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CCPO Publications

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Articles 121 - 150 of 280

Full-Text Articles in Oceanography

Improving Simulations Of The Upper Ocean By Inclusion Of Surface Waves In The Mellor-Yamada Turbulence Scheme, Chuan Jiang Huang, Fangli Qiao, Zhenya Song, Tal Ezer Jan 2011

Improving Simulations Of The Upper Ocean By Inclusion Of Surface Waves In The Mellor-Yamada Turbulence Scheme, Chuan Jiang Huang, Fangli Qiao, Zhenya Song, Tal Ezer

CCPO Publications

The Mellor-Yamada turbulence closure scheme, used in many ocean circulation models, is often blamed for overly high simulated surface temperature and overly low simulated subsurface temperature in summer due to insufficient vertical mixing. Surface waves can enhance turbulence kinetic energy and mixing of the upper ocean via wave breaking and nonbreaking-wave-turbulence interaction. The influences of wave breaking and wave-turbulence interaction on the Mellor-Yamada scheme and upper ocean thermal structure are examined and compared with each other using one-dimensional and three-dimensional ocean circulation models. Model results show that the wave-turbulence interaction can effectively amend the problem of insufficient mixing in the …

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Detection Of The 2010 Chilean Tsunami Using Satellite Altimetry, B. D. Hamlington, R. R. Leben, O. A. Godin, J. F. Legeais, E. Gica, V. V. Titov Jan 2011

Detection Of The 2010 Chilean Tsunami Using Satellite Altimetry, B. D. Hamlington, R. R. Leben, O. A. Godin, J. F. Legeais, E. Gica, V. V. Titov

CCPO Publications

Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude is much smaller than it is closer to shore. An effective early warning system, however, must be able to observe an impending tsunami threat far away from the shore in order to provide the necessary lead-time for coastal inhabitants to find safety. Given the expansiveness of the ocean, sensors capable of detecting the tsunami must also have very broad areal coverage. The 2004 Sumatra-Andaman tsunami was definitively detected in the open ocean from both sea surface height and sea surface roughness measurements provided by satellite …

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Editorial-The 2nd International Workshop On Modeling The Ocean (Iwmo-2010), Tal Ezer, Lie-Yauw Oey, Huijie Xue, Xiao Hua Wang Jan 2011

Editorial-The 2nd International Workshop On Modeling The Ocean (Iwmo-2010), Tal Ezer, Lie-Yauw Oey, Huijie Xue, Xiao Hua Wang

CCPO Publications

The formation of the International Workshop on Modeling the Ocean (IWMO) in 2009 has been motivated by the rapid growth in ocean modeling research around the world. In particular, the spread of ocean modeling research in Asia during recent years and the establishment of many international collaborative modeling projects led to the first meeting, IWMO-2009, which was held in Taipei, Taiwan, 23–26 February 2009 (see the two special issues resulted from this meeting: Oey et al. 2010a, b). The second meeting (IWMO-2010; http://www.ccpo.odu.edu/∼tezer/ IWMO_2010/) was hosted by the Center for Coastal Physical Oceanography at Old Dominion University in Norfolk, VA, …

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The Role Of The Alaskan Stream In Modulating The Bering Sea Climate, Tal Ezer, Lie-Yauw Oey Apr 2010

The Role Of The Alaskan Stream In Modulating The Bering Sea Climate, Tal Ezer, Lie-Yauw Oey

CCPO Publications

A numerical ocean circulation model with realistic topography, but with an idealized forcing that includes only lateral transports is used to study the role of the Alaskan Stream (AS) in modulating the Bering Sea (BS) variability. Sensitivity experiments, each one with a different strength of the AS transport reveal a nonlinear BS response. An increase of AS transport from 10 to 25 Sv causes warming (similar to 0.25 degrees C mean, similar to 0.5 degrees C maximum) and sea level rise in the BS shelf due to increased transports of warmer Pacific waters through the eastern passages of the Aleutian …

