Metadata: Identification_Information: Citation: Citation_Information: Originator: P. Soupy Dalyander Publication_Date: 2012 Title: Percentage of time sediment is mobile for May, 2010 - May, 2011 at select points in the Middle Atlantic Bight (MAB_mobile_perc.SHP) Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P999PY84 Publication_Information: Publication_Place: Woods Hole Coastal and Marine Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program Online_Linkage: https://doi.org/10.5066/P999PY84 Online_Linkage: https://cmgds.marine.usgs.gov/data/whcmsc/data-release/doi-P999PY84/MiddleAtlanticBight/ Larger_Work_Citation: Citation_Information: Originator: P.S. Dalyander Originator: B. Butman Originator: C.R. Sherwood Originator: R.P. Signell Publication_Date: 2012 Title: U.S. Geological Survey Sea Floor Stress and Sediment Mobility Database Edition: 1.0 Series_Information: Series_Name: Database Issue_Identification: DOI:10.5066/P999PY84 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: 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. Online_Linkage: https://doi.org/10.5066/P999PY84 Description: Abstract: The U.S. Geological Survey has been characterizing the regional variation in shear stress on the sea floor and sediment mobility through statistical descriptors. The purpose of this project is to identify patterns in stress in order to inform habitat delineation or decisions for anthropogenic use of the continental shelf. The statistical characterization spans the continental shelf from the coast to approximately 120 m water depth, at approximately 5 km resolution. Time-series of wave and circulation are created using numerical models, and near-bottom output of steady and oscillatory velocities and an estimate of bottom roughness are used to calculate a time-series of bottom shear stress at 1-hour intervals. Statistical descriptions such as the median and 95th percentile, which are the output included with this database, are then calculated to create a two-dimensional picture of the regional patterns in shear stress. In addition, time-series of stress are compared to critical stress values at select points calculated from observed surface sediment texture data to determine estimates of sea floor mobility. Purpose: This GIS layer contains an estimate of the percentage of time sediment is mobile at select points in the Middle Atlantic Bight. This output is based on numerical models of wave and circulation used to estimate bottom shear stress over an approximately one year time frame, which is subsequently compared to critical stress values estimated from observed surface sediment texture data. This data layer is primarily intended to show the overall distribution of sediment mobility on large spatial scales, and should be used qualitatively. Intended users include scientific researchers and the coastal and marine spatial planning community. Supplemental_Information: This data layer is a subset of the U.S. Geological Survey Sea Floor Stress and Sediment Mobility database, and contains the percentage of time sediment is mobile at select points in the Middle Atlantic Bight. This portion of the database was released in November, 2012. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100501 Ending_Date: 20110501 Currentness_Reference: ground condition Status: Progress: Planned Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -76.626671 East_Bounding_Coordinate: -68.388000 North_Bounding_Coordinate: 41.558331 South_Bounding_Coordinate: 34.173328 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:d20772d7-61ba-48ed-b30b-a70dc4b10bd5 Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: bottom shear stress Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Woods Hole Coastal and Marine Science Center Theme_Keyword: WHCMSC Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: wave Theme_Keyword: current Theme_Keyword: SWAN Theme_Keyword: ROMS Theme_Keyword: Grant-Madsen Theme_Keyword: Coastal and marine spatial planning Theme_Keyword: CMSP Theme_Keyword: sea floor habitat Theme_Keyword: sediment mobility Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: predictions Theme_Keyword: substrate Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords Theme_Keyword: numerical modeling Theme_Keyword: seabed Theme_Keyword: sediment transport Theme_Keyword: alteration of benthic habitats Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: mathematical modeling Theme_Keyword: sea-floor characteristics Theme_Keyword: sediment transport Theme_Keyword: ocean processes Theme_Keyword: habitat alteration and disturbance Theme: Theme_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Theme_Keyword: Marine Nearshore Subtidal Theme_Keyword: Marine Offshore Subtidal Theme_Keyword: Continental/Island Shelf Place: Place_Keyword_Thesaurus: None Place_Keyword: Middle Atlantic Bight Place_Keyword: U.S. East Coast Place_Keyword: Chesapeake Bay Place_Keyword: United States Place_Keyword: North America Place_Keyword: Atlantic Ocean Place_Keyword: Long Island Place_Keyword: New York Bight Place_Keyword: Nantucket Shoals Place_Keyword: Hudson Shelf Valley Place_Keyword: Long Island Sound Place_Keyword: Delaware Bay Place_Keyword: Pamlico Sound Place_Keyword: Rhode Island Sound Place: Place_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Place_Keyword: Virginian Ecoregion Stratum: Stratum_Keyword_Thesaurus: None Stratum_Keyword: seafloor Stratum_Keyword: sea floor Stratum: Stratum_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Stratum_Keyword: Substrate 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. