| Title | SA-Southeast Forecast V1.0 |
|---|---|
| Authors |
Fearon, Giles |
| Publisher | South African Environmental Observation Network (2026) |
| Contributors |
Contact Person: Veitch, Jennifer Contact Person: Fearon, Giles |
| Abstract | The SA-Southeast Forecast product provides a 5 day forecast of the ocean state along the southeastern coast of South Africa centered around Algoa Bay, and is updated daily. This product represents the operational version of the SA-Southeast Hindcast V1.0 product, and forms part of SOMISANA's South African Coastal Ocean Forecast System West (SACOFS). The model was developed using the Coastal and Regional Ocean COmmunity (CROCO) modelling system. The model curvilinear grid has a variable horizontal grid resolution (0.5 – 3 km) which increases toward the coast. The model has 30 terrain-following (sigma) vertical levels. Model bathymetry is interpolated from digital navigation charts provided by the South African National Hydrographic Office (SANHO). Open boundary conditions for our models are obtained from two ~9 km resolution global ocean analysis and forecast products: Mercator and the Hybrid Coordinate Ocean Model (HYCOM). Surface forcing for our models is obtained from both the ~25 km resolution Global Forecasting System (GFS) and a 4.4 km resolution atmospheric forecast model run operationally by the South African Weather Service (SAWS). The use of two different boundary forcing products and two different surface forcing products allows us to provide a four-member ensemble of forecasts: MERCATOR-GFS, MERCATOR-SAWS, HYCOM-GFS and the HYCOM-SAWS. Each of the ensemble members are additionally forced with tides from TPXO10. Each ensemble member is initialized once a day, producing output throughout the water column at an hourly temporal resolution for a period of 5 days into the past to 5 days into the future. The SAWS-forced simulations are however limited to a 2.5-day forecast due to the limited temporal availability of the atmospheric forcing. NetCDF model output files are available as hourly averages throughout the water column. Subsets of the files can be downloaded via Thredds protocol or alternatively entire files can be downloaded via our Mnemosyne file server. The raw model output files are made available along with regridded files which conform to CF-compliant standards. An archive of the operational forecast is maintained by SAEON, and historical forecasts can be made available upon request. |
| Methods | The simulation was developed using the Coastal and Regional Ocean COmmunity (CROCO) modelling system. Lateral open boundary conditions are interpolated from Mercator or HYCOM. The surface forcing is interpolated from the GFS or SAWS. The model bathymetry is interpolated from SANHO. |
| Data | |
| Temporal extent | 01 Apr 2020 – 31 Dec 2026 |
| Geographic extent |
Southeast Coast, South Africa
North: -33.0 |
| Keywords | grid , OCEAN CURRENTS , OCEAN TEMPERATURE , OCEANS , onGoing , salinity , SOMISANA , WGS84 |