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On The Nature Of Winter Cooling And The Recent Temperature Shift On The Northern Gulf Of Alaska Shelf, Markus A. Janout, Thomas J. Weingartner, Thomas C. Royer, Seth L. Danielson Jan 2010

On The Nature Of Winter Cooling And The Recent Temperature Shift On The Northern Gulf Of Alaska Shelf, Markus A. Janout, Thomas J. Weingartner, Thomas C. Royer, Seth L. Danielson

CCPO Publications

[1] In spring 2006 and 2007, northern Gulf of Alaska (GOA) shelf waters were ∼1.5°C below average throughout the similar to ∼250 m deep shelf and the salinity-dependent winter stratification was anomalously weak due to above (below) average surface (bottom) salinities. Spring 2007 and 2008 temperatures were also similar to ∼-1.5°C below average, but the anomalies were confined to the upper 100 m due to moderate salt stratification. Shelf temperatures in these 2 years were among the lowest observed since the early 1970s, thus interrupting an approximately 30-year warming trend. We examined winter cooling processes using historical conductivity-temperature-depth (CTD) profiles …

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Mixing By Shear Instability At High Reynolds Number, W. R. Geyer, A. C. Lavery, M. E. Scully, J. H. Trowbridge Jan 2010

Mixing By Shear Instability At High Reynolds Number, W. R. Geyer, A. C. Lavery, M. E. Scully, J. H. Trowbridge

CCPO Publications

Shear instability is the dominant mechanism for converting fluid motion to mixing in the stratified ocean and atmosphere. The transition to turbulence has been well characterized in laboratory settings and numerical simulations at moderate Reynolds number-it involves "rolling up", i.e., overturning of the density structure within the cores of the instabilities. In contrast, measurements in an energetic estuarine shear zone reveal that the mixing induced by shear instability at high Reynolds number does not primarily occur by overturning in the cores; rather it results from secondary shear instabilities within the zones of intensified shear separating the cores. This regime is …

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Operation And Application Of A Regional High-Frequency Radar Network In The Mid-Atlantic Bight, Hugh Roarty, Scott Glenn, Josh Kohut, Donglai Gong, Ethan Handel, Erick Rivera, Teresa Garner, Larry Atkinson, Wendell Brown, Chris Jakubiak, Mike Muglia, Sara Haines, Harvey Seim Jan 2010

Operation And Application Of A Regional High-Frequency Radar Network In The Mid-Atlantic Bight, Hugh Roarty, Scott Glenn, Josh Kohut, Donglai Gong, Ethan Handel, Erick Rivera, Teresa Garner, Larry Atkinson, Wendell Brown, Chris Jakubiak, Mike Muglia, Sara Haines, Harvey Seim

CCPO Publications

The Mid-Atlantic Regional Coastal Ocean Observing System (MARCOOS) High- Frequency Radar Network, which comprises 13 long-range sites, 2 medium-range sites, and 12 standard-range sites, is operated as part of the Integrated Ocean Observing System. This regional implementation of the network has been operational for 2 years and has matured to the point where the radars provide consistent coverage from Cape Cod to Cape Hatteras. A concerted effort was made in the MARCOOS project to increase the resiliency of the radar stations from the elements, power issues, and other issues that can disable the hardware of the system. The quality control …

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Understanding How Disease And Environment Combine To Structure Resistance In Estuarine Bivalve Populations, Eileen E. Hofmann, David Bushek, Susan E. Ford, Ximing Guo, Dale Haidvogel, Dennis Hedgecock, John M. Klinck, Coren Milbury, Diego Narvaez, Eric Powell, Yongping Wang, Zhiren Wang, Liusuo Zhang Jan 2009

Understanding How Disease And Environment Combine To Structure Resistance In Estuarine Bivalve Populations, Eileen E. Hofmann, David Bushek, Susan E. Ford, Ximing Guo, Dale Haidvogel, Dennis Hedgecock, John M. Klinck, Coren Milbury, Diego Narvaez, Eric Powell, Yongping Wang, Zhiren Wang, Liusuo Zhang

