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Full-Text Articles in Physical Sciences and Mathematics
A Collaborative International Research Program On The Coupled North Atlantic-Arctic System: Science Plan, Eileen E. Hoffmann, Mike St. John, Heather M. Benway
A Collaborative International Research Program On The Coupled North Atlantic-Arctic System: Science Plan, Eileen E. Hoffmann, Mike St. John, Heather M. Benway
CCPO Publications
This North Atlantic-Arctic science plan is derived from an international workshop held in April 2014 with support from the National Science Foundation Division of Ocean Sciences and the European Union (EU). The workshop was designed to facilitate development of a core vision for advancing the next phase of research on the North Atlantic-Arctic system and strengthening international collaborations within and between the EU and North America.
Sea Level Rise, Spatially Uneven And Temporally Unsteady: Why The U.S. East Coast, The Global Tide Gauge Record, And The Global Altimeter Data Show Different Trends, Tal Ezer
CCPO Publications
Impacts of ocean dynamics on spatial and temporal variations in sea level rise (SLR) along the U.S. East Coast are characterized by empirical mode decomposition analysis and compared with global SLR. The findings show a striking latitudinal SLR pattern. Sea level acceleration consistent with a weakening Gulf Stream is maximum just north of Cape Hatteras and decreasing northward, while SLR driven by multidecadal variations, possibly from climatic variations in subpolar regions, is maximum in the north and decreasing southward. The combined impact of sea level acceleration and multidecadal variations explains why the global mean SLR obtained from similar to 20 …
Gulf Stream's Induced Sea Level Rise And Variability Along The U.S. Mid-Atlantic Coast, Tal Ezer, Larry P. Atkinson, William B. Corlett, Jose L. Blanco
Gulf Stream's Induced Sea Level Rise And Variability Along The U.S. Mid-Atlantic Coast, Tal Ezer, Larry P. Atkinson, William B. Corlett, Jose L. Blanco
CCPO Publications
Recent studies indicate that the rates of sea level rise (SLR) along the U. S. mid-Atlantic coast have accelerated in recent decades, possibly due to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) and its upper branch, the Gulf Stream (GS). We analyzed the GS elevation gradient obtained from altimeter data, the Florida Current transport obtained from cable measurements, the North Atlantic Oscillation (NAO) index, and coastal sea level obtained from 10 tide gauge stations in the Chesapeake Bay and the mid-Atlantic coast. An Empirical Mode Decomposition/Hilbert-Huang Transformation (EMD/HHT) method was used to separate long-term trends from oscillating modes. …
A Conceptual Model Of An Arctic Sea, P. St-Laurent, F. Straneo, D. G. Barber
A Conceptual Model Of An Arctic Sea, P. St-Laurent, F. Straneo, D. G. Barber
CCPO Publications
We propose a conceptual model for an Arctic sea that is driven by river runoff, atmospheric fluxes, sea ice melt/growth, and winds. The model domain is divided into two areas, the interior and boundary regions, that are coupled through Ekman and eddy fluxes of buoyancy. The model is applied to Hudson and James Bays (HJB, a large inland basin in northeastern Canada) for the period 1979-2007. Several yearlong records from instruments moored within HJB show that the model results are consistent with the real system. The model notably reproduces the seasonal migration of the halocline, the baroclinic boundary current, spatial …
Transverse Structure Of Wind-Driven Flow At The Entrance To An Estuary: Nansemond River, Diego A. Narváez, Arnoldo Valle-Levinson
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 …
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
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 …
Vertical Distribution Of Decapod Larvae In The Entrance Of An Equatorward Facing Bay Of Central Chile: Implications For Transport, Beatriz Yannicelli, Leonardo R. Castro, Arnoldo Valle-Levinson, Larry Atkinson, Dante Figueroa
