Dalyander, P. Soupy , Long, Joseph W. , Plant, Nathaniel G. , and Thompson, David, 2012, Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Locations of decelerations in the direction of flow in the maximum alongshore current: Open-File Report (OFR) 2012-1234, U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.This is part of the following larger work.Online Links:
Plant, Nathaniel G. , Long, Joseph W. , Dalyander, P.Soupy, and Thompson, David, 2012, Hydrodynamic and Sediment Transport Model Application for OSAT3 Guidance: Open-File Report (OFR) 2012-1234, U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.Online Links:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
| Range of values | |
|---|---|
| Minimum: | 1 |
| Maximum: | 5 |
| Units: | non-dimensional |
| Resolution: | 1 |
| Range of values | |
|---|---|
| Minimum: | 1 |
| Maximum: | 16 |
| Units: | non-dimensional |
| Resolution: | 1 |
| Range of values | |
|---|---|
| Minimum: | -100 |
| Maximum: | 100 |
| Units: | m/s^2 |
| Resolution: | 0.001 |
(508) 548-8700 x2290 (voice)
(508) 457-2310 (FAX)
sdalyander@usgs.gov
This GIS layer contains an estimate of the locations of spatial decelerations in the direction of flow in the maximum (in terms of absolute value) alongshore current in the shallow northern Gulf of Mexico (Alabama and portion of the Florida coast) for a single set of wave conditions. These decelerations are defined as locations where there is a significant decrease in the spatial acceleration (u*du/dy) moving in the direction of flow, or, conceptually, where a particle moving with the flow would encounter a reduced flow velocity as it moved from one grid cell to the next. This output is based on numerical model output of wave and circulation patterns for a given wave height scenario, corresponding to a particular set of offshore wave conditions at NOAA NDBC buoy 42040. The specific wave conditions for a given layer are indicated by the file name (of format Hh_Dd_decel), also found in the shapefile attributes, and may be found by comparing the scenario name (Hh_Dd) to the look-up table included in the GIS zip file, wave_scenarios.txt. This data layer is intended to show patterns in alongshore current for intended use by individuals in SRB mitigation attempting to explain redistribution of SRBs under specific wave conditions.
NOAA National Centers for Environmental Prediction (NCEP), 20110601, NOAA/NCEP Global Forecast System (GFS) Atmospheric Model: NOAA National Centers for Environmental Prediction, Camp Springs, MD.Online Links:
NOAA National Centers for Environmental Prediction (NCEP, 20121001, NOAA/NWS/NCEP 4' Wavewatch III Operational Wave Forecast: NOAA National Centers for Environmental Prediction, Camp Springs, MD.Online Links:
Significant wave height, dominant wave period, and wave direction were prescribed as D-Wave TPAR format files every 30 grid cells along the model boundary using results from the NOAA Wavewatch III 4' multi-grid model for a representative moment in time corresponding to the offshore wave conditions of the scenario, the specific time of which may be found in the included wave_scenarios.txt file. A JONSWAP (JOint NOrth Sea WAve Project) spectral shape was assumed at these boundary points. Wind forcing was provided using the archived WavewatchIII 4' winds, extracted from the NOAA GFS wind model, for this time. The D-Wave directional space covers a full circle with a resolution was 5 degrees (72 bins). The frequency range was specified as 0.05-1 Hz with logarithmic spacing. Bottom friction calculations used the JONSWAP formulation with a uniform roughness coefficient of 0.067 m2/s3. 3rd-generation physics are activated which accounts for wind wave generation, triad wave interactions and whitecapping (via the Komen et al parameterization). Depth-induced wave breaking dissipation is included using the method of Battjes and Janssen with default values for alpha (1) and gamma (0.73). Current model outputs of east and north current velocity component were extracted and interpolated to the wave model grid (staggered points in relation to the current model grid).
NDBC observations from station 42012 for the representative scenario time periods were used to validate the wave model results.
Person who carried out this activity:
(727) 803-8747 x3024 (voice)
(727) 803-2032 (FAX)
jwlong@usgs.gov
Data sources produced in this process:
For each alongshore transect, the surf zone is defined as the area between the shoreline and the location of maximum wave height (found in a search area extending from the shoreline to the most offshore point of modeled depth-induced wave breaking dissipation). The extent of the surf zone (as indices into the grid at each alongshore location of the cross-shore position of the shoreline and seaward edge of the surf zone) was saved for all of the scenarios into a MATLAB .mat structure.
Person who carried out this activity:
(727) 803-8747 x3079 (voice)
(727) 803-2032 (FAX)
dthompson@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
(727) 803-8747 x3079 (voice)
(727) 803-2032 (FAX)
dthompson@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
(727) 803-8747 x3024 (voice)
(727) 803-2032 (FAX)
jwlong@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
(508) 548-8700 x2290 (voice)
(508) 457-2310 (FAX)
sdalyander@usgs.gov
The attributes in this data layer correspond to spatial decelerations in the maximum (in terms of absolute value) alongshore current velocity in the surf zone for Hh_Dd, characteristics of which may be found in the included wave_scenarios.txt file. Statistical values will vary if a different numerical model is used to estimate the waves and circulation.
Numerical models are used in estimating alongshore currents used in creating this data layer. Because the overall horizontal accuracy of the data set depends on the accuracy of the model, the underlying bathymetry, forcing values used, and so forth, the spatial accuracy of this data layer cannot be meaningfully quantified.
All model output values were used in the calculation of this statistic. The statistic was calculated for a particular scenario (Hh_Dd), the characteristics of which may be found in the included wave_scenarios.txt file. The spatial decelerations of the maximum (in terms of absolute value) alongshore current in the surf zone were calculated from wave and current estimates generated with Delft3D, and would vary if different models were used or if different model inputs (such as bathymetry, forcing winds, and boundary conditions) or parameterizations were chosen.
No duplicate features are present. All polygons are closed, and all lines intersect where intended. No undershoots or overshoots are present.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
(508) 548-8700 x2290 (voice)
(508) 457-2310 (FAX)
sdalyander@usgs.gov
Hh_Dd_decel.shp: locations of spatial decelerations for the Hh_Dd scenario. NOTE: Specific layer name indicates the scenario (Hh_Dd), with characteristics given in the included wave_scenarios.txt file.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
| Data format: | WinZip archive file containing the shapefile components. The WinZip file also includes FGDC compliant metadata. in format SHP (version 3.3) ESRI shapefile Size: 300-500 KB |
|---|---|
| Network links: |
<http://pubs.usgs.gov/of/2012/1234/datafiles.html> |
These data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.
(508) 548-8700 x2290 (voice)
(508) 457-2310 (FAX)
sdalyander@usgs.gov