Search

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 5129–5172, doi:10.1002/jgrc.20376., A Gulf of Mexico performance evaluation and comparison of coastal circulation and wave models was executed through harmonic analyses of tidal simulations, hindcasts of Hurricane Ike (2008) and Rita (2005), and a benchmarking study. Three unstructured coastal circulation models (ADCIRC, FVCOM, and SELFE) validated with similar skill on a new common Gulf scale mesh (ULLR) with identical frictional parameterization and forcing for the tidal validation and hurricane hindcasts. Coupled circulation and wave models, SWAN+ADCIRC and WWMII+SELFE, along with FVCOM loosely coupled with SWAN, also validated with similar skill. NOAA's official operational forecast storm surge model (SLOSH) was implemented on local and Gulf scale meshes with the same wind stress and pressure forcing used by the unstructured models for hindcasts of Ike and Rita. SLOSH's local meshes failed to capture regional processes such as Ike's forerunner and the results from the Gulf scale mesh further suggest shortcomings may be due to a combination of poor mesh resolution, missing internal physics such as tides and nonlinear advection, and SLOSH's internal frictional parameterization. In addition, these models were benchmarked to assess and compare execution speed and scalability for a prototypical operational simulation. It was apparent that a higher number of computational cores are needed for the unstructured models to meet similar operational implementation requirements to SLOSH, and that some of them could benefit from improved parallelization and faster execution speed., This project was supported by NOAA via the U.S. IOOS Office (award: NA10NOS0120063 and NA11NOS0120141)

On 22- 23 June 2010, the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) L band radar imaged the Deepwater Horizon oil spill and the effects of oil that was transported within the Gulf of Mexico. We describe the campaign and discuss the unique contributions of the UAVSAR radar to the study of the detection, migration, and impact of oil from the spill. We present an overview of UAVSAR data analyses that support the original science goals of the campaign, namely, (1) algorithm development for oil slick detection and characterization, (2) mapping of oil intrusion into coastal wetlands and intercoastal waterways, and (3) ecosystem impact studies. Our study area focuses on oil-affected wetlands in Barataria Bay, Louisiana. The results indicate that fine resolution, low-noise, L band radar can detect surface oil-on-water with sufficient sensitivity to identify regions in a slick with different types of oil/emulsions and/or oil coverage; identify oil on waters in inland bays and differentiate mixed/weathered oil from fresh oil as it moves into the area; identify areas of potentially impacted wetlands and vegetation in the marshes; and support the crisis response through location of compromised booms and heavily oiled beaches.

Author Posting. © American Meteorological Society 2006. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 23 (2006): 325–338, doi:10.1175/JTECH1848.1., Neural network analyses based on the self-organizing map (SOM) and the growing hierarchical self-organizing map (GHSOM) are used to examine patterns of the sea surface temperature (SST) variability on the West Florida Shelf from time series of daily SST maps from 1998 to 2002. Four characteristic SST patterns are extracted in the first-layer GHSOM array: winter and summer season patterns, and two transitional patterns. Three of them are further expanded in the second layer, yielding more detailed structures in these seasons. The winter pattern is one of low SST, with isotherms aligned approximately along isobaths. The summer pattern is one of high SST distributed in a horizontally uniform manner. The spring transition includes a midshelf cold tongue. Similar analyses performed on SST anomaly data provide further details of these seasonally varying patterns. It is demonstrated that the GHSOM analysis is more effective in extracting the inherent SST patterns than the widely used EOF method. The underlying patterns in a dataset can be visualized in the SOM array in the same form as the original data, while they can only be expressed in anomaly form in the EOF analysis. Some important features, such as asymmetric SST anomaly patterns of winter/summer and cold/warm tongues, can be revealed by the SOM array but cannot be identified in the lowest mode EOF patterns. Also, unlike the EOF or SOM techniques, the hierarchical structure in the input data can be extracted by the GHSOM analysis., Support was provided by the Office of Naval Research under Grant N00014-98-1-0158 for observations and modeling of the west Florida continental shelf circulation and Grant N00014-02-1-0972 for the Southeast Atlantic Coastal Ocean Observing System.