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: P. Soupy Dalyander Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2290 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: sdalyander@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://cmgds.marine.usgs.gov/data/whcmsc/data-release/doi-P999PY84/MiddleAtlanticBight/data/mobility_browse_mab_percent.jpg Browse_Graphic_File_Description: Image displaying estimated percentage of time sediment is mobile at select points in the Middle Atlantic Bight. Browse_Graphic_File_Type: JPEG Native_Data_Set_Environment: Microsoft Windows Vista Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.1850 Cross_Reference: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2012 Title: Documentation of the U.S. Geological Survey Sea Floor Stress and Sediment Mobility Database Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 2012-1137 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ofr20121137 Online_Linkage: https://pubs.usgs.gov/of/2012/1137/ Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Each attribute in this data layer covers a specific time period of interest. The attributes include winter (December - February), spring (March - May), summer (June - August), fall (September - November), and the entire year. Each of these attributes was calculated from model output spanning May, 2010 to May, 2011. Statistical values will vary somewhat if calculated from model parameters covering a different time period, or if a different numerical model is used to estimate the time-series of waves and circulation used in calculating the time-series of bottom shear stress. Critical stress values are based on estimates made from observed surface sediment texture data, and would vary somewhat if different texture data and/or a different model of critical shear stress calculation were used. Logical_Consistency_Report: No duplicate features are present. All polygons are closed, and all lines intersect where intended. No undershoots or overshoots are present. Completeness_Report: All model output values were used in the calculation of this statistic. The statistic was calculated for the date range of May, 2010 to May, 2011, and would potentially vary somewhat if performed on a different time period. The underlying time-series of bottom shear stress was calculated from wave and current estimates generated with numerical models, and would vary if different models are used or if different model inputs (such as bathymetry or forcing winds) or parameterizations were chosen. Critical shear stress values used to estimate sediment mobility are based on observed surface sediment texture data, and mobility results would vary if different sediment texture data and/or a different model of critical shear stress were used. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Numerical models are used in the generation of time-series of bottom shear stress 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, and forcing values used, and so forth, the spatial accuracy of this data layer cannot be meaningfully quantified. These maps are intended to provide a qualitative and relative regional assessment of sea floor mobility at select points; users are advised not to use the data set to estimate mobility quantitatively at any specific geographic location, or to extrapolate mobility estimates to points not included in the database. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: NOAA National Centers for Environmental Prediction (NCEP) Publication_Date: 20110601 Title: NOAA/NCEP Global Forecast System (GFS) Atmospheric Model Publication_Information: Publication_Place: Camp Springs, MD Publisher: NOAA National Centers for Environmental Prediction Online_Linkage: http://nomads.ncdc.noaa.gov/data.php Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100401 Ending_Date: 20110601 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NOAA GFS Source_Contribution: The NOAA Global Forecast System (GFS) 0.5 degree model was used to provide wind speed data at 10 m above the sea surface to drive the numerical wave model used to generate bottom orbital wave velocities for calculations of a time-series of bottom shear stress. Source_Information: Source_Citation: Citation_Information: Originator: NOAA National Centers for Environmental Prediction (NCEP) Publication_Date: 20110601 Title: NOAA/NCEP North American Mesoscale (NAM) Atmospheric Model Publication_Information: