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Sample records for atlantic ocean supplementary

  1. Atmospheric Blocking and Atlantic Multidecadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by affecting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially 1996 to 2010). It also describes much longer time scale Atlantic multidecadal ocean variability (AMV), including the extreme pre-greenhouse-gas northern warming of the 1930s to 1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat exchange, both of which contribute to the warm phase of AMV.

  2. 78 FR 57796 - Safety Zone; Pro Hydro-X Tour, Atlantic Ocean, Islamorada, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-20

    .... SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Pro Hydro-X Tour, Atlantic Ocean... Hydro- X Tour. The Pro Hydro-X Tour is a series of Jet Ski races. The race course is in an...

  3. 77 FR 50019 - Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ...) 366-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard...

  4. Atlantic and indian oceans pollution in africa

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  5. Atlantic and Indian Oceans Pollution in Africa

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  6. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized...

  7. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized...

  8. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized...

  9. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized...

  10. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Northwest Atlantic Ocean fishery. 600.520... Northwest Atlantic Ocean fishery. (a) Purpose. Sections 600.520 and 600.525 regulate all foreign fishing conducted under a GIFA within the EEZ in the Atlantic Ocean north of 35°00′ N. lat. (b) Authorized...

  11. Atlantic and indian oceans pollution in africa

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  12. Anisotropic tomography of the Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Silveira, G.; Stutzmann, E.

    2003-04-01

    We present a regional tri-dimensional model of the Atlantic Ocean with anisotropy. The model, derived from Rayleigh and Love phase velocity measurements, is defined from the Moho down to 300 km depth with a lateral resolution of about 500 km and is presented in terms of average isotropic S-wave velocity, azimuthal anisotropy and transverse isotropy. The cratons beneath North America, Brazil and Africa are clearly associated with fast S-wave velocity anomalies. The Mid Atlantic Ridge is a shallow structure in the North Atlantic corresponding to a negative velocity anomaly down to about 150 km depth. In contrast, the ridge negative signature is visible in the South Atlantic down to the deepest depth inverted, that is 300~km depth. This difference is probably related to the presence of hot-spots along or close to the ridge axis in the South Atlantic and may indicate a different mechanism for the ridge between the North and South Atlantic. Negative velocity anomalies are clearly associated with hot-spots from the surface down to at least 300km depth, they are much broader that the supposed size of the hot-spots and seem to be connected along a North-South direction. Down to 100 km depth, a fast S-wave velocity anomaly is extenting from Africa into the Atlantic Ocean within the zone defined as the Africa superswell area. This result indicates that the hot material rising from below does not reach the surface in this area but may be pushing the lithosphere upward. In most parts of the Atlantic, the azimuthal anisotropy directions remain stable with increasing depth. Close to the ridge, the fast S-wave velocity direction is roughly parallel to the sea floor spreading direction. The hot-spot anisotropy signature is striking beneath Bermuda, Cape Verde and Fernando Noronha islands where the fast S-wave velocity direction seems to diverge radially from the hot-spots. The Atlantic average radial anisotropy is similar to that of the PREM model, that is positive down to about

  13. Ocean Modeling of the North Atlantic

    NASA Technical Reports Server (NTRS)

    Seminar, A. J.

    1984-01-01

    Present modeling of the North Atlantic is inadequate and can be improved in a number of ways. A number of important physical processes are listed in five categories from the viewpoints of how they are treated in isolation, how they are usually represented in present ocean basin models, and how they may be better represented in future models. In the first two categories of vertical boundary processes and internal vertical mixing, parameterizations exist which can easily be incorporated into models and which will have important effects on the simulated structure of the North Atlantic. For the third catagory (mesoscale eddy effects), adequate parameterizations do not exist; but the order of magnitude of the effects is known from observational and process-model studies. A horizontal grid spacing of 100 km or less in required to allow parameterizations with this order of magnitude, as well as to resolve the time-averaged ocean fields. In the fourth category of large scale transports improvements are suggested by way of increased vertical resolution and by the requirement that lateral mixing due to eddies takes place on isopycnal surfaces. Model incorporation of the latter phenomenta is underway. In the fifth category of miscellaneous high-latitude processes, formulations for the treatment of sea ice are available for use. However, the treatment of gravitational instability, which is crucial to deepwater formation in the Atlantic Ocean, will require additional refinements to account for the unresolved physics of chimney formations in the open ocean and buoyant plumes near ocean boundaries.

  14. Tectonic provinces of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Pushcharovsky, Yu. M.

    2009-05-01

    The tectonic structure of the floor of the Atlantic Ocean beyond the continental margins is insufficiently studied. This is also true of its tectonic demarcation. The segmentation of the floor into regional-scale tectonic provinces of several orders proposed in this paper is primarily based on structural and historical geological features. It is shown that deep oceanic basins and fault tectonics are of particular importance in this respect. Tectonic provinces of two orders are distinguished by a set of attributes. The first-order provinces are the North, Central, South, and Antarctic domains of the Atlantic Ocean. They are separated by wide demarcation fracture zones into Transatlantic (transverse) second-order tectonic provinces. Ten such provinces are recognized (from the north southward): Greenland-Lofoten, Greenland-Scandinavia, Greenland-Ireland, Newfoundland-European, North American-African, Antilles-African, Angola-Brazil, Cape-Argentine, North Antarctic, and South Antarctic. This subdivision demonstrates significant differentiation in the geodynamic state of the oceanic lithosphere that determines nonuniform ocean formation and the tectonic features of the ocean floor. The latitudinal orientation of the second-order provinces inherits the past tectonic pattern, though newly formed structural units cannot be ruled out. The Earth rotation exerts a crucial effect on the crust and the mantle.

  15. NOAA Research Vessel Explores Atlantic Ocean Seamounts

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2014-10-01

    Mike Ford, a biological oceanographer with the National Oceanic and Atmospheric Administration (NOAA), sat rapt in front of a bank of high-definition monitors. They provided live video and data feeds from a tethered pair of instrument-laden remotely operated vehicles (ROVs) that were descending 4692 meters on their deepest dive ever. Their target: an unnamed and unexplored New England seamount discovered in the North Atlantic last year.

  16. Hurricane Bonnie, Northeast of Bermuda, Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Hurricane Bonnie was over the North Atlantic Ocean about 500 miles northeast of Bermuda (39.0N, 56.5W) when this photo was taken. Compare this view with Hurricane Iniki, also photographed on this mission (STS-47-77-058). Bonnie is small but in her prime, having a well defined eye, a tight spiral gyre indicating high wind speeds and numerous thunderheads. Iniki, on the other hand, was decaying when photographed and no longer presented a threat.

  17. 78 FR 32556 - Safety Zone; 2013 Ocean City Air Show, Atlantic Ocean; Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ...The Coast Guard is establishing a temporary safety zone on the navigable waters of the Atlantic Ocean in the vicinity of Ocean City, MD to support the Ocean City Air Show. This action is intended to restrict vessel traffic movement in the restricted area in order to protect mariners from the hazards associated with air show...

  18. 75 FR 18778 - Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast...

  19. 77 FR 22523 - Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... Federal Register (73 FR 3316). ] Public Meeting We do not now plan to hold a public meeting. But you may... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast...

  20. Turbidity distribution in the Atlantic Ocean

    USGS Publications Warehouse

    Eittreim, S.; Thorndike, E.M.; Sullivan, L.

    1976-01-01

    The regional coverage of Lamont nephelometer data in the North and South Atlantic can be used to map seawater turbidity at all depths. At the level of the clearest water, in the mid-depth regions, the turbidity distribution primarily reflects the pattern of productivity in the surface waters. This suggests that the 'background' turbidity level in the oceans is largely a function of biogenic fallout. The bottom waters of the western Atlantic generally exhibit large increases in turbidity. The most intense benthic nepheloid layers are in the southwestern Argentine basin and northern North American basin; the lowest bottom water turbidity in the western Atlantic is in the equatorial regions. Both the Argentine and North American basin bottom waters appear to derive their high turbidity largely from local resuspension of terrigenous input in these basins. In contrast to the west, the eastern Atlantic basins show very low turbidities with the exception of three regions: the Mediterranean outflow area, the Cape basin, and the West European basin. ?? 1976.

  1. Seismic Imaging Of The South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Sheen, K.; White, N.; Hobbs, R.

    2008-12-01

    Seismic oceanography is a powerful, new technique which utilises seismic reflection profiling to yield detailed acoustic images of ocean finestructure. The method uses seismic reflections generated by acoustic impedance changes which occur across water mass boundaries as a result of variations in temperature and salinity. Here we present a series of seismic images of the water column from a region in the southwest Atlantic using legacy seismic reflection datasets shot in the 1990s. The seismic surveys follow the Antarctic Circumpolar Current as it veers northward after exiting Drake Passage, looping around the Falkland Trough and finally entering the Argentinian Basin, largely following the Sub Antarctic Front route. Finestructure imaged in the data occurs dominantly in the boundary layer between Antarctic Intermediate Water and underlying Upper Circumpolar Deep Water, and correlates well with hydrographic interpretations. Structures such as dipping bands of heterogeneous water and eddies characterized by homogeneous cores and strong reflective inter-leaving edges are seen in the vicinity of ocean fronts. Further to the north, interesting thermohaline structures associated with the intrusion of North Atlantic Deep Water into the region have been captured. Seasonal variations in the time of data acquisition and the subsequent differences in the acoustic images provide interesting insights into the temporal variability of the water masses. Turbulent mixing in this part of the Southern Ocean is known to be remarkably intense and widespread and thought to contribute significantly to driving the upward transport of water closing the ocean's meridional overturning circulation. The deformation of thermohaline finestructure by such mixing and the ambient internal wavefield results in small undulations along seismic reflection horizons. Spectral analysis of these sinusoidal displacements has been used to extract quantitative information on internal wave energy and deduce

  2. North Atlantic Finite Element Ocean Modeling

    NASA Astrophysics Data System (ADS)

    Veluthedathekuzhiyil, Praveen

    This thesis presents a modified version of the Finite Element Ocean Model (FEOM) developed at Alfred Wegener Institute for Polar and Marine Research (AWI) for the North Atlantic Ocean. A reasonable North Atlantic Ocean simulation is obtained against the observational data sets in a Control simulation (CS) where the surface boundary conditions are relaxed to a climatology. The vertical mixing in the model was tuned to represent convection in the model, also the horizontal mixing and diffusion coefficients to represent the changes in the resolution of the model’s unstructured grid. In addition, the open boundaries in the model are treated with a sponge layer where tracers are relaxed to climatology. The model is then further modified to accept the atmospheric flux forcing at the surface boundary with an added net heat flux correction and freshwater forcing from major rivers that are flowing into the North Atlantic Ocean. The impact of this boundary condition on the simulation results is then analyzed and shows many improvements albeit the drift in tracer properties around the Gulf Stream region remains as that of the CS case. However a comparison of the vertical sections at Cape Desolation and Cape Farewell with the available observational data sets shows many improvements in this simulation compared to that of the CS case. But the freshwater content in the Labrador Sea interior shows a continued drift as that of the CS case with an improvement towards the 10th model year. A detailed analysis of the boundary currents around the Labrador Sea shows the weak offshore transport of freshwater from the West Greenland Current (WGC) as one of the causes. To further improve the model and reasonably represent the boundary currents and associated sub-grid scale eddies in the model, a modified sub-grid scale parameterization based on Gent and McWilliams, (1990) is adopted. The sensitivity of using various approaches in the thickness diffusion parameter ( Kgm) for this

  3. Space Radar Image of North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a radar image showing surface features on the open ocean in the northeast Atlantic Ocean. There is no land mass in this image. The purple line in the lower left of the image is the stern wake of a ship. The ship creating the wake is the bright white spot on the middle, left side of the image. The ship's wake is about 28 kilometers (17 miles) long in this image and investigators believe that is because the ship may be discharging oil. The oil makes the wake last longer and causes it to stand out in this radar image. A fairly sharp boundary or front extends from the lower left to the upper right corner of the image and separates two distinct water masses that have different temperatures. The different water temperature affects the wind patterns on the ocean. In this image, the light green area depicts rougher water with more wind, while the purple area is calmer water with less wind. The dark patches are smooth areas of low wind, probably related to clouds along the front, and the bright green patches are likely due to ice crystals in the clouds that scatter the radar waves. The overall 'fuzzy' look of this image is caused by long ocean waves, also called swells. Ocean radar imagery allows the fine detail of ocean features and interactions to be seen, such as the wake, swell, ocean front and cloud effects, which can then be used to enhance the understanding of ocean dynamics on smaller and smaller scales. The image is centered at 42.8 degrees north latitude, 26.2 degrees west longitude and shows an area approximately 35 kilometers by 65 kilometers (22 by 40 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C-band horizontally transmitted, horizontally received; blue is L-band vertically transmitted, vertically received. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR

  4. Equatorial deep jets in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Brandt, P.; Greatbatch, R. J.; Didwischus, S.-H.; Claus, M.; Hormann, V.; Funk, A.; Dengler, M.

    2012-04-01

    Vertically alternating deep zonal jets of short vertical wavelength were discovered in the equatorial oceans more than 35 years ago. These jets that are observed to be coherent across the equatorial basins are characterized by vertically alternating eastward and westward currents lying within 1° of the equator, with amplitudes of 0.1-0.2 ms-1 and vertical wavelengths between 300 and 700 m. In the Atlantic, equatorial deep jets oscillate with a period of about 4.5 years, while their energy propagates upward. The 4.5 year signal can be seen in sea surface temperature as well as atmospheric data (e.g. surface wind and rainfall) indicating the significance of the deep jets for climate. Here we analyse velocity data from more than 7 years of moored observations at the equator, 23°W as well as shipboard hydrographic and current observations along the 23°W repeat section. Our focus is on intermediate depth levels (300-700 m), where the deep jets are superimposed on a mean flow composed of the westward flowing Equatorial Intermediate Current centred on the equator and the eastward Southern and Northern Intermediate Countercurrents located at 2°S and 2°N, respectively. The large zonal oxygen gradient from the well ventilated western boundary toward low-oxygen values near the eastern boundary makes the meridional oxygen distribution in the central equatorial Atlantic sensitive to zonal flow variations in time and latitude. We compare the observed meridional structures of the mean and anomalous oxygen and zonal velocity distributions as well as their temporal evolution with results of an advection-diffusion model driven by a prescribed velocity field, restoring to high oxygen values at the western boundary, and otherwise constant oxygen consumption. The prescribed velocity field is composed of a high order baroclinic vertical normal mode aimed at representing the 4.5-year cycle and a mean velocity field resembling the observed mean zonal current structure. Similarities

  5. North Atlantic forcing of tropical Indian Ocean climate.

    PubMed

    Mohtadi, Mahyar; Prange, Matthias; Oppo, Delia W; De Pol-Holz, Ricardo; Merkel, Ute; Zhang, Xiao; Steinke, Stephan; Lückge, Andreas

    2014-05-01

    The response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells, but the dearth of high-resolution records outside the monsoon realm in the Indian Ocean precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian Ocean. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian Ocean for the past 45,000 years, combined with climate model simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian Ocean hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian Ocean realm and wet and warm conditions in the southern realm during North Atlantic cold spells. PMID:24784218

  6. Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean

    NASA Astrophysics Data System (ADS)

    Cunningham, Stuart A.; Roberts, Christopher D.; Frajka-Williams, Eleanor; Johns, William E.; Hobbs, Will; Palmer, Matthew D.; Rayner, Darren; Smeed, David A.; McCarthy, Gerard

    2013-12-01

    show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales.

  7. AtlantOS - Optimizing and Enhancing the Integrated Atlantic Ocean Observing System

    NASA Astrophysics Data System (ADS)

    Reitz, Anja; Visbeck, Martin; AtlantOS consortium, the

    2016-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements of heterogeneous international, national and regional design to support science and a wide range of information products. Thus there is tremendous opportunity to develop the systems towards a fully integrated Atlantic Ocean Observing System consistent with the recently developed 'Framework of Ocean Observing'. The vision of AtlantOS is to improve and innovate Atlantic observing by using the Framework of Ocean Observing to obtain an international, more sustainable, more efficient, more integrated, and fit-for-purpose system. Hence, the AtlantOS initiative will have a long-lasting and sustainable contribution to the societal, economic and scientific benefit arising from this integrated approach. This will be delivered by improving the value for money, extent, completeness, quality and ease of access to Atlantic Ocean data required by industries, product supplying agencies, scientist and citizens. The overarching target of the AtlantOS initiative is to deliver an advanced framework for the development of an integrated Atlantic Ocean Observing System that goes beyond the state-of -the-art, and leaves a legacy of sustainability after the life of the project. The legacy will derive from the following aims: i) to improve international collaboration in the design, implementation and benefit sharing of ocean observing, ii) to promote engagement and innovation in all aspects of ocean observing, iii) to facilitate free and open access to ocean data and information, iv) to enable and disseminate methods of achieving quality and authority of ocean information, v) to strengthen the Global Ocean Observing System (GOOS) and to sustain observing systems that are critical for the Copernicus Marine Environment Monitoring Service and its applications and vi) to contribute to the aims of the Galway Statement on Atlantic

  8. Changes in North Atlantic nitrogen fixation controlled by ocean circulation.

    PubMed

    Straub, Marietta; Sigman, Daniel M; Ren, Haojia; Martínez-García, Alfredo; Meckler, A Nele; Hain, Mathis P; Haug, Gerald H

    2013-09-12

    In the ocean, the chemical forms of nitrogen that are readily available for biological use (known collectively as 'fixed' nitrogen) fuel the global phytoplankton productivity that exports carbon to the deep ocean. Accordingly, variation in the oceanic fixed nitrogen reservoir has been proposed as a cause of glacial-interglacial changes in atmospheric carbon dioxide concentration. Marine nitrogen fixation, which produces most of the ocean's fixed nitrogen, is thought to be affected by multiple factors, including ocean temperature and the availability of iron and phosphorus. Here we reconstruct changes in North Atlantic nitrogen fixation over the past 160,000 years from the shell-bound nitrogen isotope ratio ((15)N/(14)N) of planktonic foraminifera in Caribbean Sea sediments. The observed changes cannot be explained by reconstructed changes in temperature, the supply of (iron-bearing) dust or water column denitrification. We identify a strong, roughly 23,000-year cycle in nitrogen fixation and suggest that it is a response to orbitally driven changes in equatorial Atlantic upwelling, which imports 'excess' phosphorus (phosphorus in stoichiometric excess of fixed nitrogen) into the tropical North Atlantic surface. In addition, we find that nitrogen fixation was reduced during glacial stages 6 and 4, when North Atlantic Deep Water had shoaled to become glacial North Atlantic intermediate water, which isolated the Atlantic thermocline from excess phosphorus-rich mid-depth waters that today enter from the Southern Ocean. Although modern studies have yielded diverse views of the controls on nitrogen fixation, our palaeobiogeochemical data suggest that excess phosphorus is the master variable in the North Atlantic Ocean and indicate that the variations in its supply over the most recent glacial cycle were dominated by the response of regional ocean circulation to the orbital cycles. PMID:23965620

  9. Open ocean dead zones in the tropical North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Karstensen, J.; Fiedler, B.; Schütte, F.; Brandt, P.; Körtzinger, A.; Fischer, G.; Zantopp, R.; Hahn, J.; Visbeck, M.; Wallace, D.

    2015-04-01

    Here we present first observations, from instrumentation installed on moorings and a float, of unexpectedly low (<2 μmol kg-1) oxygen environments in the open waters of the tropical North Atlantic, a region where oxygen concentration does normally not fall much below 40 μmol kg-1. The low-oxygen zones are created at shallow depth, just below the mixed layer, in the euphotic zone of cyclonic eddies and anticyclonic-modewater eddies. Both types of eddies are prone to high surface productivity. Net respiration rates for the eddies are found to be 3 to 5 times higher when compared with surrounding waters. Oxygen is lowest in the centre of the eddies, in a depth range where the swirl velocity, defining the transition between eddy and surroundings, has its maximum. It is assumed that the strong velocity at the outer rim of the eddies hampers the transport of properties across the eddies boundary and as such isolates their cores. This is supported by a remarkably stable hydrographic structure of the eddies core over periods of several months. The eddies propagate westward, at about 4 to 5 km day-1, from their generation region off the West African coast into the open ocean. High productivity and accompanying respiration, paired with sluggish exchange across the eddy boundary, create the "dead zone" inside the eddies, so far only reported for coastal areas or lakes. We observe a direct impact of the open ocean dead zones on the marine ecosystem as such that the diurnal vertical migration of zooplankton is suppressed inside the eddies.

  10. 78 FR 34879 - Special Local Regulations for Marine Events, Atlantic City Offshore Race, Atlantic Ocean...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A... amend the Table to Sec. 100.501, as revised May 21, 2013 (78 FR 29632), as follows: 0 a. Under ``(a... City Offshore Race, Atlantic Ocean; Atlantic City, NJ AGENCY: Coast Guard, DHS. ACTION: Temporary...

  11. Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa; Rhines, Peter B.; Worthlen, Denise L.

    2011-01-01

    Based on the 20th century atmospheric reanalysis, winters with more frequent blocking, in a band of blocked latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability. Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by impacting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially, 1996-2010). It also describes much longer-timescale Atlantic multidecadal ocean variability (AMV), including the extreme, pre-greenhouse-gas, northern warming of the 1930s-1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat-exchange, both of which contribute to the warm phase of AMV.