CCPO Publications

Delaware Bay oyster (Crassostrea virginica) populations are influenced by two lethal parasites that cause Dermo and MSX diseases. As part of the US National Science Foundation Ecology of Infectious Diseases initiative, a program developed for Delaware Bay focuses on understanding how oyster population genetics and population dynamics interact with the environment and these parasites to structure he host populations, and how these interactions might modified by climate change. Laboratory and field studies undertaken during this program include identifying genes related to MSX and Dermo disease resistance, potential regions for refugia and the mechanisms that allow them to exist, …

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Variations In Sea Surface Roughness Induced By The 2004 Sumatra-Andaman Tsunami, O. A. Godin, V. G. Irisov, R. R. Leben, B. D. Hamlington, G. A. Wick Jan 2009

Variations In Sea Surface Roughness Induced By The 2004 Sumatra-Andaman Tsunami, O. A. Godin, V. G. Irisov, R. R. Leben, B. D. Hamlington, G. A. Wick

CCPO Publications

Observations of tsunamis away from shore are critically important for improving early warning systems and understanding of tsunami generation and propagation. Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude there is much smaller than it is close to shore. Currently, tsunami observations in deep water rely on measurements of variations in the sea surface height or bottom pressure. Here we demonstrate that there exists a different observable, specifically, ocean surface roughness, which can be used to reveal tsunamis away from shore. The first detailed measurements of the tsunami effect on sea surface height …

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Enso And Variability Of The Antarctic Peninsula Pelagic Marine Ecosystem, Valerie J. Loeb, Eileen E. Hofmann, John M. Klinck, Osmund Holm-Hansen, Warren B. White Jan 2009

Enso And Variability Of The Antarctic Peninsula Pelagic Marine Ecosystem, Valerie J. Loeb, Eileen E. Hofmann, John M. Klinck, Osmund Holm-Hansen, Warren B. White

CCPO Publications

The West Antarctic Peninsula region is an important source of Antarctic krill (Euphausia superba) in the Southern Ocean. From 1980-2004 abundance and concentration of phytoplankton and zooplankton, krill reproductive and recruitment success and seasonal sea ice extent here were significantly correlated with the atmospheric Southern Oscillation Index and exhibited three- to five-year frequencies characteristic of El Nino-Southern Oscillation (ENSO) variability. This linkage was associated with movements of the Southern Antarctic Circumpolar Current Front and Boundary, a changing influence of Antarctic Circumpolar Current and Weddell Sea waters, and eastward versus westward flow and mixing processes that are consistent with forcing by …

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Southern Ocean Globec Research And The Future, Eileen Hofmann Jan 2009

Southern Ocean Globec Research And The Future, Eileen Hofmann

CCPO Publications

(First paragraph) The International Global Ocean Ecosystems Dynamics (GLOBEC) Programme will end in early 2010, after almost 20 years. GLOBEC science has provided fundamental changes in our understanding of the scales of interactions in marine ecosystems, alternative views of marine food webs, and the influence of humans in marine ecosystem processes. Since Southern Ocean GLOBEC (SO GLOBEC) was one of the regional research programmes it is appropriate to reflect on i) its specific contributions, ii) how these might guide future Southern Ocean research, and iii) the key gaps for our future understanding of Southern Ocean ecosystems and the impact that …

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Multiple Stable Reference Points In Oyster Populations: Biological Relationships For The Eastern Oyster (Crassostrea Virginica) In Delaware Bay, Eric N. Powell, John M. Klinck, Kathryn A. Ashton-Alcox, John N. Kraeuter Jan 2009

Multiple Stable Reference Points In Oyster Populations: Biological Relationships For The Eastern Oyster (Crassostrea Virginica) In Delaware Bay, Eric N. Powell, John M. Klinck, Kathryn A. Ashton-Alcox, John N. Kraeuter

