多普勒雷达基本观测量直接同化对模式物理量场的影响

INFLUENCE OF DOPPLER RADAR OBSERVATION DIRECT ASSIMILATION ON GRAPES MODEL PHYSICS FIELD

在GRAPES-3DVar雷达同化模块的基础上,建立了多普勒径向速度和基本反射率因子的直接同化观测算子,实现了雷达反射率因子和径向速度的直接同化,并对2007年7月3日的江淮梅雨进行了模拟试验。结果表明,多普勒径向速度的直接同化的主要影响表现在风场上,能够改善几乎整个三维风场分析,在雷达影响半径范围内,风场明显得到加强,影响当时天气的系统及其高低层配置被合理模拟,但对湿度场影响甚微。雨水混合比的直接同化的主要影响表现在湿度场上,改进了模式对湿度场的模拟,对降水的影响十分显著,有利于准确模拟降水的发展和维持,减小了Spin-up现象;其亦可使整个风场微弱增强,但影响甚微。

Based on the GRAPES-3DVar module, the direct assimilation arithmetic operators are set up to directly assimilate Doppler radar radial velocity and reflectivity, and the Jianghuai Meiyu for the period of July 3, 2007 is simulated. The results show that the radial velocity direct assimilation primarily influences the wind field and has little influence on humidity field, which can improve almost all the 3-dimension wind filed. And the reflectivity direct assimilation mainly influences the humidity field, it can improve the humidity simulation and affect precipitation evidently, which favors to accurately simulate the development and persistence of precipitation and minish the SPIN-UP phenomenon, and also to strengthen the wind field slightly.