  12. The distribution of dissolved iron in the West Atlantic Ocean.

    PubMed

    Rijkenberg, Micha J A; Middag, Rob; Laan, Patrick; Gerringa, Loes J A; van Aken, Hendrik M; Schoemann, Véronique; de Jong, Jeroen T M; de Baar, Hein J W

    2014-01-01

    Iron (Fe) is an essential trace element for marine life. Extremely low Fe concentrations limit primary production and nitrogen fixation in large parts of the oceans and consequently influence ocean ecosystem functioning. The importance of Fe for ocean ecosystems makes Fe one of the core chemical trace elements in the international GEOTRACES program. Despite the recognized importance of Fe, our present knowledge of its supply and biogeochemical cycle has been limited by mostly fragmentary datasets. Here, we present highly accurate dissolved Fe (DFe) values measured at an unprecedented high intensity (1407 samples) along the longest full ocean depth transect (17,500 kilometers) covering the entire western Atlantic Ocean. DFe measurements along this transect unveiled details about the supply and cycling of Fe. External sources of Fe identified included off-shelf and river supply, hydrothermal vents and aeolian dust. Nevertheless, vertical processes such as the recycling of Fe resulting from the remineralization of sinking organic matter and the removal of Fe by scavenging still dominated the distribution of DFe. In the northern West Atlantic Ocean, Fe recycling and lateral transport from the eastern tropical North Atlantic Oxygen Minimum Zone (OMZ) dominated the DFe-distribution. Finally, our measurements showed that the North Atlantic Deep Water (NADW), the major driver of the so-called ocean conveyor belt, contains excess DFe relative to phosphate after full biological utilization and is therefore an important source of Fe for biological production in the global ocean. PMID:24978190

  13. The Distribution of Dissolved Iron in the West Atlantic Ocean

    PubMed Central

    Rijkenberg, Micha J. A.; Middag, Rob; Laan, Patrick; Gerringa, Loes J. A.; van Aken, Hendrik M.; Schoemann, Véronique; de Jong, Jeroen T. M.; de Baar, Hein J. W.

    2014-01-01

    Iron (Fe) is an essential trace element for marine life. Extremely low Fe concentrations limit primary production and nitrogen fixation in large parts of the oceans and consequently influence ocean ecosystem functioning. The importance of Fe for ocean ecosystems makes Fe one of the core chemical trace elements in the international GEOTRACES program. Despite the recognized importance of Fe, our present knowledge of its supply and biogeochemical cycle has been limited by mostly fragmentary datasets. Here, we present highly accurate dissolved Fe (DFe) values measured at an unprecedented high intensity (1407 samples) along the longest full ocean depth transect (17500 kilometers) covering the entire western Atlantic Ocean. DFe measurements along this transect unveiled details about the supply and cycling of Fe. External sources of Fe identified included off-shelf and river supply, hydrothermal vents and aeolian dust. Nevertheless, vertical processes such as the recycling of Fe resulting from the remineralization of sinking organic matter and the removal of Fe by scavenging still dominated the distribution of DFe. In the northern West Atlantic Ocean, Fe recycling and lateral transport from the eastern tropical North Atlantic Oxygen Minimum Zone (OMZ) dominated the DFe-distribution. Finally, our measurements showed that the North Atlantic Deep Water (NADW), the major driver of the so-called ocean conveyor belt, contains excess DFe relative to phosphate after full biological utilization and is therefore an important source of Fe for biological production in the global ocean. PMID:24978190

  14. Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Atmospheric blocking over the northern North Atlantic involves isolation of large regions of air from the westerly circulation for 5-14 days or more. From a recent 20th century atmospheric reanalysis (1,2) winters with more frequent blocking persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability (AMV). Ocean circulation is forced by wind-stress curl and related air/sea heat exchange, and we find that their space-time structure is associated with dominant blocking patterns: weaker ocean gyres and weaker heat exchange contribute to the warm phase of AMV. Increased blocking activity extending from Greenland to British Isles is evident when winter blocking days of the cold years (1900-1929) are subtracted from those of the warm years (1939-1968).

  15. Atlantic Ocean CARINA data: overview and salinity adjustments

    SciTech Connect

    Tanhua, T.; Steinfeldt, R.; Key, Robert; Brown, P.; Gruber, N.; Wanninkhof, R.; Perez, F.F.; Kortzinger, A.; Velo, A.; Schuster, U.; Van Heuven, S.; Bullister, J.L.; Stendardo, I.; Hoppema, M.; Olsen, Are; Kozyr, Alexander; Pierrot, D.; Schirnick, C.; Wallace, D.W.R.

    2010-01-01

    Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon dioxide IN the Atlantic Ocean). The data have gone through rigorous quality control procedures to assure the highest possible quality and consistency. The data for the pertinent parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the three data products: merged data files with measured, calculated and interpolated data for each of the three CARINA regions, i.e. the Arctic Mediterranean Seas, the Atlantic and the Southern Ocean. These products have been corrected to be internally consistent. Ninety-eight of the cruises in the CARINA database were conducted in the Atlantic Ocean, defined here as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30 S. Here we present an overview of the Atlantic Ocean synthesis of the CARINA data and the adjustments that were applied to the data product. We also report the details of the secondary QC (Quality Control) for salinity for this data set. Procedures of quality control including crossover analysis between stations and inversion analysis of all crossover data are briefly described. Adjustments to salinity measurements were applied to the data from 10 cruises in the Atlantic Ocean region. Based on our analysis we estimate the internal consistency of the CARINA-ATL salinity data to be 4.1 ppm. With these adjustments the CARINA data products are consistent both internally was well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, oceanic carbon inventories

  16. Enhanced warming of the Northwest Atlantic Ocean under climate change

    NASA Astrophysics Data System (ADS)

    Saba, Vincent S.; Griffies, Stephen M.; Anderson, Whit G.; Winton, Michael; Alexander, Michael A.; Delworth, Thomas L.; Hare, Jonathan A.; Harrison, Matthew J.; Rosati, Anthony; Vecchi, Gabriel A.; Zhang, Rong

    2016-01-01

    The Intergovernmental Panel on Climate Change (IPCC) fifth assessment of projected global and regional ocean temperature change is based on global climate models that have coarse (˜100 km) ocean and atmosphere resolutions. In the Northwest Atlantic, the ensemble of global climate models has a warm bias in sea surface temperature due to a misrepresentation of the Gulf Stream position; thus, existing climate change projections are based on unrealistic regional ocean circulation. Here we compare simulations and an atmospheric CO2 doubling response from four global climate models of varying ocean and atmosphere resolution. We find that the highest resolution climate model (˜10 km ocean, ˜50 km atmosphere) resolves Northwest Atlantic circulation and water mass distribution most accurately. The CO2 doubling response from this model shows that upper-ocean (0-300 m) temperature in the Northwest Atlantic Shelf warms at a rate nearly twice as fast as the coarser models and nearly three times faster than the global average. This enhanced warming is accompanied by an increase in salinity due to a change in water mass distribution that is related to a retreat of the Labrador Current and a northerly shift of the Gulf Stream. Both observations and the climate model demonstrate a robust relationship between a weakening Atlantic Meridional Overturning Circulation (AMOC) and an increase in the proportion of Warm-Temperate Slope Water entering the Northwest Atlantic Shelf. Therefore, prior climate change projections for the Northwest Atlantic may be far too conservative. These results point to the need to improve simulations of basin and regional-scale ocean circulation.

  17. Toxic Trichodesmium bloom occurrence in the southwestern South Atlantic Ocean.

    PubMed

    Sacilotto Detoni, Amália Maria; Costa, Luiza Dy Fonseca; Pacheco, Lucas Abrão; Yunes, João Sarkis

    2016-02-01

    Harmful Trichodesmium blooms have been reported on the continental slope of the southwestern South Atlantic Ocean; we sampled six such blooms. The highest saxitoxin concentration was observed where the number of colonies was proportionally greater relative to the total density of trichomes. Trichodesmium blooms are harmful to shrimp larvae and may lead to plankton community mortality. This study is the first record of neurotoxic blooms in the open waters of the South Atlantic. PMID:26695000

  18. Ocean science: Vagaries of Atlantic overturning

    NASA Astrophysics Data System (ADS)

    Haine, Thomas W. N.

    2016-07-01

    A weakening of the Atlantic meridional overturning circulation has emerged from noise after years of painstaking measurements. Three independent lines of evidence suggest that an anthropogenic influence on this overturning is not yet detectable.

  19. Abstracting the Pacific Ocean's Impact on North Atlantic Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Faghmous, J.; Le, M.; Liess, S.; Mesquita, M.; Kumar, V.

    2012-12-01

    The warming anomalies of sea surface temperatures (SSTs) along the near- equatorial Pacific Ocean (ENSO) have well documented global long-range weather teleconnections from rainfall in southern India to mudslides in the western United States. In this work, we focus on ENSO's teleconnections with North Atlantic tropical cyclone (TC) activity. Traditionally, ENSO's impact on Atlantic TCs has been abstracted by monitoring the warming of static regions along the equatorial Pacific Ocean. We propose that the spatial distribution of Pacific Ocean warming might provide better predictive insights into ENSO-Atlantic TC impact than warming anomalies alone. We present a distance-based ENSO index (S-ENSO for spatial ENSO) that tracks the location of the maximum near-tropical Pacific warming anomaly instead the absolute warming of a static region. Our spatial ENSO index correlates better with seasonal TC activity than standard ENSO indices, especially with increased lead times.

  20. Radiocarbon in dissolved organic carbon of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Druffel, E. R. M.; Griffin, S.; Coppola, A. I.; Walker, B. D.

    2016-05-01

    Marine dissolved organic carbon (DOC) is produced in the surface ocean though its radiocarbon (14C) age in the deep ocean is thousands of years old. Here we show that ≥10% of the DOC in the deep North Atlantic is of postbomb origin and that the 14C age of the prebomb DOC is ≥4900 14C year, ~900 14C year older than previous estimates. We report 14C ages of DOC in the deep South Atlantic that are intermediate between values in the North Atlantic and the Southern Ocean. Finally, we conclude that prebomb DOC 14C ages are older and a portion of deep DOC is more dynamic than previously reported.

  1. An updated anthropogenic CO2 inventory in the Atlantic Ocean

    SciTech Connect

    Lee, K.; Choi, S.-D.; Park, G.-H.; Peng, T.-H.; Key, Robert; Sabine, Chris; Feely, R. A.; Bullister, J.L.; Millero, F. J.; Kozyr, Alexander

    2003-01-01

    This paper presents a comprehensive analysis of the basin-wide inventory of anthropogenic CO2 in the Atlantic Ocean based on high-quality inorganic carbon, alkalinity, chlorofluorocarbon, and nutrient data collected during the World Ocean Circulation Experiment (WOCE) Hydrographic Program, the Joint Global Ocean Flux Study (JGOFS), and the Ocean-Atmosphere Carbon Exchange Study (OACES) surveys of the Atlantic Ocean between 1990 and 1998. Anthropogenic CO2 was separated from the large pool of dissolved inorganic carbon using an extended version of the DC* method originally developed by Gruber et al. [1996]. The extension of the method includes the use of an optimum multiparameter analysis to determine the relative contributions from various source water types to the sample on an isopycnal surface. Total inventories of anthropogenic CO2 in the Atlantic Ocean are highest in the subtropical regions at 20 40, whereas anthropogenic CO2 penetrates the deepest in high-latitude regions (>40N). The deeper penetration at high northern latitudes is largely due to the formation of deep water that feeds the Deep Western Boundary Current, which transports anthropogenic CO2 into the interior. In contrast, waters south of 50S in the Southern Ocean contain little anthropogenic CO2. Analysis of the data collected during the 1990 1998 period yielded a total anthropogenic CO2 inventory of 28.4 4.7 Pg C in the North Atlantic (equator-70N) and of 18.5 3.9 Pg C in the South Atlantic (equator-70S). These estimated basin-wide inventories of anthropogenic CO2 are in good agreement with previous estimates obtained by Gruber [1998], after accounting for the difference in observational periods. Our calculation of the anthropogenic CO2 inventory in the Atlantic Ocean, in conjunction with the inventories calculated previously for the Indian Ocean [Sabine et al., 1999] and for the Pacific Ocean [Sabine et al., 2002], yields a global anthropogenic CO2 inventory of 112 17 Pg C that has accumulated

  2. Reconstructing past particle fluxes in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Curry, W. B.; Lohmann, G. P.

    1990-08-01

    Using a research strategy analogous to modern sediment trap studies, sediment accumulation patterns on submarine rises can be interpreted in terms of past ocean chemistry and circulation. We have followed this research strategy to reconstruct the history of surface water productivity and deep-water chemistry and circulation in the eastern equatorial Atlantic (Sierra Leone Rise) and western equatorial Atlantic (Ceara Rise) during the last glacial maximum (˜18,000 B.P.). On shallow sections of these rises, at depths with little carbonate particle degradation, we assume that the accumulation of skeletal carbonate approximates the carbonate production rate in surface water. During the last glacial maximum, the rate of carbonate productivity was lower in the eastern Atlantic than it is today, while the western Atlantic exhibited no glacial-interglacial difference in carbonate productivity. Based on the difference in carbonate accumulation rates between shallow and deep cores on the rises, we observed greater dissolution in both basins during the last glaciation. The eastern Atlantic always had a lower rate of dissolution than the western Atlantic, despite having deep water with a lower δ13C during the last glacial maximum. Organic carbon accumulation in the eastern Atlantic increased with depth in the water column during the last glaciation, suggesting that there was a bathymetric decrease in dissolved oxygen concentration at that time. These observations are consistent with a glacial decrease in the production rate of northern source deep water during the last glaciation. At that time, the mixing zone between northern source and southern source deep water migrated to the north in the Atlantic, resulting in a greater proportion of corrosive, southern source deep water in the western Atlantic, and entering the eastern Atlantic through low-latitude fracture zones. Today the ratio of northern and southern components entering the eastern Atlantic is about 4:1. Based on

  3. How North Atlantic cooling alters Southern Ocean wind

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2011-07-01

    At least seven times during the last ice age, large portions of the polar glaciers crumbled, sending rafts of ice floating into the North Atlantic Ocean. When these icebergs melted, the resultant injection of cold freshwater was enough to drive down ocean temperatures by as much as 12°C. These so-called Heinrich events are associated with rising atmospheric carbon dioxide (CO2) levels, but a mechanism to explain the connection convincingly has yet to arise. One proposed explanation sees the melting-iceberg-triggered North Atlantic cooling tied to increases in CO2 venting from the Southern Ocean, which surrounds Antarctica, through increased wind-driven upwelling. To test this hypothesis, which was initially proposed by researchers in 2009 based on paleoclimate evidence, Lee et al. ran ocean-atmosphere coupled climate simulations to determine the physical mechanism that could support this cross-hemisphere connection. (Paleoceanography, doi:10.1029/ 2010PA002004, 2011)

  4. The Atlantic Multidecadal Oscillation without a role for ocean circulation.

    PubMed

    Clement, Amy; Bellomo, Katinka; Murphy, Lisa N; Cane, Mark A; Mauritsen, Thorsten; Rädel, Gaby; Stevens, Bjorn

    2015-10-16

    The Atlantic Multidecadal Oscillation (AMO) is a major mode of climate variability with important societal impacts. Most previous explanations identify the driver of the AMO as the ocean circulation, specifically the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot be the driver. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the characteristics of the AMO in the current generation of climate models. These results suggest that the AMO is the response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling playing a role in the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response to, not a cause of, the AMO. PMID:26472908

  5. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port...

  6. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of...

  7. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of...

  8. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of...

  9. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port...

  10. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of...

  11. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Safety Zone: Atlantic Ocean... Guard District § 165.535 Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. (a) Location. The following area is a safety zone: All waters of the Atlantic Ocean within the area bounded...

  12. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port...

  13. 33 CFR 110.188 - Atlantic Ocean off Miami and Miami Beach, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean off Miami and... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.188 Atlantic Ocean off Miami and... in cases of great emergency, no vessel shall be anchored in the Atlantic Ocean in the vicinity of...

  14. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port...

  15. 33 CFR 110.185 - Atlantic Ocean, off the Port of Palm Beach, FL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean, off the Port of... HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.185 Atlantic Ocean, off the Port... regulations. (1) Vessels in the Atlantic Ocean near Lake Worth Inlet awaiting berthing space at the Port...

  16. North Atlantic Ocean drivers of the 2015 European heat wave

    NASA Astrophysics Data System (ADS)

    Duchez, Aurélie; Frajka-Williams, Eleanor; Josey, Simon A.; Hirschi, Joël; Evans, Gwyn

    2016-04-01

    Major European heat waves have occurred on several occasions in the past two decades, including the summer of 2015, with dramatic socioeconomic impacts and in a globally warming world, heat waves are expected to become longer, more frequent and more intense. Nevertheless, our understanding of heat wave causes remains at a basic level, limiting the usefulness of event prediction. We show that 2015 was the most extreme heat wave in central Europe in the past 35 years. We find that the heat wave was preceded by cold mid-latitude North Atlantic Ocean surface temperatures, which contributed to its development. In order to explain the genesis of the cold ocean anomaly, we consider surface heat loss, ocean heat content and wind driven upwelling. The anomaly is primarily due to extreme ocean heat loss in the preceding two winters and re-emergent cold ocean water masses. Further analysis indicates that this ocean anomaly was a driver for the 2015 heat wave as it favoured a stationary position of the Jet Stream, which steered Atlantic cyclones away from central Europe towards northern Europe. The cold Atlantic anomaly was also present during the most devastating European heat waves since the 1980s indicating that it is a common factor in the development of these extreme events.

  17. Upper-level circulation in the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Peterson, Ray G.; Stramma, Lothar

    In this paper we present a literature survey of the South Atlantic's climate and its oceanic upper-layer circulation and meridional heat transport. The opening section deals with climate and is focused upon those elements having greatest oceanic relevance, i.e., distributions of atmospheric sea level pressure, the wind fields they produce, and the net surface energy fluxes. The various geostrophic currents comprising the upper-level general circulation are then reviewed in a manner organized around the subtropical gyre, beginning off southern Africa with the Agulhas Current Retroflection and then progressing to the Benguela Current, the equatorial current system and circulation in the Angola Basin, the large-scale variability adn interannual warmings at low latitudes, the Brazil Current, the South Atlantic Current, and finally to the Antarctic Circumpolar Current system in which the Falkland (Malvinas) Current is included. A summary of estimates of the meridional heat transport at various latitudes in the South Atlantic ends the survey.

  18. 33 CFR 165.T05-0494 - Safety Zone, Atlantic Ocean; Ocean City, NJ.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to comply with the general regulations governing safety zones in 33 CFR 165.33. (1) All persons or... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Safety Zone, Atlantic Ocean; Ocean City, NJ. 165.T05-0494 Section 165.T05-0494 Navigation and Navigable Waters COAST...

  19. Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean

    PubMed Central

    Cunningham, Stuart A; Roberts, Christopher D; Frajka-Williams, Eleanor; Johns, William E; Hobbs, Will; Palmer, Matthew D; Rayner, Darren; Smeed, David A; McCarthy, Gerard

    2013-01-01

    [1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales. PMID:26074634

  20. CARINA (Carbon dioxide in the Atlantic Ocean) Data from CDIAC

    DOE Data Explorer

    The idea for CARINA developed at a workshop (CO2 in the northern North Atlantic) that was held at the HANSE-Wissenschaftskolleg (HANSE Institute for Advanced Study) in Delmenhorst, Germany from June 9 to 11, 1999. While the main scientific focus is the North Atlantic, some data from the South Atlantic have been included in the project, along with data from the Arctic Ocean. Data sets go back to 1972, and more than 100 are currently available. The data are also being used in conjunction with other projects and research groups, such as the Atlantic Ocean Carbon Synthesis Group. See the inventory of data at http://store.pangaea.de/Projects/CARBOOCEAN/carina/data_inventory.htm See a detailed table of information on the cruises at http://cdiac.ornl.gov/oceans/CARINA/Carina_table.html and also provides access to data files. The CARBOOCEAN data portal provides a specialized interface for CARINA data, a reference list for historic carbon data, and password protected access to the "Data Underway Warehouse.".

  1. Dilution of the northern North Atlantic Ocean in recent decades.

    PubMed

    Curry, Ruth; Mauritzen, Cecilie

    2005-06-17

    Declining salinities signify that large amounts of fresh water have been added to the northern North Atlantic Ocean since the mid-1960s. We estimate that the Nordic Seas and Subpolar Basins were diluted by an extra 19,000 +/- 5000 cubic kilometers of freshwater input between 1965 and 1995. Fully half of that additional fresh water-about 10,000 cubic kilometers-infiltrated the system in the late 1960s at an approximate rate of 2000 cubic kilometers per year. Patterns of freshwater accumulation observed in the Nordic Seas suggest a century time scale to reach freshening thresholds critical to that portion of the Atlantic meridional overturning circulation. PMID:15961666

  2. Carbon disulfide in the North Atlantic and Pacific Oceans

    NASA Astrophysics Data System (ADS)

    Xie, Huixiang; Moore, Robert M.

    1999-03-01

    Carbon disulfide (CS2) was determined in surface waters of the North Atlantic and Pacific Oceans. The mean concentrations (and ranges) of CS2 in open ocean waters were 13.4 (7.8-26.1) pM S (picomol sulfur per liter) for the North Atlantic and 14.6 (7.2-27.5) pM S for the Pacific. The concentrations in the coastal waters of the North Atlantic averaged 26.4 pM S and ranged from 17.9 to 40.4 pM S. Warm waters generally contained higher levels of CS2 than did cold waters. All the study areas were found to be supersaturated in CS2 relative to the atmosphere based on calculations from published CS2 mixing ratios in the marine boundary layer and their Henry's law constants. Sea-to-air fluxes of CS2 were estimated using exchange velocities for spot and climatological wind speeds. The global oceanic flux extrapolated from this study is 0.18 Tg CS2 yr-1 and in the range 0.13-0.24 Tg CS2 yr-1. It is suggested that microbial processes, photochemical reactions, and phytoplankton activity are potential sources for oceanic CS2.

  3. Modeling Mesoscale Eddies in the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Chao, Yi

    1999-01-01

    Ocean modeling plays an important role in understanding the current climatic conditions and predicting the future climate change. Modeling the ocean at eddy-permitting and/or eddy resolving resolutions (1/3 degree or higher) has a two-fold objective. One part is to represent the ocean as realistically as possible, because mesoscale eddies have an impact on the large-scale circulation. The second objective is to learn how to represent effects of mesoscale eddies without explicitly resolving them. This is particularly important for climate models which cannot be run at eddy-resolving resolutions because of the computational constraints. At JPL, a 1/6 degree latitude by 1/6 degree longitude with 37 vertical levels Atlantic Ocean model has been developed. The model is based on the Parallel Ocean Program (POP) developed at Los Alamos National Laboratory (LANL). Using the 256-processor Cray T3D, we have conducted a 40-year integration of this Atlantic eddy-resolving ocean model. A regional analysis demonstrate that many observed features associated with the Caribbean Sea eddies can be realistically simulated by this model. Analysis of this Atlantic eddy-resolving ocean model further suggests that these Caribbean Sea eddies are connected with eddies formed outside the Caribbean Sea at the confluence of the North Brazil Current (NBC) and the North Equatorial Countercurrent. The diagram of the model simulated surface current shows that the Caribbean eddies ultimately originate in the NBC retroflection region, traveling more than a year from the North Brazil coast through the Lesser Antilles into the Caribbean Sea and eventually into the Gulf of Mexico. Additional information is contained in the original.

