A hydrodynamic model for Galveston Bay and the shelf in the northwestern Gulf of Mexico

Abstract. A 3-D unstructured-grid hydrodynamic model for the northern Gulf of Mexico was developed, with a hybrid s–z vertical grid and high-resolution horizontal grid for the main estuarine systems along the Texas–Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM), is driven by the observed river discharge, reanalysis atmospheric forcing, and open boundary conditions from global HYCOM output. The model reproduces the temporal and spatial variation of observed water level, salinity, temperature, and current velocity in Galveston Bay and on the shelf. The validated model was applied to examine the remote influence of neighboring large rivers, specifically the Mississippi–Atchafalaya River (MAR) system, on salinity, stratification, vertical mixing, and longshore transport along the Texas coast. Numerical experiments reveal that the MAR discharge could significantly decrease the salinity and change the stratification and vertical mixing on the inner Texas shelf. It would take about 25 and 50 d for the MAR discharge to reach the mouth of Galveston Bay and Port Aransas, respectively. The influence of the MAR discharge is sensitive to the wind field. Winter wind constrains the MAR freshwater to form a narrow lower-salinity band against the shore from the Mississippi Delta all the way to the southwestern Texas coast, while summer wind reduces the downcoast longshore transport significantly, weakening the influence of the MAR discharge on surface salinity along Texas coast. However, summer wind causes a much stronger stratification on the Texas shelf, leading to a weaker vertical mixing. The decrease in salinity of up to 10 psu at the mouth of Galveston Bay due to the MAR discharge results in a decrease in horizontal density gradient, a decrease in the salt flux, and a weakened estuarine circulation and estuarine–ocean exchange. We highlight the flexibility of the model and its capability to simulate not only estuarine dynamics and shelf-wide transport, but also the interactions between them.

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A hydrodynamic model for Galveston Bay and the shelf in the northwestern Gulf of Mexico

10.5194/os-2019-9 ◽

2019 ◽

Cited By ~ 1

Author(s):

Jiabi Du ◽

Kyeong Park ◽

Jian Shen ◽

Yinglong J. Zhang ◽

Xin Yu ◽

...

Keyword(s):

Gulf Of Mexico ◽

Hydrodynamic Model ◽

Integrated System ◽

Salt Flux ◽

Open Boundary ◽

Galveston Bay ◽

Open Boundary Conditions ◽

Texas Coast ◽

Salinity Regime ◽

Horizontal Density Gradient

Abstract. We present a 3D unstructured-grid hydrodynamic model for the northwestern Gulf of Mexico that utilizes a high-resolution grid for the main estuarine systems along the Texas-Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) with hybrid horizontal and vertical grids, is driven by the observed river discharge, reanalysis atmospheric forcing, and open boundary conditions from the global models. The model reproduces well the temporal and spatial variation of observed water level, salinity, temperature, and current velocity both in Galveston Bay and on the shelf. We apply the validated model to examine the remote influence from large rivers, specifically the Mississippi and Atchafalaya rivers, on the salinity regime along the Texas coast. Numerical experiments reveal that the Mississippi-Atchafalaya discharge could significantly decrease the salinity on the inner shelf along the Texas coast and its influence highly depends on the wind field and the resulting shelf current. Winter wind tends to constrain the Mississippi-Atchafalaya water against the shore, forming a narrow lower-salinity band all the way to the southwestern Texas coast. Under summer wind, the influence of the discharge on salinity is limited to the upper Texas coast while extended offshore. The decrease in salinity at the mouth of Galveston Bay due to the Mississippi-Atchafalaya discharge leads to a decrease in horizontal density gradient, a weakened estuarine circulation inside the bay, a decrease in the salt flux, and a smaller estuarine-ocean exchange. We highlight the flexibility of the model that simulates not only estuarine dynamics and shelf-wide transport but also the interaction between them.

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MACRO-GOM: Long Term Multi-Resolution Ocean Current Reanalysis Dataset for the Gulf of Mexico

10.4043/31152-ms ◽

2021 ◽

Author(s):

Neha Groves ◽

Ashwanth Srinivasan ◽

Leonid Ivanov ◽

Jill Storie ◽

Drew Gustafson ◽

...

