WRF模式中土壤湿度对位势高度模拟影响的敏感性分析  

A High Temperature Weather Case Study About Sensitivity of Geopotential Height to Different Soil Moisture by Using WRF Model

作　　者：易翔[1] 曾新民[1] 王宁[1] 王明[1] 周骁[1] 汪彪[2] 

机构地区：[1]解放军理工大学气象海洋学院,江苏南京211101 [2]中国人民解放军海军南海舰队海洋气象水文中心,广东湛江524001

出　　处：《干旱气象》2016年第1期113-124,共12页Journal of Arid Meteorology

基　　金：国家自然科学基金项目(41275012)资助

摘　　要：利用WRFV3.6中尺度预报模式对我国东部地区2003年5、6、7月下旬天气过程进行模拟,研究分析了土壤湿度对位势高度的影响。结果表明：（1）对流层中低层位势高度对土壤湿度有较强的敏感性,且各月的位势高度随土壤湿度的改变都有一致的变化规律,但相对于5、6月,7月高温过程中位势高度对土壤湿度更为敏感。土壤湿度的增加（减少）会导致750-500 hPa位势高度减小（增大）、850 hPa以下气压层位势高度增大（减小）;（2）不同土壤湿度试验模拟的不同地表热通量可直接影响气温变化,在静力平衡和质量守恒条件下可进一步影响不同高度的气压,并最终导致位势高度的差异;（3）位势高度白天受土壤湿度的影响程度最大。白天热通量传输旺盛,在干（湿）的土壤湿度条件下,地表温度增温（降温）幅度大,850 hPa位势高度减小（增大）、500 hPa位势高度增大（减小）更为明显;夜间情况相反。In this paper,the Weather Research and Forecasting model version 3. 6（ WRFV3. 6） is used to simulate the weather processes during the late May,June and July of 2003 in eastern China and analyze the impact of soil moisture on geopotential height（ GPH）.The results are as follows：（ 1） The GPHs of the middle and lower troposphere were very sensitive to soil moisture change,and the laws of GPHs change with the soil moisture in all the months were consistent with each other,but the GPH in the late July was more sensitive to soil moisture than that in the late May and June. The increase（ decrease） of soil moisture would lead to the decrease（ increase）of GPHs on 750- 500 hPa levels and the increase（ decrease） of GPHs below 850 hPa level.（ 2） Through the analysis of physical mechanism,it was found that the surface temperature was directly affected by simulated heat fluxes in different soil- moisture experiments,which modified the pressures on various height under the constraint of static equilibrium and air mass conservation,and finally caused the differences of the GPHs.（ 3） The GPH was most influenced by soil moisture during the daytime because of the strong diurnal heat flux transfer,under the dry（ wet） soil moisture conditions,the surface temperature could rise（ reduce） with a larger amplitude,which resulted in an apparently decrease（ increase） of 850 hPa GPH and increase（ decrease） of 500 hPa GPH,there was an opposite situation during the nighttime. The above results indicated that the soil moisture is very important in forecast and analysis of weather（ especially high temperature weather） processes by using GPH,and it can help us better understand the influence mechanism of soil moisture in the land- atmosphere feedback processes.

关 键 词：WRF模式 高温 土壤湿度 位势高度 

分 类 号：P461.4[天文地球—大气科学及气象学]