The Assimilation of Synthetic "Observations" from NCEP Global Analysis into the Regional Model

The assimilation of high-quality observation information has the potential to improve the regional model forecasting. The National Centers for Environmental Prediction (NCEP) operational global data assimilation system uses advanced assimilation technique and ingests all available global satellite, conventional (rawinsonde, aircraft, land and sea surface data et al.) and radar observations. In this study, the synthetic “observations” derived from analysis fields of NCEP are assimilated into the regional Weather Research and Forecasting Model (WRF) data assimilation system. The impact of assimilating the added synthetic “observations” on the 6-24 h forecasting in South China during May 2014 is evaluated by comparing with the control experiment in which only Global Telecommunication System (GTS) observational data is assimilated. The results show slightly positive impact on forecast verification statistics for upper air variables with respect to rawinsonde. For case-by-case verifications, the assimilation of synthetic data can improve the Quantitative Precipitation Forecasts (QPF) skills.