scholarly journals Acoustic Imaging of Oceanic Mixing in the Gulf of Mexico

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Sarah Stanley
Keyword(s):  
Gulf Of Mexico ◽  
Detailed Analysis ◽  
Vertical Mixing ◽  
Acoustic Imaging ◽  
Oceanic Water ◽  
Weak Stratification

Detailed analysis of acoustic reflections suggests that vertical mixing of oceanic water is enhanced at greater depths, thanks to weak stratification and the roughness of the seabed.

scholarly journals A hydrodynamic model for Galveston Bay and the shelf in the northern Gulf of Mexico

Ocean Science ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 951-966 ◽  
Author(s):  
Jiabi Du ◽  
Kyeong Park ◽  
Jian Shen ◽  
Yinglong J. Zhang ◽  
Xin Yu ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Hydrodynamic Model ◽  
Vertical Mixing ◽  
Integrated System ◽  
Salt Flux ◽  
Open Boundary ◽  
Galveston Bay ◽  
Texas Coast ◽  
Northern Gulf Of Mexico ◽  
Longshore Transport

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.

scholarly journals Submesoscale Mixing Across the Mixed Layer in the Gulf of Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
Guangpeng Liu ◽  
Annalisa Bracco ◽  
Alexandra Sitar
Keyword(s):  
Gulf Of Mexico ◽  
Water Column ◽  
Mixed Layer ◽  
Vertical Mixing ◽  
Global Ocean ◽  
Relative Role ◽  
Loop Current ◽  
Turbulent Layer ◽  
Open Questions ◽  
Order Of Magnitude

Submesoscale circulations influence momentum, buoyancy and transport of biological tracers and pollutants within the upper turbulent layer. How much and how far into the water column this influence extends remain open questions in most of the global ocean. This work evaluates the behavior of neutrally buoyant particles advected in simulations of the northern Gulf of Mexico by analyzing the trajectories of Lagrangian particles released multiple times at the ocean surface and below the mixed layer. The relative role of meso- and submesoscale dynamics is quantified by comparing results in submesoscale permitting and mesoscale resolving simulations. Submesoscale circulations are responsible for greater vertical transport across fixed depth ranges and also across the mixed layer, both into it and away from it, in all seasons. The significance of the submesoscale-induced transport, however, is far greater in winter. In this season, a kernel density estimation and a detailed vertical mixing analysis are performed. It is found that in the large mesoscale Loop Current eddy, upwelling into the mixed layer is the major contributor to the vertical fluxes, despite its clockwise circulation. This is opposite to the behavior simulated in the mesoscale resolving case. In the “submesoscale soup,” away from the large mesoscale structures such as the Loop Current and its detached eddies, upwelling into the mixed layer is distributed more uniformly than downwelling motions from the surface across the base of the mixed layer. Maps of vertical diffusivity indicate that there is an order of magnitude difference among simulations. In the submesoscale permitting case values are distributed around 10–3 m2 s–1 in the upper water column in winter, in agreement with recent indirect estimates off the Chilean coast. Diffusivities are greater in the eastern portion of the Gulf, where the submesoscale circulations are more intense due to sustained density gradients supplied by the warmer and saltier Loop Current.

scholarly journals Sediment accumulation rates and vertical mixing of deep-sea sediments derived from14C and 210Pb in the southern Gulf of Mexico

2020 ◽  
Vol 429 ◽  
pp. 106288
Author(s):  
Misael Díaz-Asencio ◽  
Juan Carlos Herguera ◽  
Patrick T. Schwing ◽  
Rebekka A. Larson ◽  
Gregg R. Brooks ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Deep Sea ◽  
Sediment Accumulation ◽  
Vertical Mixing ◽  
Accumulation Rates ◽  
Deep Sea Sediments ◽  
Southern Gulf Of Mexico

scholarly journals Kirchhoff imaging beyond aliasing

Geophysics ◽  
2001 ◽  
Vol 66 (2) ◽  
pp. 654-666 ◽  
Author(s):  
Biondo Biondi
Keyword(s):  
Gulf Of Mexico ◽  
Detailed Analysis ◽  
A Priori ◽  
Salt Dome ◽  
Image Resolution ◽  
A Priori Knowledge ◽  
General Applicability ◽  
Different Types ◽  
Priori Knowledge

