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Home > STOFS 2D Global and STOFS 3D Atlantic documentation

The Surge and Tide Operational Forecast System 2D Global (STOFS-2D-Global) provides users with nowcasts (analyses of near present conditions) and forecast guidance of water level conditions for the entire globe. The forecast outputs include water levels caused by the combined effects of storm surge and tides, by astronomical tides alone, and by sub-tidal water levels (isolated storm surge) out to 180 hours. The hydrodynamic model employed by STOFS-2D-Global is the ADvanced CIRCulation (ADCIRC) finite element model. The unstructured grid used by STOFS-2D-Global consists of 12,784,991 nodes and 24,875,313 triangular elements. Coastal resolution is up to 80 m for the U.S. West Coast and Alaska, up to 90-120 m for the Pacific Islands including Hawaii, Guam, American Samoa, Marianas, Wake Island, Marshall Islands, and Palau, and up to 120 m for the U.S. East Coast and Puerto Rico. The flood plain extends overland to approximately 10 m elevation above MSL for the U.S. East Coast, and up to 20 m elevation above MSL for the Pacific Islands. STOFS-2D-Global includes internal tides and sea-ice effect on wind drag.

STOFS-2D-Global output files are provided here in two formats: structured GRIB2 files for the contiguous U.S. East region (2.5 km resolution), contiguous U.S. West region (2.5 km resolution), Alaska (6 km resolution), Hawaii (2.5 km resolution), Guam (2.5 km resolution), North Pacific (10 km resolution), and Puerto Rico (1.25 km resolution) grids, and unstructured NetCDF files on the native STOFS-2D-Global finite element grid, consisting of ~13 million nodes. NetCDF output is also provided at 1,687 verification sites globally. GRIB2 files are created for hourly forecasts during each forecast cycle, consisting of hourly records of combined water level (surge with tide), harmonic tidal prediction (astronomical tides), and sub-tidal water levels (the isolated surge). There are also GRIB2 files that contain an entire run cycle, for each of combined, harmonic tidal prediction, and sub-tidal water levels. NetCDF files contain an entire run cycle, and consist of the hourly combined, harmonic tidal prediction, and sub-tidal water levels over the native STOFS-2D-Global grid, or six-minute combined, harmonic tidal prediction, and sub-tidal water level records at 1687 verification sites. SHEF files are provided, containing half hourly water levels for the forecast period at the 133 verification sites.

The 3-D Atlantic component of STOFS, namely STOFS-3D-Atlantic, provides users with 24-hour nowcasts (analyses of near present conditions) and up to 48-hour forecast guidance of water level conditions, as well as 2- and 3-dimensional fields of water temperature, salinity, and currents. The STOFS-3D-Atlantic domain encompasses the U.S. East Coast, Gulf of Mexico, and Puerto Rico. The water levels produced by STOFS-3D-Atlantic represent the combined tidal and subtidal water surface elevations and are referenced to NAVD88 (or geoid referenced where there is no NAVD88 coverage, e.g. Puerto Rico).

STOFS-3D-Atlantic employs the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) as the hydrodynamic model core. Its unstructured grid consists of 2,654,153 nodes and 5,137,229 triangular or quadrilateral elements. Grid resolution is 1.5-2 km near the shoreline, 200-550 m for the floodplain, and up to 10 m for both levees and some small rivers. Along the U.S. coasts, the land boundary of the domain aligns with the 10-m contour above NAVD88, encompassing the coastal transitional zone most vulnerable to coastal and inland flooding. Coupled (one-way coupling) with the National Water Model (NWM), STOFS-3D-Atlantic simulates rainfall-induced overland flow, river flow, and storm surge effects simultaneously.

The STOFS-3D-Atlantic output files are provided in three formats: structured GRIB2 files of hourly water level for the forecast period over the contiguous U.S. East region (2.5 km resolution) and Puerto Rico (1.25 km resolution) grids; SHEF files of half hourly water level for the forecast period at 342 verification sites; and NetCDF files containing the suite of ocean state variables that include water level, horizontal velocity, temperature, and salinity.

The NetCDF files provide hourly time series of the ocean state variables at either the 342 individual verification sites or over the entire unstructured, native model grid. The station files are for 6-minute water level, surface water temperature, surface salinity, and surface horizontal water velocity; and the hourly horizontal 10 m wind velocity, and vertical profiles of water temperature, salinity, and horizontal water velocity at verification sites.

The domain-wide field NetCDF files are for the hourly instantaneous, or maximum of water level fields; hourly horizontal water velocity fields at water surface, water bottom, 4.5 m below water surface, or the average across the water depth; and hourly water temperature and salinity fields at both water surface and water bottom.

STOFS web page:
Storm Surge

 



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