Coupled Seasonal to Subseasonal Model Development within NOAA’s Unified Forecasting System

Abstract:

NOAA’s Unified Forecast System is a community-based modeling system being developed to provide a common framework for all NCEP Production Suite (NPS) operational forecasting systems. One of the modeling applications currently in development is the Coupled Seasonal-to-Subseasonal system (ufs-s2s). The ufs-s2s system is developed iteratively by testing configurations with increasing complexity. In its most recent configuration, the ufs-s2s system is composed of the GFDL’s Finite Volume Cubed Sphere (FV3) dynamical core with GFS physics and GFDL microphysics parameterization, the Modular Ocean Model (MOM6), the Los Alamos Sea Ice Model (CICE5), and a global wave model (WAVEWATCH III). The system components are coupled via the NEMS framework and the Community Mediator for Earth Prediction Systems (CMEPS). As the ufs-s2s evolves in maturity and complexity, its performance is systematically monitored to ensure integrity and quality. Because all model components are continuously upgraded through community effort, a complete evaluation after every change is not feasible. Instead, such evaluations are reserved for discrete “prototypes” representing significant development milestones. Here, we will describe the state of the ufs-s2s system to date, present the evaluation of forecast error and skill for key completed prototypes, and describe the plans for future development of the system.