积云对流参数化方案模拟我国东南沿海及台湾海峡地区降水的适用性

我国东南沿海及台湾海峡地区地形和下垫面情况复杂,积云对流活动强烈,这给该地区降水的模拟和预测带来很大困难。为探讨不同积云对流参数化方案在我国东南沿海及台湾海峡地区的适用性,选择了4种参数化方案(Anthes-Kuo方案、Arakawa-Schubert方案、Fritsch-Chappell方案和MIT-Emanuel方案),基于区域气候模式RegCM 4.0分别模拟了该地区的降水情况,并选用了与模式分辨率相当的TRMM(Tropical Rainfall Measuring Mission,0.25°×0.25°)月平均降水资料进行验证。模拟结果表明,4种方案均能大致模拟出我国东南沿海及台湾海峡地区降水的空间结构和季节变化特征。其中,Fritsch-Chappell方案和MIT-Emanuel方案均能较好地模拟出降水空间分布,包括台湾岛南部和广东沿海的降水极值中心,而MIT-Emanuel方案降水的季节和年际变化特征模拟最好,如能够基本再现夏季降水在6月和8月份的双峰结构。此外,基于各高度层假相当位温的计算结果表明,MIT-Emanuel方案模拟的对流活动强烈,产生的对流性降水较多,使得其模拟的降水量值更接近实测资料。因此,MIT-Emanuel方案可能是最适用于模拟我国东南沿海和台湾海峡地区降水的积云对流参数化方案。

Applicability of different cumulus parameterization schemes on modeling precipitation in Southeastern China and Taiwan Strait

The complex terrain and surface conditions in Southeastern China and Taiwan Strait bring large uncertainties of cumulus convection activity,making it difficult to simulate and predict the precipitation in this region.In order to discuss the applicability of Regional Climate Model on simulating precipitation in Southeastern China,this paper selects 4 different cumulus parameterization schemes(i.e.,Anthes-Kuo,Arakawa-Schubert,Fritsch-Chappell and MIT-Emanuel)to simulate the precipitation and compares for the test with high-resolution(0.25°×0.25°)monthly mean TRMM(Tropical Rainfall Measuring Mission).The four schemes can roughly reproduce the spatial structure and seasonal variation of precipitation.Specially,the Fritsch-Chappell scheme and MIT-Emanuel scheme can both well reproduce the spatial distribution of precipitation,especially the simulated extremes of precipitation in the southern part of Taiwan Island and the coast of Guangdong.Further,MIT-Emanuel scheme has the best simulation for the seasonal and interannual variations of precipitation.The equivalent potential temperature at different height levels shows that the simulated convection activity by the MIT-Emanuel scheme is strong,which makes the simulated precipitation amount closer to the observed results.Therefore,it is reasonable to choose the MIT-Emanuel scheme to simulate the regional climate in Southeastern China and Taiwan Strait.