Crucial image resolution may be lost when spatially aliased data are imaged with Kirchhoff algorithms that employ standard antialiasing methods. To maximize resolution, I introduce a method that enables the proper imaging of some aliased components in the data, while avoiding aliasing artifacts. The proposed method is based on a detailed analysis of the different types of aliasing that affect Kirchhoff imaging. In particular, it is based on the observation that operator aliasing depends on the dip spectrum of the data. A priori knowledge on the characteristics of the dip spectrum of the data, in particular on its asymmetry, can thus be exploited to enable “imaging beyond aliasing.” The method is not of general applicability, but it successfully improves the image resolution when a priori assumptions on the data dips are realistic. The imaging of salt‐dome flanks in the Gulf of Mexico has been enhanced by the application of the proposed method.

TRAJECTORY PREDICTION FOR BARGE BUFFALO 292 SPILL

1997 ◽  
Vol 1997 (1) ◽  
pp. 25-31
Author(s):  
Bill Lehr ◽  
Debra Simecek-Beatty ◽  
Debbie Payton ◽  
Jerry Galt ◽  
Glen Watabayashi ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Gulf Of Mexico ◽  
Detailed Analysis ◽  
Oil Spill ◽  
Trajectory Analysis ◽  
Trajectory Prediction ◽  
Wind Drift ◽  
Corpus Christi ◽  
Unusual Amount ◽  
High Degree

ABSTRACT The oil spill trajectory prediction for the barge Buffalo 292 spill was provided by NOAA and TGLO. The bulk of the 5000 barrels of IFO 380 that was leaked moved rapidly through the Galveston Channel entrance and into the Gulf of Mexico as a result of a strong meteorological event. Because of the nature of the product, it was possible to track the resulting slicks for more than 3 weeks. Initially, the oil trailed east away from shore. Changing winds and currents moved the oil south and west, leading to sporadic impacts along the shore from east of Galveston to south of Corpus Christi. Trajectory forecasts were used to alert response personnel of impending beach impacts and to direct offshore skimming operations. Real-time current and wind meters, oil-tracking drifters, visual overflights, and remote-sensing observations provided an unusual amount of calibrating data for trajectory forecasting. This fact, along with detailed analysis assisted by computer models, allowed for a surprisingly high degree of accuracy in trajectory prediction in spite of complex current and wind patterns and changing wind drift factors for the product as it weathered. In this paper, these favorable results are compared with results of an earlier spill in the region where fewer resources were available for trajectory analysis.

scholarly journals Vertical mixing and weak stratification over zebra mussel colonies in western Lake Erie

2008 ◽  
Vol 53 (3) ◽  
pp. 1093-1110 ◽  
Author(s):  
L. Boegman ◽  
M. R. Loewen ◽  
P. F. Hamblin ◽  
D. A. Culver
Keyword(s):  
Zebra Mussel ◽  
Lake Erie ◽  
Vertical Mixing ◽  
Western Lake ◽  
Weak Stratification ◽  
Western Lake Erie

Prosodic Impairment Associated With Traumatic Brain Injury

2009 ◽  
Vol 19 (3) ◽  
pp. 97-102
Author(s):  
Billy Irwin
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Detailed Analysis ◽  
Acoustic Characteristics ◽  
Individual Variations

Abstract Purpose: This article discusses impaired prosody production subsequent to traumatic brain injury (TBI). Prosody may affect naturalness and intelligibility of speech significantly, often for the long term, and TBI may result in a variety of impairments. Method: Intonation, rate, and stress production are discussed in terms of the perceptual, physiological, and acoustic characteristics associated with TBI. Results and Conclusions: All aspects of prosodic production are susceptible to the effects of damage resulting from TBI. There are commonly associated prosodic impairments; however, individual variations in specific aspects of prosody require detailed analysis.

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