Tuesday, 11 February 2003: 8:45 AM
Status of NCEPís Operational Regional Ocean Forecasting Systems for US Coastal Domains
NCEP has been involved in the development of nowcast/forecast models for predicting the three-dimensional state of the US coastal oceans and implementing the models to produce daily forecasts on an operational basis. As a first step in this direction, an area off the East Coast of the US was chosen as the pilot domain to test the feasibility of producing coastal ocean nowcast/forecast fields on a daily basis in real-time. The model domain extends from approximately 26.50 to 480N and from the coast out to 500W. This domain off the East Coast was initially chosen because of the robust and identifiable signal provided by the Gulf Stream, which covers a major portion of the domain, and also because of the availability of better atmospheric forcing compared to the West Coast. The Princeton Ocean Model (POM) is used as a prototype to produce daily nowcast/forecast oceanographic fields. The horizontal resolution in the ocean model changes from 10 km near the coast to about 20 km offshore and the model has 19 sigma levels in the vertical. The prescription of open-ocean and landward boundary conditions is based on monthly climatologies. The ocean model is forced by surface fluxes derived from the Eta model which is NCEPís operational mesoscale meteorological model. Forcing due to three semi-diurnal and three diurnal tidal components are also included in the model. Assimilation of SST data from in-situ and satellite sensors as well the sea surface height anomalies from TOPEX and ERS-2 is also included in the forecast system. The system produces a nowcast and a 48-hour forecast every day. The oceanographic products produced by the POM based system have been extensively evaluated internally by the Marine Prediction Center of NCEP and also by a group of selected marine users during two marine demonstrations projects conducted during the summer of 1999 and winter of 2000 (funded by NOPP). The nowcast/forecast system for the East Coast has become fully operational at NCEP in March 2002. Graphic products and grid point numerical fields are made available to the user community over the internet at http://polar.ncep.noaa.gov.
The current operational East Coast system is limited in its geographical coverage and also improvements are needed in the prescription of the lateral open-ocean boundary conditions. In order to rectify these deficiencies, work is continuing on the development of basin scale models to provide the means for extending the forecasting capability to other coastal areas of the US and to generate more realistic open-ocean forcing on these regional domains.