋势，并从东北向西南逐渐升高。

Abstract: The model simulation results of the Sixth International Coupled Model Comparison Program (CMIP6) and national precipitation observations were used to evaluate the simulation ability of 20 global models for summer precipitation and summer extreme precipitation in southwest China from 1961 to 2014, and the seven models with better simulation performance were selected for ensemble averaging to predict the changes in summer precipitation trends in southwest China un-der the SSP126 and SSP585 scenarios from 2015 to 2100. The main conclusions are as follows: 1) The summer precipitation in southwest China simulated by 20 models are all excessive, half of the models have precipitation deviations of more than 50%, and the ratio of standard deviations of most models relative to the observed values is between 1 and 1.5, with large differences in spatial correlation coefficients. 2) The ability to simulate extreme summer precipitation in southwest China is better than that of summer precipitation, and the main precipitation centers simulated by the model are basically consistent with the observed data. 3) Under the SSP126 scenario, the future summer precipitation increases in most areas of southwest China, with obvious increases in north-western Sichuan and the western Sichuan plateau; under the SSP585 scenario, the overall trend of future summer precipitation in southwest China increases and gradually rises from northeast to southwest.