  4. Decadal acidification in the water masses of the Atlantic Ocean.

    PubMed

    Ríos, Aida F; Resplandy, Laure; García-Ibáñez, Maribel I; Fajar, Noelia M; Velo, Anton; Padin, Xose A; Wanninkhof, Rik; Steinfeldt, Reiner; Rosón, Gabriel; Pérez, Fiz F

    2015-08-11

    Global ocean acidification is caused primarily by the ocean's uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50 °S-36 °N) for the Atlantic Ocean over two decades (1993-2013). Changes in pH associated with the uptake of anthropogenic CO2 (ΔpHCant) and with variations caused by biological activity and ocean circulation (ΔpHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (∆pH) were observed in central, mode, and intermediate waters, with a maximum ΔpH value in South Atlantic Central Waters of -0.042 ± 0.003. The ΔpH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between -0.0015 and -0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative ΔpHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic. PMID:26216947

  5. Deglacial Atlantic Radiocarbon: A Southern Ocean Perspective

    NASA Astrophysics Data System (ADS)

    Robinson, L. F.; Burke, A.; Adkins, J. F.; Chen, T.; Spooner, P.

    2014-12-01

    It is widely accepted that the Southern Ocean is an important component of the climate system, acting as a key site for carbon and heat exchange between the atmosphere and oceans. The deglaciation with its associated millenial climate changes is a key time period for testing the mechanisms behind these exchanges. Ascertaining the precise timing of these events is a challenge given complications from variable and largely unconstrained reservoir ages, dissolution of carbonate hard parts and sediment redistribution by strong currents. Nevertheless improvements to our understanding of Southern Ocean dynamics in the past requires accurately-dated proxy records that can be embedded in GCM models. Radiocarbon measured in deep-sea corals offers just such an archive and proxy. Using the skeletons of deep-sea corals we are now able to reconstruct aspects of the history of three distinct water masses in the Drake Passage on a precise timescale, allowing direct comparison to U-series dated speleothem terrestrial records and polar ice cores. We present here a new deglacial radiocarbon record from the Drake Passage which more than doubles the resolution of published records. We focus on the deglacial, as well as providing insights from the contrasting period leading up to the LGM. Together with new data from far-field sites we interpret our results as evidence for a Southern Ocean control on atmospheric carbon dioxide and radiocarbon evolution during the deglaciation, and a northern hemisphere control during the run up to the LGM.

  6. Organic pollutants and ocean fronts across the Atlantic Ocean: A review

    NASA Astrophysics Data System (ADS)

    Lohmann, Rainer; Belkin, Igor M.

    2014-11-01

    Little is known about the effect of ocean fronts on pollutants dynamics, particularly organic pollutants. Since fronts are associated with convergent currents and productive fishing grounds, any possible convergence of pollutants at fronts would raise concerns. The focus here is on relatively persistent organic pollutants, POPs, as non-persistent organic pollutants are rarely found in the open ocean. Results from recent cruises in the Atlantic Ocean are examined for POP distributions across ocean fronts in (i) the Canary Current; (ii) the Gulf Stream; and (iii) the Amazon and Rio de la Plata Plumes. Few studies achieved a spatial resolution of 10-20 km, while most had 100-300 km between adjacent stations. The majority of the well-resolved studies measured perfluorinated compounds (PFCs), which seem particularly well suited for frontal resolution. In the NE Atlantic, concentrations of PFCs sharply decreased between SW Europe and NW Africa upon crossing the Canary Current Front at 24-27°N. In the Western Atlantic, the PFC concentrations sharply increased upon entering the Amazon River Plume and Rio de la Plata Plume. In the NW Atlantic, concentrations of several pollutants such as polycyclic aromatic hydrocarbons are very high in Rhode Island Sound, decreasing to below detection limit in the open ocean. The more persistent and already phased-out polychlorinated biphenyls (PCBs) displayed elevated concentrations in the Gulf Stream and Rhode Island Sound, thereby highlighting the importance of ocean fronts, along-front currents, and cross-frontal transport for the dispersal of PCBs.

  7. Deglacial pulses of deep-ocean silicate into the subtropical North Atlantic Ocean.

    PubMed

    Meckler, A N; Sigman, D M; Gibson, K A; François, R; Martínez-García, A; Jaccard, S L; Röhl, U; Peterson, L C; Tiedemann, R; Haug, G H

    2013-03-28

    Growing evidence suggests that the low atmospheric CO2 concentration of the ice ages resulted from enhanced storage of CO2 in the ocean interior, largely as a result of changes in the Southern Ocean. Early in the most recent deglaciation, a reduction in North Atlantic overturning circulation seems to have driven CO2 release from the Southern Ocean, but the mechanism connecting the North Atlantic and the Southern Ocean remains unclear. Biogenic opal export in the low-latitude ocean relies on silicate from the underlying thermocline, the concentration of which is affected by the circulation of the ocean interior. Here we report a record of biogenic opal export from a coastal upwelling system off the coast of northwest Africa that shows pronounced opal maxima during each glacial termination over the past 550,000 years. These opal peaks are consistent with a strong deglacial reduction in the formation of silicate-poor glacial North Atlantic intermediate water (GNAIW). The loss of GNAIW allowed mixing with underlying silicate-rich deep water to increase the silicate supply to the surface ocean. An increase in westerly-wind-driven upwelling in the Southern Ocean in response to the North Atlantic change has been proposed to drive the deglacial rise in atmospheric CO2 (refs 3, 4). However, such a circulation change would have accelerated the formation of Antarctic intermediate water and sub-Antarctic mode water, which today have as little silicate as North Atlantic Deep Water and would have thus maintained low silicate concentrations in the Atlantic thermocline. The deglacial opal maxima reported here suggest an alternative mechanism for the deglacial CO2 release. Just as the reduction in GNAIW led to upward silicate transport, it should also have allowed the downward mixing of warm, low-density surface water to reach into the deep ocean. The resulting decrease in the density of the deep Atlantic relative to the Southern Ocean surface promoted Antarctic overturning

  8. 77 FR 11387 - Safety Zone; Lauderdale Air Show, Atlantic Ocean, Fort Lauderdale, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lauderdale Air Show, Atlantic Ocean, Fort... establishing a temporary safety zone on the waters of the Atlantic Ocean in the vicinity of Fort Lauderdale... Lauderdale Air Show will include numerous aircraft engaging in aerobatic maneuvers over the Atlantic...

  9. Deep ocean early warning signals of an Atlantic MOC collapse

    NASA Astrophysics Data System (ADS)

    Feng, Qing Yi; Viebahn, Jan P.; Dijkstra, Henk A.

    2014-08-01

    A future collapse of the Atlantic Meridional Overturning Circulation (MOC) has been identified as one of the most dangerous tipping points in the climate system. It is therefore crucial to develop early warning indicators for such a potential collapse based on relatively short time series. So far, attempts to use indicators based on critical slowdown have been marginally successful. Based on complex climate network reconstruction, we here present a promising new indicator for the MOC collapse that efficiently monitors spatial changes in deep ocean circulation. Through our analysis of the performance of this indicator, we formulate optimal locations of measurement of the MOC to provide early warning signals of a collapse. Our results imply that an increase in spatial resolution of the Atlantic MOC observations (i.e., at more sections) can improve early detection, because the spatial coherence in the deep ocean arising near the transition is better captured.

  10. Measurements of Ocean Derived Aerosol Over the North Atlantic

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Quinn, P.; Frossard, A. A.; Russell, L. M.; Hakala, J. P.; Kieber, D. J.; Keene, W. C.

    2012-12-01

    Breaking waves on the ocean surface inject sea spray particles into the atmosphere which can act as CCN. Characterization of particles freshly emitted from the ocean surface requires a sampling method that is able to isolate those particles and prevent them from interacting with ambient gases and particles. Here we report measurements of particles directly emitted from the ocean using a newly developed in-situ particle generator (Sea Sweep). The Sea Sweep was deployed alongside RV Ronald H. Brown in the North Atlantic during August of 2012 in two contrasting regions; one in the eutrophic waters on Georges Bank and one in the oligotrophic waters near Bermuda. Bubbles were generated 0.75 m below the ocean surface with stainless steel frits and swept into a hood/vacuum hose to feed a suite of aerosol instrumentation on board the ship. The measured aerosol properties from the two regions will be compared.

  11. Trace metal accumulation in carbonate biominerals of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Demina, L. L.; Oskina, N. S.; Galkin, S. V.

    2016-01-01

    New data on trace metal (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) distribution in carbonate biominerals formed in geochemically different oceanic environments are discussed. Calcite shells of shelf and deepwater hydrothermal vent mussels as well as planktic foraminifers and pteropods from the central Atlantic Ocean have been studied. The variability in concentrations of most trace elements between different groups of calcifying organisms are usually within one order of magnitude, except for Fe and Mn, the elevated contents of which in microfossils are caused by post-sedimentation interaction. Different groups of calcifying organisms demonstrate a biogeochemical uniformity in trace metal accumulation during the biomineralization processes.

  12. Decadal acidification in the water masses of the Atlantic Ocean

    PubMed Central

    Ríos, Aida F.; Resplandy, Laure; García-Ibáñez, Maribel I.; Fajar, Noelia M.; Velo, Anton; Padin, Xose A.; Wanninkhof, Rik; Steinfeldt, Reiner; Rosón, Gabriel; Pérez, Fiz F.

    2015-01-01

    Global ocean acidification is caused primarily by the ocean’s uptake of CO2 as a consequence of increasing atmospheric CO2 levels. We present observations of the oceanic decrease in pH at the basin scale (50°S–36°N) for the Atlantic Ocean over two decades (1993–2013). Changes in pH associated with the uptake of anthropogenic CO2 (ΔpHCant) and with variations caused by biological activity and ocean circulation (ΔpHNat) are evaluated for different water masses. Output from an Institut Pierre Simon Laplace climate model is used to place the results into a longer-term perspective and to elucidate the mechanisms responsible for pH change. The largest decreases in pH (∆pH) were observed in central, mode, and intermediate waters, with a maximum ΔpH value in South Atlantic Central Waters of −0.042 ± 0.003. The ΔpH trended toward zero in deep and bottom waters. Observations and model results show that pH changes generally are dominated by the anthropogenic component, which accounts for rates between −0.0015 and −0.0020/y in the central waters. The anthropogenic and natural components are of the same order of magnitude and reinforce one another in mode and intermediate waters over the time period. Large negative ΔpHNat values observed in mode and intermediate waters are driven primarily by changes in CO2 content and are consistent with (i) a poleward shift of the formation region during the positive phase of the Southern Annular Mode in the South Atlantic and (ii) an increase in the rate of the water mass formation in the North Atlantic. PMID:26216947

  13. Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean

    NASA Technical Reports Server (NTRS)

    Hakkinen, Sirpa M.; Rhines, P. B.; Worthen, D. L.

    2012-01-01

    Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system.

  14. Organic matter in eolian dusts over the Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Simoneit, B. R. T.

    1977-01-01

    The elemental and mineralogical composition and the microfossil and detritus content of particulate fallout from the lower troposphere over the Atlantic Ocean have been extensively documented in earlier work, and it was possible to ascribe terrigenous source areas to such fallout. A brief review of the organic geochemistry of eolian dusts is also presented here. The lipids of eolian dusts sampled from the air mass over the eastern Atlantic from about 35 deg N to 30 deg S were analyzed here. These lipids consisted mainly of normal alkanes, carboxylic acids and alcohols. The n-alkanes were found to range from n-C23 to n-C35 with high CPI values and maximizing at n-C27 in the North Atlantic, at n-C29 in the equatorial Atlantic and at n-C31 in the South Atlantic. The n-fatty acids had mostly bimodal distributions, ranging from n-C12 to n-C30 (high CPI), with maxima at n-C16 and in the northern samples at n-C24 and in the southern samples at n-C26. The n-alcohols ranged from n-C12 to n-C32, with high CPI values and maxima mainly at n-C28. The compositions of these lipids indicated that their terrigenous sources were comprised mainly of higher plant vegetation and desiccated lacustrine mud flats on the African continent.

  15. The Low-Frequency Variability of the Tropical Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa; Mo, Kingtse C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Upper ocean temperature variability in the tropical Atlantic is examined from the Comprehensive Ocean Atmosphere Data Set (COADS) as well as from an ocean model simulation forced by COADS anomalies appended to a monthly climatology. Our findings are as follows: Only the sea surface temperatures (SST) in the northern tropics are driven by heat fluxes, while the southern tropical variability arises from wind driven ocean circulation changes. The subsurface temperatures in the northern and southern tropics are found to have a strong linkage to buoyancy forcing changes in the northern North Atlantic. Evidence for Kelvin-like boundary wave propagation from the high latitudes is presented from the model simulation. This extratropical influence is associated with wintertime North Atlantic Oscillation (NAO) forcing and manifests itself in the northern and southern tropical temperature anomalies of the same sign at depth of 100-200 meters as result of a Rossby wave propagation away from the eastern boundary in the wake of the boundary wave passage. The most apparent association of the southern tropical sea surface temperature anomalies (STA) arises with the anomalous cross-equatorial winds which can be related to both NAO and the remote influence from the Pacific equatorial region. These teleconnections are seasonal so that the NAO impact on the tropical SST is the largest it mid-winter but in spring and early summer the Pacific remote influence competes with NAO. However, NAO appears to have a more substantial role than the Pacific influence at low frequencies during the last 50 years. The dynamic origin of STA is indirectly confirmed from the SST-heat flux relationship using ocean model experiments which remove either anomalous wind stress forcing or atmospheric forcing anomalies contributing to heat exchange.

  16. Hydrographic observations in the western tropical and subtropical north atlantic ocean: Atlantic Climate Change Program (ACCP) and western tropical atlantic experiment (WESTRAX) during 1990. Data report

    SciTech Connect

    Johns, E.; Wilburn, A.M.

    1993-03-01

    Data collected during the 1990 Atlantic Climate Change Program and the Western Tropical Atlantic Experiment were presented. The goals of the programs were to increase the understanding of the roles of the regional circulation and ocean circulation in global climate. Salinity, ocean temperature as a function of depth, and other hydrographic data were collected from shipborne platforms.

  17. Hydrographic observations in the western tropical and subtropical north atlantic ocean: Atlantic Climate Change Program (ACCP) and western tropical atlantic experiment (WESTRAX) during 1991. Data report

    SciTech Connect

    Johns, E.; Wilburn, A.M.

    1993-03-01

    Data collected during the 1991 Atlantic Climate Change Program and the Western Tropical Atlantic Experiment were presented. The goals of the programs were to increase the understanding of the roles of regional circulation and ocean circulation in global climate. Salinity, ocean temperature as a function depth and other hydrographic data were collected from shipborne platforms.

  18. The sources of deep ocean infragravity waves observed in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Crawford, Wayne; Ballu, Valerie; Bertin, Xavier; Karpytchev, Mikhail

    2015-07-01

    Infragravity waves are long-period (25-250 s) ocean surface gravity waves generated in coastal zones through wave-wave interactions or oscillation of the breaking point. Most of the infragravity wave energy is trapped or dissipated near coastlines, but a small percentage escapes into the open oceans. The source of deep ocean infragravity waves is debated, specifically whether they come mostly from regions with strong source waves or from sites with particular morphologies/orientations. We correlate measurements of infragravity waves in the deep North Atlantic Ocean with infragravity wave generation parameters throughout the Atlantic Ocean to find the dominant sources of deep ocean infragravity wave energy in the North Atlantic Ocean. The deep ocean infragravity wave data are from a 5 year deployment of absolute pressure gauges west of the Azores islands (37°N, 35°W) and shorter data sets from seafloor tsunami gauges (DART buoys). Two main sources are identified: one off of the west coast of southern Europe and northern Africa (25°N-40°N) in northern hemisphere winter and the other off the west coast of equatorial Africa (the Gulf of Guinea) in southern hemisphere winter. These regions have relatively weak source waves and weak infragravity wave propagation paths to the main measurement site, indicating that that the site morphology/orientation dominates the creation of deep ocean infragravity waves. Both regions have also been identified as potential sources of global seismological noise, suggesting that the same mechanisms may be behind the generation of deep ocean infragravity waves and global seismological noise in the frequency band from 0.001 to 0.04 Hz.

  19. Monitoring the North Atlantic using ocean colour data

    NASA Astrophysics Data System (ADS)

    Fuentes-Yaco, C.; Caverhill, C.; Maass, H.; Porter, C.; White, GN, III

    2016-04-01

    The Remote Sensing Unit (RSU) at the Bedford Institute of Oceanography (BIO) has been monitoring the North Atlantic using ocean colour products for decades. Optical sensors used include CZCS, POLDER, SeaWiFS, MODIS/Aqua and MERIS. The monitoring area is defined by the Atlantic Zone Monitoring Program (AZMP) but certain products extend into Arctic waters, and all-Canadian waters which include the Pacific coast. RSU provides Level 3 images for various products in several formats and a range of temporal and spatial resolutions. Basic statistics for pre-defined areas of interest are compiled for each product. Climatologies and anomaly maps are also routinely produced, and custom products are delivered by request. RSU is involved in the generation of Level 4 products, such as characterizing the phenology of spring and fall phytoplankton blooms, computing primary production, using ocean colour to aid in EBSA (Ecologically and Biologically Significant Area) definition and developing habitat suitability maps. Upcoming operational products include maps of diatom distribution, biogeochemical province boundaries, and products from sensors such as VIIRS (Visible Infrared Imaging Radiometer Suite), OLCI (Ocean Land Colour Instrument), and PACE (Pre-Aerosol, Clouds and ocean Ecosystem) hyperspectral microsatellite mission.

  20. Oceanic Situational Awareness over the North Atlantic Corridor

    NASA Technical Reports Server (NTRS)

    Welch, Bryan; Greenfield, Israel

    2005-01-01

    Air traffic control (ATC) mandated, aircraft separations over the oceans impose a limitation on traffic capacity for a given corridor, given the projected traffic growth over the oceanic domain. The separations result from a lack of acceptable situational awareness over oceans where radar position updates are not available. This study considers the use of Automatic Dependent Surveillance (ADS) data transmitted over a commercial satellite communications system as an approach to provide ATC with the needed situational awareness and thusly allow for reduced aircraft separations. This study uses Federal Aviation Administration data from a single day for the North Atlantic Corridor to analyze traffic loading to be used as a benchmark against which to compare several approaches for coordinating data transmissions from the aircraft to the satellites.

  1. Quantification of dissolved iron sources to the North Atlantic Ocean.

    PubMed

    Conway, Tim M; John, Seth G

    2014-07-10

    Dissolved iron is an essential micronutrient for marine phytoplankton, and its availability controls patterns of primary productivity and carbon cycling throughout the oceans. The relative importance of different sources of iron to the oceans is not well known, however, and flux estimates from atmospheric dust, hydrothermal vents and oceanic sediments vary by orders of magnitude. Here we present a high-resolution transect of dissolved stable iron isotope ratios (δ(56)Fe) and iron concentrations ([Fe]) along a section of the North Atlantic Ocean. The different iron sources can be identified by their unique δ(56)Fe signatures, which persist throughout the water column. This allows us to calculate the relative contribution from dust, hydrothermal venting and reductive and non-reductive sedimentary release to the dissolved phase. We find that Saharan dust aerosol is the dominant source of dissolved iron along the section, contributing 71-87 per cent of dissolved iron. Additional sources of iron are non-reductive release from oxygenated sediments on the North American margin (10-19 per cent), reductive sedimentary dissolution on the African margin (1-4 per cent) and hydrothermal venting at the Mid-Atlantic Ridge (2-6 per cent). Our data also indicate that hydrothermal vents in the North Atlantic are a source of isotopically light iron, which travels thousands of kilometres from vent sites, potentially influencing surface productivity. Changes in the relative importance of the different iron sources through time may affect interactions between the carbon cycle and climate. PMID:25008528

  2. Fennerosquilla heptacantha (Crustacea: Stomatopoda: Squillidae) in South Atlantic Ocean.

    PubMed

    Lucatelli, Débora

    2015-01-01

    Fennerosquilla is a monotypic genus that belongs to the family Squillidae, which has the highest generic diversity within Stomatopoda. This genus has been recorded in the north Atlantic Ocean, the Gulf of Mexico and Caribbean Sea, between 105 and 458 m depth. The present specimen was collected during the project "Avaliação da Biota Bentônica e Planctônica na porção offshore das Bacias Potiguar e Ceará", in 2011, from the continental slope region of Brazil. In this expedition Fennerosquilla heptacantha was found at 178-193 m depth, and represents the first record of the species in the south Atlantic Ocean (Rio Grande do Norte State, northeastern Brazil), expanding the southern limit distribution. The specimen is the largest recorded, measuring 149 mm total length. The pigmentation zone on median region of telson and all diagnostic characters are still preserved and agree with the original description. Fennerosquilla heptacantha has a disjunct deep water distribution (more than 100 m) in the tropical western Atlantic, mostly along the continental slope. PMID:26624302

  3. The Cretaceous opening of the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Granot, Roi; Dyment, Jérôme

    2015-03-01

    The separation of South America from Africa during the Cretaceous is poorly understood due to the long period of stable polarity of the geomagnetic field, the Cretaceous Normal Superchron (CNS, lasted between ∼121 and 83.6 Myr ago). We present a new identification of magnetic anomalies located within the southern South Atlantic magnetic quiet zones that have arisen due to past variations in the strength of the dipolar geomagnetic field. Using these anomalies, together with fracture zone locations, we calculate the first set of magnetic anomalies-based finite rotation parameters for South America and Africa during that period. The kinematic solutions are generally consistent with fracture zone traces and magnetic anomalies outside the area used to construct them. The rotations indicate that seafloor spreading rates increased steadily throughout most of the Cretaceous and decreased sharply at around 80 Myr ago. A change in plate motion took place in the middle of the superchron, roughly 100 Myr ago, around the time of the final breakup (i.e., separation of continental-oceanic boundary in the Equatorial Atlantic). Prominent misfit between the calculated synthetic flowlines (older than Anomaly Q1) and the fracture zones straddling the African Plate in the central South Atlantic could only be explained by a combination of seafloor asymmetry and internal dextral motion (<100 km) within South America, west of the Rio Grande fracture zone. This process has lasted until ∼92 Myr ago after which both Africa and South America (south of the equator) behaved rigidly. The clearing of the continental-oceanic boundaries within the Equatorial Atlantic Gateway was probably completed by ∼95 Myr ago. The clearing was followed by a progressive widening and deepening of the passageway, leading to the emergence of north-south flow of intermediate and deep-water which might have triggered the global cooling of bottom water and the end for the Cretaceous greenhouse period.

