加密探空资料同化对一次降水预报能力改进研究

通过设计不同的试验方案,将加密探空资料同化到WRF模式中,对一次层状云系的降水过程进行了数值模拟.采用实时四维资料同化的方法,使得背景场和观测资料相协调,在一定程度上解决了模式的spin up问题.将温度同化到模式里,改变了模式原有的热力场,使得模式动力场随之改变,模式模拟的结果更接近实际观测.经过松弛(nudging)之后,得到的雷达回波、高度场、温度和实况很像,降水也要比不加探空资料的降水更接近实况.鉴于只有两个地方的探空资料,并不能覆盖整个模式区域,以及同化过程还需要改进,模式模拟的结果和实际观测之间还有一定的差异,有待更深入的研究.

Improvement of Precipitation Forecasts by the Assimilation of Encrypted Sounding Data

Different experiments were designed to assimilate encrypted sounding data into the WRF model, and a numerical simulation was conducted to investigate one precipitation event from a stratiform cloud system. Real-time four-dimensional data assimilation yielded good coordination of the background field and observational data, solving the problem of the spin-up mode to a certain extent. Assimilating the temperature into the model changed the original thermal field model and then the dynamic field, and the results of the model simulation became closer to the actual observation. After being processed by the nudging technique, the radar echo, height field, temperature, and precipitation were in reasonable agreement with the observations. However, because the sounding data were obtained from only two places, the results cannot cover the entire model domain. Moreover, the assimilation process also needs to be improved, and further studies are needed because some differences still appear between the simulated results and the actual observation data.