Evaluation of All-Sky Assimilation of FY-3C/MWHS-2 on Mei-yu Precipitation Forecasts over the Yangtze-Huaihe River Basin  

作　　者：Yu LI Keyi CHEN Zhipeng XIAN 

机构地区：[1]School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610025,China [2]International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Advances in Atmospheric Sciences》2021年第8期1397-1414,共18页大气科学进展（英文版）

基　　金：the National Natural Science Funds of China(Grant No.41875039);the Fengyun-3 meteorological satellite ground application system project;the development of the application software for southwest regional road traffic using the Fengyun-3 satellite remote sensing monitoring service(Grant No.ZQC-J19193)are also appreciated to support this research。

摘　　要：All-sky (i.e., clear, cloudy, and precipitating conditions) assimilation of microwave observations shows potentially positive impacts on the improvement of the forecasts of cloud-associated weather processes. In this study, a typical mei-yu heavy precipitation event that occurred in 2017 was investigated, and the Weather Research and Forecasting data assimilation (WRFDA) as well as its 3D-Var assimilation scheme (excluding cloud and precipitation control variables) were applied to assimilate the Fengyun-3C (FY-3C) Microwave Humidity Sounder-2 (MWHS-2) observations under clear- sky (excluding the observations that are strongly affected by ice clouds and precipitation) and all-sky conditions. Three experiments including a control experiment without assimilating any observations, clear-sky, and all-sky experiments with only FY-3C/MWHS-2 observations assimilated were carried out. The results show that the all-sky assimilation approach that provides more cloud and precipitation information and increased more than 10% of the satellite data usage than the clear-sky experiment. Meanwhile, as compared with the control experiment, the all-sky assimilation reduced nearly 0.5% of the root mean square errors in the humidity fields, leading to more accurate forecast performances regarding the distribution and intensity of heavy rainfall;but it exhibited a neutral to negative impacts on the wind and temperature. Although the system used to conduct all-sky assimilation is only able to adjust control variables for moisture-, wind-, and temperature- related variables in the presence of cloud and does not benefit directly from cloud or precipitation information, the positive effects on heavy rainfall forecasts achieved in this study indicate a potential future benefit regarding disaster prevention and mitigation.

关 键 词：all-sky assimilation FY-3C MWHS-2 mei-yu rainfall 

分 类 号：P457.6[天文地球—大气科学及气象学]