  4. FERROMANGANESE CRUST RESOURCES IN THE PACIFIC AND ATLANTIC OCEANS.

    USGS Publications Warehouse

    Commeau, R.F.; Clark, A.; Johnson, Chad; Manheim, F. T.; Aruscavage, P. J.; Lane, C.M.

    1984-01-01

    Ferromanganese crusts on raised areas of the ocean floor have joined abyssal manganese nodules and hydrothermal sulfides as potential marine resources. Significant volumes of cobalt-rich (about 1% Co) crusts have been identified to date within the US Exclusive Economic Zone (EEZ) in the Central Pacific: in the NW Hawaiian Ridge and Seamount region and in the seamounts in the Johnston Island and Palmyra Island regions. Large volumes of lower grade crusts, slabs, and nodules are also present in shallow ( greater than 1000 m) waters on the Blake plateau, off Florida-South Carolina in the Atlantic Ocean. Data on ferromanganese crusts have been increased by recent German and USGS cruises, but are still sparse, and other regions having crust potential are under current investigation. The authors discuss economic potentials for cobalt-rich crusts in the Central Pacific and Western North Atlantic oceans, with special reference to US EEZ areas. Additional research is needed before more quantitative resource estimates can be made.

  5. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and photographers get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  6. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Media and spectators get a close-up view of the Liberty Bell 7 Project Mercury capsule after its recovery from the Atlantic Ocean floor where it lay for 38 years. Launched July 21, 1961, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. Curt Newport, an underwater salvage expert, located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The expedition was sponsored by the Discovery Channel. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  7. Atlantic Ocean forcing of North American and European summer climate.

    PubMed

    Sutton, Rowan T; Hodson, Daniel L R

    2005-07-01

    Recent extreme events such as the devastating 2003 European summer heat wave raise important questions about the possible causes of any underlying trends, or low-frequency variations, in regional climates. Here, we present new evidence that basin-scale changes in the Atlantic Ocean, probably related to the thermohaline circulation, have been an important driver of multidecadal variations in the summertime climate of both North America and western Europe. Our findings advance understanding of past climate changes and also have implications for decadal climate predictions. PMID:15994552

  8. North Atlantic Deep Water and the World Ocean

    NASA Technical Reports Server (NTRS)

    Gordon, A. L.

    1984-01-01

    North Atlantic Deep Water (NADW) by being warmer and more saline than the average abyssal water parcel introduces heat and salt into the abyssal ocean. The source of these properties is upper layer or thermocline water considered to occupy the ocean less dense than sigma-theta of 27.6. That NADW convects even though it's warmer than the abyssal ocean is obviously due to the high salinity. In this way, NADW formation may be viewed as saline convection. The counter force removing heat and salinity (or introducing fresh water) is usually considered to to take place in the Southern Ocean where upwelling deep water is converted to cold fresher Antarctic water masses. The Southern ocean convective process is driven by low temperatures and hence may be considered as thermal convection. A significant fresh water source may also occur in the North Pacific where the northward flowing of abyssal water from the Southern circumpolar belt is saltier and denser than the southward flowing, return abyssal water. The source of the low salinity input may be vertical mixing of the low salinity surface water or the low salinity intermediate water.

  9. Atmospheric deposition of methanol over the Atlantic Ocean

    PubMed Central

    Yang, Mingxi; Nightingale, Philip D.; Beale, Rachael; Liss, Peter S.; Blomquist, Byron; Fairall, Christopher

    2013-01-01

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air–sea methanol transfer along a ∼10,000-km north–south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air–sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface—an important term for improving air–sea gas exchange models. PMID:24277830

  10. Polychaete abundance, biomass and diversity patterns at the Mid-Atlantic Ridge, North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Shields, Mark A.; Blanco-Perez, Raimundo

    2013-12-01

    Recent studies have revealed that the Mid-Atlantic Ridge (MAR) in the North Atlantic Ocean accounts for a large proportion of available bathyal soft-sediment habitat. When comparing the MAR to the continental margins of the North Atlantic, it is apparent that very little is known about the soft-sediment macrofaunal community associated with the MAR. In the present study, as part of the ECOMAR (Ecosystems of the Mid-Atlantic Ridge at the Sub-Polar Front and Charlie-Gibbs Fracture Zone) project, the polychaete component of the MAR macrofaunal community was investigated. A total of 751 polychaete specimens and 133 species were identified from megacorer samples collected at four MAR sites (48-54°N, depth: 2500-2800 m) sampled during the RRS James Cook 48 cruise in the summer of 2010. Polychaetes were the most abundant member of the macrofaunal community, and there was no significant difference in polychaete abundance, biomass and diversity between any of the MAR sites. In addition, the MAR did not appear to provide a physical barrier to the distribution of bathyal polychaetes either side of the ridge.

  11. Correcting North Atlantic sea surface salinity biases in the Kiel Climate Model: influences on ocean circulation and Atlantic Multidecadal Variability

    NASA Astrophysics Data System (ADS)

    Park, T.; Park, W.; Latif, M.

    2016-01-01

    A long-standing problem in climate models is the large sea surface salinity (SSS) biases in the North Atlantic. In this study, we describe the influences of correcting these SSS biases on the circulation of the North Atlantic as well as on North Atlantic sector mean climate and decadal to multidecadal variability. We performed integrations of the Kiel Climate Model (KCM) with and without applying a freshwater flux correction over the North Atlantic. The quality of simulating the mean circulation of the North Atlantic Ocean, North Atlantic sector mean climate and decadal variability is greatly enhanced in the freshwater flux-corrected integration which, by definition, depicts relatively small North Atlantic SSS biases. In particular, a large reduction in the North Atlantic cold sea surface temperature bias is observed and a more realistic Atlantic Multidecadal Variability simulated. Improvements relative to the non-flux corrected integration also comprise a more realistic representation of deep convection sites, sea ice, gyre circulation and Atlantic Meridional Overturning Circulation. The results suggest that simulations of North Atlantic sector mean climate and decadal variability could strongly benefit from alleviating sea surface salinity biases in the North Atlantic, which may enhance the skill of decadal predictions in that region.

  12. Oceanic Situational Awareness Over the Western Atlantic Track Routing System

    NASA Technical Reports Server (NTRS)

    Welch, Bryan; Greenfeld, Israel

    2005-01-01

    Air traffic control (ATC) mandated, aircraft separations over the oceans impose a limitation on traffic capacity for a given corridor, given the projected traffic growth over the Western Atlantic Track Routing System (WATRS). The separations result from a lack of acceptable situational awareness over oceans where radar position updates are not available. This study considers the use of Automatic Dependent Surveillance (ADS) data transmitted over a commercial satellite communications system as an approach to provide ATC with the needed situational awareness and thusly allow for reduced aircraft separations. This study uses Federal Aviation Administration data from a single day for the WATRS corridor to analyze traffic loading to be used as a benchmark against which to compare several approaches for coordinating data transmissions from the aircraft to the satellites.

  13. Pathways of Atlantic Waters into the Arctic Ocean: Eddy-permitting ocean and sea ice simulations

    NASA Astrophysics Data System (ADS)

    Wekerle, Claudia; von Appen, Wilken-Jon; Danilov, Sergey; Jung, Thomas; Kanzow, Torsten; Schauer, Ursula; Timmermann, Ralph; Wang, Qiang

    2015-04-01

    Fram Strait is the only deep gateway connecting the central Arctic with the North Atlantic. Boundary currents on each side are responsible for the exchange of water masses between the Arctic and North Atlantic. The East Greenland Current (EGC) carries fresh and cold Arctic waters and sea ice southward, whereas the West Spitsbergen Current (WSC) carries warm Atlantic Waters (AW) into the Arctic Ocean. The complex topography in Fram Strait leads to a branching of the northward flowing WSC, with one branch recirculating between 78°N and 81°N which then joins the EGC. To date, the dynamics as well as the precise location of this recirculation are unclear. The goal of this research project is to quantify the amount and variability of AW which recirculates immediately in Fram Strait, and to investigate the role of atmospheric forcing and oceanic meso-scale eddies for the recirculation. We use simulations carried out with a global configuration of the Finite Element Sea ice-Ocean Model (FESOM) at eddy-permitting scales. The advantage of this model is the finite element discretization of the governing equations, which allows us to locally refine the mesh in areas of interest and keep it coarse in other parts of the global oceans without the need for traditional nesting. Here we will show the first results of the model validation. The model has ~9 km resolution in the Nordic Seas and Fram Strait and 1 deg south of 50°N. We assess the model capabilities in simulating the ocean circulation in the Nordic Seas and Fram Strait by comparing with the available observational data, e.g. with data from the Fram Strait oceanographic mooring array. The ocean volume and heat transport from the Atlantic Ocean into the Nordic Seas and at the Fram Strait are analyzed. Our results show that the model can capture some of the observed key ocean properties in our region of interest, while some tuning is required to further improve the model. In the next phase of this project we will focus

  14. Estimating mixed layer nitrate in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Steinhoff, T.; Friedrich, T.; Hartman, S. E.; Oschlies, A.; Wallace, D. W. R.; Körtzinger, A.

    2009-09-01

    Here we present an equation for the estimation of nitrate in surface waters of the North Atlantic Ocean (40° N to 52° N, 10° W to 60° W). The equation was derived by multiple linear regression (MLR) from nitrate, sea surface temperature (SST) observational data and model mixed layer depth (MLD) data. The observational data were taken from merchant vessels that have crossed the North Atlantic on a regular basis in 2002/2003 and from 2005 to present. It is important to find a robust and realistic esitmate of MLD because the deepening of the mixed layer is crucial for nitrate supply to the surface. We compared model data from two models (FOAM and Mercator) with MLD derived from float data (using various criteria). The Mercator model gives a MLD estimate that is close to the MLD derived from floats. MLR was established using SST, MLD from Mercator, time and latitude as predictors. Additionally a neural network was trained with the same dataset and the results were validated against both model data as a "ground truth" and an independent observational dataset. This validation produced RMS errors of the same order for MLR and the neural network approach. We conclude that it is possible to estimate nitrate concentrations with an uncertainty of ±1.5 μmol L-1 in the North Atlantic.

  15. Estimating mixed layer nitrate in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Steinhoff, T.; Friedrich, T.; Hartman, S. E.; Oschlies, A.; Wallace, D. W. R.; Körtzinger, A.

    2010-03-01

    Here we present an equation for the estimation of nitrate in surface waters of the North Atlantic Ocean (40° N to 52° N, 10° W to 60° W). The equation was derived by multiple linear regression (MLR) from nitrate, sea surface temperature (SST) observational data and model mixed layer depth (MLD) data. The observational data were taken from merchant vessels that have crossed the North Atlantic on a regular basis in 2002/2003 and from 2005 to the present. It is important to find a robust and realistic estimate of MLD because the deepening of the mixed layer is crucial for nitrate supply to the surface. We compared model data from two models (FOAM and Mercator) with MLD derived from float data (using various criteria). The Mercator model gives a MLD estimate that is close to the MLD derived from floats. MLR was established using SST, MLD from Mercator, time and latitude as predictors. Additionally a neural network was trained with the same dataset and the results were validated against both model data as a "ground truth" and an independent observational dataset. This validation produced RMS errors of the same order for MLR and the neural network approach. We conclude that it is possible to estimate nitrate concentrations with an uncertainty of ±1.4 μmol L-1 in the North Atlantic.

  16. Physical supply of nitrogen to phytoplankton in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Mahaffey, Claire; Williams, Richard G.; Wolff, George A.; Anderson, William T.

    2004-03-01

    Mechanisms supplying nitrogen (N) to phytoplankton, and thus constraining the levels of export production, over the oligotrophic subtropical Atlantic are assessed along a meridional transect. Stable nitrogen isotope signals reveal a localized region of N2 fixation over the northern subtropical gyre. Elsewhere, particulate organic nitrogen was isotopically enriched and there was no widespread evidence of a trophic bias. Thus phytoplankton are utilizing an enriched source of N along the transect through much of the oligotrophic Atlantic, which may reflect utilization of nitrate from the deep ocean or, possibly, a supply of dissolved organic nitrogen (DON) from a non-N2 fixing source. While there is a significant supply of DON over the subtropical gyres, reaching 0.15 mol Nm-2 yr-1, less than 10% of the DON is semilabile and thus only implies a relatively small contribution to the nitrogen supply required for export production. Over the central part of the subtropical gyres, the supply of N to phytoplankton is probably from nitrate in the underlying thermocline, possibly from convection and diapycnic transfer, or more likely, from finescale upwelling by mesoscale eddies and frontal circulations. The lateral supply of dissolved organic phosphorus (DOP) appears to be a factor of 2-3 times more important than the lateral supply of semilabile DON, and thus might play a role in contributing to the phosphorus (P) supply for phytoplankton. The lateral supply of DON and DOP might also be important in closing the N and P budgets over the North Atlantic.

  17. Covariances and linear predictability of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2013-01-01

    The problem of understanding linear predictability of elements of the ocean circulation is explored in the Atlantic Ocean for two disparate elements: (1) sea surface temperature (SST) under the storm track in a small region east of the Grand Banks and, (2) the meridional overturning circulation north of 30.5°S. To be worthwhile, any nonlinear method would need to exhibit greater skill, and so a rough baseline from which to judge more complex methods is the goal. A 16-year ocean state estimate is used, under the assumption that internal oceanic variability is dominating externally imposed changes. No evidence exists of significant nonlinearity in the bulk of the system over this time span. Linear predictability is the story of time and space correlations, and some predictive skill exists for a few months in SST, with some minor capability extending to a few years. Sixteen years is, however, far too short for an evaluation for interannual, much less decadal, variability, although orders of magnitude are likely stably estimated. The meridional structure of the meridional overturning circulation (MOC), defined as the time-varying vertical integral to the maximum meridional volume transport at each latitude, shows nearly complete decorrelation in the variability across about 35°N—the Gulf Stream system. If a time-scale exists displaying coherence of the MOC between subpolar and subtropical gyres, it lies beyond the existing observation duration, and that has consequences for observing system strategies and the more general problem of detectability of change.

  18. 78 FR 39995 - Safety Zone; Margate Mother's Association Fireworks Display, Atlantic Ocean; Margate, NJ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... Display, Atlantic Ocean; Margate, NJ AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Atlantic Ocean in Margate, NJ. The...

  19. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part 329... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off John...

  20. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area...

  1. 33 CFR 334.130 - Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. 334.130 Section 334.130 Navigation and Navigable Waters... REGULATIONS § 334.130 Atlantic Ocean off Wallops Island and Chincoteague Inlet, Va.; danger zone. (a) The...

  2. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A...

  3. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A...

  4. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area...

  5. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A...

  6. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area...

  7. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A...

  8. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part 329... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off John...

  9. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area...

  10. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A...

  11. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part 329... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean off John...

  12. 33 CFR 165.714 - Regulated Navigation Area; Atlantic Ocean, Charleston, SC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Regulated Navigation Area; Atlantic Ocean, Charleston, SC. 165.714 Section 165.714 Navigation and Navigable Waters COAST GUARD... § 165.714 Regulated Navigation Area; Atlantic Ocean, Charleston, SC. (a) Location. The following area...

  13. 75 FR 34929 - Safety Zones: Neptune Deep Water Port, Atlantic Ocean, Boston, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-21

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zones: Neptune Deep Water Port, Atlantic Ocean... comment at the Web site http://www.regulations.gov . These safety zones are needed pending implementation... Deep Water Port, Atlantic Ocean, Boston, MA; Final Rule (USCG-2009-0589), to protect vessels from...

  14. 78 FR 56151 - Safety Zone, North Atlantic Ocean; Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, North Atlantic Ocean; Virginia Beach, VA... zone on the navigable waters of the North Atlantic Ocean in Virginia Beach, VA to support the...

  15. The Indian Ocean Dipole's influence on Atlantic tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Marinaro, Alan Joseph

    Improving early tropical cyclone forecasts would assist reinsurance decision makers as they seek information that can minimize risks. Early lead forecasts are based on model variables before December 1 (Year 0) that predict Atlantic tropical cyclone activity (Year +1). The autumn Indian Ocean Dipole (IOD) has an 8 to 14 month antecedent correlation with the El Nino - Southern Oscillation (ENSO). ENSO is traditionally the best non-lead and overall predictor of Atlantic tropical cyclone activity. Analyses were performed over a 30-year period from 1984/85-2013/14, with some time variation depending on the test. Correlation, spatial, and wavelet analyses were utilized to find associations between the IOD, west and east components of the IOD, and four other variables related to the following season's ENSO state and tropical cyclone activity. The prior western pole of the October IOD (WIOD) was demonstrated to have statistically significant r-squared values (i.e. 99% confidence interval) to upcoming tropical storm activity (i.e. explained 25% of the variance), named storm counts (28%), and ENSO (21%). The WIOD has no connection with U.S. hurricane landfalls. Wavelet analysis between October IOD variables and following August-October ENSO data was observed to have the best time-frequency relationship. Dynamic reasoning for these relationships reside within the idealized biennial IOD-ENSO cycle, Walker circulation process, and the impact of ENSO on the state of the Atlantic Basin. The WIOD's integration into early-lead forecast models could be an advantage for those in the reinsurance industry and other decision makers impacted by Atlantic tropical cyclonesn.

  16. Factors influencing particulate lipid production in the East Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gašparović, B.; Frka, S.; Koch, B. P.; Zhu, Z. Y.; Bracher, A.; Lechtenfeld, O. J.; Neogi, S. B.; Lara, R. J.; Kattner, G.

    2014-07-01

    Extensive analyses of particulate lipids and lipid classes were conducted to gain insight into lipid production and related factors along the biogeochemical provinces of the Eastern Atlantic Ocean. Data are supported by particulate organic carbon (POC), chlorophyll a (Chl a), phaeopigments, Chl a concentrations and carbon content of eukaryotic micro-, nano- and picophytoplankton, including cell abundances for the latter two and for cyanobacteria and prokaryotic heterotrophs. We focused on the productive ocean surface (2 m depth and deep Chl a maximum (DCM). Samples from the deep ocean provided information about the relative reactivity and preservation potential of particular lipid classes. Surface and DCM particulate lipid concentrations (3.5-29.4 μg L-1) were higher than in samples from deep waters (3.2-9.3 μg L-1) where an increased contribution to the POC pool was observed. The highest lipid concentrations were measured in high latitude temperate waters and in the North Atlantic Tropical Gyral Province (13-25°N). Factors responsible for the enhanced lipid synthesis in the eastern Atlantic appeared to be phytoplankton size (micro, nano, pico) and the low nutrient status with microphytoplankton having the most expressed influence in the surface and eukaryotic nano- and picophytoplankton in the DCM layer. Higher lipid to Chl a ratios suggest enhanced lipid biosynthesis in the nutrient poorer regions. The various lipid classes pointed to possible mechanisms of phytoplankton adaptation to the nutritional conditions. Thus, it is likely that adaptation comprises the replacement of membrane phospholipids by non-phosphorus containing glycolipids under low phosphorus conditions. The qualitative and quantitative lipid compositions revealed that phospholipids were the most degradable lipids, and their occurrence decreased with increasing depth. In contrast, wax esters, possibly originating from zooplankton, survived downward transport probably due to the fast sinking

  17. Are Global In-Situ Ocean Observations Fit-for-purpose? Applying the Framework for Ocean Observing in the Atlantic.

    NASA Astrophysics Data System (ADS)

    Visbeck, M.; Fischer, A. S.; Le Traon, P. Y.; Mowlem, M. C.; Speich, S.; Larkin, K.

    2015-12-01

    There are an increasing number of global, regional and local processes that are in need of integrated ocean information. In the sciences ocean information is needed to support physical ocean and climate studies for example within the World Climate Research Programme and its CLIVAR project, biogeochemical issues as articulated by the GCP, IMBER and SOLAS projects of ICSU-SCOR and Future Earth. This knowledge gets assessed in the area of climate by the IPCC and biodiversity by the IPBES processes. The recently released first World Ocean Assessment focuses more on ecosystem services and there is an expectation that the Sustainable Development Goals and in particular Goal 14 on the Ocean and Seas will generate new demands for integrated ocean observing from Climate to Fish and from Ocean Resources to Safe Navigation and on a healthy, productive and enjoyable ocean in more general terms. In recognition of those increasing needs for integrated ocean information we have recently launched the Horizon 2020 AtlantOS project to promote the transition from a loosely-coordinated set of existing ocean observing activities to a more integrated, more efficient, more sustainable and fit-for-purpose Atlantic Ocean Observing System. AtlantOS takes advantage of the Framework for Ocean observing that provided strategic guidance for the design of the project and its outcome. AtlantOS will advance the requirements and systems design, improving the readiness of observing networks and data systems, and engaging stakeholders around the Atlantic. AtlantOS will bring Atlantic nations together to strengthen their complementary contributions to and benefits from the internationally coordinated Global Ocean Observing System (GOOS) and the Blue Planet Initiative of the Global Earth Observation System of Systems (GEOSS). AtlantOS will fill gaps of the in-situ observing system networks and will ensure that their data are readily accessible and useable. AtlantOS will demonstrate the utility of

  18. Predicting plankton net community production in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Serret, Pablo; Robinson, Carol; Fernández, Emilio; Teira, Eva; Tilstone, Gavin; Pérez, Valesca

    2009-07-01

    We present, test and implement two contrasting models to predict euphotic zone net community production (NCP), which are based on 14C primary production (PO 14CP) to NCP relationships over two latitudinal (ca. 30°S-45°N) transects traversing highly productive and oligotrophic provinces of the Atlantic Ocean (NADR, CNRY, BENG, NAST-E, ETRA and SATL, Longhurst et al., 1995 [An estimation of global primary production in the ocean from satellite radiometer data. Journal of Plankton Research 17, 1245-1271]). The two models include similar ranges of PO 14CP and community structure, but differ in the relative influence of allochthonous organic matter in the oligotrophic provinces. Both models were used to predict NCP from PO 14CP measurements obtained during 11 local and three seasonal studies in the Atlantic, Pacific and Indian Oceans, and from satellite-derived estimates of PO 14CP. Comparison of these NCP predictions with concurrent in situ measurements and geochemical estimates of NCP showed that geographic and annual patterns of NCP can only be predicted when the relative trophic importance of local vs. distant processes is similar in both modeled and predicted ecosystems. The system-dependent ability of our models to predict NCP seasonality suggests that trophic-level dynamics are stronger than differences in hydrodynamic regime, taxonomic composition and phytoplankton growth. The regional differences in the predictive power of both models confirm the existence of biogeographic differences in the scale of trophic dynamics, which impede the use of a single generalized equation to estimate global marine plankton NCP. This paper shows the potential of a systematic empirical approach to predict plankton NCP from local and satellite-derived P estimates.

