On February 21, the Global Assimilation Forecasting System (CMA-GFS V4.0, named as GRAPES-GFS before) of China Meteorological Administration (CMA) passed the pre-operational acessment and will put into operational run. The expert group, consists of scientists and forecasters, agreed that CMA-GFS V4.0 has made a great technical improvements and enhanced forecasting skills and has met the requirements for operational upgrade. 

In response to the forecaster’s feedback of the previous version of the system (CMA-GFS V3.3), the CEMC of CMA further improved and upgraded the key technologies of the global forecast system, such as dynamic framework, physical processes, data assimilation, parallel computing and new product development. 

After this upgrade, the horizontal resolution of the model will increase from 0.25° to 0.125°, the precipitation forecasting capability of the model is significantly improved, the proportion of the assimilation of satellite data reaches 80% and Chinese FY satellite data is increased from 12% to 14%, and the model efficiency is also significantly improved by new solver of the dynamic core. The weather pattern forecast was improved comprehensively, and forecast lead-time at which the anomaly correlation of the 500hPa geopotential reaches 60% in the northern hemisphere exceeded 8 days for the first time. In addition, track and intensity forecasts for the tropical cyclones were significantly improved.

CMA-GFS is a global medium-range numerical forecast model developed by Chinese scientists, which is at the core of national numerical weather forecasting operations. The vertical and horizontal resolutions have been continuously improved, and the forecast performance and service functions have been steadily upgraded and expanded. 

（Editor: Cheng Guangguang, Sun jian, and Zhou Qingliang）