Vertical Distribution Of Decapod Larvae In The Entrance Of An Equatorward Facing Bay Of Central Chile: Implications For Transport, Beatriz Yannicelli, Leonardo R. Castro, Arnoldo Valle-Levinson, Larry Atkinson, Dante Figueroa
CCPO Publications
Two short biophysical surveys were carried out in order to assess how the decapod crustacean larvae vertical distribution and circulation patterns in an equatorward facing embayment (Gulf of Arauco, 37° S; 73° W) influenced larval transport into and out of the Gulf. The embayment is located at the upwelling area of south central Chile and features a deep (60 m) and a shallow (25 m) pathway of communication with the adjacent coastal ocean. Profiles of zooplankton, temperature, salinity, dissolved oxygen and current velocity were measured during a 22-h period at the shallow entrance to the gulf. In addition, three zooplankton …
Flow Induced By Upwelling Winds In An Equatorward Facing Bay: Gulf Of Arauco, Chile, Arnoldo Valle-Levinson, Larry P. Atkinson, Dante Figueroa, Leonardo Castro
Flow Induced By Upwelling Winds In An Equatorward Facing Bay: Gulf Of Arauco, Chile, Arnoldo Valle-Levinson, Larry P. Atkinson, Dante Figueroa, Leonardo Castro
CCPO Publications
[1] Shipborne observations of hydrographic and flow velocity profiles were combined with wind velocity measurements to describe the characteristics of the wind-induced flow in an equatorward facing bay of central Chile in South America. The measurements, which were taken from two transects and one anchor station, were made during late austral spring, between 4 and 10 December 2000. Most observations concentrated on Boca Grande, a transect that crossed the deep, northern ( equatorward) entrance to the bay. The other transect crossed the smaller and shallower, westward entrance to the bay, Boca Chica. The anchor station was located inside the bay, …
Observations Of Cross Channel Structure Of Flow In An Energetic Tidal Channel, Mario Caceres, Arnoldo Valle-Levinson, Larry P. Atkinson
Observations Of Cross Channel Structure Of Flow In An Energetic Tidal Channel, Mario Caceres, Arnoldo Valle-Levinson, Larry P. Atkinson
CCPO Publications
[1] Measurements of velocity and density profiles were made to describe the transverse structure of flow in Chacao Channel, Southern Chile (41.75 degreesS), where typical tidal velocities are similar to4 m/s. Current profiles were obtained with a 307.2 kHz Acoustic Doppler Current Profiler (ADCP) over 25 repetitions of a cross-channel transect during one semidiurnal tidal cycle. The 2.2 km long transect ran northeast/southwest across the channel. A northern channel (120 m deep) and a southern channel (85 m deep) were separated by Remolinos Rock, a pinnacle that rises to 20 m depth at similar to0.7 km from the southern side. …
Reconstructing Basin-Scale Eulerian Velocity Fields From Simulated Drifter Data, M. Toner, A. C. Poje, A. D. Kirwan, C. K. R. T. Jones, B. L. Lipphardt, C. E. Grosch
Reconstructing Basin-Scale Eulerian Velocity Fields From Simulated Drifter Data, M. Toner, A. C. Poje, A. D. Kirwan, C. K. R. T. Jones, B. L. Lipphardt, C. E. Grosch
CCPO Publications
A single-layer, reduced-gravity, double-gyre primitive equation model in a 2000 km x 2000 km square domain is used to test the accuracy and sensitivity of time-dependent Eulerian velocity fields reconstructed from numerically generated drifter trajectories and climatology. The goal is to determine how much Lagrangian data is needed to capture the Eulerian velocity field within a specified accuracy. The Eulerian fields are found by projecting, on an analytic set of divergence-free basis functions, drifter data launched in the active western half of the basin supplemented by climatology in the eastern domain. The time-dependent coefficients are evaluated by least squares minimization …
Flow Near Submarine Canyons Driven By Constant Winds, Jun She, John M. Klinck
Flow Near Submarine Canyons Driven By Constant Winds, Jun She, John M. Klinck
CCPO Publications