CCPO Publications

In the first of two companion papers, a 54-yr time series for the oyster population in the New Jersey waters of Delaware Bay was analyzed to develop biological relationships necessary to evaluate maximum sustainable yield (MSY) reference points and to consider how multiple stable points affect reference point-based management. The time series encompassed two regime shifts, one circa 1970 that ushered in a 15-yr period of high abundance, and a second in 1985 that ushered in a 20-yr period of low abundance. The intervening and succeeding periods have the attributes of alternate stable states. The biological relationships between abundance, recruitment, …

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Profiles Of Ocean Surface Heating (Posh): A New Model Of Upper Ocean Diurnal Warming, Chelle L. Gentemann, Peter J. Minnett, Brian Ward Jan 2009

Profiles Of Ocean Surface Heating (Posh): A New Model Of Upper Ocean Diurnal Warming, Chelle L. Gentemann, Peter J. Minnett, Brian Ward

CCPO Publications

Shipboard radiometric measurements of diurnal warming at the ocean surface and profiles through the diurnal thermocline were utilized to assess the temporal and vertical variability and to develop a new physics-based model of near-surface warming. The measurements and modeled diurnal warming were compared, with the goal of comprehensively evaluating differences between the data and model results. On the basis of these results, the diurnal model was refined while attempting to maintain agreement with the measurements. Simplified bulk models commonly do not provide information on the vertical structure within the warm layer, but this new model predicts the vertical temperature profile …

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Combining Remote Sensing Data And An Inundation Model To Map Tidal Mudflat Regions And Improve Flood Predictions: A Proof Of Concept Demonstration In Cook Inlet, Alaska, Tal Ezer, Hua Liu Jan 2009

Combining Remote Sensing Data And An Inundation Model To Map Tidal Mudflat Regions And Improve Flood Predictions: A Proof Of Concept Demonstration In Cook Inlet, Alaska, Tal Ezer, Hua Liu

CCPO Publications

Accurate flood predictions require high resolution inundation numerical models and detailed coastal and land topography data. However, such data are not always available. A new method to obtain topographic information of flood zones from remote sensing data is demonstrated here for Cook Inlet, Alaska, where tidal range reaches 8-10 m. The moving shoreline is detected from analysis of water coverage in satellite images taken at different tidal stages, and then the shoreline data from different times are combined with water level data from observations and models to produce new topographic maps of previously unobserved mudflats. The remote sensing-based analysis provides …

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On The Movement Of Beluga Whales In Cook Inlet, Alaska: Simulations Of Tidal And Environmental Impacts Using A Hydrodynamic Inundation Model, Tal Ezer, Roderick Hobbs, Lie-Yauw Oey Dec 2008

On The Movement Of Beluga Whales In Cook Inlet, Alaska: Simulations Of Tidal And Environmental Impacts Using A Hydrodynamic Inundation Model, Tal Ezer, Roderick Hobbs, Lie-Yauw Oey

CCPO Publications

The population of beluga whales in Cook Inlet, Alaska, is in decline, and since 2000 these whales have been under consideration for designation as "endangered" under the Endangered Species Act (and were placed on the list in October 2008, just before this article went to press). In order to study environmental and hydrodynamic impacts on the belugas' movements and survival in the unique habitat of the inlet, a three-dimensional ocean circulation and inundation model is combined with satellite-tracked beluga whale data. Model-wale data comparisons from two whale paths during a five-day period (september 17-21, 2000) covering 10 tidal cycles suggest …

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Hydrodynamic Numerical Ocean Models Support Environmental Studies And Conservation Efforts: From An Arctic Estuary To A Caribbean Coral Reef, Tal Ezer Apr 2008

Hydrodynamic Numerical Ocean Models Support Environmental Studies And Conservation Efforts: From An Arctic Estuary To A Caribbean Coral Reef, Tal Ezer

CCPO Publications

Potential future climate changes, as highlighted recently by the Intergovernmental Panel on Climate Change (IPCC) report, are likely to have different local impacts in different regions of the globe. Oceanic ecosystems may be especially sensitive to large environmental variation, and they are closely connected to physical changes such as temperature, salinity, currents and sea level. Two examples, from very different environments – one in a cold climate and one in a tropical climate, will be discussed here to show how hydrodynamic numerical models are helping to understand physical-biological interactions and potentially help dealing with future climate changes.