Keyword(s):

High Resolution ◽

Gulf Of Mexico ◽

Observational Data ◽

Hydrodynamic Model ◽

Life Extension ◽

Ocean Current ◽

Reanalysis Dataset ◽

Time Period ◽

Offshore Industry

Abstract The Gulf of Mexico's unique circulation characteristics pose a particular threat to marine operations and play a significant role in driving the criteria used for design and life extension analyses of offshore infrastructure. Estimates from existing reanalysis datasets used by operators in GOM show less than ideal correlation with in situ measurements and have a limited resolution that disallows for the capture of ocean features of interest. In this paper, we introduce a new high-resolution long-term reanalysis dataset, Multi-resolution Advanced Current Reanalysis for the Ocean – Gulf of Mexico (MACRO-GOM), based on a state-of the-science hydrodynamic model configured specifically for ocean current forecasting and hindcasting services for the offshore industry that assimilates extensive non-conventional observational data. The underlying hydrodynamic model used is the Woods Hole Group – Tendral Ocean Prediction System (WHG-TOPS). MACRO-GOM is being developed at the native resolution of the TOPS-GOM domain, i.e. 1/32° (~3 km) hourly grid for the 1994-2019 time period (25 years). A 3-level downscaling methodology is used wherein observation based estimates are first dynamically interpolated using a 1/4° model before being downscaled to the 1/16° Inter-American Seas (IAS) domain, which in turn is used to generate time-consistent boundary conditions for the 1/32° reanalysis. A multiscale data assimilation technique is used to constrain the model at synoptic and longer time scales. For this paper, a shorter, 5-year reanalysis run was conducted for the 2015-2019 time period for verification against assimilated and unassimilated observations, WHG's proprietary frontal analyses, and other reanalyses. Both the frontal analyses and Notice to Lesses (NTL) rig mounted ADCP data was withheld from assimilation for comparison. Offshore operations in the GOM can benefit from an improved reanalysis dataset capable of assimilating existing non-conventional observational datasets. Existing hindcast and reanalysis model datasets are limited in their ability to comprehensively and reliably quantify the 3D circulation and kinematic properties of the main features partly because of limited assimilation of observational data. MACRO-GOM incorporates all the advantages of available HYCOM-based reanalyses and further enhances the resolution, accuracy, and reliability by the assimilation of over three decades of WHG's proprietary datasets and frontal analyses for continuous model correction and ground-truthing. The final 25-year high resolution dataset will provide highly reliable design and operational criteria for new and existing infrastructure in GOM.

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DESIGN OF DEEP DRAFT NAVIGATION CHANNEL FROM GULF OF MEXICO INTO MATAGORDA BAY, TEXAS

Coastal Engineering Proceedings ◽

10.9753/icce.v8.34 ◽

2011 ◽

Vol 1 (8) ◽

pp. 34

Author(s):

E.A. Weiser ◽

Jack Armstrong

Keyword(s):

Gulf Of Mexico ◽

River Discharge ◽

Colorado River ◽

Study Data ◽

Beach Erosion ◽

Galveston Bay ◽

Project Report ◽

Model Study ◽

Navigation Channel ◽

Tidal Hydraulics

It was in July 1956 when the senior writer of this paper was requested to prepare a program for investigations and studies required in connection with the proposed deep-draft channel from the Gulf of Mexico to Point Comfort. During 1938 to 19^0, the senior writer had attempted to analyze the available field and model study data which were then available on Galveston Bay in the hope of thus being able to reduce the shoaling in the various deep draft channels in Galveston Bay. In 19^0, the senior writer had been in charge of two field parties one of which measured the flow of water in the Colorado River and the Gulf Intracoastal Waterway near their crossing near Matagorda, Texas. A peak discharge of about 80,000 cubic feet per second was measured in the Colorado River at the Palacios Road bridge, about 15 miles upstream from its mouth during this period. At that time there were no locks nor gates in the Intracoastal Waterway adjacent to the Colorado River. It was found then that about one third of this peak river discharge flowed southwest through the Intracoastal Waterway. On the basis of the above experience and the information obtained from a review of the Matagorda Ship Channel, Texas, project report (l) and other literature, then, available (2) thru (5) a program was formulated in June 1958 and submitted to the Division Engineer in Dallas with the request that the Office of the Chief of Engineers, the Southwestern Division Engineer Office, the Beach Erosion Board and the Committee on Tidal Hydraulics review the program.

