土壤砾石参数化对高原涡形成发展作用的敏感性分析

Sensitivity Analysis of Soil Gravel Parameterization on the Formation and Development of the Plateau Vortex

采用耦合了砾石参数化方案CLM4.5的区域气候模式RegCM4对一次高原涡进行了模拟分析,并做了3组敏感性试验,结合欧洲中心ERA5再分析资料进行验证分析,使用了高空、低空及土壤水热属性参数等资料,分析了砾石参数化对高原涡初生、发展、消亡等影响。结果表明:在500 hPa形势场中,特别是在高原涡发生和发展的阶段,砾石含量越接近实际,模拟效果越好,RegCM4对青藏高原降水量的模拟能力随砾石含量接近实际而提升;在高原涡区及其东北移动路径上,2 m温度的模拟结果随砾石含量的增加而升高,为高原涡的生成和发展提供条件;砾石参数化方案明显提升了土壤导热率和土壤导水率,在高原涡初生和发展过程中,砾石含量接近实际,模拟土壤温度和土壤体积含水量也接近实际,在高原涡消亡阶段,土壤含砾石较高使浅层温度明显降低,加速了高原涡的消亡,并且随着土壤深度的增加,砾石对土壤升温作用明显减弱,在高原涡生成和发展阶段,砾石对模式的提升作用明显,但在高原涡减弱和消亡阶段,砾石对模式的提升作用逐渐降低。

There were three groups of sensitivity tests to simulate and analyze a plateau low vortex that using the regional climate model RegCM4 coupled with the gravel parameterization scheme CLM4.5,which combined with the reanalysis data of high altitude,low altitude and Soil Hydrothermal parameters from European Center ERA5 for verifying simultaneously,in order to study the influence of gravel parameterization scheme on high vortex.Then the main conclusions are as follows.In the 500 hPa high-altitude situation field,especially in the stage of the occurrence and development of the plateau vortex,the closer the gravel content is to the reality,the better the simulation effect is,which means that the simulation ability of the regional climate model RegCM4 to the precipitation of Qinghai-Xizang Plateau increases with the gravel content close to the reality.In the plateau vortex area and its northeast moving path,the simulation result of 2 m temperature ascends with the increase of gravel content and the increase of gravel content provides conditions for the formation and development of the plateau vortex.The gravel parameterization scheme significantly improves the soil thermal conductivity and soil hydraulic conductivity.During the initiation and development of the plateau vortex,the closer gravel content to the reality,the closer simulated results of soil temperature and soil volume water content will be to the reality.In the extinction stage of the plateau vortex,the high content of soil gravel reduced the temperature of shallow soil significantly,which accelerates the extinction of the plateau vortex,and the effect of gravel on soil warming decreases significantly with the deeper soil layer.In the stage of generation and development of the plateau vortex,the gravel parameterization scheme CLM4.5 improve the accuracy of simulation results of the regional climate model RegCM4 obviously;and conversely,in the stage of weakening and extinction of the plateau vortex,the effects of the gravel parameterization scheme gradually reduced on the accuracy of simulation results of the regional climate model RegCM4.