Abstract: In order to test the capability of the high, resolution regional climate model RegCM3, simulations of summer precipitation in China between 1951 and 2000 are carried out. In these simulations, NCEP/NCAR (National Center for Environmental Prediction and National Center for Atmospheric Research) reanalysis data are used as initial and boundary conditions. The model domain covers the whole China and surrounding areas, and centers at 32.5°N, 95°E. It has 160 and 95 grids in zonal and meridional directions, respectively, with a grid space of 60?km. The Fritsch & Chapper of Grell scheme is employed. Monfthly sea surface temperatures used are GISST2.3b from the Hadley Center. Simulations are carried out from May 1 to September 1 for each year. Analysis of precipitation focuses on the period of June, July, August. In order to test results, simulated results and observations are converted into grid data with 1° latitude multiply by 1° longitude. Seasonal and total rainfalls are compared with observations from 160 stations by the National Climate Center (NCC) to validate the model's performance in simulating the climatological mean and interannual variations of the summer precipitation. Main results are: (1) for the climatological mean precipitation over China, the simulated rainfall is close to observations, much better than that from NCEP/NCAR reanalysis data. (2) for the spatial distribution of precipitation anomalies, the simulated results over the Northeastern part of China are better than over other parts, and the simulated precipitations in the valley of the Yellow River and the Yangtze are the worst; (3) for the temporal evolution, the simulated results display decadal variations, and the simulated results over the 1960's and 1990's are better and stable, however, the results over the 1970's and 1980's show large variations; (4) simulated precipitation over the 1970's and 1980's is poor, heavier than observations, suggesting that the model is unable to generate observed decadal variations.

Key words: climate modeling, regional climate model, model performance, summer precipitation

摘要： 为了检验区域气候模式对我国夏季降水的模拟能力,利用高分辨率区域气候模式RegCM3对1951?2000年的夏季中国区域降水进行了数值模拟。初始值及边界值取自美国国家环境预测中心(NCEP)和国家大气中心(NCAR)的全球再分析资料。每年的模拟积分时段从5月1日开始到9月1日结束, 但是每年降水量的分析只使用6?8月的模拟结果。主要结论如下: (1) 从全国平均总降水量看,该区域模式的模拟结果与观测比较接近,明显好于NCEP的降水资料,但模拟的降水量空间分布不理想; (2) 从降水量距平的空间分布来看,该区域模式对我国的东北夏季降水的模拟结果明显好于全国其他地区,黄河中下游最差; (3) 从时间分布上看,该模式模拟能力呈现出明显的年代际变化,20世纪60年代及90年代模拟较好,也比较稳定,70年代及80年代的模拟能力呈大起大落不稳定状态; (4) 模式未能模拟出70—80年代我国降水偏少的观测事实,说明模式对我国夏季降水年代际变率的模拟能力不足。

关键词: 气候模拟, 区域气候模式, 模拟能力检验, 夏季降水