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 31 (2004): L14303, doi:10.1029/2003GL019261., Atmosphere model-derived flux fields are used to force coastal ocean models. Coarse resolution and incomplete boundary layer dynamics limit the accuracy of these forcing fields and hence the performance of the ocean models. We address this limitation for the west Florida shelf using optimal interpolation to blend winds measured in situ with winds produced by model analyses. By improving the coastal wind field we improve the fidelity between currents modeled and currents observed. Comparisons between momentum analyses performed independently from the model and the data demonstrate the fidelity to be of a correct dynamical basis. We conclude that the primary limitation to coastal ocean model performance lies with the boundary conditions., Support was provided by the Office of Naval Research, Grant #s N00014-98-1-0158 and N00014-02-1-0972.

Nested non-assimilative simulations of the West Florida Shelf for 2004-2005 are used to quantify the impact of initial and boundary conditions provided by Global Ocean Data Assimilation Experiment ocean products. Simulations are nested within an optimum interpolation hindcast of the Atlantic Ocean, the initial test of the US Navy Coupled Ocean Data Assimilation system for the Gulf of Mexico, and a global ocean hindcast that used the latter assimilation system. These simulations are compared to one that is nested in a non-assimilative Gulf of Mexico model to document the importance of assimilation in the outer model. Simulations are evaluated by comparing model results to moored Acoustic Doppler Current Profiler measurements and moored sea surface temperature time series. The choice of outer model has little influence on simulated velocity fluctuations over the inner and middle shelf where fluctuations are dominated by the deterministic wind-driven response. Improvement is documented in the representation of alongshore flow variability over the outer shelf, driven in part by the intrusion of the Loop Current and associated cyclones at the shelf edge near the Dry Tortugas. This improvement was realized in the simulation nested in the global ocean hindcast, the only outer model choice that contained a realistic representation of Loop Current transport associated with basin-scale wind-driven gyre circulation and the Atlantic Meridional Overturning Circulation. For temperature, the non-assimilative outer model had a cold bias in the upper ocean that was substantially corrected in the data-assimilative outer models, leading to improved temperature representation in the simulations nested in the assimilative outer models., The original document contains color images. All DTIC reproductions will be in black and white. Pub. in Ocean Dynamics, v59 p139-155, 2009.

The South Florida Hybrid Coordinate Ocean Model (SoFLA-HYCOM) encompasses a variety of coastal regions (the broad Southwest Florida shelf, the narrow Atlantic Keys shelf, the shallow Florida Bay, and Biscayne Bay) and deep regions (the Straits of Florida), including Marine Protected Areas (the Florida Keys Marine Sanctuary and the Dry Tortugas Ecological Reserve). The presence of the strong Loop Current/Florida Current system and associated eddies connects the local and basin-wide dynamics. A multi-nested approach has been developed to ensure resolution of coastal-scale processes and proper interaction with the large scale flows. The simulations are free running and effects of data assimilation are introduced through boundary conditions derived from Global Ocean Data Assimilation Experiment products. The study evaluates the effects of boundary conditions on the successful hindcasting of circulation patterns by a nested model, applied on a dynamically and topographically complex shelf area. Independent (not assimilated) observations are employed for a quantitative validation of the numerical results. The discussion of the prevailing dynamics that are revealed in both modeled and observed patterns suggests the importance of topography resolution and local forcing on the inner shelf to middle shelf areas, while large scale processes are found to dominate the outer shelf flows. The results indicate that the successful hindcasting of circulation patterns in a coastal area that is characterized by complex topography and proximity to a large scale current system requires a dynamical downscaling approach, with simulations that are nested in a hierarchy of data assimilative outer models., The original document contains color images. All DTIC reproductions will be in black and white. Pub. in Ocean Dynamics, v59 p47-66, 2009.

Author Posting. © Oceanography Society, 2004. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 17, 2 (2004): 68-75., Satellite-sensed ocean optical features are derived from a combination of factors, including the concentration of water properties by the ocean circulation and the modifications of these properties by biological and chemical processes. To demonstrate the role of the ocean circulation, we consider a case study on the upwelling of anomalously cold, nutrient-rich water and a related sea-surface temperature pattern that was observed on the West Florida Shelf. We use in situ data and a numerical model simulation to show how this pattern evolved in time and space and to draw a connection between a narrow band of cold water observed at the coast and the origin of this water a few hundred kilometers away at the shelf break via shoreward and southward advection within the bottom frictional (Ekman) boundary layer., Support was provided by the Office of Naval Research, grant N00014-98-1-1058 as part of the HyCODE Program.

