Ocean forecasts in the southwestern Atlantic: Impact of different sources of sea surface height in data assimilation

Abstract

The objective in this paper is to analyze which Sea Surface Height (SSH) source applied to HYCOM (HYbrid Coordinate Ocean Model) is best suited to numerical prediction of the Southwest Atlantic Ocean. To this end two nested grids were used. One grid for the entire Atlantic Ocean (1/4°) nesting the grid for the Southwest Atlantic (1/12°) in the one-way mode. Three forecast experiments with different SSH data sources (Naval Research Laboratory - NRL; Archiving, Validation and Interpolation of Oceanographic Data - AVISO and MERCATOR) applied to constrain the initial conditions and a control forecast experiment without SSH constrain were compared. The comparison of forecasted temperature and salinity profiles with Argo data showed good correlation, over 0.98 for temperature and 0.87 for salinity. The NRL experiment - with SSH obtained by HYCOM+NCODA (Navy Coupled Ocean Data Assimilation System) GLOBAL 1/12° analysis was the one that best represented the average temperature and salinity profile with respect to the Argo data. © 2013 Sociedade Brasileira de Geofísica.