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A Modelling Study Of Developmental Stage And Environmental Variability Effects On Copepod Foraging, Jerry D. Wiggert, Eileen E. Hofmann, Gustav-Adolf Paffenhöfer Jan 2008

A Modelling Study Of Developmental Stage And Environmental Variability Effects On Copepod Foraging, Jerry D. Wiggert, Eileen E. Hofmann, Gustav-Adolf Paffenhöfer

CCPO Publications

We used a stochastic Lagrangian model to study how behaviour contributes to copepod grazing success. The model simulates distinct foraging behaviours of Clausocalanus furcatus, Paracalanus aculeatus, and Oithona plumifera. Three sets of simulations were performed to investigate the effects of (a) prey-size preference; (b) variation in prey-size spectra; and (c) turbulence intensity on these species’ grazing rates. The size preference simulations demonstrate that, compared with copepodites, mature females have cell ingestion rates that are an order of magnitude lower, while carbon uptake is reduced by 35%. A prey spectrum that is skewed towards cells ,<6 >μm promotes copepodite …

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Otolith Chemistry Indicates Population Structuring By The Antarctic Circumpolar Current, Julian R. Ashford, Cynthia M. Jones, Eileen E. Hofmann, Inigo Everson, Carlos A. Moreno, Guy Duhamel, Richard Williams Jan 2008

Otolith Chemistry Indicates Population Structuring By The Antarctic Circumpolar Current, Julian R. Ashford, Cynthia M. Jones, Eileen E. Hofmann, Inigo Everson, Carlos A. Moreno, Guy Duhamel, Richard Williams

CCPO Publications

Large-scale transport of seawater in ocean currents may generate spatially complex population structure through the advection of life stages of marine fish species. To test this, we compared the chemistry of otolith nuclei from Patagonian toothfish (Dissostichus eleginoides), presently managed as spatially discrete Populations corresponding to fishing management areas along the Antarctic Circumpolar Current (ACC), which transports water eastward around the Southern Ocean. The chemistry of otolith nuclei, laid down during early life, differed significantly between fishing areas Off South America and the Antarctic and between some Antarctic areas. However, we found significant discrepancies from expectation for a …

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Mesoamerican Reef Spawning Aggregations Help Maintain Fish Population: A Review Of Connectivity Research And Priorities For Science Management, W. Heyman, W. B. Kjerfve, T. Ezer Jan 2008

Mesoamerican Reef Spawning Aggregations Help Maintain Fish Population: A Review Of Connectivity Research And Priorities For Science Management, W. Heyman, W. B. Kjerfve, T. Ezer

CCPO Publications

The life history of most marine organisms includes an obligate period of pelagic larval dispersal. Migration to spawning areas and pelagic dispersal is often well beyond the home range of these organisms. Designing marine protected areas to include a broad range of taxa and their various dispersal patterns is an important and daunting challenge. This paper addresses the issue of connectivity for one set of species in a limited geographic area. We focus on transient spawning reef fish within the Mesoamerican Reef and their connectivity. We divide our scientific review into four sections as follows: (1) ecological characterization of transient …

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Quantifying Vertical Mixing In Estuaries, W. Rockwell Geyer, Malcolm E. Scully, David K. Ralston Jan 2008

Quantifying Vertical Mixing In Estuaries, W. Rockwell Geyer, Malcolm E. Scully, David K. Ralston

CCPO Publications

Estuarine turbulence is notable in that both the dissipation rate and the buoyancy frequency extend to much higher values than in other natural environments. The high dissipation rates lead to a distinct inertial subrange in the velocity and scalar spectra, which can be exploited for quantifying the turbulence quantities. However, high buoyancy frequencies lead to small Ozmidov scales, which require high sampling rates and small spatial aperture to resolve the turbulent fluxes. A set of observations in a highly stratified estuary demonstrate the effectiveness of a vessel-mounted turbulence array for resolving turbulent processes, and for relating the turbulence to the …

