Assimilation Sensitivity Experiment of Automatic Observation Stations in WRF 3DVAR

For understanding the influence of automatic observation stations on the numerical weather prediction (NWP), four tests are carried out about different element of automatic station data in WRF 3D-Var system and WRF model.Test results of two months show that:1) Assimilating temperature observations have obviously negative effects on geopotential height, temperature and relative humidity forecasts.Assimilating pressure or wind direction & wind speed observations have small influence on the above factors, and can improve geopotential height forecast and partly temperature forecast, but no improvement to the relative humidity forecast;2) For the precipitation forecast, the TS score of assimilating wind direction & wind speed is the worst, and the assimilation temperature program secondly.Assimilation pressure program can improve the 24h precipitation forecast results.The above analysis shows that when assimilating surface observations, the pressure is very important to the assimilation system whose vertical coordinate is the isobaric surface, also shows that in order to make good use of ground observations in NWP, there are a lot of research.