The overarching goal is to determine how simulations and forecasts of currents and water properties in the coastal ocean, and the scientific understanding obtained from them, are influenced by the initial and boundary conditions provided to nested coastal ocean models. In addition to surface atmospheric forcing and coastal freshwater runoff, the coastal ocean is influenced by offshore ocean variability resulting from processes ranging from basin-scale wind-driven gyre and thermohaline circulation down to regional and local circulation associated with boundary currents and eddies. To accurately represent the offshore ocean influence, the coastal model must be nested within fields that accurately represent (1) the initial state of the ocean throughout the model domain and (2) currents and water properties at the nested model boundaries during the model run. We specifically evaluate the HYCOM (HYbrid Coordinate Ocean Model) data assimilation products developed as part of the Global Ocean Data Assimilation Experiment (GODAE) for providing these fields. Coastal model evaluation is being performed over a range of environments to provide feedback that will guide improvements to the HYCOM-GODAE products. The overall regional focus encompasses the coastal northern and eastern Gulf of Mexico through the Florida Straits, which represent a broad range of shelf geometries, river runoff, seasonal atmospheric forcing, and offshore forcing. Three regions are emphasized: (1) the West Florida Shelf (WFS); (2) the South Florida Coastal Region (SoFLA), including the Florida Straits, the Florida Keys and Atlantic Keys shelf, Florida Bay, and the adjacent southwest Florida shelf; and (3) the coastal northern Gulf of Mexico (NGoM). This project focuses only on downscaling open-ocean variability to the coastal ocean (one way nesting)., Prepared in collaboration with the College of Marine Science, University of South Florida, St. Petersburg, FL ; Naval Research Laboratory, Stennis Space Center, MS; Planning Systems, Incorporated, Stennis Space Center, MS; and Naval Research Laboratory, Monterey, CA. The original document contains color images. All DTIC reproductions will be in black and white.

Our long term goals are the development of robust model nesting strategies for coupling regional and global ocean circulation models and the implementation of data assimilation schemes suitable for the regional ocean models. From the perspective of advancing coastal ocean science we seek to improve our understanding on how the deep-ocean and the coastal ocean interact., The original document contains color images.

The overarching goal is to determine how simulations and forecasts of currents and water properties in the coastal ocean, and the scientific results obtained from them, are influenced by the initial and boundary conditions provided to nested coastal ocean models. In addition to surface atmospheric forcing and coastal freshwater runoff, the coastal ocean is influenced by offshore ocean variability resulting from processes ranging from basin-scale wind-driven gyre and thermohaline circulation down to regional and local circulation associated with boundary currents and eddies. To accurately represent the offshore ocean influence, the coastal model must be nested within fields that accurately represent (1) the initial state of the ocean throughout the model domain and (2) currents and water properties at the nested model boundaries during the model run. We specifically evaluate the HYCOM (HYbrid Coordinate Ocean Model) data assimilation products developed as part of the Global Ocean Data Assimilation Experiment (GODAE) for providing these fields. Coastal model evaluation is being performed over a range of environments to provide feedback that will guide improvements to the HYCOM-GODAE products. The overall regional focus encompasses the coastal northern and eastern Gulf of Mexico through the Florida Straits, which represent a broad range of shelf geometries, river runoff, seasonal atmospheric forcing, and offshore forcing. Three regions are emphasized: (1) the West Florida Shelf (WFS); (2) the South Florida Coastal Region (SoFLA), including the Florida Straits, the Florida Keys and Atlantic Keys shelf, Florida Bay, and the adjacent southwest Florida shelf; and (3) the coastal northern Gulf of Mexico (NGoM). This project focuses only on downscaling open-ocean variability to the coastal ocean (one way nesting)., A National Oceanographic Partnership Program Award. The original document contains color images.