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Transverse Structure Of Wind-Driven Flow At The Entrance To An Estuary: Nansemond River, Diego A. Narváez, Arnoldo Valle-Levinson Jan 2008

Transverse Structure Of Wind-Driven Flow At The Entrance To An Estuary: Nansemond River, Diego A. Narváez, Arnoldo Valle-Levinson

CCPO Publications

Observations of current velocity profiles were combined with an analytical solution to study the transverse partition of the wind-driven flow in an estuary, the Nansemond River, which is a tributary of the James River in the Chesapeake Bay. Observations spanned two periods of nearly 3 months in autumn-winter of 2003-2004 and spring-summer 2004. The wind-driven circulation consisted of downwind flow over the shoal and upwind flow in the channel at the entrance to the estuary. This pattern developed mainly with landward winds and provided observational evidence that sustains analytical and numerical model results. The transverse structure of the flow showed …

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The Sensitivity Of The Southwest Monsoon Phytoplankton Bloom To Variations In Aeolian Iron Deposition Over The Arabian Sea, Jerry D. Wiggert, Raghu G. Murtugudde May 2007

The Sensitivity Of The Southwest Monsoon Phytoplankton Bloom To Variations In Aeolian Iron Deposition Over The Arabian Sea, Jerry D. Wiggert, Raghu G. Murtugudde

CCPO Publications

[1] A coupled, 3-D biophysical ocean general circulation model is used to investigate how aeolian iron deposition affects the Arabian Sea ecosystem. Two separate aeolian iron deposition fields, derived from the GISS and GOCART atmospheric transport models, have been applied as surface boundary conditions. The model results exhibit widespread biogeochemical sensitivity to the choice of deposition field. With GOCART deposition, SW Monsoon phytoplankton blooms in the western and central Arabian Sea are enhanced and exhibit greater realism. The central Arabian Sea bloom is supported by supplemental input of horizontally advected iron from a pool that undergoes a yearlong progression that …

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Bottom-Up Forcing And The Decline Of Steller Sea Lions (Eumetopias Jubatus) In Alaska: Assessing The Ocean Climate Hypothesis, Andrew W. Trites, Arthur J. Miller, Michael A. Alexander, Steven J. Bograd, John A. Calder, Antonietta Capotondi, Kenneth O. Coyle, Emanuele Di Lorenzo, Bruce P. Finney, Edward J. Gregr, Chester E. Grosch, Thomas C. Royer Jan 2007

Bottom-Up Forcing And The Decline Of Steller Sea Lions (Eumetopias Jubatus) In Alaska: Assessing The Ocean Climate Hypothesis, Andrew W. Trites, Arthur J. Miller, Michael A. Alexander, Steven J. Bograd, John A. Calder, Antonietta Capotondi, Kenneth O. Coyle, Emanuele Di Lorenzo, Bruce P. Finney, Edward J. Gregr, Chester E. Grosch, Thomas C. Royer

CCPO Publications

Declines of Steller sea lion ( Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976–77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon …

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Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann Jan 2007

Simulations Of Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean 2. Effects Of Physical And Biogeochemical Processes, Baris Salihoglu, Eileen E. Hofmann

CCPO Publications

A one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology is used to investigate the response of phytoplankton community and carbon production and export to variations in physical and biochemical processes in the Cold Tongue region of the equatorial Pacific Ocean at ON, 140W. Results show that high-frequency variability in vertical advection and temperature is an important mechanism driving the carbon export. Filtering out low frequency physical forcing results in a 30% increase in primary production and dominance of high-light adapted Prochlorococcus and autotrophic eukaryotes. Sensitivity studies show that iron availability is the primary control on carbon …

