不同平缓-混合坐标对一次高原准静止锋降水过程模拟影响对比分析  

Impact of height-based terrain-following coordinates on a case of quasi-stationary front simulations around the Tibetan Plateau

作　　者：李超 陈德辉 李兴良 胡江林 LI Chao;CHEN Dehui;LI Xingliang;HU Jianglin(National Meteorological Center,Beijing 100081)

机构地区：[1]国家气象中心,北京100081

出　　处：《暴雨灾害》2020年第2期117-124,共8页Torrential Rain and Disasters

基　　金：国家自然科学基金项目(41605080);国家重点研发计划(2017YFC1501901)。

摘　　要：GRAPES_Meso模式预报存在南风偏大、虚假降水偏多等问题,且在大地形下游地区异常明显。平缓-混合坐标可以有效减小气压梯度力计算误差以及平流输送误差,而这两种误差与风场和水汽场预报密切相关。基于GRAPES_Meso模式选择四种平缓-混合坐标对一次典型的高原东部准静止锋降水过程进行模拟分析。模拟结果表明,较弱的天气形势演变下,平缓-混合坐标的改进效果比较明显,可以有效缓解风场预报偏差、虚假降水、虚假天气系统等问题,个例模拟的结果与实况更接近。The GRAPES_Meso model has some forecast problems,such as larger south wind and more false precipitation in the downstream region of the Tibetan plateau.The proper smoothed-level terrain-following coordinate(SLEVE T-F coordinate for short)could efficiently reduce the pressure gradient force error and the mass transport error that are closely related to the wind and water vapor forecasting,therefore,potentially increase prediction performance.Four kinds of T-F coordinates are selected here to simulate a typical quasi-stationary front process.The results of the simulation indicate that under the weak evolution of synoptic background,the improvement of the SLEVE T-F coordinate would be more significant.The SLEVE T-F coordinate can reduce the bias of the wind,false precipitation,false synoptic systems and so on,which results in small calculating error and the better performance of the simulation.

关 键 词：GRAPES模式 平缓-混合坐标 准静止锋 动力框架 数值模式 

分 类 号：P435[天文地球—大气科学及气象学]