  19. Heterogeneous oxygenation states in the Atlantic and Tethys oceans during Oceanic Anoxic Event 2

    NASA Astrophysics Data System (ADS)

    Westermann, Stéphane; Vance, Derek; Cameron, Vyllinniskii; Archer, Corey; Robinson, Stuart A.

    2014-10-01

    The Cenomanian-Turonian boundary (ca. 93.5 Ma) is marked by an episode of profound environmental change, including a major perturbation of the carbon cycle and an Oceanic Anoxic Event (OAE-2). Here, we present molybdenum (Mo) isotope variations within the OAE-2 interval for four sections from the western Tethys (Furlo and La Contessa) and the North-Atlantic (ODP site 1276 and DSDP site 367). The main target of this study is to investigate the extent of reducing conditions (truly global in extent or restricted to poorly-ventilated restricted deep basins), with particular reference to the relationship between the change in the oxygenation state of the ocean and the link to global perturbations of the carbon cycle recorded in carbon isotopes. All four sections show fluctuations in the redox sensitive trace metal (RSTE) distribution, suggesting rapid variations in local redox conditions, ranging from anoxic to euxinic. The RSTE enrichment factors (EFs) also suggest different depositional conditions and paleoceanographic processes in the western Tethys versus the North Atlantic. Whereas the North Atlantic sites show evidence of weak watermass restriction associated with the action of a particulate shuttle within the water column, the EFs of the Tethyan sections are characteristic of unrestricted marine systems. Mo isotopes show surprisingly negative values through the Tethyan sections. At the onset of OAE-2, an increasing trend in δMo98 is observed, with values ranging from -0.6 to 0.6‰. During the second half of OAE-2, the δMo98 curve shows a progressive shift towards more negative values. In the North Atlantic, δMo98 signatures from ODP site 1276 show a similar behaviour as observed in the western Tethys. At DSDP site 367, Mo isotopes are generally heavier during OAE-2, fluctuating around an average value of 1.1‰. This is consistent with fully euxinic conditions and the black shales deposited may have recorded the seawater signature during OAE-2. The Mo isotope

  20. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Retrieved from the ocean floor three miles deep, the Liberty Bell 7 Project Mercury capsule is revealed to photographers and the media in Port Canaveral, Fla. The capsule was found and raised by Curt Newport (left), leading an expedition sponsored by the Discovery Channel. After its successful 16-minute suborbital flight on July 21, 1961, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  1. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A close-up of the recently recovered Liberty Bell 7 Project Mercury capsule from the ocean floor shows the lettering 'United States' still clearly visible on its side. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14-year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  2. Aerosol isotopic ammonium signatures over the remote Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Lin, C. T.; Jickells, T. D.; Baker, A. R.; Marca, A.; Johnson, M. T.

    2016-05-01

    We report aerosol ammonium 15N signatures for samples collected from research cruises on the South Atlantic and Caribbean using a new high sensitivity method. We confirm a pattern of isotopic signals from generally light (δ15N -5 to -10‰), for aerosols with very low (<2  nmol m-3) ammonium concentrations from the remote high latitude ocean, to generally heavier values (δ15N +5 to +10‰), for aerosols collected in temperate and tropical latitudes and with higher ammonium concentrations (>2  nmol m-3). We discuss whether this reflects a mixing of aerosols from two end-members (polluted continental and remote marine emissions), or isotopic fractionation during aerosol transport.

  3. GLOBEC (Global Ocean Ecosystems Dynamics: Northwest Atlantic program

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The specific objective of the meeting was to plan an experiment in the Northwestern Atlantic to study the marine ecosystem and its role, together with that of climate and physical dynamics, in determining fisheries recruitment. The underlying focus of the GLOBEC initiative is to understand the marine ecosystem as it related to marine living resources and to understand how fluctuation in these resources are driven by climate change and exploitation. In this sense the goal is a solid scientific program to provide basic information concerning major fisheries stocks and the environment that sustains them. The plan is to attempt to reach this understanding through a multidisciplinary program that brings to bear new techniques as disparate as numerical fluid dynamic models of ocean circulation, molecular biology and modern acoustic imaging. The effort will also make use of the massive historical data sets on fisheries and the state of the climate in a coordinated manner.

  4. Anthropogenic CO2 changes in the Equatorial Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Fajar, N. M.; Guallart, E. F.; Steinfeldt, R.; Ríos, A. F.; Pelegrí, J. L.; Pelejero, C.; Calvo, E.; Pérez, F. F.

    2015-05-01

    Methods based on CO2 and chlorofluorocarbon (CFC) data are used to describe and evaluate the anthropogenic CO2 (Cant) concentrations, Cant specific inventories, and Cant storage rates in the Equatorial Atlantic Ocean. The Cant variability in the water masses is evaluated from the comparison of two hydrographic sections along 7.5°N carried out in 1993 and 2010. During both cruises, high Cant concentrations are detected in the upper layers, with values decreasing progressively towards the deep layers. Overall, the Cant concentrations increase from 1993 to 2010, with a large increment in the upper North Atlantic Deep Water layer of about 0.18 ± 0.03 μmol kg-1 y-1. In 2010, the Cant inventory along the whole section amounts to 58.9 ± 2.2 and 45.1 ± 2.0 mol m-2 using CO2 and CFC based methods, respectively, with most Cant accumulating in the western basin. Considering the time elapsed between the two cruises, Cant storage rates of 1.01 ± 0.18 and 0.75 ± 0.17 mol m-2 y-1 (CO2 and CFC based methods, respectively) are obtained. Below ∼1000 m, these rates follow the pace expected from a progressive increase of Cant at steady state; above ∼1000 m, Cant increases faster, mainly due to the retreat of the Antarctic Intermediate Waters.

  5. On the water masses and mean circulation of the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Stramma, Lothar; England, Matthew

    1999-09-01

    We examine recent observations of water mass distribution and circulation schemes at different depths of the South Atlantic Ocean to propose a layered, qualitative representation of the mean distribution of flow in this region. This furthers the simple upper layer geostrophic flow estimates of Peterson and Stramma [1991]. In addition, we assess how well ocean general circulation models (GCMs) capture the overall structure of flow in the South Atlantic in this regard. The South Atlantic Central Water (SACW) is of South Atlantic origin in the subtropical gyre, while the SACW in the tropical region in part originates from the South Indian Ocean. The Antarctic Intermediate Water in the South Atlantic originates from a surface region of the circumpolar layer, especially in the northern Drake Passage and the Falkland Current loop, but also receives some water from the Indian Ocean. The subtropical South Atlantic above the North Atlantic Deep Water and north of the Antarctic Circumpolar Current (ACC) is dominated by the anticyclonic subtropical gyre. In the eastern tropical South Atlantic the cyclonic Angola Gyre exists, embedded in a large tropical cyclonic gyre. The equatorial part of the South Atlantic shows several depth-dependent zonal current bands besides the Angola Gyre. Ocean GCMs have difficulty capturing this detailed zonal circulation structure, even at eddy-permitting resolution. The northward extent of the subtropical gyre reduces with increasing depth, located near Brazil at 16°S in the near-surface layer and at 26°S in the Antarctic Intermediate Water layer, while the tropical cyclonic gyre progresses southward. The southward shift of the northern part of the subtropical gyre is well resolved in global ocean GCMs. However, high horizontal resolution is required to capture the South Atlantic Current north of the ACC. The North Atlantic Deep Water in the South Atlantic progresses mainly southward in the Deep Western Boundary Current, but some water also

  6. 76 FR 65699 - South Atlantic Fishery Management Council; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... National Oceanic and Atmospheric Administration RIN 0648-XA779 South Atlantic Fishery Management Council... Administration, Commerce. ACTION: Notice of public hearing series. SUMMARY: The South Atlantic Fishery Management... Snapper Grouper Fishery Management Plan (FMP) for the South Atlantic Region. See SUPPLEMENTARY...

  7. Chondrichthyan egg cases from the south-west Atlantic Ocean.

    PubMed

    Mabragaña, E; Figueroa, D E; Scenna, L B; Díaz de Astarloa, J M; Colonello, J H; Delpiani, G

    2011-11-01

    Egg cases of 21 oviparous chondrichthyan species from the south-west Atlantic Ocean are described and compared. The catshark Schroederichthys bivius has a cigar-shaped egg case with curled tendrils only at the posterior end. Egg cases of the elephant fish Callorhinchus callorynchus are spindle-shaped with anterior and posterior tubular extensions and lateral flanges. The skate Amblyraja doellojuradoi presents medium-sized egg cases (71 mm in length) with a lateral keel extending to the first portion of the horns. The endemic skate species of the genus Atlantoraja have medium to large egg cases (69-104 mm in length) and present relatively large posterior horns. Egg cases of the genus Bathyraja have a medium size, 75-98 mm in length, and are characterized by a very similar morphology, a relatively smooth to rough surface case and posterior horns strongly curved inwards. Egg cases of the genera Dipturus and Zearaja are very large, 115-230 mm in length, and have a well-developed posterior apron. Despite the problematical identification of skates at species level, the egg capsules of the endemic genus Psammobatis are easily diagnosed; the capsules are small (25-53 mm in length), those of Psammobatis rutrum being the smallest known to date in the world. Egg cases of Rioraja agassizi have a medium size, 61-68 mm in length, relatively straight sides, a smooth surface and silky attachment fibres placed in the lateral keel next to each horn. Those of the genus Sympterygia are small to medium sized, 51-86 mm in length, and display the thickest lateral keel and the longest posterior horns among the skates of the world. Egg cases can be a useful tool for identifying species and egg-laying areas; therefore, a provisional key for the south-west Atlantic Ocean chondrichthyan capsules is presented. PMID:22026605

  8. Does eddy subduction matter in the northeast Atlantic Ocean?

    NASA Astrophysics Data System (ADS)

    Gebbie, Geoffrey

    2007-06-01

    Mesoscale eddies are an important contributor to subduction in the Gulf Stream region and the Antarctic Circumpolar Current, but is eddy subduction also important in the relatively quiescent interior of the world's subtropical gyres? Observations from the Subduction Experiment of the northeast Atlantic do not have the spatial resolution necessary to calculate eddy subduction and answer this question. Regional numerical models can diagnose subduction, but their representativeness is unknown. Furthermore, water mass budgets in an open-ocean domain show that the simulated properties of subducted water directly depend upon uncertain open-boundary conditions and surface fluxes. To remedy these problems, a state estimate of the ocean circulation is formed by constraining an eddy-permitting general circulation model to observations by adjusting the model parameters within their uncertainty. The resulting estimate is self-consistent with the equations of motion and has the necessary resolution for diagnosing subduction. In the northeast Atlantic during 1991-1993, the time-variable circulation contributes less than 1 Sv of net subduction, while the total subduction is 4 Sv. Eddy volume fluxes of 40 m/yr in the North Equatorial Current and the Azores Current, however, are significant and rival the subduction by Ekman pumping locally. Furthermore, a state estimate at 1/6° resolution has 2-3 Sv more subduction in the density bands centered around σ = 24.0 kg/m3 and σ = 26.0 kg/m3 than a 2° state estimate. This result implies that the inability to accurately simulate mesoscale phenomena and surface fluxes in climate models would lead to an accumulation of errors in water mass properties over 10-20 years, even in the interior of the subtropical gyre.

  9. On The Atlantic Water Inflow Into The Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Walczowski, W.; Maslowski, W.

    Water mass exchanges between the Nordic Seas and the Arctic Ocean are analysed using results from two high-resolution models of the Arctic Ocean and sea ice, and observation obtained by the Institute of Oceanology Polish Academy of Sciences. The two models used are developed at the Naval Postgraduate School and they are con- figured at (i) 1/6 and 30-level and (ii) 1/12 and 45-level grids. Model results show that more intensive inflow into the Arctic Ocean occurs via the Spitsbergen-Norway opening than through Fram Strait. The strait determines the outflow from the Arctic Ocean via the East Greenland Current. The net mean transport through Fram Strait, es- timated from the 18-km model integration forced with the 1979-1998 ECMWF daily realistic data, is 2.19 Sv southward, with 1.73 Sv flowing to the north and 3.92 to the south. The net mean transport into the Barents Sea, based on the same results is 2.5 Sv, consisting of 3.12 Sv inflow and 0.62 Sv outflow. The Barents Sea also appears to be an efficient route of Atlantic Water (AW) inflow into the Arctic Ocean. The net mean AW (S>34.92 psu) transport into the Barents Sea is 2.25 Sv (2.78 Sv inflow, 0.53 Sv outflow) compared to 0.23 Sv (1.22 Sv inflow, 0.99 Sv outflow) through Fram Strait. Preliminary results from the 9-km model show similar relations. A high seasonal and annual variability of those transports exists. A strong negative correlation between the net transport through the Barents Sea Opening and Fram Strait is determined. During periods of intensive inflow from the Nordic Seas into the Barents Sea, the southward flow of the East Greenland Current increases, representing a stronger export of wa- ter from the Arctic Ocean. Estimates from measurements support model results about the net volume transport and the inflow of AW being larger across the Spitsbergen- Norway section than through Fram Strait. The net baroclinic transport calculated from the summer data (1988-1998) into the Barents Sea is 2.32 Sv

  10. Atmospheric and ocean measurements of reactive organic species from the Tropical Atlantic ocean.

    NASA Astrophysics Data System (ADS)

    Williams, J.; Holzinger, R.; Gros, V.; Hofmann, R.; Xu, X.; Wallace, D.

    2003-04-01

    Reactive organic species play an important role in the chemistry of the atmosphere. Large uncertainties exist in how the ocean influences the global budgets of reactive organic species. The first German SOLAS cruise M55 carried instrumentation to measure a range of organic species in the atmosphere and ocean surface layer. Between 12th October and 15th November the research vessel Meteor steamed from Curacao to Cameroon approximately along 10^o N. Approximately mid-Atlantic the ship performed two transects (N-S and S-N) reaching the equator and crossing the ITCZ twice. An assessment will be given of the organics over the Tropical Atlantic including data from 2 PTR-MS systems (air and water), canister air collection followed by GC-MS analysis, cartridge collection followed by 2D-GC-FID analysis, as well as ozone and CO instruments. The prevailing wind was easterly at all times so that air with decreasing extents of ocean contact time was encountered during the crossing. Longitudinal and interhemispheric gradients of organic species will be presented.

  11. Tropical climate variability: interactions across the Pacific, Indian, and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Kajtar, Jules B.; Santoso, Agus; England, Matthew H.; Cai, Wenju

    2016-06-01

    Complex interactions manifest between modes of tropical climate variability across the Pacific, Indian, and Atlantic Oceans. For example, the El Niño-Southern Oscillation (ENSO) extends its influence on modes of variability in the tropical Indian and Atlantic Oceans, which in turn feed back onto ENSO. Interactions between pairs of modes can alter their strength, periodicity, seasonality, and ultimately their predictability, yet little is known about the role that a third mode plays. Here we examine the interactions and relative influences between pairs of climate modes using ensembles of 100-year partially coupled experiments in an otherwise fully coupled general circulation model. In these experiments, the air-sea interaction over each tropical ocean basin, as well as pairs of ocean basins, is suppressed in turn. We find that Indian Ocean variability has a net damping effect on ENSO and Atlantic Ocean variability, and conversely they each promote Indian Ocean variability. The connection between the Pacific and the Atlantic is most clearly revealed in the absence of Indian Ocean variability. Our model runs suggest a weak damping influence by Atlantic variability on ENSO, and an enhancing influence by ENSO on Atlantic variability.

  12. Changes in ocean circulation in the South-east Atlantic Ocean during the Pliocene

    NASA Astrophysics Data System (ADS)

    Petrick, B. F.; McClymont, E.; Felder, S.; Leng, M. J.

    2013-12-01

    The Southeast Atlantic Ocean is an important ocean gateway because major oceanic systems interact with each other in a relatively small geographic area. These include the Benguela Current, Antarctic Circumpolar Current, and the input of warm and saline waters from the Indian Ocean via the Agulhas leakage. However, there remain questions about circulation change in this region during the Pliocene, including whether there was more or less Agulhas Leakage, which may have implications for the strength of the global thermohaline circulation. ODP Site 1087 (31°28'S, 15°19'E, 1374m water depth) is located outside the Benguela upwelling region and is affected by Agulhas leakage in the modern ocean. Sea-surface temperatures (SSTs) are thus sensitive to the influence of Agulhas Leakage at this site. Our approach is to apply several organic geochemistry proxies and foraminiferal analyses to reconstruct the Pliocene history of ODP 1087, including the UK37' index (SSTs), pigments (primary productivity) and planktonic foraminifera (water mass changes). SSTs during the Pliocene range from 17 to 22.5 °C (mean SSTs at 21 °C), and show variability on orbital and suborbital time scales. Our results indicate that the Benguela upwelling system had intensified and/or shifted south during the Pliocene. We find no evidence of Agulhas leakage, meaning that either Agulhas Leakage was severely reduced or displaced during the mid-Pliocene. Potential causes of the observed signals include changes to the local wind field and/or changes in the temperature of intermediate waters which upwell in the Benguela system. Pronounced cooling is observed during cold stages in the Pliocene, aligned with the M2 and KM2 events. These results may indicate that changes to the extent of the Antarctic ice sheet had impact on circulation in the south east Atlantic during the Pliocene via displacement of the Antarctic Circumpolar Currents.

  13. Acoustic habitat of an oceanic archipelago in the Southwestern Atlantic

    NASA Astrophysics Data System (ADS)

    Bittencourt, Lis; Barbosa, Mariana; Secchi, Eduardo; Lailson-Brito, José; Azevedo, Alexandre

    2016-09-01

    Underwater soundscapes can be highly variable, and in natural conditions are often dominated by biological signals and physical features of the environment. Few studies, however, focused on oceanic islands soundscapes. Islands in the middle of ocean basins can provide a good example of how untouched marine soundscapes are. Autonomous acoustic recordings were carried out in two different seasons in Trindade-Martin Vaz Archipelago, Southwestern Atlantic, providing nearly continuous data for both periods. Sound levels varied daily and between seasons. During summer, higher frequencies were noisier than lower frequencies, with snapping shrimp being the dominating sound source. During winter, lower frequencies were noisier than higher frequencies due to humpback whale constant singing. Biological signal detection had a marked temporal pattern, playing an important role in the soundscape. Over 1000 humpback whale sounds were detected hourly during winter. Fish vocalizations were detected mostly during night time during both summer and winter. The results show an acoustic habitat dominated by biological sound sources and highlight the importance of the island to humpback whales in winter.

  14. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This photograph shows two mercury dimes that were found inside the recently recovered Liberty Bell 7 Project Mercury capsule. Thirty-eight years ago, the capsule made a successful 16-minute suborbital flight, with astronaut Virgil 'Gus' Grissom aboard, and splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. In an expedition sponsored by the Discovery Channel, underwater salvage expert Curt Newport fulfilled a 14- year dream in finding and, after one abortive attempt, successfully raising the capsule and bringing it to Port Canaveral. The dimes had apparently been placed in the capsule before its launch July 21, 1961. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  15. Liberty Bell 7 is retrieved from Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Gunther Wendt takes a turn at the podium after viewing the recovered Liberty Bell 7 Project Mercury capsule, seen in the background. At right is Curt Newport who led the expedition to find and retrieve the capsule. The expedition was sponsored by the Discovery Channel. Wendt worked on the Liberty Bell 7 before its launch July 21, 1961. After its successful 16-minute suborbital flight, the Liberty Bell 7, with astronaut Virgil 'Gus' Grissom aboard, splashed down in the Atlantic Ocean. A prematurely jettisoned hatch caused the capsule to flood and a Marine rescue helicopter was unable to lift it. It quickly sank to a three-mile depth. Grissom was rescued but his spacecraft remained lost on the ocean floor, until now. An underwater salvage expert, Newport located the capsule through modern technology, and after one abortive attempt, successfully raised it and brought it to Port Canaveral. The recovery of Liberty Bell 7 fulfilled a 14-year dream for the expedition leader. The capsule is being moved to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas, where it will be restored for eventual public display. Newport has also been involved in salvage operations of the Space Shuttle Challenger and TWA Flight 800 that crashed off the coast of Long Island, N.Y.

  16. Simulation of Ocean-Generated Microseismic Noise Propagation in the North-East Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Ying, Y.; Bean, C. J.; Lokmer, I.; Faure, T.

    2013-12-01

    Ocean-generated microseisms are small ground oscillations associated with the occurrence of the interactions between the solid Earth and ocean water waves. Microseismic noise field is mostly composed of surface waves, where the wave energy propagate along the ocean floor predominantly in the form of Rayleigh waves, but some Love waves are also present. Microseisms will pick up some information about the medium on the propagation paths due to the interaction between the seismic waves and the structure. Recently, seismologists become more and more interested in using cross-correlations of continuously recorded microseismic noise to retrieve information about the Earth's structure. In order to use this information well, it's important to identify the rich noise source domain in the ocean and quantify the propagation process of microseism from the origins to the land-based seismic stations. In this work, we try to characterize how a microseism propagates along a fluid-solid interface through numerical simulations, in which a North-East Atlantic Ocean model is adopted and a microseism is generated on the bottom of deep ocean with the expected source mechanism. The spectral element method is used to simulate coupled acoustic/elastic wave propagation in an unstructured mesh, and the coupling between fluid and solid regions is accommodated by using a domain decomposition method. The effects of crustal structure, sediment layer, bathymetry and ocean load on the microseismic wave propagation will be examined, and a special attention will be paid to the fluid-solid coupling. We find that microseismic wave will be highly dispersive propagating in the ocean environment.

