Earth System Prediction Capability (ESPC) Initial Operational Capability (IOC) Ensemble System
NAVAL RESEARCH LAB MONTEREY CA MONTEREY United States
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The Navy Earth System Prediction Capability Navy-ESPC is the new global coupled atmosphere-ocean-sea ice prediction system developed at the Naval Research Laboratory NRL for operational forecasting for timescales of days to subseasonal. This report describes and evaluates the Navy-ESPC model. When the Navy-ESPC model becomes operational, it will be the first time NRLs operational partner, Fleet Numerical Meteorology and Oceanography Center, will provide coupled atmosphere ocean sea-ice forecasts, atmosphere forecasts past 16 days, and ocean and sea ice ensemble forecasts. A unique aspect of the Navy-ESPC model is that the global ocean model is eddy resolving at 112 in the ensemble and at 125 in high-resolution deterministic configurations. The component models consist of currently operational systems and include atmosphere - NAVy Global Environmental Model NAVGEM ocean - HYbrid Coordinate Ocean Model HYCOM and sea ice - Community Ice CodE CICE. Physics updates to improve the simulation of equatorial phenomena, particularly the Madden Julian Oscillation MJO, and to provide more consistent air-sea fluxes, were introduced into NAVGEM. No physics updates to accommodate coupling were included in HYCOM or CICE. Data assimilation is loosely coupled between the NRL Atmospheric Variational Data Assimilation System - Accelerated Representer NAVDAS-AR for the atmosphere and the Navy Coupled Ocean Data Assimilation NCODA for the oceanice components. A 16 member ensemble configuration and high-resolution deterministic configuration are evaluated based on analyses and forecasts run from February 2017 to January 2018. When compared to other operational centers, the Navy-ESPC model performs in a similar manner when examining large-scale atmospheric characteristics, such as the MJO, North Atlantic Oscillation NAO, Antarctic Oscillation AAO, and other indices. Forecasts of ocean sea surface temperatures perform better than climatology in the tropics.
- Physical and Dynamic Oceanography