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Nearshore Surface Temperatures In Antofagasta Bay (Chile) And Adjacent Upwelling Centers, A. Piñones, J. C. Castilla, R. Guiñez, J. L. Largier Jan 2007

Nearshore Surface Temperatures In Antofagasta Bay (Chile) And Adjacent Upwelling Centers, A. Piñones, J. C. Castilla, R. Guiñez, J. L. Largier

CCPO Publications

Several years of sea surface temperature data (1997-2003) for the coast of Antofagasta Bay-a semi-enclosed bay in northern Chile-were analyzed in order to further exploring the nature of a warm-water retention pattern inside the bay. Based on time series techniques, we were able to confirm the persistence of warm water in the bay. This warm feature was found immediately downwind of the upwelling center at Jorgillo Point, where temperatures averaged 2-3 degrees C more than at the exposed upwelling sites outside and the bay. Temporal and spatial patterns in sea surface temperature were determined and showed being well associated with …

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Baroclinic Effects And Tides On The Cape Hatteras Continental Shelf, Dana K. Savidge, Catherine R. Edwards, Mark Santana Jan 2007

Baroclinic Effects And Tides On The Cape Hatteras Continental Shelf, Dana K. Savidge, Catherine R. Edwards, Mark Santana

CCPO Publications

Seasonal variability has been identified on the shelf near Cape Hatteras in the semidiurnal and diurnal frequency bands. Large summertime semidiurnal currents appear to be an M2 internal tide whose propagation shoreward is supported by strong Middle Atlantic Bight (MAB) seasonal stratification. At the southern limit of the MAB, strong MAB stratification gives way to weaker seasonal stratification in the South Atlantic Bight (SAB), and the M2 internal tide propagates shoreward less effectively. Strong diurnal variability appears in K1 and O1 components in summer, achieving magnitudes as large as the M2. The diurnal components are typically much smaller than M2 …

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Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert Jan 2007

Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert

CCPO Publications

[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models' performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted …

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A Temporal Approximate Deconvolution Model For Large-Eddy Simulation, C. D. Pruett, B. C. Thomas, C. E. Grosch, T. B. Gatski Feb 2006

A Temporal Approximate Deconvolution Model For Large-Eddy Simulation, C. D. Pruett, B. C. Thomas, C. E. Grosch, T. B. Gatski

CCPO Publications

A temporal approximate deconvolution model (TADM) is developed for large-eddy simulation and is demonstrated for plane-channel flow at Re-tau=590. The TADM combines explicit causal time-domain filtering with linear deconvolution (defiltering) to approximate unfiltered fields and residual stress to arbitrarily high order. The TADM methodology appears to lead to a robust family of residual-stress models that should provide a viable alternative to conventional (spatial) filtering for applications in which spatial filtering is problematic, e.g., for problems requiring unstructured or highly stretched grids. (c) 2006 American Institute of Physics.

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Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch Jan 2006

Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch

CCPO Publications

Water column temperatures on the shelf in the northern Gulf of Alaska have increased more than 0.8 degrees C and vertical density stratification has increased since 1970 near Seward, Alaska throughout the 250 m depth. This high latitude marine system has low water temperatures, high rates of precipitation, glacial melting, high wind speeds and high rates of biological productivity. A more than 300 km alongshore shift ( locally westward) of isotherms is suggested. The observations are consistent with a conceptual ocean-atmosphere circulation model that employs coastal freshwater discharge, glacial ablation and wind forcing. Positive regional feedback mechanisms accelerate the discharge …

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Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan Jan 2006

Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan

CCPO Publications

Hourly time series at seven locations throughout the southern Gulf of Mexico were used to calculate the trend and the inter-annual sea level. The sea level series from January 1966 to December 1976 were filtered using a Lanczos low pass filter to remove oscillations with periods smaller than one year. The results revealed a sea level increment of about 1.4 mm yr(-1) from 1966 to 1976 in the southern Gulf of Mexico. The monthly sea level variability obtained after the trends were removed, presented a sea level setup during winter and a sea level depression in summer attributed to seasonal …

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