摘要: 本文使用动力降尺度方法模拟汉江流域气象因素，将大尺度气象观测值转化到流域上，得到流域站点降水和气候模拟值。使用RegCM4区域气候模式，嵌套ERA40再分析资料，分别采用Grell方案、Kuo方案、Emanuel方案和Tiedtke方案等积云对流方案，对汉江流域进行了10年(1991~2000年)模拟试验，重点分析了RegCM4对汉江流域地表气温和降水的模拟结果。结果表明，模式对汉江流域地表气温温度值和变化趋势具有较好的模拟能力。月平均温度模拟值与实测值误差小于2℃，但存在系统性的“冷偏差”。该模式对降水的模拟精度比温度模拟要差。对年降雨量的模拟，不同积云对流方案模拟结果相差较大；在几种对流方案比较中，Emanuel方案对月平均降水量相对模拟效果最好；然而RegCM4对不同站点的插值模拟效果差异比较大，表明模式对降水的空间分布还有待改进。

Abstract: This work simulated climate factors in Hanjiang Basin by using dynamical downscaling method, transforming large scale observed climate variables into station precipitation and temperature. A 10-year (1991-2000) numerical integration simulation of climate over Hanjiang Basin was conducted with the latest version of a regional climate model RegCM4 nested in one-way ERA40 Re-analysis data. The Grell, AnthesKuo, MIT-Emanuel and Tiedtke cumulus convection parameterization schemes were applied in the running of RegCM4 to test their capability in simulating precipitation and temperature of Hanjiang Basin. The results demonstrated that RegCM4 was capable of well simulating the values and the changing trend of ground temperature during a year. In most cases, the error between simulated mean monthly temperature and observation was within 2°C, but there existed systematic “cold bias”. However, the simulation accuracy of precipitation is not as optimal as that of temperature. Different cumulus convection parameterization schemes displayed different capability in simulating annual precipitation. Among all 4 cumulus convection parameterization schemes, the MIT-Emanuel scheme had been proven to be the most accurate in simulating monthly precipitation. The accuracy of the scheme also showed great difference in simulated station interpolation of precipitation, which urges the improvement for the simulation capability of spatial distribution of precipitation.