Results 1 - 10
of
18
BAROCLINICITY, FORCING MECHANISM AND PREDICTION OF CHEMICAL PROPAGATION OF SAN DIEGO BAY AND THEIR EFFECTS ON NAVAL APPLICATIONS
, 2005
"... Approved for public release; distribution is unlimited ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
Approved for public release; distribution is unlimited
Tidal Effect on Chemical Spill in San Diego
, 2009
"... A coupled hydrodynamic-chemical spill model is used to investigate the chemical spill in the San Diego Bay. The hydrodynamic model shows that the San Diego Bay is tidally dominated. Two different patterns of chemical spill were found with pollutants (methanol, benzene, liquefied ammonia, etc.) relea ..."
Abstract
- Add to MetaCart
A coupled hydrodynamic-chemical spill model is used to investigate the chemical spill in the San Diego Bay. The hydrodynamic model shows that the San Diego Bay is tidally dominated. Two different patterns of chemical spill were found with pollutants (methanol, benzene, liquefied ammonia, etc.) released at 0.5 m depth in the northern bay (32o43’N, 117o13.05 ’ W) and in the southern bay (32o39’N, 117o07.92 ’ W). For the north-bay release, the chemical pollutants spreading in the whole basin with a fast speed of spill in the northern part (12 hours) and a slow speed of spill in the southern part (20 days) with very small concentration. For the south-bay release, the chemical pollutants are kept in the southern part. Very few pollutants reach 32o41’N parallel (the boundary between the north and south bays).
Variational Estimation of Wave-Affected Parameters in a Two-Equation Turbulence Model
, 2014
"... A variational method is used to estimate wave-affected parameters in a two-equation turbulence model with assimilation of temperature data into an ocean boundary layer model. Enhancement of turbulent kinetic energy dissipation due to breaking waves is considered. The Mellor–Yamada level 2.5 turbulen ..."
Abstract
- Add to MetaCart
A variational method is used to estimate wave-affected parameters in a two-equation turbulence model with assimilation of temperature data into an ocean boundary layer model. Enhancement of turbulent kinetic energy dissipation due to breaking waves is considered. The Mellor–Yamada level 2.5 turbulence closure scheme (MY2.5) with the two uncertain wave-affected parameters (wave energy factor a and Charnock coefficient b) is selected as the two-equation turbulence model for this study. Two types of experiments are conducted. First, within an identical synthetic experiment framework, the upper-layer temperature ‘‘observations’’ in summer generated by a ‘‘truth’ ’ model are assimilated into a biased simulationmodel to investigate if (a, b) can be successfully estimated using the variational method. Second, real temperature profiles from Ocean Weather Station Papa are assimilated into the biased simulation model to obtain the optimal wave-affected param-eters. With the optimally estimated parameters, the upper-layer temperature can be well predicted. Fur-thermore, the horizontal distribution of the wave-affected parameters employed in a high-order turbulence closure scheme can be estimated optimally by using the four-dimensional variational method that assimilates the upper-layer available temperature data into an ocean general circulation model.
regional ocean models
, 2004
"... Statistical characteristics of irreversible predictability time in regional ocean models ..."
Abstract
- Add to MetaCart
(Show Context)
Statistical characteristics of irreversible predictability time in regional ocean models
regional ocean models
"... Statistical characteristics of irreversible predictability time in ..."
(Show Context)
Accuracy Progressive Calculation of LagrangianAU1 Trajectories from a Gridded Velocity Field
, 2013
"... Reduction of computational error is a key issue in computing Lagrangian trajectories using gridded ve-locities. Computational accuracy enhances from using the first term (constant velocity scheme), the first two terms (linear uncoupled scheme), the first three terms (linear coupled scheme), to using ..."
Abstract
- Add to MetaCart
Reduction of computational error is a key issue in computing Lagrangian trajectories using gridded ve-locities. Computational accuracy enhances from using the first term (constant velocity scheme), the first two terms (linear uncoupled scheme), the first three terms (linear coupled scheme), to using all four terms (nonlinear coupled scheme) of the two-dimensional interpolation. A unified ‘‘analytical form’ ’ is presented in this study for different truncations. Ordinary differential equations for predicting Lagrangian trajectory are linear using the constant velocity/linear uncoupled schemes (both commonly used in atmospheric and ocean modeling), the linear coupled scheme, and the nonlinear using the nonlinear coupled scheme (both proposed in this paper). The location of the Lagrangian drifter inside the grid cell is determined by two algebraic equations that are solved explicitly with the constant velocity/linear uncoupled schemes, and implicitly using the Newton–Raphson iteration method with the linear/nonlinear coupled schemes. The analytical Stommel ocean model on the f plane is used to illustrate great accuracy improvement from keeping the first term to keeping all the terms of the two-dimensional interpolation. 1.