The overarching goal is to improve our capability to map, understand, and predict changes in currents and water properties in the coastal ocean. Providing real-time (nowcast) and future (forecast) coastal ocean fields requires a coastal ocean nowcast/forecast system that consists of several components: 1. a high-quality ocean general circulation model; 2. accurate surface flux (atmospheric forcing) fields to drive the ocean model; 3. accurate estimates of coastal ocean fields at the start of a model run and along the lateral boundaries of the coastal domain during model runs; 4. accurate estimates of freshwater input from rivers and estuaries; and 5. high-quality ocean observations. The observations are necessary to provide the accurate initial and boundary fields required by component (3) and to evaluate the performance of the nowcast/forecast system. The central focus of this project is component (3), specifically to quantify and understand the impact of initial and boundary fields on coastal ocean nowcasts and forecasts, and to provide feedback that will motivate improvements in generating these fields. We are evaluating initial and boundary fields provided by a nowcast/forecast system based on the HYbrid Coordinate Ocean Model (HYCOM) developed at the Naval Research Laboratory (NRL-Stennis) as part of the Global Ocean Data Assimilation Experiment (GODAE). Results are being communicated to NRL to guide improvement strategies for their nowcast/forecast system. Although our central focus is on component (3), we also consider the other four components of the coastal nowcast/forecast system. We are striving to improve ocean model performance, evaluate model sensitivity to different atmospheric forcing products, study sensitivity to river runoff, and assess the adequacy of available coastal ocean observations. Coastal ocean simulations are also being analyzed to improve our scientific understanding of ocean variability observed in our region of interest., A National Oceanographic Partnership Program Award. Prepared in collaboration with the Florida State University, Tallahassee, FL; College of Marine Science, University of South Florida, St. Petersburg, FL; Naval Research Laboratory, Stennis Space Center, MS; Planning Systems, Incorporated, Stennis Space Center, MS; and the Naval Research Laboratory, Monterey, CA. The original document contains color images.

The overarching goal is to improve our capability to model and understand currents and water properties in the coastal ocean, and to improve our capability to forecast future changes in these currents and water properties. Coastal ocean models are used for a wide range of purposes, including naval operations, commercial marine operations (including the influence of ocean currents on shipping and oil rigs), storm surge prediction, prediction of pollution dispersion, studies of coastal fisheries and ecosystems, and providing ocean currents for search and rescue operations. This project focuses on one important aspect of improving the performance of coastal ocean models, specifically improving the quality of the fields that are used to initialize these models and provide information on water properties and currents outside of the coastal region being modeled. Although the coastal ocean is strongly influenced by surface atmospheric forcing and coastal freshwater runoff, offshore ocean variability exerts a very significant influence in many regions due to a wide range of processes such as basin-scale climate variability, boundary current meanders, and offshore ocean eddies. To accurately represent the influence of this offshore variability on a coastal ocean model, the model must be nested within fields that accurately represent (1) the initial state of the coastal ocean throughout the model domain and (2) currents and water properties at the nested model boundaries. We will specifically evaluate the use of the HYbrid Coordinate Ocean Model (HYCOM) data assimilation product developed as part of the Global Ocean Data Assimilation Experiment (GODAE) for this purpose. The influence of these initial and boundary fields on the performance of the coastal model will be thoroughly evaluated. This information will provide important feedback that will be used to guide improvements to the HYCOM-GODAE product that provides the initial and boundary fields. The overall regional focus, Prepared in cooperation with University of South Florida, St. Petersburg, FL, Naval Research Laboratory, Stennis Space Center, MS, Planning Systems, Inc., Stennis Space Center, MS, and Naval Research Laboratory, Monterey, CA.

My long-term goal is improved understanding of how physical processes affect material property distributions on continental shelves. These include biological (red-tide algae and fish larvae), chemical (nutrients), and geological (sediment resuspension/transport) measures, and the physical responses of the currents and sea level. To achieve this goal I must accomplish a related set of objectives. In logical order, these are. 1) I am developing a description of the seasonally varying circulation on the West Florida Continental Shelf (WFS) using a combination of in-situ measurements and numerical circulation models. 2) Along with description, I am developing a quantitative understanding of how the various forcing functions: tides; synoptic weather; and surface, coastal, and offshore buoyancy fluxes affect the WFS circulation. 3) I am determining how these processes affect along and across-shelf material property transports, with emphasis on the frictional boundary layers. 4) Given large seasonal transitions, I am assessing the relative importances of the surface heat and fresh water fluxes and the coastal ocean dynamics in determining WFS water properties. 5) I want to relate these foregoing physical factors to questions of geological, biological, and chemical importance; for example, storm surges, sediment redistributions, nutrient distributions, species migrations and successions, primary productivity, red-tides, and how all of these factors affect inherent optical properties (IOPs). 6) Since these objectives require sampling over various time and length scales using an assortment of instruments, I am working toward a WFS Autonomous Ocean Sampling Network (AOSN) site south of Tampa Bay that may be useful for naval defense related experimentation.

My long-term goal is to contribute toward the understanding of how physical processes affect the distribution of material properties on the continental shelf. These include biological factors such as red-tide algae and fish larvae, chemical factors such as nutrients that promote phytoplankton blooms, and geological factors such as sediment resuspension that affects both inherent optical properties within the water column and erosion/accretion on the bottom, and the physical responses themselves that affect the currents and sea level responses to storms., See also ADM002252.