Development/Implementation of Data Assimilation System for Operational Ocean Forecasting at NCEP

NOAA’s NWS mission is to provide the best possible numerical guidance to a variety of customers including emergency managers, forecasters and the aviation community. The Next Generation Global Prediction System (NGGPS) at NWS/NCEP is aimed at building a state-of-the-art operational modeling system in a unified coupled system framework encompassing atmosphere, ocean, sea-ice, aerosols, land and waves, including those which target Hurricanes. Currently, NCEP is providing eight days of global ocean numerical forecasts from its operational Real-Time Ocean Forecast System (RTOFS), which is based on HYbrid Coordinate Ocean Model (HYCOM). A major development is in progress to build an ocean data assimilation system (through NCODA -- Navy’s Coupled Ocean Data Assimilation) which will provide the initial analysis fields for these ocean forecasts.

Observations are an integral part of any data assimilation system. Hence, ocean observations from various sources (SST from satellites, altimeters, profiles, XBT’s, moorings, sea-ice cover, buoys, etc.) are collected and served via NCEP data-tanks to all its operational models. NCODA has an advanced Quality Control (QC)/ Quality Analysis (QA) module which works in conjunction with its 3D variational (VAR) assimilation algorithm. Tools are being developed to reformat ocean data from NCEP data-tanks to enable ingest into NCODA. Results from this QC/QA system along with climatology and model forecasts will be discussed.

Under a separate effort, a community-based unified data assimilation system is being developed through the JEDI (Joint Effort for Data assimilation Integration) framework which will also include support for ocean data assimilation needs at NCEP. The eventual transition to operations to a unified DA system based on JEDI for real-time ocean analysis will also allow for development of a coupled ocean-atmosphere-sea ice data assimilation system. This unified DA system will be capable of providing initial conditions for all coupled modeling systems targeted for transition to operations at NCEP. Some salient features of this proposed unified DA system, which enable quick R2O, will also be discussed.