Circulation over coastal submarine canyons driven by constant upwelling or downwelling wind stress is simulated and analyzed with a primitive equation ocean model. Astoria Canyon, on the west coast of North America, is the focus of this study, and model results are consistent with most major features of mean canyon circulation observed in Astoria Canyon. Near-surface flow crosses over the canyon, while a closed cyclone occurs within the canyon. Upwelling prevails within the canyon and is larger than wind-driven upwelling along the adjacent shelf break. Water rises from depths reaching 300 m to the canyon rim and, subsequently, onto the …
Measurements Of Salinity In The Coastal Ocean: A Review Of Requirements And Technologies, Catherine Woody, Eddie Shih, Jerry Miller, Thomas Royer, Larry P. Atkinson, Richard S. Moody
Measurements Of Salinity In The Coastal Ocean: A Review Of Requirements And Technologies, Catherine Woody, Eddie Shih, Jerry Miller, Thomas Royer, Larry P. Atkinson, Richard S. Moody
CCPO Publications
Salinity, a measure of the dissolved salts in seawater, is a fundamental property of seawater and basic to understanding biological and physical processes in coastal waters. In the open ocean long term salinity measurements are identified as necessary to understand global climate studies, hydrological cycle, and circulation. In the coastal oceans, information on salinity is critical to understanding biological effects on ecosystem function such as disease, nursery grounds, or harmful algal blooms and on physical processes such as freshwater runoff estuarine mixing, and coastal currents. While the importance of salinity is recognized, little attention has been given to making routine …
Convergence Of Lateral Flow Along A Coastal Plain Estuary, Arnoldo Valle-Levinson, Chunyan Li, Kuo-Chuin Wong, Kamazima M. M. Lwiza
Convergence Of Lateral Flow Along A Coastal Plain Estuary, Arnoldo Valle-Levinson, Chunyan Li, Kuo-Chuin Wong, Kamazima M. M. Lwiza
CCPO Publications
A set of velocity profiles obtained in the James River estuary with an acoustic Doppler current profiler was used in combination with the results of an analytic tidal model to depict the appearance of surface lateral flow convergences (δv/δy) during both flood and ebb stages of the tidal cycle. The bathymetry of the estuary was characterized by a main channel and a secondary channel separated by relatively narrow shoals. Lateral surface flow convergences appeared over the edges of the channels and were produced by the phase lag of the flow in the channel relative to the …
Frontogenesis In The North Pacific Oceanic Frontal Zones--A Numerical Simulation, Michael S. Dinniman, Michele M. Rienecker
Frontogenesis In The North Pacific Oceanic Frontal Zones--A Numerical Simulation, Michael S. Dinniman, Michele M. Rienecker
CCPO Publications
A primitive equation model [Geophysical Fluid Dynamics Laboratory's (GFDL's) MOM 2] with one degree horizontal resolution is used to simulate the seasonal cycle of frontogenesis in the subarctic frontal zone (SAFZ) and the subtropical frontal zone (STFZ) of the North Pacific Ocean. The SAFZ in the model contains deep (greater than 500 m in some places) regions with seasonally varying high gradients in temperature and salinity. The gradients generally weaken toward the east. The STFZ consists of a relatively shallow (less than 200 m in most places) region of high gradient in temperature that disappears in the summer/fall. The high …
Modification Of No, Po, And No/Po During Flow Across The Bering And Chukchi Shelves: Implications For Use As Arctic Water Mass Tracers, Lee W. Cooper, Glenn F. Cota, Lawrence R. Pomeroy, Jacqueline M. Grebmeier, Terry E. Whitledge
Modification Of No, Po, And No/Po During Flow Across The Bering And Chukchi Shelves: Implications For Use As Arctic Water Mass Tracers, Lee W. Cooper, Glenn F. Cota, Lawrence R. Pomeroy, Jacqueline M. Grebmeier, Terry E. Whitledge
CCPO Publications
The NO and PO tracers (9[NO3-] + 02 and 135[PO4-] + 02, respectively,) and their derivative NO/PO have found increasing use in Arctic water mass analyses for identifying the specific basin or shelf areas from which surface waters originate, based upon assumed differences in Pacific- and Atlantic-derived content and basin-to-basin differences within the Arctic. Following shipboard sampling in June-September 1993 and May-June 1994, both north and south of Bering Strait, we have found evidence that Pacific-derived waters flowing north to Bering Strait do not necessarily have any unique NO, PO, or NO/PO identity that would permit …