Publication_Place: Camp Springs, MD Publisher: NOAA National Centers for Environmental Prediction Online_Linkage: http://nomads.ncdc.noaa.gov/data.php Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100401 Ending_Date: 20110601 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NOAA NAM Source_Contribution: The NOAA North American Mesoscale (NAM) model was used to provide wind speed data at 10 m above the sea surface to drive the numerical wave model used to generate bottom orbital wave velocities for calculations of a time-series of bottom shear stress. Source_Information: Source_Citation: Citation_Information: Originator: Rutgers Ocean Modeling Group Publication_Date: 20110601 Title: Esperimental System for Predicting Shelf and Slope Optics (ESPreSSO) Publication_Information: Publication_Place: New Brunswick, NJ Publisher: Rutgers Ocean Modeling Group Online_Linkage: http://www.myroms.org/espresso/ Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100501 Ending_Date: 20110501 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: RU ESP Source_Contribution: The Rutgers University ESPreSSO model was used to provide estimates of near-bed current velocity used for calculating the time-series of bottom shear stress. The ESPreSSO hydrodynamic model (http://www.myroms.org/espresso/) has been operated by Rutgers University since October 2009 as a data-assimilative nowcast/forecast system for the Mid-Atlantic Regional Association Coastal Ocean Observing System (MARACOOS, http://maracoos.org/), part of the U.S. Integrated Ocean Observing System (https://ioos.noaa.gov). The underlying circulation model is the Regional Ocean Modeling System (ROMS; http://www.myroms.org), a finite-difference, hydrostatic, primitive equation ocean model that solves for the free surface elevation and three dimensional flow patterns, temperature, and salinity. The ESPreSSO configuration of ROMS has 5 km horizontal resolution and 36 layers in vertical terrain-following coordinates. Bathymetry and land-sea masking is from the National Geophysical Data Center (NGDC) Coastal Relief Model. The vertical turbulence closure is the k-kl option of the Generalized Length Scale (GLS) formulation. Air-sea fluxes of momentum and heat are computed using bulk formulae applied to ROMS ocean surface conditions and meteorological conditions (wind velocity, rain, downward long- and short-wave radiation, and marine boundary layer temperature, pressure, and relative humidity) from the NOAA NAM atmospheric forecast. Ocean open boundary values are from a global forecast that uses the HYbrid Coordinate Ocean Model (HyCOM) with assimilation of satellite and in situ data with the Navy Coupled Ocean Data Assimilation (NCODA) system. ESPreSSO river inflows are from daily U.S. Geological Survey (USGS) stream gauge data, and tidal harmonic boundary variability is determined from a regional tidal model. Output from the ESPreSSO forecast system is saved every 2 hours. Access to model results is made practical through the use of Thematic Real-time Environmental Distributed Data Services (THREDDS) technology, which allows subsets of large data sets to be accessed directly via Open-source Project for a Network Data Access Protocol (OPeNDAP) over the Internet from remote locations without transferring the entire multi-gigabyte model output. The ESPreSSO data assimilation methodology consists of using the incremental strong constraint 4-dimensional variational (IS4DVar) approach to optimally adjust the model state within a 3-day duration analysis interval that precedes each 72-hour forecast. The assimilation cycle is repeated daily (hence the 3-day analysis windows overlap) and the first 24 hours of each forecast is retained as the "best estimate" of the ocean state for that day. It was these "best estimate" data that were analyzed here. The data assimilated include surface currents from the MARACOOS HF-Radar (CODAR) network, sea surface temperature from satellite infrared (AVHRR) and microwave (AMSR-E) radiometers, and sea surface height anomalies from the Jason-2 altimeter satellite. In addition, a regional high-resolution climatology based on a 4-dimensional weighted least squares mapping of historical hydrographic data is assimilated to constrain biases in temperature and salinity introduced by the boundary conditions and/or internal model drift. Source_Information: Source_Citation: Citation_Information: Originator: NOAA National Centers for Environmental Prediction (NCEP) Publication_Date: 20110601 Title: NOAA/NWS/NCEP Global Wavewatch III Operational Wave Forecast Publication_Information: Publication_Place: Camp Springs, MD Publisher: NOAA National Centers for Environmental Prediction Online_Linkage: http://polar.ncep.noaa.gov/waves/index2.shtml Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100401 Ending_Date: 20110601 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: NOAA WW3 Source_Contribution: Boundary conditions for the wave model were provided by the global NOAA/NWS/NCEP Wavewatch III operational ocean wave forecast. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2011 Title: ECSTDB2011.xls: U.S. Geological Survey East Coast Sediment Texture Database (2011) Edition: 2.2 Geospatial_Data_Presentation_Form: spreadsheet Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1001 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: At the time the data were taken for this study, the surficial sediment texture data had been updated to include samples analyzed through January, 2011. Online_Linkage: http://pubs.usgs.gov/of/2005/1001/data/surficial_sediments/ecstdb2011.xls Online_Linkage: http://pubs.usgs.gov/of/2005/1001/htmldocs/datacatalog.htm Larger_Work_Citation: Citation_Information: Originator: L.J. Poppe Originator: S.J. Williams Originator: V.F. Paskevich Publication_Date: 2005 Title: USGS East-Coast Sediment Analysis: Procedures, Database, and GIS Data Edition: 1.0 Geospatial_Data_Presentation_Form: spreadsheet Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1001 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ofr20051001 Online_Linkage: https://pubs.usgs.gov/of/2005/1001/ Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20110101 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: USGS ECSTD Source_Contribution: Critical stress threshold values were calculated from surface sediment texture data found in the U.S. Geological Survey East-Coast Sediment Texture Database Process_Step: Process_Description: The Simulating WAves Nearshore (SWAN) numerical wave model (version 40.81, modified for proper calculation of RMS bottom orbital velocity and for output of bottom wave direction) was used to create a time-series of bottom orbital velocity, bottom representative period, and bottom wave direction over the one year time period of May, 2010 - May, 2011 in each grid cell in the model domain. The wave model SWAN is a 3rd generation phase-averaged numerical wave model which conserves wave energy subject to generation, dissipation, and transformation processes and resolves spectral energy density over a range of user-specified frequencies and directions. Although stress calculations were only performed over the spatial extent of the hydrodynamic model, SWAN was run over a larger spatial scale. This ~5 km resolution grid, which covers the U.S. East Coast, Gulf of Mexico, and much of the western north Atlantic, was originally developed for use with the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) model system forecast and is shown elsewhere (Warner et al., 2010). This domain pushes the boundaries of the grid far from the region of interest to allow the wave spectrum (relatively important in calculations of stress) to evolve away from the boundary. The model was run for April 2010 using the default SWAN initial condition formulation for a non-stationary run, e.g., a JONSWAP spectrum from prescribed initial wind conditions, to develop initial conditions for the one year study period (May 2010 to May 2011). Significant wave height, dominant wave period, and wave direction were prescribed as SWAN TPAR format files on the model grid boundary with a spatial resolution of a boundary point every 25 grid cells using results from the NOAA Wavewatch III global multi-grid model, updated every 3 hours. A JONSWAP (JOint NOrth Sea WAve Project) spectral shape was assumed at these boundary points. Wind forcing was provided at 3-hour resolution from the NOAA North American Mesoscale (NAM) model (12 km resolution) over its domain, with forcing at the most offshore portions of the grid (outside the NAM grid) provided by the NOAA Global Forecasting System (GFS) model at 0.5 degree resolution. The SWAN directional resolution was 6 degrees (60 bins), determined via sensitivity analysis as the coarsest (and hence least computationally expensive) resolution that does not result in the "Garden-Sprinkler Effect" (GSE), wherein swell traveling over large distances inaccurately disintegrates into non-continuous wave fields as a result of frequency and directional discretization. The minimum frequency bin should be set to a value less than 0.7 times the lowest expected peak frequency and the maximum frequency bin should be set at least 2.5-3 times the highest expected peak frequency expected. In order to determine appropriate values, the peak periods from 43 NDBC buoys throughout the wave model domain were analyzed (when available) over the one year period of the study, yielding 297,533 hourly observations. The 99th and 1st percentiles of peak period were 15 s and 3 s, corresponding to frequencies of 0.07 Hz and 0.33 Hz, noting that these values may be biased by buoy limits of detection at high and low frequencies. The frequency range was therefore specified as 0.04-1 Hz. SWAN was allowed to internally determine the frequency resolution as one tenth of each frequency bin for best performance of the discrete interaction approximation (DIA) method of nonlinear 4-wave interactions, resulting in 34 frequency bins. Bottom friction