  17. Comment on "The Atlantic Multidecadal Oscillation without a role for ocean circulation".

    PubMed

    Zhang, Rong; Sutton, Rowan; Danabasoglu, Gokhan; Delworth, Thomas L; Kim, Who M; Robson, Jon; Yeager, Stephen G

    2016-06-24

    Clement et al (Reports, 16 October 2015, p. 320) claim that the Atlantic Multidecadal Oscillation (AMO) is a thermodynamic response of the ocean mixed layer to stochastic atmospheric forcing and that ocean circulation changes have no role in causing the AMO. These claims are not justified. We show that ocean dynamics play a central role in the AMO. PMID:27339976

  18. Molecular biogeochemical provinces in the Atlantic Surface Ocean

    NASA Astrophysics Data System (ADS)

    Koch, B. P.; Flerus, R.; Schmitt-Kopplin, P.; Lechtenfeld, O. J.; Bracher, A.; Cooper, W.; Frka, S.; Gašparović, B.; Gonsior, M.; Hertkorn, N.; Jaffe, R.; Jenkins, A.; Kuss, J.; Lara, R. J.; Lucio, M.; McCallister, S. L.; Neogi, S. B.; Pohl, C.; Roettgers, R.; Rohardt, G.; Schmitt, B. B.; Stuart, A.; Theis, A.; Ying, W.; Witt, M.; Xie, Z.; Yamashita, Y.; Zhang, L.; Zhu, Z. Y.; Kattner, G.

    2010-12-01

    One of the most important aspects to understand marine organic carbon fluxes is to resolve the molecular mechanisms which convert fresh, labile biomolecules into semi-labile and refractory dissolved and particulate organic compounds in the ocean. In this interdisciplinary project, which was performed on a cruise with RV Polarstern, we carried out a detailed molecular characterisation of dissolved organic matter (DOM) on a North-South transect in the Atlantic surface ocean in order to relate the data to different biological, climatic, oceanographic, and meteorological regimes as well as to terrestrial input from riverine and atmospheric sources. Our goal was to achieve a high resolution data set for the biogeochemical characterisation of the sources and reactivity of DOM. We applied ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS), nutrient, trace element, amino acid, and lipid analyses and other biogeochemical measurements for 220 samples from the upper water column (0-200m) and eight deep profiles. Various spectroscopic techniques were applied continuously in a constant sample water flow supplied by a fish system and the moon pool. Radiocarbon dating enabled assessing DOC residence time. Bacterial abundance and production provided a metabolic context for the DOM characterization work and pCO2 concentrations. Combining molecular organic techniques and inductively coupled plasma mass spectrometry (ICP-MS) established an important link between organic and inorganic biogeochemical studies. Multivariate statistics, primarily based on FT-ICR-MS data for 220 samples, allowed identifying geographical clusters which matched ecological provinces proposed previously by Longhurst (2007). Our study demonstrated that marine DOM carries molecular information reflecting the “history” of ocean water masses. This information can be used to define molecular biogeochemical provinces and to improve our understanding of element fluxes in

  19. Hafnium and Neodymium Isotopes in Atlantic Ocean Waters

    NASA Astrophysics Data System (ADS)

    Rickli, J.; Frank, M.; Halliday, A.

    2007-12-01

    Neodymium isotopic compositions (ICs) have been established as a tracer of water masses in the present and past oceans since the late 1970s. Hafnium isotopes share the capability of tracing water masses and in combination with Nd isotopes provide information on continental weathering regimes. Whereas Nd released during weathering reflects the bulk Nd IC of the weathered lithology, the released Hf is more radiogenic than the weathered lithology. This effect is due to highly variable Lu/Hf--ratios in rock--forming minerals ("zircon effect") and as a consequence physical weathering apparently leads to more congruent weathering of Hf than chemical weathering does. Our understanding of the Hf IC of seawater to date has been derived (with the exception of some as yet unpublished data from the Arctic and Pacific oceans (Zimmermann et al., in prep.)) from ferromanganese crusts and nodules, since Hf concentrations in seawater are low and have until recently hampered direct measurements of Hf IC of seawater. We present IC for the dissolved Hf and Nd in Atlantic seawater. Samples were taken mainly on a transect from the Bay of Biscay to Cape Town (RV Polarstern cruise ANT XXIII/1 in 2005). A few additional samples are from the Labrador Sea and the Drake Passage. Hafnium and Nd were pre--concentrated by iron co--precipitation from 60 to 140 liters of filtered (0.45 μm) seawater. Separation of Hf and Nd followed previously established ion chromatographic procedures. Hafnium and Nd ICs were measured by MC--ICPMS (Nu Plasma) with a 2σ external reproducibility of 0.65 and 0.3 ǎrepsilon--units, respectively. Sample sizes varied but were in most cases larger than 3ng of Hf. Surface seawater as well as deep water samples extending to ~5,000 m, plot on the "seawater array" defined previously from measurements of ferromanganese crusts and nodules. Surface seawater ICs are quite uniform for Hf ranging from ǎrepsilonHf = 0 to +2 at most sampling sites on the Atlantic transect. In the

  20. Thorium-234 as a tracer of particle dynamics and upper ocean export in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Owens, S. A.; Pike, S.; Buesseler, K. O.

    2015-06-01

    The flux of sinking particles is an important removal mechanism of carbon and other chemical species from the surface ocean as part of the biological pump. Euphotic zone export of 234Th was measured on GEOTRACES transects of the Atlantic Ocean to evaluate basin-scale export variability. High-resolution sampling through the entire water-column allowed for the identification of unique 234Th features in intermediate and deep waters. These data will be important for describing distributions and estimating the fluxes of trace elements measured by other investigators in the GEOTRACES program. This extensive data set will also be useful when combined with other particulate and radioisotope data for improving our understanding of particle cycling and the relation of particle flux to particle composition and abundance.

  1. Knowledge of marine fish trematodes of Atlantic and Eastern Pacific Oceans.

    PubMed

    Bray, Rodney A; Diaz, Pablo E; Cribb, Thomas H

    2016-03-01

    A brief summary of the early history of the study of Atlantic Ocean marine fish digeneans is followed by a discussion of the occurrence and distribution of these worms in the Atlantic Ocean and adjacent Eastern Pacific Ocean, using the Provinces of the 'Marine Ecoregions' delimited by Spalding et al. (Bioscience 57:573-583, 2007). The discussion is based on a database of 9,880 records of 1,274 species in 430 genera and 45 families. 8,633 of these records are from the Atlantic Ocean, including 1,125 species in 384 genera and 45 families. About 1,000 species are endemic to the Atlantic Ocean Basin. The most species-rich families in the Atlantic Ocean are the Opecoelidae Ozaki, 1925, Hemiuridae Looss, 1899 and Bucephalidae Poche, 1907, and the most wide-spread the Opecoelidae, Hemiuridae, Acanthocolpidae Lühe, 1906, Lepocreadiidae Odhner, 1905 and Lecithasteridae Odhner, 1905. A total of 109 species are shared by the Atlantic Ocean and the Eastern Pacific, made up of cosmopolitan, circum-boreal, trans-Panama Isthmus and Magellanic species. The lack of genetic evaluation of identifications is emphasised and the scope for much more work is stressed. PMID:26898586

  2. Speciation of Fe in the Eastern North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Thuróczy, C.-E.; Gerringa, L. J. A.; Klunder, M. B.; Middag, R.; Laan, P.; Timmermans, K. R.; de Baar, H. J. W.

    2010-11-01

    In the Eastern North Atlantic Ocean iron (Fe) speciation was investigated in three size fractions: the dissolvable from unfiltered samples, the dissolved fraction (<0.2 μm) and the fraction smaller than 1000 kDa (<1000 kDa). Fe concentrations were measured by flow injection analysis and the organic Fe complexation by voltammetry. In the research area the water column consisted of North Atlantic Central Water (NACW), below which Mediterranean Overflow Water (MOW) was found with the core between 800 and 1000 m depth. Below 2000 m depth the North Atlantic Deep Water (NADW) proper was recognised. Dissolved Fe and Fe in the <1000 kDa fraction showed a nutrient like profile, depleted at the surface, increasing until 500-1000 m depth below which the concentration remained constant. Fe in unfiltered samples clearly showed the MOW with high concentrations (4 nM) compared to the overlying NACW and the underlying NADW, with 0.9 nM and 2 nM Fe, respectively. By using excess ligand (Excess L) concentrations as parameter we show a potential to bind Fe. The surface mixed layer had the highest excess ligand concentrations in all size fractions due to phytoplankton uptake and possible ligand production. The ratio of Excess L over Fe proved to be a complementary tool in revealing the relative saturation state of the ligands with Fe. In the whole water column, the organic ligands in the larger colloidal fraction (between 0.2 μm and 1000 kDa) were saturated with Fe, whereas those in the smallest fraction (<1000 kDa) were not saturated with Fe, confirming that this fraction was the most reactive one and regulates dissolution and colloid aggregation and scavenging processes. This regulation was remarkably stable with depth since the alpha factor (product of Excess L and K'), expressing the reactivity of the ligands, did not vary and was 10 13. Whereas, in the NACW and the MOW, the ligands in the particulate (>0.2 μm) fraction were unsaturated with Fe with respect to the dissolved

  3. Recent Changes in Arctic Ocean Sea Ice Motion Associated with the North Atlantic Oscillation

    NASA Technical Reports Server (NTRS)

    Kwok, R.

    1999-01-01

    Examination of a new ice motion dataset of the Arctic Ocean over a recent eighteen year period (1978-1996) reveals patterns of variability that can be linked directly to the North Atlantic Oscillation.

  4. Early opening of initially closed Gulf of Mexico and central North Atlantic ocean

    SciTech Connect

    Van Siclen, D.C.

    1984-09-01

    This paper presents ideas on the early opening and evolution of the Gulf of Mexico and the central North Atlantic ocean. It discusses rifting activity, plate tectonics, magnetic anomalies, and the geologic time elements involved.

  5. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic...

  6. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic...

  7. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic...

  8. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic...

  9. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic...

  10. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic...

  11. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic...

  12. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic...

  13. 33 CFR 110.182 - Atlantic Ocean off Fort George Inlet, near Mayport, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Atlantic Ocean off Fort George Inlet, near Mayport, Fla. 110.182 Section 110.182 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.182 Atlantic...

  14. 33 CFR 334.580 - Atlantic Ocean near Port Everglades, Fla.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean near Port Everglades, Fla. 334.580 Section 334.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.580 Atlantic...

  15. Depth Profiles of Persistent Organic Pollutants in the North and Tropical Atlantic Ocean.

    PubMed

    Sun, Caoxin; Soltwedel, Thomas; Bauerfeind, Eduard; Adelman, Dave A; Lohmann, Rainer

    2016-06-21

    Little is known of the distribution of persistent organic pollutants (POPs) in the deep ocean. Polyethylene passive samplers were used to detect the vertical distribution of truly dissolved POPs at two sites in the Atlantic Ocean. Samplers were deployed at five depths covering 26-2535 m in the northern Atlantic and Tropical Atlantic, in approximately one year deployments. Samplers of different thickness were used to determine the state of equilibrium POPs reached in the passive samplers. Concentrations of POPs detected in the North Atlantic near the surface (e.g., sum of 14 polychlorinated biphenyls, PCBs: 0.84 pg L(-1)) were similar to previous measurements. At both sites, PCB concentrations showed subsurface maxima (tropical Atlantic Ocean -800 m, North Atlantic -500 m). Currents seemed more important in moving POPs to deeper water masses than the biological pump. The ratio of PCB concentrations in near surface waters (excluding PCB-28) between the two sites was inversely correlated with congeners' subcooled liquid vapor pressure, in support of the latitudinal fractionation. The results presented here implied a significant amount of HCB is stored in the Atlantic Ocean (4.8-26% of the global HCB environmental burdens), contrasting traditional beliefs that POPs do not reach the deep ocean. PMID:27174500

  16. Southern Ocean origin for the resumption of Atlantic thermohaline circulation during deglaciation.

    PubMed

    Knorr, Gregor; Lohmann, Gerrit

    2003-07-31

    During the two most recent deglaciations, the Southern Hemisphere warmed before Greenland. At the same time, the northern Atlantic Ocean was exposed to meltwater discharge, which is generally assumed to reduce the formation of North Atlantic Deep Water. Yet during deglaciation, the Atlantic thermohaline circulation became more vigorous, in the transition from a weak glacial to a strong interglacial mode. Here we use a three-dimensional ocean circulation model to investigate the impact of Southern Ocean warming and the associated sea-ice retreat on the Atlantic thermohaline circulation. We find that a gradual warming in the Southern Ocean during deglaciation induces an abrupt resumption of the interglacial mode of the thermohaline circulation, triggered by increased mass transport into the Atlantic Ocean via the warm (Indian Ocean) and cold (Pacific Ocean) water route. This effect prevails over the influence of meltwater discharge, which would oppose a strengthening of the thermohaline circulation. A Southern Ocean trigger for the transition into an interglacial mode of circulation provides a consistent picture of Southern and Northern hemispheric climate change at times of deglaciation, in agreement with the available proxy records. PMID:12891352

  17. Enhanced Weathering Strategies for Stabilizing Climate and Averting Ocean Acidification - Supplementary Information

    NASA Technical Reports Server (NTRS)

    Taylor, Lyla L.; Quirk, Joe; Thorley, Rachel M. S.; Kharecha, Pushker A.; Hansen, James; Ridgwell, Andy; Lomas, Mark R.; Banwart, Steve A.; Beerling, David J.

    2015-01-01

    Chemical breakdown of rocks, weathering, is an important but very slow part of the carbon cycle that ultimately leads to CO2 being locked up in carbonates on the ocean floor. Artificial acceleration of this carbon sink via distribution of pulverized silicate rocks across terrestrial landscapes may help offset anthropogenic CO2 emissions. We show that idealized enhanced weathering scenarios over less than a third of tropical land could cause significant drawdown of atmospheric CO2 and ameliorate ocean acidification by 2100. Global carbon cycle modelling driven by ensemble Representative Concentration Pathway (RCP) projections of twenty-first-century climate change (RCP8.5, business-as-usual; RCP4.5, medium-level mitigation) indicates that enhanced weathering could lower atmospheric CO2 by 30-300 ppm by 2100, depending mainly on silicate rock application rate (1 kg or 5 kg m(exp. -2) yr (exp -1)) and composition. At the higher application rate, end-of-century ocean acidification is reversed under RCP4.5 and reduced by about two-thirds under RCP8.5. Additionally, surface ocean aragonite saturation state, a key control on coral calcification rates, is maintained above 3.5 throughout the low latitudes, thereby helping maintain the viability of tropical coral reef ecosystems. However, we highlight major issues of cost, social acceptability, and potential unanticipated consequences that will limit utilization and emphasize the need for urgent efforts to phase down fossil fuel emissions.

  18. Reduced North Atlantic Deep Water flux to the glacial Southern Ocean inferred from neodymium isotope ratios

    PubMed

    Rutberg; Hemming; Goldstein

    2000-06-22

    The global circulation of the oceans and the atmosphere transports heat around the Earth. Broecker and Denton suggested that changes in the global ocean circulation might have triggered or enhanced the glacial-interglacial cycles. But proxy data for past circulation taken from sediment cores in the South Atlantic Ocean have yielded conflicting interpretations of ocean circulation in glacial times--delta13C variations in benthic foraminifera support the idea of a glacial weakening or shutdown of North Atlantic Deep Water production, whereas other proxies, such as Cd/Ca, Ba/Ca and 231Pa/230Th ratios, show little change from the Last Glacial Maximum to the Holocene epoch. Here we report neodymium isotope ratios from the dispersed Fe-Mn oxide component of two southeast Atlantic sediment cores. Both cores show variations that tend towards North Atlantic signatures during the warm marine isotope stages 1 and 3, whereas for the full glacial stages 2 and 4 they are closer to Pacific Ocean signatures. We conclude that the export of North Atlantic Deep Water to the Southern Ocean has resembled present-day conditions during the warm climate intervals, but was reduced during the cold stages. An increase in biological productivity may explain the various proxy data during the times of reduced North Atlantic Deep Water export. PMID:10879531

  19. Multi-phase halogen chemistry in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Sommariva, R.; von Glasow, R.

    2012-04-01

    We used a one-dimensional model to simulate the chemical evolution of air masses in the eastern tropical Atlantic Ocean (Cape Verde region), with a focus on halogen chemistry. The model results were compared to the observations of inorganic halogen (particularly chlorine and bromine) species made in this region. The model could reproduce the measurements of chlorine species, especially under unpolluted conditions, but it overestimated sea-salt chloride and bromine species. Agrement with the measurements could be improved by taking into account the reactivity with aldehydes and the effects of DMS and Saharan dust on aerosol pH; an hypothetical HOX -> X- aqueous-phase reaction could also improve the agreement with measured Cl2 and HOCl, particularly under semi-polluted conditions. The results showed that halogen levels and speciation are very sensitive to cloud processing, although the model could not reproduce the observations under cloudy conditions. The model results were used to calculate the impact of the observed levels of halogens: Cl accounted for 5.4 - 11.6% of total methane sinks and halogens (mostly bromine and iodine) accounted for 35 - 40% of total ozone destruction.

  20. Microbial growth and macromolecular synthesis in the northwestern Atlantic Ocean

    SciTech Connect

    Cuhel, R.L.; Jannasch, H.W.; Taylor, C.D.

    1983-01-01

    Simultaneous time-course measurements of /sup 35/SO/sub 4//sup 2 -/, /sup 32/PO/sup 43 -/, /sup 15/NH/sub 4//sup +/, and (/sup 14/C)acetate, glucose, and glutamate uptake were made at three stations in the northwestern Atlantic Ocean, using water samples taken from well below the euphotic zone. Marked deviations from linearity were observed in 14 of the 15 cases. At the two most inshore stations uptake of /sup 15/NH/sub 4//sup +/ or incorporation of /sup 35/SO/sub 4//sup 2 -/ into protein was undetectable for 16-30 h, followed by very rapid increases in the rates of activity. The sudden burst of SO/sub 4//sup 2 -/and NH/sub 4//sup +/ uptake was accompanied by a major increase in the incorporation of /sup 32/P into RNA and lipid fractions of the microbial population at a continental slope station. At a station in Sargasso Sea, all substrates were taken up without lag. Extended incubations led to a growth plateau which may be a measure of the total biologically labile organic nutrient supply. In all cases tested, chloramphenicol severely restricted uptake. One of the inshore stations was revisited a year later with similar results. The combined data demonstrate the utility of using inorganic nutrient uptake and subcellular incorporation patterns to measure microbial growth and metabolism and stress the necessity of time-course rather than end-point incubations.

  1. Macroecological study of Centropages typicus in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Beaugrand, G.; Lindley, J. A.; Helaouet, P.; Bonnet, D.

    2007-02-01

    Centropages typicus is a temperate neritic-coastal species of the North Atlantic Oceans, generally found between the latitudes of the Mediterranean and the Norwegian Sea. Therefore, the species experiences a large number of environments and adjusts its life cycle in response to changes in key abiotic parameters such as temperature. Using data from the Continuous Plankton Recorder (CPR) survey, we review the macroecology of C. typicus and factors that influence its spatial distribution, phenology and year-to-year to decadal variability. The ecological preferences are identified and quantified. Mechanisms that allow the species to occur in such different environments are discussed and hypotheses are proposed as to how the species adapts to its environment. We show that temperature and both quantity and quality of phytoplankton are important factors explaining the space and time variability of C. typicus. These results show that C. typicus will not respond only to temperature increase in the region but also to changes in phytoplankton abundance, structure and composition and timing of occurrence. Methods such as a decision tree can help to forecast expected changes in the distribution of this species with hydro-climatic forcing.

  2. Carbon disulfide measurements in the atmosphere of the western North Atlantic and the northwestern South Atlantic Oceans

    NASA Technical Reports Server (NTRS)

    Bandy, Alan R.; Thornton, Donald C.; Johnson, James E.

    1993-01-01

    Carbon disulfide (CS2) measurements were made over the western and equatorial North Atlantic Ocean and the northwestern and equatorial South Atlantic Ocean. Carbon disulfide was in the range 0.4-50 pptrv in the atmosphere of the western North Atlantic Ocean. Emissions from anthropogenic sources and wet lands were found to be important although anthropogenic sources were 4-6 times larger than biogenic sources. The flux of CS2 from eastern North America between 30 and 39 deg latitude was estimated to be 2 x 10(exp 8)g/yr or sulfur. The anthropogenic contribution was 1.8 x 10(exp 8)g/yr of sulfur whereas the contribution of marshes was 0.2 x 10(exp 8)g/yr of sulfur. Sources of CS2 at high latitudes in the northern hemisphere were comparatively weak. Carbon disulfide levels in the western South Atlantic Ocean between -5 and 1 deg latitude were in the range 0.2-6 pptrv. Most of the CS2 appeared to come from biomass burning in Africa. Carbon disulfide was much higher close to shore suggesting that the South American continent was a significant source although too few data were available to quantify it. On ferry lights from Wallops, Virginia to Natal, Brazil, CS2 levels at the ferry altitude of about 6 km averaged 1.2 pptrv. This background CS2 was adequate to account for all the carbonyl sulfide (OCS) in the atmosphere.

  3. Ocean impact on decadal Atlantic climate variability revealed by sea-level observations

    NASA Astrophysics Data System (ADS)

    McCarthy, Gerard D.; Haigh, Ivan D.; Hirschi, Joël J.-M.; Grist, Jeremy P.; Smeed, David A.

    2015-05-01

    Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres--the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States.

