摘要
为探索卫星资料同化在山西暴雨数值预报中的应用效果,应用WRF-3DVar同化系统同化ATOVS资料,并利用同化后的分析场作为中尺度数值模式的初始场,对2013年7月3—4日发生在山西南部的一次暴雨天气过程进行数值模拟和对比分析。结果表明:(1)直接同化ATOVS资料能够很好地改善模式初始场的温度场、湿度场及风场,主要表现为山西中南部湿度增大、南北温差减小以及对流层中低层西风分量增大,这样更有利于低层水汽向山西中南部输送、集聚;(2)直接同化ATOVS资料后,模式能够很好地模拟降水发生、发展过程中各个相关物理量的演变,特别是更好地刻画了大暴雨站点上空湿度和垂直速度的演变过程,在湿度增大、垂直上升运动加强时刻,出现短时强降水,且对于触发短时强降水的切变线的移动发展以及反映短时强降水的对流有效位能和反射率因子也有较好体现;(3)直接同化ATOVS资料后模式对强降水落区和量级的预报都有较大改进,对中雨以上降水量级的预报站点TS评分都有明显提高,空报率和漏报率明显降低。
A regional heavy rain occurred in the southern Shanxi during 3 -4 July 2013. In order to study the application effect of satel- lite data assimilation on the operational numerical weather forecast model in Shanxi, the assimilation with and without ATOVS satellite radiance data by using WRF - 3DVAR were experimented and compared. The result are as follows ： （ 1 ） The analysis field obtained by direct assimilation of the ATOVS satellite radiance could improve temperature, humidity and wind fields of the initial field of predic- tion, the main performance was increasing humidity in the central and southern of Shanxi and decreasing temperature difference between the southern and northern Shanxi, increasing the westerly component of the middle and lower troposphere, which was more conducive to low - level moisture transportation and gathering to the central and soutbem Shanxi. （2） The assimilation experiment was better in description of evolution of physical quantities during this precipitation process, especially for the evolution of humidity and vertical veloci- ty over the heavy rainstorm stations. The short - time strong rainfall occurred in the moment that humidity increased and vertical upward movement strengthened, the movement and development of the shear line as a trigger of short - time strong rainfall, convective available potential energy and reflectivity factor had been better reflected. What is more, the location and intensity of the heavy rain had been improved obviously, the TS score of moderate rain or above had increased significantly, and false alarm rate and false negative rate were decreased.
出处
《干旱气象》
2016年第3期522-532,546,共12页
Journal of Arid Meteorology
基金
国家自然科学基金项目"黄河中游地区突发性大暴雨MCC结构特征研究"(41475050)
山西省青年课题"直接同化ATOVS辐射率资料对山西暴雨预报的影响"(SXKQNTQ20147856)共同资助
关键词
ATOVS资料
变分同化
暴雨
TS评分
ATOVS data
variational data assimilation
a heavy rain process
TS score
