1. Coastal/Marine Hazards and Resources
2. Woods Hole Coastal and Marine Science Center
3. U.S. Geological Survey Sea Floor Stress and Sediment Mobility Database

Map showing the bathymetry of the Gulf of Mexico and regional physiographic features. Characterizations of bottom shear stress and sea floor mobility in this database extend offshore to approximately the 120-m isobath.

U.S. Geological Survey Sea Floor Stress and Sediment Mobility Database: Gulf of Mexico

Publication Date: June 2014

The Gulf of Mexico region extends from the southeast coast of Texas eastward to the Florida Keys. Very shallow regions around the Mississippi River Delta are not resolved.

Spatially and temporally resolved estimates of bottom shear stress are calculated for seasonal and annual time periods. Seasons are defined as Winter (December-February), Spring (March-May), Summer (June-August), and Fall (September-November).

Specifications for stress and mobility time series:

• Spatial Resolution: Approximately 5 km.
• Time Period: May 2010, to May 2011.
• Temporal Resolution: Hourly.

Datasets used to compute the bottom stress and sediment mobility time series:

• Currents: The South Atlantic Bight and Gulf of Mexico Circulation Nowcast/Forecast (SABGOM) model, which uses the Regional Ocean Modeling System (ROMS). The SABGOM domain includes the coastal regions of the South Atlantic Bight and the Gulf of Mexico. These two areas have been split in order to better delineate regions based on similar physical processes and forcing; results presented here are for the Gulf of Mexico only. Developed at North Carolina State University.
  Contact: Model run by Dr. Ruoying He, Ocean Observing and Modeling Group.
• Waves: Simulating WAves Nearshore (SWAN) model applied to the western North Atlantic.
  Contact: Model run by Dr. P. Soupy Dalyander, formerly with U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
• Sediment Texture Data: USGS East-Coast Sediment Texture database (Poppe and others, 2005) (https://doi.org/10.3133/ofr20051001)

Complete details on the procedure used to create the data files may be found in the associated metadata

Suggested citation: Dalyander, P.S., Butman, B., Sherwood, C.R., and Signell, R.P., 2012, U.S. Geological Survey sea floor stress and sediment mobility database: U.S. Geological Survey data release, https://doi.org/10.5066/P999PY84.

Statistics of sea floor wave-current stress and sediment mobility in Arc polygon and point shapefile format for the South Atlantic Bight from model output. Stress statistics are determined for the entire model grid, whereas mobility statistics are determined only at locations where sediment texture data are available. See metadata files for details of the calculations. Click on zip file to download.

Data Layer Name and Explanation	Preview	Metadata	Download
Median of Bottom Shear Stress The value of bottom shear stress exceeded 50% of the time. (Shapefile polygon)		HTML FAQ TEXT XML	GMEX_median.zip
Interpercentile Range of Bottom Shear Stress Half the difference between the 84th and 16th percentile. A measure of variability, equivalent to the standard deviation in a normal distribution. (Shapefile polygon)		HTML FAQ TEXT XML	GMEX_hIPR.zip
95th Percentile of Bottom Shear Stress Value of bottom shear stress exceeded 5% of the time. A measure of the largest stresses. (Shapefile polygon)		HTML FAQ TEXT XML	GMEX_95th_perc.zip
Bed Mobility Percentage Percentage of time the critical stress is exceeded (determined for locations with sediment texture data). A measure of the extent of bed mobility. (Shapefile point)		HTML FAQ TEXT XML	GMEX_mobile_perc.zip
Bed Mobility Recurrence Interval Time between mobility events (determined for locations with sediment texture data). A measure of the of frequency of mobility events. (Shapefile point)		HTML FAQ TEXT XML	GMEX_mobile_freq.zip