Modeling Nutrient And Plankton Processes In The California Coastal Transition Zone: 3. Lagrangian Drifters, J. R. Moisan, Eileen E. Hofmann
Modeling Nutrient And Plankton Processes In The California Coastal Transition Zone: 3. Lagrangian Drifters, J. R. Moisan, Eileen E. Hofmann
CCPO Publications
Two types of numerical Lagrangian drifter experiments were conducted, using a set of increasingly complex and sophisticated models, to investigate the processes associated with the plankton distributions in the California coastal transition zone (CTZ). The first experiment used a one-dimensional (1-D; vertical) time-dependent physical-bio-optical model, which contained a nine-component food web. Vertical velocities, along the track of simulated Lagrangian drifters, derived from a three-dimensional (3-D), primitive equation circulation model developed to simulate the flow observed within the CTZ; were used to parameterize the upwelling and downwelling processes. The second experiment used 880 simulated Lagrangian drifters from a 3-D primitive equation …
Current Meter Observations In The Old Bahama Channel, L. P. Atkinson, T. Berger, P. Hamilton, E. Waddell, K. Leaman, T. N. Lee
Current Meter Observations In The Old Bahama Channel, L. P. Atkinson, T. Berger, P. Hamilton, E. Waddell, K. Leaman, T. N. Lee
CCPO Publications
Current meter observations were made at 50, 250, and 435 m in 495 m of water at the center of the Old Bahama Channel between November 1990 and November 1991. The mean speed at those depths was 2.6, 50, and 26 cm s-1 toward the Straits of Florida. A maximum speed of 193 cm s-1 was found at the 250-m level. There was evidence of a speed maximum between 50 and 250 m. Large internal diurnal tidal currents were observed that produced high shears in the water column under some conditions. Transport calculated from the single mooring using …
Mississippi River Flood Waters That Reached The Gulf Stream, Peter B. Ortner, Thomas N. Lee, Peter J. Milne, Rod G. Zika, M. Elizabeth Clarke, Guillermo P. Podesta, Peter K. Swart, Patricia A. Tester, Larry P. Atkinson, Walter R. Johnson
Mississippi River Flood Waters That Reached The Gulf Stream, Peter B. Ortner, Thomas N. Lee, Peter J. Milne, Rod G. Zika, M. Elizabeth Clarke, Guillermo P. Podesta, Peter K. Swart, Patricia A. Tester, Larry P. Atkinson, Walter R. Johnson
CCPO Publications
Distributions of physical, biological, and chemical parameters in Florida Keys coastal waters seaward of the reef track were surveyed on September 9 to 13, 1993, as part of a coordinated multidisciplinary study of surface transport processes. A band of low-salinity water was observed along the shoreward side of the Florida Current over the downstream extent of the survey from Miami to Key West. Biological and chemical indicators within the band, together with its large volume, satellite imagery, and a surface drifter trajectory suggested the recent Mississippi River flood as the source.
Observations Of A Cyclonic Ring: Gulf Stream Coalescence Event Over The Blake Plateau, Julie Mcclean-Padman, Larry P. Atkinson
Observations Of A Cyclonic Ring: Gulf Stream Coalescence Event Over The Blake Plateau, Julie Mcclean-Padman, Larry P. Atkinson
CCPO Publications
Hydrographic data collected in September 1980 over the Blake Plateau were analyzed using a combination of empirical search and inverse techniques. Five sections, extending from the continental shelf break eastward across the Blake Plateau, were positioned at approximately 1-degrees intervals between 28-degrees and 32-degrees-N. The empirical search procedure was applied to four closed regions (boxes), constructed from adjacent sections, where each region was assumed to consist of two conservative layers. Five geostrophic velocity sections were obtained using the average optimum reference level for the four boxes. The inverse technique provided barotropic correction velocities that caused all layers to conserve mass. …