  4. Ocean impact on decadal Atlantic climate variability revealed by sea-level observations.

    PubMed

    McCarthy, Gerard D; Haigh, Ivan D; Hirschi, Joël J-M; Grist, Jeremy P; Smeed, David A

    2015-05-28

    Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres--the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States. PMID:26017453

  5. Alkalinity distribution in the western North Atlantic Ocean margins

    NASA Astrophysics Data System (ADS)

    Cai, Wei-Jun; Hu, Xinping; Huang, Wei-Jen; Jiang, Li-Qing; Wang, Yongchen; Peng, Tsung-Hung; Zhang, Xin

    2010-08-01

    Total alkalinity (TA) distribution and its relationship with salinity (S) along the western North Atlantic Ocean (wNAO) margins from the Labrador Sea to tropical areas are examined in this study. Based on the observed TA-S patterns, the mixing processes that control alkalinity distribution in these areas can be categorized into a spectrum of patterns that are bracketed by two extreme mixing types, i.e., alongshore current-dominated and river-dominated. Alongshore current-dominated mixing processes exhibit a segmented mixing line with a shared mid-salinity end-member. In such cases (i.e., Labrador Sea, Gulf of Maine, etc.), the y-intercept of the high salinity segment of the mixing line is generally higher than the local river alkalinity values, and it reflects the mixing history of the alongshore current. In contrast, in river-dominated mixing (Amazon River, Caribbean Sea, etc.), good linear relationships between alkalinity and salinity are generally observed, and the zero salinity intercepts of the TA-S regressions roughly match those of the regional river alkalinity values. TA-S mixing lines can be complicated by rapid changes in the river end-member value and by another river nearby with a different TA value (e.g., Mississippi-Atchafalaya/Gulf of Mexico). In the wNAO margins, regression intercepts and river end-members have a clear latitudinal distribution pattern, increasing from a low of ˜300 μmol kg-1 in the Amazon River plume to a high value between ˜500-1100 μmol kg-1 in the middle and high latitude margins. The highest value of ˜2400 μmol kg-1 is observed in the Mississippi River influenced areas. In addition to mixing control, biological processes such as calcification and benthic alkalinity production may also affect ocean margin alkalinity distribution. Therefore, deriving inorganic carbon system information in coastal oceans using alkalinity-salinity relationships, in particular, those of generic nature, may lead to significant errors.

  6. On forecasting abnormal climatic events in the tropical Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Servain, Jacques; Arnault, Sabine

    1995-09-01

    Modelling and observational evidence indicate that interannual variabilities of dynamic height and sea surface temperature (SST) in the eastern part of the tropical Atlantic Ocean (Gulf of Guinea) are largely induced by preceding fluctuations in wind stress, mainly in the western equatorial basin. A wind-driven linear ocean model is used here to test the possibility of forecasting the abnormal dynamic heights. A control run of the model, forced by 1964-1993 wind stress monthly means, is first conducted. Yearly test runs (1964-1994) are subsequently performed from January to August by forcing the model with observed winds from January to May, and then by forcing with the May wind assumed to persist from June to August. During the last three decades the largest deviations of dynamic height simulated by the control run in the Gulf of Guinea in boreal summer would have been correctly forecast from wind data related only to conditions in May of each year. However, for weak climatic anomalies, the model may forecast overestimated values. For the most part (about 20 times during the last 30 years), the sign of the observed SST anomaly in the centre of the Gulf of Guinea during the boreal summer is identical to the sign of simulated anomalies of dynamic height deduced from both control and test runs. Along the eastern equatorial waveguide, the sea level forecasting skill slowly decreases from the first 2 weeks of June until the second 2 weeks of August, but remains high on both sides of the equator throughout boreal summer, as is expected from the adjustment in a linear ocean model. It is established that throughout the year in the Gulf of Guinea the accuracy of the 1-month forecast dynamic height anomaly provided by the simple linear method is greater than that of the 1-month forecast assuming persistence. Acknowledgements. The authors are grateful to Prof. A. K. Sen of the Institute of Radio Physics and Electronics, University of Calcutta for valuable discussions. One of

  7. Heat content variability in the North Atlantic Ocean in ocean reanalyses

    PubMed Central

    Häkkinen, Sirpa; Rhines, Peter B; Worthen, Denise L

    2015-01-01

    Warming of the North Atlantic Ocean from the 1950s to 2012 is analyzed on neutral density surfaces and vertical levels in the upper 2000 m. Three reanalyses and two observational data sets are compared. The net gain of 5 × 1022 J in the upper 2000 m is roughly 30% of the global ocean warming over this period. Upper ocean heat content (OHC) is dominated in most regions by heat transport convergence without widespread changes in the potential temperature/salinity relation. The heat convergence is associated with sinking of midthermocline isopycnals, with maximum sinking occurring at potential densities σ0 = 26.4−27.3, which contain subtropical mode waters. Water masses lighter than σ0 = 27.3 accumulate heat by increasing their volume, while heavier waters lose heat by decreasing their volume. Spatially, the OHC trend is nonuniform: the low latitudes, 0–30°N are warming steadily while large multidecadal variability occurs at latitudes 30–65°N. Key Points Heat content change dominated by heat transport convergence Due to widespread sinking trend of midthermocline isopycnals over 50+ years PMID:26709321

  8. 76 FR 65697 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries; 2012...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ...; Atlantic Surfclam and Ocean Quahog Fisheries; 2012 Cage Tags AGENCY: National Marine Fisheries Service... provide fishing year 2012 cage tags. SUMMARY: NMFS informs surfclam and ocean quahog individual... (January 1, 2012-December 31, 2012) cage tags from the National Band and Tag Company. The intent of...

  9. 77 FR 64316 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-19

    ...; Atlantic Surfclam and Ocean Quahog Fisheries; Notice That Vendor Will Provide Year 2013 Cage Tags AGENCY.... ACTION: Notice of vendor to provide fishing year 2013 cage tags. SUMMARY: NMFS informs surfclam and ocean... their fishing year 2013 (January 1, 2013-December 31, 2013) cage tags from the National Band and...

  10. Five new records of Luvarus imperialis (Acanthuroidei: Luvaridae) in the south-west Atlantic Ocean.

    PubMed

    Domingues, R R; Montealegre-Quijano, S; Soto, J M R; Amorim, A F

    2015-03-01

    Five new records of louvars Luvarus imperialis are documented for the south-west Atlantic Ocean, extending its distribution range in this ocean. The presence of one ripe specimen, associated with the previous records of larvae and juveniles, suggests that L. imperialis spawn in this region. The possible association of juveniles with shoals of skipjack tuna Katsuwonus pelamis is discussed. PMID:25639157

  11. Interannual variability of temperature at a depth of 125 meters in the north atlantic ocean.

    PubMed

    Levitus, S; Antonov, J I; Boyer, T P

    1994-10-01

    Analyses of historical ocean temperature data at a depth of 125 meters in the North Atlantic Ocean indicate that from 1950 to 1990 the subtropical and subarctic gyres exhibited linear trends that were opposite in phase. In addition, multivariate analyses of yearly mean temperature anomaly fields between 20 degrees N and 70 degrees N in the North Atlantic show a characteristic space-time temperature oscillation from 1947 to 1990. A quasidecadal oscillation, first identified at Ocean Weather Station C, is part of a basin-wide feature. Gyre and basin-scale variations such as these provide the observational basis for climate diagnostic and modeling studies. PMID:17814003

  12. Zooplankton grazing in the Atlantic Ocean: A latitudinal study

    NASA Astrophysics Data System (ADS)

    Calbet, Albert; Atienza, Dacha; Henriksen, Casper I.; Saiz, Enric; Adey, Timothy R.

    2009-07-01

    Mesozooplankton and 63-200 μm net-collected microzooplankton grazing on phytoplankton and protozoans was evaluated by 24-h incubations on a latitudinal transect in the Atlantic Ocean, from 35°N to 38°S (AMT-15; September-October 2004). The sampling area comprised contrasting ecosystems, including upwelling zones and oligotrophic subtropical gyres. Grazing impacts of mesozooplankton and 63-200 μm microzooplankton on total chlorophyll a (Chl a), >5 μm Chl a, ciliates, and dinoflagellates were low for both zooplankton size fractions, always removing<1.5% of the standing stocks of these groups. Grazing had a slightly greater impact upon primary production (up to 10% of primary production consumed daily), although on most occasions grazing removed<1% of primary production per day. To account for the reduction of micrograzers by predators in the experimental bottles and the consequent reduction of grazing pressure, the data were corrected with knowledge on the decrease of microzooplankton during incubations and global estimates of microzooplankton grazing. The corrected grazing rates for mesozooplankton ranged from 4% to 28% of the primary production consumed daily, and from 1% to 2% of the standing stock of Chl a removed every day. The 63-200 μm microzooplankton corrected grazing impact was always<5% of the primary production and standing stock consumed per day. The corrected grazing activity of 63-200 μm microzooplankton and mesozooplankton rendered daily rations ranging from 3% to 38% of the body carbon consumed daily, not sufficient for basal metabolism in most of the areas studied. Finally, the data on mesozooplankton grazing on primary production confirm the recent hypothesis of a decline of the relative importance of mesozooplankton grazing on primary producers with increasing primary production [Calbet, A., 2001. Mesozooplankton grazing effect on primary production: a global comparative analysis in marine ecosystems. Limnology and Oceanography 46, 1824-1830].

  13. The signature of low-frequency oceanic forcing in the Atlantic Multidecadal Oscillation

    NASA Astrophysics Data System (ADS)

    O'Reilly, Christopher H.; Huber, Markus; Woollings, Tim; Zanna, Laure

    2016-03-01

    The Atlantic Multidecadal Oscillation (AMO) significantly influences the climate of the surrounding continents and has previously been attributed to variations in the Atlantic Meridional Overturning Circulation. Recently, however, similar multidecadal variability was reported in climate models without ocean circulation variability. We analyze the relationship between turbulent heat fluxes and sea surface temperatures (SSTs) over the midlatitude North Atlantic in observations and coupled climate model simulations, both with and without ocean circulation variability. SST anomalies associated with the AMO are positively correlated with heat fluxes on decadal time scales in both observations and models with varying ocean circulation, whereas in models without ocean circulation variability the anomalies are negatively correlated when heat flux anomalies lead. These relationships are captured in a simple stochastic model and rely crucially on low-frequency forcing of SST. The fully coupled models that better capture this signature more effectively reproduce the observed impact of the AMO on European summertime temperatures.

  14. 75 FR 4348 - Mid-Atlantic Fishery Management Council; Public Hearings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... National Oceanic and Atmospheric Administration RIN 0648-XU05 Mid-Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of public hearings. SUMMARY: The Mid-Atlantic Fishery Management... Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP). See SUPPLEMENTARY...

  15. Identification of Atlantic Ocean Sea Surface Temperatures Drivers of French Streamflow

    NASA Astrophysics Data System (ADS)

    Aziz, O. A.; Tootle, G. A.; Anderson, S.

    2010-12-01

    The identification of Atlantic Ocean climatic drivers [e.g., Sea Surface Temperature (SST) variability] may be valuable in long lead-time forecasting of streamflow in France. Previous research efforts have identified the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) as drivers of European hydrology. The current research applies, for the first time, the Singular Value Decomposition (SVD) statistical method to Atlantic Ocean SSTs and French streamflow to identify the primary Atlantic Ocean climatic driver of French streamflow. The use of Atlantic Ocean SSTs as a whole eliminates any biased that may be associated with using a predefined region of SSTs (e.g., AMO). Approximately 60 unimpaired streamflow stations with a period of record beginning around 1960 were evaluated and 25 were usable due to missing data. These data were obtained from the hydrology website of the Ministry of Ecology and Sustainable Development - Ministère de l’Ecologie et du Developpment Durable (http://www.hydro.eaufrance.fr). The Atlantic Ocean SST data cover the region spanning from 20° South to 60° North and 80° West to 2° West and were obtained from the National Climatic Data Center website (http://www.cdc.noaa.gov/cdc/data.noaa.erSST.html). AMO index values are available from the National Oceanic and Atmospheric Administration (NOAA) Climate Diagnostics Center (CDC) (http://www.cdc.noaa.gov/ClimateIndices/) and NAO index values were obtained from the National Center for Atmospheric Research (NCAR) website (http://www.cgd.ucar.edu/cas/jhurrell/indices.html). SVD has been used previously in similar studies, evaluating Pacific (should this be Pacific?), Atlantic, and global SSTs with various hydrologic responses including streamflow, precipitation, snowpack, and drought. Seasonal and yearly French streamflow are the hydrologic response while average Atlantic Ocean SSTs calculated for three different six month windows (January-June or JFMAMJ, April

  16. Response to Comment on "The Atlantic Multidecadal Oscillation without a role for ocean circulation".

    PubMed

    Clement, Amy; Cane, Mark A; Murphy, Lisa N; Bellomo, Katinka; Mauritsen, Thorsten; Stevens, Bjorn

    2016-06-24

    Zhang et al interpret the mixed-layer energy budget in models as showing that "ocean dynamics play a central role in the AMO." Here, we show that their diagnostics cannot reveal the causes of the Atlantic Multidecadal Oscillation (AMO) and that their results can be explained with minimal ocean influence. Hence, we reaffirm our findings that the AMO in models can be understood primarily as the upper-ocean thermal response to stochastic atmospheric forcing. PMID:27339977

  17. Response to Comment on “The Atlantic Multidecadal Oscillation without a role for ocean circulation”

    NASA Astrophysics Data System (ADS)

    Clement, Amy; Cane, Mark A.; Murphy, Lisa N.; Bellomo, Katinka; Mauritsen, Thorsten; Stevens, Bjorn

    2016-06-01

    Zhang et al. interpret the mixed-layer energy budget in models as showing that “ocean dynamics play a central role in the AMO.” Here, we show that their diagnostics cannot reveal the causes of the Atlantic Multidecadal Oscillation (AMO) and that their results can be explained with minimal ocean influence. Hence, we reaffirm our findings that the AMO in models can be understood primarily as the upper-ocean thermal response to stochastic atmospheric forcing.

  18. Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

    PubMed Central

    Rosenbaum, Howard C.; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S.; Best, Peter B.; Findlay, Ken P.; Minton, Gianna; Ersts, Peter J.; Collins, Timothy; Engel, Marcia H.; Bonatto, Sandro L.; Kotze, Deon P. G. H.; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-01-01

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region. PMID:19812698

  19. Population structure of humpback whales from their breeding grounds in the South Atlantic and Indian Oceans.

    PubMed

    Rosenbaum, Howard C; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S; Best, Peter B; Findlay, Ken P; Minton, Gianna; Ersts, Peter J; Collins, Timothy; Engel, Marcia H; Bonatto, Sandro L; Kotze, Deon P G H; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-01-01

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region. PMID:19812698

  20. The influence of Southern Ocean winds on the North Atlantic carbon sink

    NASA Astrophysics Data System (ADS)

    Bronselaer, Ben; Zanna, Laure; Munday, David R.; Lowe, Jason

    2016-06-01

    Observed and predicted increases in Southern Ocean winds are thought to upwell deep ocean carbon and increase atmospheric CO2. However, Southern Ocean dynamics affect biogeochemistry and circulation pathways on a global scale. Using idealized Massachusetts Institute of Technology General Circulation Model (MITgcm) simulations, we demonstrate that an increase in Southern Ocean winds reduces the carbon sink in the North Atlantic subpolar gyre. The increase in atmospheric CO2 due to the reduction of the North Atlantic carbon sink is shown to be of the same magnitude as the increase in atmospheric CO2 due to Southern Ocean outgassing. The mechanism can be described as follows: The increase in Southern Ocean winds leads to an increase in upper ocean northward nutrient transport. Biological productivity is therefore enhanced in the tropics, which alters the chemistry of the subthermocline waters that are ultimately upwelled in the subpolar gyre. The results demonstrate the influence of Southern Ocean winds on the North Atlantic carbon sink and show that the effect of Southern Ocean winds on atmospheric CO2 is likely twice as large as previously thought in past, present, and future climates.

  1. 78 FR 31840 - Safety Zone; USO Patriotic Festival Air Show, Atlantic Ocean; Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-28

    ...-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... Ocean; Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast... Beach, VA. This action is necessary to provide for the safety of life on navigable waters during the...

  2. Atmospheric transport of pollutants from North America to the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Harriss, R. C.; Browell, E. V.; Sebacher, D. I.; Gregory, G. L.; Hinton, R. R.; Beck, S. M.; Mcdougal, D. S.; Shipley, S. T.

    1984-01-01

    Ground-based measurements strongly support the hypothesis that pollutant materials of anthropogenic origin are being transported over long distances in the midtroposphere and are a significant source of acid rain, acid snow, trace metal deposition, ozone and visibility-reducing aerosols in remote oceanic and polar regions of the Norhern Hemisphere. Atmospheric sulphur budget calculations and studies of acid rain on Bermuda indicate that a large fraction of pollutant materials emitted into the atmosphere in eastern North America are advected eastwards over the North Atlantic Ocean. The first direct airborne measurements of the vertical distribution of tropospheric aerosols over the western North Atlantic is reported here. A newly developed airborne differential adsorption lidar system was used to obtain continuous, remotely sensed aerosol distributions along its flight path. The data document two episodes of long-distance transport of pollutant materials from North America over the North Atlantic Ocean.

  3. Is the oceanic heat transport with Atlantic water towards the Arctic changing?

    NASA Astrophysics Data System (ADS)

    Østerhus, Svein

    2013-04-01

    The flow of Atlantic water (Atlantic inflow) across the Greenland-Scotland Ridge (GSR) is critical for conditions in the Nordic Seas and Arctic Ocean by importing heat and salt. All three branches crossing the GSR have been monitored since the mid-1990ies and the transports of water and heat have been estimated. The Atlantic inflow, that forms the surface part of the thermohaline circulation in the North Atlantic, is affected by wind forcing and freshwater input but the most important driving appears to be the cooling of the ocean by the atmosphere in the subarctic seas and increasing of salinity in the Arctic Ocean through freezing of seawater. This results in the sinking of the surface waters that subsequently flow out of the area close to the bottom over the GSR. This removal of water from the Arctic region by the overflow generates sea level slopes that drive a northward transport of water and heat. With global climate change, the Arctic atmosphere is expected to warm and freshwater input to the Arctic to increase, both of which may act to slow the mechanism that drives these flows, and climate models predict a weakening of the North Atlantic thermohaline circulation. This presentation addresses the question, whether the weakening has already been initiated and what regions may have been affected. Based on observations and model results, we conclude that the volume transport of the Atlantic inflow has not weakened consistently whereas the temperature has increased.

  4. Simulated strengthening of the Atlantic Meridional Overturning Circulation in response to abyssal ocean warming around Antarctica

    NASA Astrophysics Data System (ADS)

    Patara, L.; Boning, C. W.

    2013-12-01

    Studies of repeat hydrographic observations have revealed a conspicuous multi-decadal warming, and partly, freshening, of the frigid abyssal ocean waters originating from the fringes of the Antarctic continent. The warming and contraction of Antarctic Bottom Water (AABW) represents one of the most prominent signals of change in Earth's climate and accounts for a substantial fraction of the present global energy and sea level budgets. Here we present a set of ocean model experiments demonstrating that the ongoing loss of AABW also has important dynamical consequences for the large-scale meridional overturning circulation in the Atlantic Ocean. In conjunction with a slowdown of the bottom cell, we find that the upper cell of the Atlantic Meridional Overturning Circulation (AMOC) progressively strengthens in response to changes in density gradients in the deep South Atlantic. Changes in the AMOC are tightly connected to increased meridional heat transport and therefore have a strong influence on global and regional climate patterns in the North Atlantic. The simulations suggest that the AABW-induced strengthening of the AMOC is already extending into the North Atlantic, progressing at a rate of about 0.2 Sv per decade, implying that the process may need to be taken into account in projections of future North Atlantic climate.

  5. Arctic contribution to upper-ocean variability in the North Atlantic

    NASA Technical Reports Server (NTRS)

    Walsh, John E.; Chapman, William L.

    1990-01-01

    The potential climatic leverage of salinity and temperature anomalies in the high-latitude North Atlantic is large. Substantial variations of sea ice have accompanied North Atlantic salinity and temperature anomalies. Atmospheric pressure data are used here to show that the local forcing of high-latitude North Atlantic Ocean fluctuations is augmented by antecedent atmospheric circulation anomalies over the central Arctic. These circulation anomalies are consistent with enhanced wind-forcing of thicker older ice into the Transpolar Drift Stream and an enhanced export of sea ice (fresh water) from the Arctic into the Greenland Sea prior to major episodes of ice severity in the Greenland and Iceland seas.

  6. Meridional Distribution of Aerosol Optical Thickness over the Tropical Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Kishcha, P.; Silva, Arlindo M.; Starobinets, B.; Long, C. N.; Kalashnikova, O.; Alpert, P.

    2015-01-01

    Previous studies showed that, over the global ocean, there is hemispheric asymmetry in aerosols and no noticeable asymmetry in cloud fraction (CF). In the current study, we focus on the tropical Atlantic (30 Deg N 30 Deg S) which is characterized by significant amounts of Saharan dust dominating other aerosol species over the North Atlantic. We found that, by contrast to the global ocean, over a limited area such as the tropical Atlantic, strong meridional asymmetry in dust aerosols was accompanied by meridional CF asymmetry. During the 10-year study period (July 2002 June 2012), NASA Aerosol Reanalysis (aka MERRAero) showed that, when the meridional asymmetry in dust aerosol optical thickness (AOT) was the most pronounced (particularly in July), dust AOT averaged separately over the tropical North Atlantic was one order of magnitude higher than dust AOT averaged over the tropical South Atlantic. In the presence of such strong meridional asymmetry in dust AOT in July, CF averaged separately over the tropical North Atlantic exceeded CF averaged over the tropical South Atlantic by 20%. Our study showed significant cloud cover, up to 0.8 - 0.9, in July along the Saharan Air Layer which contributed to above-mentioned meridional CF asymmetry. Both Multi-Angle Imaging SpectroRadiometer (MISR) measurements and MERRAero data were in agreement on seasonal variations in meridional aerosol asymmetry. Meridional asymmetry in total AOT over the Atlantic was the most pronounced between March and July, when dust presence over the North Atlantic was maximal. In September and October, there was no noticeable meridional asymmetry in total AOT and meridional CF distribution over the tropical Atlantic was almost symmetrical.