calculations used the Madsen formulation with a uniform roughness length scale of 0.05 m. This value was selected for the best comparison of model output and buoy observations within the domain, and does not correspond to physical roughness values or the bottom roughness used in stress calculations. Wind generation and whitecapping parameterizations follow the modified Komen approach prescribed by Rogers et al. (2003), which reduces inaccurate attenuation of swell energy by whitecapping. Wave model outputs of bottom orbital velocity, bottom representative period, and bottom wave direction were output hourly and interpolated onto the ESPreSSO model grid. NDBC observations were used for model validation; ten full-spectra wave buoys are within the domain. Due to maintenance problems observations from all buoys were not available over the entire time period and data from Texas Tower Station 44066 for January 2011, when the buoy was adrift but still reporting, were manually removed. Using the GM method and the same bottom roughness of 0.005 m used to process model output, surface and bottom parameters were calculated from buoy spectra and compared to model output at the same locations. The same person that conducted this processing step conducted each subsequent processing step. References: Rogers, W.E., Hwang, P.A., Wang, D.W., 2003. Investigation of Wave Growth and Decay in the SWAN Model: Three Regional-Scale Applications. J. Phys. Oceanogr. 33, 366-389. Warner, J.C., Armstrong, B., He, R., Zambon, J.B., 2010. Development of a Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System. Ocean Modelling 35, 230-244. Source_Used_Citation_Abbreviation: NOAA GFS Source_Used_Citation_Abbreviation: NOAA NAM Source_Used_Citation_Abbreviation: NOAA WW3 Process_Date: 2011 Source_Produced_Citation_Abbreviation: SWAN WEST ATL Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: P. Soupy Dalyander Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2290 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: sdalyander@usgs.gov Process_Step: Process_Description: Use observed surficial sediment texture data to estimate the critical shear stress at those points where sediment texture data are available. Calculations are performed in Mathworks MATLAB (v2011A). The texture data includes the distribution of sediment over grain size classes ranging from -5 to 11 phi, ranging from gravel through sand and silt to clay. Texture observations are first classified as cohesive or non-cohesive based on the fraction of clay: if the clay fraction exceeds 7.5%, the sample is deemed cohesive, if less than or equal to 7.5% the sample is non-cohesive. Critical stress thresholds for non-cohesive sediment mixtures are calculated from the median grain size following Soulsby (1997). Because a variety of unavailable parameters influence the critical shear stress for cohesive sediments, a value of 0.1 Pa is used for all samples identified as cohesive. Critical stress values, median grain sizes, and classifications as cohesive or non-cohesive at each location are saved in MATLAB .mat format. Additional information may be found in Dalyander et al. (2012). References: Dalyander, P.S., Butman, B., Sherwood, C.R., and Signell, R.P. (2012). Documentation of the U.S. Geological Survey Seafloor Stress and Sediment Mobility Database. USGS OFR 2012-1137. Soulsby, R., 1997. Dynamics of Marine Sands, a Manual for Practical Applications. Thomas Telford Publications, London. Source_Used_Citation_Abbreviation: USGS ECSTD Process_Date: 2011 Source_Produced_Citation_Abbreviation: USGS ECSTD MAT Process_Step: Process_Description: Use the wave model and current model results to calculate the time series of bottom shear stress at each point for which sediment texture data are available using Mathworks MATLAB software (v2011A). Bottom shear stress estimates are made following Grant-Madsen (GM) (Madsen, 1994), from the estimated bottom orbital velocities and bottom wave periods generated with SWAN, and near-bed current estimates from the ESPreSSO hydrodynamic model. The GM approach relies on an eddy viscosity turbulence closure model and formulates the wave stress, current stress, and combined wave-current bottom stress as functions of a representative bottom wave orbital velocity, representative bottom wave period, current flow at some reference height, the angle between wave and current propagation, and bottom roughness. Full details of the GM formulation may be found elsewhere (Glenn, 1983; Glenn and Grant, 1987; Grant and Madsen, 1979, 1982, 1986; Madsen, 1994; Madsen et al., 1988). Wave direction, bottom orbital velocities, and bottom periods are calculated internally by the wave model. Near-bed current magnitude and direction are taken from the hydrodynamic model, with the reference height taken as the distance from the cell vertical midpoint to the seabed. GM requires that the current velocity be taken above the wave boundary layer (WBL) but within the log-profile current velocity layer. If