Three Dimension Variational Study On FY-3A Microwave Temperature And Humidity Data

The characteristics of satellite data are being more consistent, covering wider area and having finer spatio-temporal resolution, so over such areas as oceans and plateau, it can making up for the shortage of conventional observations. How to make use of data assimilation to extract the effective observation information of satellite data and to form a better initial field, to improve the accuracy of numerical prediction, that is a meaningful topic.China’s new generation of polar-orbiting meteorological satellite FY-3A was successfully launched on May26th,2008, carrying microwave sounding units which had similar performance to ATOVS of NOAA series. In order to study application of Microwave Sounding data in numerical prediction, achieve the direct assimilation of microwave sounding data of our FY-3A satellite, research of direct data assimilation technology was carried out, basing on FY-3A microwave sounding data and WRF-3DVar System. Single point ideal test and ideal test were studied about to test the system. Then studied about numerical forecasting of rainstorm in Guangxi in January2010and carried out research of direct data assimilation technology。The main conclusions and results:(1)The characteristics of FY-3A microwave sounding data should be considered when carrying out the interface of direct data assimilation basing on FY-3A microwave sounding data and WRF-3DVar System. The main procedure module which should be considered is da_setup_radiance_structures module. Input the information of FY-3A microwave sounding data to the innovation vector through the input space and adjoint space.(2) Single point ideal test and ideal test were carried out to test the system, the tests show that3DVAR system can be used to assimilate FY-3A simulated microwave sounding data. The result of ideal test shows that direct assimilation of simulated FY-3A microwave sounding data improves the initial fields of numerical and has a positive improvement for the prediction of the precipitation, both on the intensity and the location of the centre. And the assimilation experiment has better TS scores than control experiment at all levels.(3) The result of numerical forecasting of rainstorm in Guangxi in January2010and research of direct data assimilation technology shows that direct assimilation of FY-3A microwave sounding data improves the initial fields of numerical and has a positive improvement for the prediction of the precipitation, better than only assimilate conventional data. The assimilation experiments are more effective than control experiment on rainfall, and the assimilation experiments have better TS scores than control experiment.