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Fluctuation and diversity of Hydromedusae (Hydrozoa, Cnidaria) in a highly productive region of the Gulf of Mexico inferred from high frequency plankton sampling

PeerJ ◽

10.7717/peerj.7848 ◽

2019 ◽

Vol 7 ◽

pp. e7848 ◽

Cited By ~ 1

Author(s):

Sarah Pruski ◽

Maria Pia Miglietta

Keyword(s):

Gulf Of Mexico ◽

First Record ◽

Multivariate Regression Analysis ◽

Future Climate Change ◽

Galveston Bay ◽

Climate Change Scenarios ◽

Efficient Tool ◽

Molecular Barcoding ◽

Seasonal Factors ◽

Peak Abundance

Hydrozoa medusae undergo blooms and seasonal fluctuations; however the drivers of such fluctuations are unknown. To understand how medusa populations fluctuate in response to seasonal factors such as temperature, salinity, dissolved oxygen, and chlorophyll a, and to enhance our taxonomic knowledge of Hydrozoa in Galveston Bay (TX), we performed frequent plankton sampling from September 2015 to September 2016. We collected 1,321 medusae in 190 sampling days. Using molecular barcoding and morphological analyses we identified 25 species, of which 21 are a first record for Galveston Bay and eight for the Gulf of Mexico. Daily medusa abundance is non-linearly related to temperature, with peak abundance estimated with multivariate regression analysis at approximately 21C. The role that temperature plays in driving medusa abundance has implications for future climate change scenarios, given that temperature in the Gulf of Mexico is expected to rise 4 °C by the end of the century. We also show that the biodiversity of the Galveston Bay and the Gulf of Mexico is underestimated and that molecular barcoding is an important and efficient tool to identify large number of medusae. We conclude that dense plankton sampling is necessary to capture both diversity and abundance of planktonic medusae.

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RECOVERY OF TARMATS USING COMMERCIAL SHRIMPING BOATS DURING THE BUFFALO 292 SPILL

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1997-1-41 ◽

1997 ◽

Vol 1997 (1) ◽

pp. 41-49 ◽

Cited By ~ 1

Author(s):

Tricia Clark ◽

Beatrice Stong ◽

Ben Benson

Keyword(s):

Gulf Of Mexico ◽

Surface Waters ◽

Barrier Island ◽

Barrier Islands ◽

Weather Conditions ◽

Fuel Oil ◽

Galveston Bay ◽

Great Success ◽

Spring Break

ABSTRACT One of the greatest challenges facing responders to a recent intermediate fuel oil (IFO 380) spill was the recovery of tar mats and patties from the surface waters of the Gulf of Mexico before they could impact the barrier islands of Texas. When the marine barge Buffalo 292 spilled approximately 3000 barrels of IFO 380 in heavy weather conditions in Galveston Bay in March 1996, it is estimated that more than half of the spilled IFO 380 was swept out into the Gulf of Mexico by high northerly winds. There was great success in tracking the oil as it moved around the Gulf and eventually formed into large tar mats and patties. The overall weathered condition of the IFO 380 soon made use of conventional offshore skimmers ineffective, so responders began looking at ways to effectively recover the tar mats and patties before they could impact the barrier island beaches of Texas during the busy spring break season. Since commercial shrimping vessels could tow a net and were designed for slow operating speeds, it was decided to try using these vessels to recover the tar mats and patties. By modifying traditional nets and using a spotter aircraft to move the shrimping vessels to the greatest concentration of tar mats and patties, participants made the operation a success.

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