The Development of UFS Coupled GEFS for Weather and Subseasonal Forecasts
Presenter: Dr. Yuejian Zhu, NOAA/NCEP/EMC – August 8, 2022
In collaboration with the Unified Forecast System (UFS) Research to Operation / Subseasonal to Seasonal (R2O/S2S) and Medium Range Weather (MRW) applications, the focus of the Weather Program Office (WPO)/Climate Test Bed (CTB) funded project is to improve the NCEP Global Ensemble Forecast System (GEFS) for weather and subseasonal prediction from the current operational GEFS.
The WPO S2S Program and National Weather Service (NWS)/OSTI-Modeling invite you to join a monthly webinar series for Weeks 3-4 and S2S.
The GEFS v12 was implemented in NCEP operation in September 2020, which is the 1st UFS application with coupling to Wave Watch 3 (WW3) ensembles with 25km uniform horizontal resolution; 31 members and out to 35 days to cover subseasonal prediction. The operational GEFS demonstrated improved forecast capability and excellent performance for weather and subseasonal time scales including MJO predictions, surface temperature and precipitation through retrospective forecasts and 31 years reforecasts before it was implemented.
In this presentation, quantifying forecast uncertainty is the main focus to discuss through the integration of a fully coupled UFS and various stochastic physical perturbation schemes to initialize a coupled global ensemble forecast experiments toward GEFS v13 implementation. The experiments are closely configured to the development of the UFS coupled prototype experiments. For this study, a UFS prototype version 5 (P5) based coupled GEFS experiment has been carried out with the optimum atmospheric model perturbations. The experiments run a 2-year period (initialized once per week at 00UTC time) with 10 perturbed and 1 unperturbed members, out to 35 days. A full evaluation of the experiment will be presented in terms of various evaluation metrics.
