Development of UFS-based Coupled GEFS for Subseasonal Forecasts
Abstract
WPO/CTB has funded a project In close collaboration with Unified Forecast System (UFS) Research to Operation / Subseasonal to Seasonal (R2O/S2S) and Medium Range Weather (MRW) application, to help improve NCEP Global Ensemble Forecast System (GEFS) for weather and subseasonal predictions. GEFS v12 was implemented in NCEP operation in September 2020, which is the 1st UFS application coupled 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, the main focus of discussion is quantifying forecast uncertainty 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. These 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 optimum atmospheric model perturbations. The experiments are run for 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.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.A26F..01F