The West Coast Operational Forecast System with Data Assimilation

Abstract:

NOAA’s National Ocean Service (NOS) has collaborated with the National Environmental Satellite, Data, and Information Service (NESDIS) to develop the West Coast Operational Forecast System (WCOFS), which will be NOS’ first operational forecast system to incorporate data assimilation capabilities. The real-time system is scheduled to transition to operations at the National Center for Environmental Prediction (NCEP) in February, 2021. Based on the Regional Ocean Modeling System (ROMS), WCOFS will provide forecast guidance of water level, currents, temperature, and salinity to a variety of user communities along the U.S. west coast. The forecast guidance can be used to facilitate safe and cost-efficient navigation, identify optimal locations of fishing grounds, inform search and rescue and environmental incident response, and support other ecological applications. The ROMS four-dimensional variational (4DVAR) data assimilation system is used to constrain the initial conditions. Initially, observations of sea surface temperature (SST) from the Visual-Infrared Imaging Radiometer System (VIIRS) onboard the Suomi-National Polar-orbiting Partnership (NPP) satellite and ocean-surface currents measured by high frequency (HF) radar were assimilated into the model on a daily basis. Recently, sea surface height (SSH) from five satellites and SST from satellites NOAA-20 and GOES-17 have been assimilated into the model. This presentation will focus on the effects of the additional observations on the 3-day forecast and how data assimilation helped to constrain eddy variability and currents in the frontal regions.