Variational Estimation of Wave-Affected Parameters in a Two-Equation Turbulence Model
, 2014
"... A variational method is used to estimate wave-affected parameters in a two-equation turbulence model with assimilation of temperature data into an ocean boundary layer model. Enhancement of turbulent kinetic energy dissipation due to breaking waves is considered. The Mellor–Yamada level 2.5 turbulen ..."
Abstract
- Add to MetaCart
A variational method is used to estimate wave-affected parameters in a two-equation turbulence model with assimilation of temperature data into an ocean boundary layer model. Enhancement of turbulent kinetic energy dissipation due to breaking waves is considered. The Mellor–Yamada level 2.5 turbulence closure scheme (MY2.5) with the two uncertain wave-affected parameters (wave energy factor a and Charnock coefficient b) is selected as the two-equation turbulence model for this study. Two types of experiments are conducted. First, within an identical synthetic experiment framework, the upper-layer temperature ‘‘observations’’ in summer generated by a ‘‘truth’ ’ model are assimilated into a biased simulationmodel to investigate if (a, b) can be successfully estimated using the variational method. Second, real temperature profiles from Ocean Weather Station Papa are assimilated into the biased simulation model to obtain the optimal wave-affected param-eters. With the optimally estimated parameters, the upper-layer temperature can be well predicted. Fur-thermore, the horizontal distribution of the wave-affected parameters employed in a high-order turbulence closure scheme can be estimated optimally by using the four-dimensional variational method that assimilates the upper-layer available temperature data into an ocean general circulation model.
Instantaneous Current Prediction for Naval Operations
"... Abstract Naval operations depend highly upon environmental conditions that can either adversely affect successful completion or hinder the safety of personnel. Each warfare community has defined environmental thresholds and operating limits that restrict the execution of any intended maneuver. As th ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract Naval operations depend highly upon environmental conditions that can either adversely affect successful completion or hinder the safety of personnel. Each warfare community has defined environmental thresholds and operating limits that restrict the execution of any intended maneuver. As the warfare environment continues to shift from the open ocean to the littoral, prediction of the shallow water environment is an urgent need in order to support these operations. The value-aided of using a hydrodynamic model (WQMAP) for the mission planning of the naval operations in San Diego Bay is demonstrated in this study. A new model verification procedure (i.e., compatibility verification) is proposed for the tidal dominated littoral basin prediction. 1.
1 Assessment of Ocean Prediction Model for Naval Operations Using Acoustic Preset
"... Abstract. The outcome of a battlefield engagement is often determined by the advantages and disadvantages held by each adversary. On the modern battlefield, the possessor of the best technology often has the upper hand, but only if that advanced technology is used properly and efficiently. In order ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract. The outcome of a battlefield engagement is often determined by the advantages and disadvantages held by each adversary. On the modern battlefield, the possessor of the best technology often has the upper hand, but only if that advanced technology is used properly and efficiently. In order to exploit this advantage and optimize the effectiveness of high technology sensor and weapon systems, it is essential to understand the impact on them by the environment. In the arena of Anti-Submarine Warfare (ASW), the ocean environment determines the performance of the acoustic sensors employed and the success of any associated weapon systems. Since acoustic sensors detect underwater sound waves, understanding how those waves propagate is crucial to knowing how the sensors will perform and being able to optimize their performance in a given situation. To gain this
Tidal Effect on Chemical Spill in San Diego
"... A coupled hydrodynamic-chemical spill model is used to investigate the chemical spill in the San Diego Bay. The hydrodynamic model shows that the San Diego Bay is tidally dominated. Two different patterns of chemical spill were found with pollutants (methanol, benzene, liquefied ammonia, etc.) relea ..."
Abstract
- Add to MetaCart
A coupled hydrodynamic-chemical spill model is used to investigate the chemical spill in the San Diego Bay. The hydrodynamic model shows that the San Diego Bay is tidally dominated. Two different patterns of chemical spill were found with pollutants (methanol, benzene, liquefied ammonia, etc.) released at 0.5 m depth in the northern bay (32o43’N, 117o13.05 ’ W) and in the southern bay (32o39’N, 117o07.92 ’ W). For the north-bay release, the chemical pollutants spreading in the whole basin with a fast speed of spill in the northern part (12 hours) and a slow speed of spill in the southern part (20 days) with very small concentration. For the south-bay release, the chemical pollutants are kept in the southern part. Very few pollutants reach 32o41’N parallel (the boundary between the north and south bays).