the thickness of the WBL calculated using GM exceeds of one or more of the deepest grid cells, the current estimate and associated reference height are used from the deepest grid cell at each location where the reference height exceeds the width of the WBL. An estimate must be used for the maximum reference height where the log-profile velocity layer assumption is valid. As discussed in Grant and Madsen (1986), the thickness of the log-profile layer based on laboratory experiments is approximately 10% of the current boundary layer thickness (Clauser, 1956). Because tidal currents, storm currents, and mean flow have a boundary layer thickness on the order of magnitude 10's of meters (Goud, 1987), a maximum value for reference height is set as 5 m. The GM bottom boundary layer model also requires a value for bottom roughness. For the mobility estimates, it is the skin friction acting on the particles, and not the total bottom shear stress, which is the relevant parameter. For that reason, observed sediment texture data from the USGS East Coast Sediment Texture Database (v2.2) are used to calculate the bottom roughness at each point for which they are available. For non-cohesive samples (see definition in Process Step 2), the median grain size is used as the roughness. For cohesive samples a roughness of 62.5 micrometers, which has a critical stress based on Soulsby (1997) of 0.1 Pa, is used. References: Madsen, O.S., 1994. Spectral wave-current bottom boundary layer flows, Proceedings 24th Conf. Coastal Eng., pp. 384-398. Glenn, S.M., 1983. A Continental Shelf Bottom Boundary Layer Model: The Effects of Waves, Currents, and a Moveable Bed. Dissertation, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, Cambridge, MA, 237 pp. Glenn, S.M., Grant, W.D., 1987. A suspended sediment stratification correction for combined wave and current flows. J. Geophys. Res. 92, 8244-8264. Goud, M.R., 1987. Prediction of Continental Shelf Sediment Transport Using a Theoretical Model of the Wave-Current Boundary Layer. Dissertation, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, Cambridge, MA, 211 pp. Grant, W.D., Madsen, O.S., 1986. The continental-shelf bottom boundary-layer. Annu. Rev. Fluid Mech. 18, 265-305. Grant, W.D., Madsen, O.S., 1982. Movable bed roughness in unsteady oscillatory flow. J. Geophys. Res. 87, 469-481. Grant, W.D., Madsen, O.S., 1979. Combined wave and current interaction with a rough bottom J. Geophys. Res. 84, 1797-1808. Madsen, O.S., 1994. Spectral wave-current bottom boundary layer flows, Proceedings 24th Conf. Coastal Eng., pp. 384-398. Madsen, O.S., Poon, Y., Graber, H.C., 1988. Spectral wave attenuation by bottom friction: theory, Proceedings 21st Int. Conf. Coast. Eng., pp. 492-504. Soulsby, R., 1997. Dynamics of Marine Sands, a Manual for Practical Applications. Thomas Telford Publications, London. Source_Used_Citation_Abbreviation: SWAN WEST ATL Source_Used_Citation_Abbreviation: RU ESP Source_Used_Citation_Abbreviation: USGS ECSTD MAT Process_Date: 2011 Source_Produced_Citation_Abbreviation: MAB STRESS TSERIES Process_Step: Process_Description: Calculate the percentage of time sediment is mobile by year and season in Mathworks MATLAB software (v2011A) by comparing the critical stress value at each point location where sediment texture data are available to the time series of combined wave-current stress at that location. The percentage of time sediment is mobile is calculated as the number of hours the critical shear stress is exceeded divided by the total number of hours in the time period of interest (year or season), converted from a fraction to a percentage by multiplying by 100. These values are saved in MATLAB .mat format. Source_Used_Citation_Abbreviation: MAB STRESS TSERIES Source_Used_Citation_Abbreviation: USGS ECSTD MAT Process_Date: 2011 Source_Produced_Citation_Abbreviation: MAB PERC Process_Step: Process_Description: Export the point values from MATLAB format into an ArcGIS shapefile using the Mathworks MATLAB Mapping Toolbox (v2011A). In some cases, data may exist during parts of the year and not others; in this case, the statistic is calculated and included for the season where model output exist, and a missing data value of -9999 is used for seasons where no valid statistic can be calculated. A geographic data structure is created in MATLAB with the following fields: Geometry ('Point'), Lon (the longitude at the point), Lat (the latitude at the point), Winter (the statistic calculated for December, January, and February), Spring (the statistic calculated for March, April, and May), Summer (the statistic calculated for June, July, and August), and Fall (the statistic calculated for September, October, and November). The shapefile is then written with the "shapewrite" command. Because MATLAB does not assign a projection, the projection corresponding to the projection associated with the bathymetry used in the numerical models is added in ArcCatalog 9.3. The file was then quality checked in ArcMap to insure values were properly exported to the shapefile from MATLAB. Source_Used_Citation_Abbreviation: MAB PERC Process_Date: 2011 Process_Step: Process_Description: Edits to the metadata were made to fix any errors that MP v 2.9.32 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Process_Date: 20160712 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02556 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20170313 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Process_Date: 20180426 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: The data release was retroactively assigned a DOI number, and that information was added to the metadata. Additionally, the location of the data release changed, and the metadata links updated accordingly. Other small edits, such as the program name, were also modified. Process_Date: 202006 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword (20200908). Fixed one of the USGS Thesaurus terms. Process_Date: 20211116 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Indirect_Spatial_Reference: Middle Atlantic Bight Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 4074 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: D_WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: MAB_mobile_perc Entity_Type_Definition: Shapefile Attribute Table Entity_Type_Definition_Source: ESRI Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: Year Attribute_Definition: This value is the percentage of time sediment is mobile at point locations calculated for the one year time period of May 1, 2010 through April 30, 2011. The NODATA value is -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 93.1735 Attribute_Units_of_Measure: percentage (%) Attribute_Measurement_Resolution: 0.0001 Attribute: Attribute_Label: Winter Attribute_Definition: This value is the percentage of time sediment is mobile at point locations calculated for the period of December 1, 2010 through February 28, 2011. The NODATA value is -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 92.7778 Attribute_Units_of_Measure: percentage (%) Attribute_Measurement_Resolution: 0.0001 Attribute: Attribute_Label: Spring Attribute_Definition: This value is the percentage of time sediment is mobile at point locations calculated for the period of March 1, 2011, through April 30, 2011, and May, 2010. The NODATA value is -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 92.9348 Attribute_Units_of_Measure: percentage (%) Attribute_Measurement_Resolution: 0.0001 Attribute: Attribute_Label: Summer Attribute_Definition: This value is the percentage of time sediment is mobile at point locations calculated for the period of June 1, 2010, through August 31, 2010. The NODATA value is -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 91.9384 Attribute_Units_of_Measure: percentage (%) Attribute_Measurement_Resolution: 0.0001 Attribute: Attribute_Label: Fall Attribute_Definition: This value is the percentage of time sediment is mobile at point locations calculated for the period of September 1, 2010, to November 30, 2010. The NODATA value is -9999. Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 95.0549 Attribute_Units_of_Measure: percentage (%) Attribute_Measurement_Resolution: 0.0001 Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: P. Soupy Dalyander Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2290 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: sdalyander@usgs.gov Resource_Description: Downloadable Data: Sea Floor Stress and Sediment Mobility Database, Percentage of Time Sediment is Mobile for the Middle Atlantic Bight (MAB_mobile_perc) Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SHP Format_Version_Number: 3.3 Format_Specification: ESRI shapefile Format_Information_Content: WinZip archive file containing the shapefile components. The WinZip file also includes FGDC compliant metadata. File_Decompression_Technique: WinZip 12.0 archive Transfer_Size: 0.109 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://cmgds.marine.usgs.gov/data/whcmsc/data-release/doi-P999PY84/MiddleAtlanticBight/data/MAB_mobile_perc.zip Network_Resource_Name: https://cmgds.marine.usgs.gov/data/whcmsc/data-release/doi-P999PY84/MiddleAtlanticBight/ Network_Resource_Name: https://doi.org/10.5066/P999PY84 Access_Instructions: The first link downloads the data in a zip file, the second link is to the dataset landing page, and the third link is to the main landing page of the data release. Fees: None Technical_Prerequisites: 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. Metadata_Reference_Information: Metadata_Date: 20211119 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: P. Soupy Dalyander Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Role City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2290 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: whsc_data_contact@usgs.gov Contact_Instructions: The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid. Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998