  7. 33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Engineers also has regulations dealing with this section in 33 CFR Part 207. ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

  8. 33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Engineers also has regulations dealing with this section in 33 CFR Part 207. ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

  9. 33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Engineers also has regulations dealing with this section in 33 CFR Part 207. ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

  10. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra...

  11. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles...

  12. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam...

  13. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles...

  14. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam...

  15. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off...

  16. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam...

  17. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles...

  18. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic...

  19. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam...

  20. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra...

  1. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off...

  2. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra...

  3. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... navigable waters of the United States, as defined at 33 CFR part 329, contiguous to the area offshore of... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Cape Canaveral... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing,...

  4. 33 CFR 334.595 - Atlantic Ocean off Cape Canaveral; 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... navigable waters of the United States, as defined at 33 CFR part 329, contiguous to the area offshore of... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Cape Canaveral... AND RESTRICTED AREA REGULATIONS § 334.595 Atlantic Ocean off Cape Canaveral; 45th Space Wing,...

  5. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic...

  6. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles...

  7. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra...

  8. 33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... AND RESTRICTED AREA REGULATIONS § 334.40 Atlantic Ocean in vicinity of Duck Island, Maine, Isles...

  9. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS... Ocean off Cape May, N.J.; Coast Guard Rifle Range. (a) The danger zone. The waters of the Atlantic...

  10. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam...

  11. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off...

  12. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off...

  13. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off...

  14. 33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... tributary to the Gulf of Mexico east and south of St. Marks, Fla.; use, administration, and navigation. (a... Atlantic Ocean south of Chesapeake Bay or with the Gulf of Mexico east and south......

  15. 33 CFR 334.1460 - Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean and Vieques Sound, in vicinity of Culebra Island; bombing and gunnery target area. 334.1460 Section 334.1460 Navigation... RESTRICTED AREA REGULATIONS § 334.1460 Atlantic Ocean and Vieques Sound, in vicinity of Culebra...

  16. 33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... tributary to the Gulf of Mexico east and south of St. Marks, Fla.; use, administration, and navigation. (a... Atlantic Ocean south of Chesapeake Bay or with the Gulf of Mexico east and south of St. Marks, Florida....

  17. Troposphere-stratosphere response to large-scale North Atlantic Ocean variability in an atmosphere/ocean coupled model

    NASA Astrophysics Data System (ADS)

    Omrani, N.-E.; Bader, Jürgen; Keenlyside, N. S.; Manzini, Elisa

    2016-03-01

    The instrumental records indicate that the basin-wide wintertime North Atlantic warm conditions are accompanied by a pattern resembling negative North Atlantic oscillation (NAO), and cold conditions with pattern resembling the positive NAO. This relation is well reproduced in a control simulation by the stratosphere resolving atmosphere-ocean coupled Max-Planck-Institute Earth System Model (MPI-ESM). Further analyses of the MPI-ESM model simulation shows that the large-scale warm North Atlantic conditions are associated with a stratospheric precursory signal that propagates down into the troposphere, preceding the wintertime negative NAO. Additional experiments using only the atmospheric component of MPI-ESM (ECHAM6) indicate that these stratospheric and tropospheric changes are forced by the warm North Atlantic conditions. The basin-wide warming excites a wave-induced stratospheric vortex weakening, stratosphere/troposphere coupling and a high-latitude tropospheric warming. The induced high-latitude tropospheric warming is associated with reduction of the growth rate of low-level baroclinic waves over the North Atlantic region, contributing to the negative NAO pattern. For the cold North Atlantic conditions, the strengthening of the westerlies in the coupled model is confined to the troposphere and lower stratosphere. Comparing the coupled and uncoupled model shows that in the cold phase the tropospheric changes seen in the coupled model are not well reproduced by the standalone atmospheric configuration. Our experiments provide further evidence that North Atlantic Ocean variability (NAV) impacts the coupled stratosphere/troposphere system. As NAV has been shown to be predictable on seasonal-to-decadal timescales, these results have important implications for the predictability of the extra-tropical atmospheric circulation on these time-scales.

  18. Bipolar Atlantic deepwater circulation in the middle-late Eocene: Effects of Southern Ocean gateway openings

    NASA Astrophysics Data System (ADS)

    Borrelli, Chiara; Cramer, Benjamin S.; Katz, Miriam E.

    2014-04-01

    We present evidence for Antarctic Circumpolar Current (ACC)-like effects on Atlantic deepwater circulation beginning in the late-middle Eocene. Modern ocean circulation is characterized by a thermal differentiation between Southern Ocean and North Atlantic deepwater formation regions. In order to better constrain the timing and nature of the initial thermal differentiation between Northern Component Water (NCW) and Southern Component Water (SCW), we analyze benthic foraminiferal stable isotope (δ18Obf and δ13Cbf) records from Ocean Drilling Program Site 1053 (upper deep water, western North Atlantic). Our data, compared with published records and interpreted in the context of ocean circulation models, indicate that progressive opening of Southern Ocean gateways and initiation of a circum-Antarctic current caused a transition to a modern-like deep ocean circulation characterized by thermal differentiation between SCW and NCW beginning ~38.5 Ma, in the initial stages of Drake Passage opening. In addition, the relatively low δ18Obf values recorded at Site 1053 show that the cooling trend of the middle-late Eocene was not global, because it was not recorded in the North Atlantic. The timing of thermal differentiation shows that NCW contributed to ocean circulation by the late-middle Eocene, ~1-4 Myr earlier than previously thought. We propose that early NCW originated in the Labrador Sea, based on tectonic reconstructions and changes in foraminiferal assemblages in this basin. Finally, we link further development of meridional isotopic gradients in the Atlantic and Pacific in the late Eocene with the Tasman Gateway deepening (~34 Ma) and the consequent development of a circumpolar proto-ACC.

  19. Genetic discontinuity among regional populations of Lophelia perfusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, Cheryl L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U.S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U.S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks

  20. Genetic discontinuity among regional populations of Lophelia pertusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, C.L.; Ross, S.W.; Nizinski, M.S.; Brooke, S.; Jarnegren, J.; Waller, R.G.; Johnson, R.L.; King, T.L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U. S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U. S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks. ?? 2011 US Government.

  1. Using Three Global Climate Indices to Forecast Hurricane Activity in the Pacific and Atlantic Oceans

    NASA Astrophysics Data System (ADS)

    Giovannettone, J. P.

    2014-12-01

    Quantitative relationships between global climate indices and hurricane activity in the Pacific and Atlantic Oceans have not been widely studied. A few studies have explored qualitative relationships between hurricane activity and such climate indices as the North Atlantic Oscillation and sea-surface temperatures, among others. The current work presents the most comprehensive analysis of the potential relationships between 39 different climate indices and hurricane activity using regression and frequency analysis. Attempts are made to develop statistical relationships between any one of these indices and hurricane activity in the eastern and western Pacific as well as the Atlantic Oceans. There were three climate indices, one per region, showing significantly higher correlation in each region. They were the ENSO Precipitation Index (EPI) in the western Pacific, the Atlantic Multi-decadal Oscillation (AMO) in the eastern Pacific, and the Atlantic Meridional Mode (AMM) in the Atlantic. The linear relationships between each index and hurricane numbers resulted in Pearson-R values of near 0.65 or greater. In addition, the Madden-Julian Oscillation showed some correlation with hurricane activity in each region and therefore was included in the analysis. Several important results were found during these analyses. For instance, the relationship between the AMM index and hurricane numbers in the Atlantic Ocean revealed that the average July - October AMM index was greater than -0.5 within a range of -5.0 to 5.0 for years within the last 70 years when the number of hurricanes during that same period was greater than 7. It is also shown that the number of hurricanes expected to be exceeded or not exceeded at frequencies of 50- to 100-years, for example, varies substantially depending on the range of AMM index values being analyzed. Similar results are shown for the eastern and western Pacific Ocean as well. Such relationships provide forecasters with a simple tool using only

  2. Dynamics of the Atlantic meridional overturning circulation and Southern Ocean in an ocean model of intermediate complexity

    NASA Astrophysics Data System (ADS)

    McCreary, Julian P.; Furue, Ryo; Schloesser, Fabian; Burkhardt, Theodore W.; Nonaka, Masami

    2016-04-01

    A steady-state, variable-density, 2-layer, ocean model (VLOM) is used to investigate basic dynamics of the Atlantic meridional overturning circulation and Southern Ocean. The domain consists of idealized (rectangular) representations of the Atlantic, Southern, and Pacific Oceans. The model equations represent the depth-averaged, layer-1 response (except for one solution in which they represent the depth-integrated flow over both layers). To allow for overturning, water can cross the bottom of layer 1 at the velocity we =wd +wm +wn , the three parts representing: interior diffusion wd that increases the layer-1 thickness h throughout the basin, mixed-layer entrainment wm that ensures h is never less than a minimum value hm , and diapycnal (cooling) processes external to the basin wn that adjust h to hn . For most solutions, horizontal mixing has the form of Rayleigh damping with coefficient ν , which we interpret to result from baroclinic instability through the closure, V∗ = - (ν /f2) ∇P , where ∇P = ∇(1/2 g‧h2) is the depth-integrated pressure gradient, g‧ is the reduced-gravity coefficient, and ν is a mixing coefficient; with this interpretation, the layer-1 flow corresponds to the sum of the Eulerian-mean and eddy-mean (V∗) transport/widths, that is, the "residual" circulation. Finally, layer-1 temperature cools polewards in response to a surface heat flux Q, and the cooling can be strong enough in the Southern Ocean for g‧ = 0 south of a latitude y0 , in which case layer 1 vanishes and the model reduces to a single layer 2. Solutions are obtained both numerically and analytically. The analytic approach splits fields into interior and boundary-layer parts, from which a coupled set of integral constraints can be derived. The set allows properties of the circulation (upwelling-driven transport out of the Southern Ocean M , downwelling transport in the North Atlantic, transport of the Antarctic Circumpolar Current) and stratification (Atlantic

  3. Long-term variations of SST and heat content in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Huonsou-gbo, Aubains; Servain, Jacques; Caniaux, Guy; Araujo, Moacyr; Bourlès, Bernard; Veleda, Doris

    2015-04-01

    Recent studies (eg. Wen et al. 2010; Servain et al. 2014) suggest that subsurface processes influence the interannual variability of sea surface temperature (SST) in the tropical Atlantic through the Meridional Overturning Circulation (MOC) with time lags of several months. In this study, we used observed SST and Ocean heat content to test such hypothesis during the period 1964-2013. First results indicate great similarities in the positive linear trends of monthly standardized anomalies of SST, upper ocean heat content (0-500m) and deeper ocean heat content (500-2000m) averaged over the whole Atlantic Ocean. Strong positive trends of SST and deeper heat content occurred in the equatorial Atlantic, while a strong positive trend of the upper heat content was observed in the northeast Atlantic. These positive trends were the highest during the last two decades. The lagged positive correlation patterns between upper heat content anomalies over the whole gridded Atlantic Ocean and SST anomalies averaged over the equatorial region (60°W-15°E; 10°N-10°S) show a slow temporal evolution, which is roughly in agreement with the upper MOC. More detailed works about the mechanism, as well as about the origin of the highest positive trend of the deeper heat content in the equatorial region, are presently under investigation. References Servain J., G. Caniaux, Y. K. Kouadio, M. J. McPhaden, M. Araujo (2014). Recent climatic trends in the tropical Atlantic. Climate Dynamics, Vol. 43, 3071-3089, DOI 10.1007/s00382-014-2168-7.

  4. Rapid freshening of the deep North Atlantic Ocean over the past four decades.

    PubMed

    Dickson, Bob; Yashayaev, Igor; Meincke, Jens; Turrell, Bill; Dye, Stephen; Holfort, Juergen

    2002-04-25

    The overflow and descent of cold, dense water from the sills of the Denmark Strait and the Faroe Shetland channel into the North Atlantic Ocean is the principal means of ventilating the deep oceans, and is therefore a key element of the global thermohaline circulation. Most computer simulations of the ocean system in a climate with increasing atmospheric greenhouse-gas concentrations predict a weakening thermohaline circulation in the North Atlantic as the subpolar seas become fresher and warmer, and it is assumed that this signal will be transferred to the deep ocean by the two overflows. From observations it has not been possible to detect whether the ocean's overturning circulation is changing, but recent evidence suggests that the transport over the sills may be slackening. Here we show, through the analysis of long hydrographic records, that the system of overflow and entrainment that ventilates the deep Atlantic has steadily changed over the past four decades. We find that these changes have already led to sustained and widespread freshening of the deep ocean. PMID:11976679

  5. Detection of Natural Oil Seeps in the Atlantic Ocean Using MODIS

    NASA Technical Reports Server (NTRS)

    Reahard, Ross; Jones, Jason B.; Mitchell, Mark

    2010-01-01

    Natural oil seepage is the release of crude oil into the ocean from fissures in the seabed. Oil seepage is a major contributor to the total amount of oil entering the world s oceans. According to a 2003 study by the National Academy of Sciences (NAS), 47 percent of oil entering the world s oceans is from natural seeps, and 53 percent is from human sources (extraction, transportation, and consumption). Oil seeps cause smooth oil slicks to form on the water s surface. Oil seeps can indicate the location of stores of fossil fuel beneath the ocean floor. Knowledge of the effect of oil seepage on marine life and marine ecosystems remains limited. In the past, remote sensing has been used to detect oil seeps in the Gulf of Mexico and off of the coast of southern California. This project utilized sun glint MODIS imagery to locate oil slicks off of the Atlantic coast, an area that had not previously been surveyed for natural oil seeps using remote sensing. Since 1982, the Atlantic Ocean has been closed to any oil and gas drilling. Recently, however, the U.S. Minerals Management Services (MMS) has proposed a lease for oil and gas drilling off the coasts of Virginia and North Carolina. Determining the location of seepage sites in the Atlantic Ocean will help MMS locate potential deposits of oil and natural gas, thereby reducing the risk of leasing areas for petroleum extraction that do not contain these natural resources.

  6. Impacts of Indian and Atlantic oceans on ENSO in a comprehensive modeling framework

    NASA Astrophysics Data System (ADS)

    Terray, Pascal; Masson, Sébastien; Prodhomme, Chloé; Roxy, Mathew Koll; Sooraj, K. P.

    2016-04-01

    The impact of the Indian and Atlantic oceans variability on El Niño-Southern-Oscillation (ENSO) phenomenon is investigated through sensitivity experiments with the SINTEX-F2 coupled model. For each experiment, we suppressed the sea surface temperature (SST) variability in either the Indian or Atlantic oceans by applying a strong nudging of the SST toward a SST climatology computed either from a control experiment or observations. In the sensitivity experiments where the nudging is done toward a control SST climatology, the Pacific mean state and seasonal cycle are not changed. Conversely, nudging toward an observed SST climatology in the Indian or Atlantic domain significantly improves the mean state and seasonal cycle, not only in the nudged domain, but also in the whole tropics. These experiments also demonstrate that decoupling the Indian or Atlantic variability modifies the phase-locking of ENSO to the annual cycle, influences significantly the timing and processes of ENSO onset and termination stages, and, finally, shifts to lower frequencies the main ENSO periodicities. Overall, these results suggest that both the Indian and Atlantic SSTs have a significant damping effect on ENSO variability and promote a shorter ENSO cycle. The reduction of ENSO amplitude is particularly significant when the Indian Ocean is decoupled, but the shift of ENSO to lower frequencies is more pronounced in the Atlantic decoupled experiments. These changes of ENSO statistical properties are related to stronger Bjerknes and thermocline feedbacks in the nudged experiments. During the mature phase of El Niño events, warm SST anomalies are found over the Indian and Atlantic oceans in observations or the control run. Consistent with previous studies, the nudged experiments demonstrate that these warm SSTs induce easterly surface wind anomalies over the far western equatorial Pacific, which fasten the transition from El Niño to La Niña and promote a shorter ENSO cycle in the control

  7. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part 329.... Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters...

  8. 33 CFR 334.525 - Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... REGULATIONS § 334.525 Atlantic Ocean off John F. Kennedy Space Center, FL; restricted area. (a) The area. The restricted area shall encompass all navigable waters of the United States, as defined at 33 CFR part 329.... Kennedy Space Center, FL; restricted area. 334.525 Section 334.525 Navigation and Navigable Waters...

  9. Draft genome sequence of a novel culturable marine chroococcalean cyanobacterium from the South atlantic ocean.

    PubMed

    Rigonato, Janaina; Alvarenga, Danillo O; Branco, Luis H Z; Varani, Alessandro M; Brandini, Frederico P; Fiore, Marli F

    2015-01-01

    The novel chroococcalean cyanobacterium strain CENA595 was isolated from the deep chlorophyll maximum layer of the continental shelf of the South Atlantic Ocean. Here, we report the draft genome sequence for this strain, consisting of 60 contigs containing a total of 5,265,703 bp and 3,276 putative protein-coding genes. PMID:25908150

  10. Draft Genome Sequence of a Novel Culturable Marine Chroococcalean Cyanobacterium from the South Atlantic Ocean

    PubMed Central

    Alvarenga, Danillo O.; Branco, Luis H. Z.; Varani, Alessandro M.; Brandini, Frederico P.; Fiore, Marli F.

    2015-01-01

    The novel chroococcalean cyanobacterium strain CENA595 was isolated from the deep chlorophyll maximum layer of the continental shelf of the South Atlantic Ocean. Here, we report the draft genome sequence for this strain, consisting of 60 contigs containing a total of 5,265,703 bp and 3,276 putative protein-coding genes. PMID:25908150

  11. 77 FR 75853 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-26

    ...The Coast Guard is establishing a temporary safety zone on the waters of the Atlantic Ocean in Key West, Florida, during the Bone Island Triathlon on Saturday, January 12, 2013. The safety zone is necessary to provide for the safety of life on navigable waters during the event. Persons and vessels are prohibited from entering, transiting through, anchoring in, or remaining within the safety......

  12. 77 FR 42651 - Disestablishment of Restricted Area, Rhode Island Sound, Atlantic Ocean, Approximately 4 Nautical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... RA. The proposed rule was published in the April 4, 2012, edition of the Federal Register (77 FR... Sound, Atlantic Ocean, Approximately 4 Nautical Miles Due South of Lands End in Newport, RI AGENCY: U.S... the site, the USN has determined that disestablishment of the area will not pose any hazard or...

  13. 78 FR 25008 - Safety Zone; Fairfield Estates Fireworks Display, Atlantic Ocean, Sagaponack, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-29

    ... FR Federal Register NPRM Notice of Proposed Rulemaking A. Public Participation and Request for... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). 4. Public Meeting We..., Atlantic Ocean, Sagaponack, NY AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed Rulemaking....

  14. 78 FR 41844 - Safety Zone; Fairfield Estates Fireworks Display, Atlantic Ocean, Sagaponack, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ... Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History... FR 25008). No public comments were received. There were no requests received for a public meeting and..., Atlantic Ocean, Sagaponack, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The...

  15. 78 FR 70901 - Safety Zone; Bone Island Triathlon, Atlantic Ocean; Key West, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ... Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Public... Federal Register (73 FR 3316). 4. Public Meeting We do not now plan to hold a public meeting. But you may... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bone Island Triathlon, Atlantic Ocean;...

  16. 78 FR 18235 - Special Local Regulations; 2013 Lauderdale Air Show, Atlantic Ocean; Fort Lauderdale, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ...The Coast Guard is establishing a special local regulation on the Atlantic Ocean and the entrance of Port Everglades in the vicinity of Fort Lauderdale, Florida during the 2013 Lauderdale Air Show. The event is scheduled to take place from Thursday April 18, 2013, until Sunday, April 21, 2013. The regulation is necessary to ensure the safety of the participants, spectators, and the general......

  17. Streamflow from the United States into the Atlantic Ocean during 1931-1960

    USGS Publications Warehouse

    Bue, Conrad D.

    1970-01-01

    Streamflow from the United States into the Atlantic Ocean, between the international stream St. Croix River, inclusive, and Cape Sable, Fla., averaged about 355,000 cfs (cubic feet per second) during the 30-year period 1931-60, or roughly 20 percent of the water that, on the average flows out of the conterminous United States. The area drained by streams flowing into the Atlantic Ocean is about 288,000 square miles, including the Canadian part of the St. Croix and Connecticut River basins, or a little less than 10 percent of the area of the conterminous United States. Hence, the average streamflow into the Atlantic Ocean, in terms of cubic feet per second per square mile, is about twice the national average of the flow that leaves the conterminous United States. Flow from about three-fourths of the area draining into the Atlantic Ocean is gaged at streamflow measuring stations of the U.S. Geological Survey. The remaining one-fourth of the drainage area consists mostly of low-lying coastal areas from which the flow was estimated, largely on the basis of nearby gaging stations. Streamflow, in terms of cubic feet per second per square mile, decreases rather progressively from north to south. It averages nearly 2 cfs along the Maine coast, about 1 cfs along the North Carolina coast, and about 0.9 cfs along the Florida coast.

  18. Micropaleontological evidence for increased meridional heat transport in the North Atlantic Ocean during the pliocene

    USGS Publications Warehouse

    Dowsett, H.J.; Cronin, T. M.; Poore, R.Z.; Thompson, R.S.; Whatley, R.C.; Wood, A.M.

    1992-01-01

    The Middle Pliocene (???3 million years ago) has been identified as the last time the Earth was significantly warmer than it was during the Last Interglacial and Holocene. A quantitative micropaleontological paleotemperature transect from equator to high latitudes in the North Atlantic indicates that Middle Pliocene warmth involved increased meridional oceanic heat transport.

  19. 33 CFR 165.535 - Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Safety Zone: Atlantic Ocean, Vicinity of Cape Henlopen State Park, Delaware. 165.535 Section 165.535 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS...

  20. Mercury-Atlas 6 spacecraft retrieved from Atlantic Ocean following mission

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The Mercury-Atlas 6 'Friendship 7' spacecraft is retrieved from the Atlantic Ocean following Astronaut John H. Glenn Jr.'s three-orbit space mission. In this view, the capsule is still in the water, with retrieval cable connected to it.

  1. 78 FR 35596 - Special Local Regulation; Long Beach Regatta, Powerboat Race, Atlantic Ocean, Long Beach, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-13

    ... Zones; Recurring Events in Captain of the Port Long Island Sound Zone'' in the Federal Register (77 FR... SECURITY Coast Guard 33 CFR Part 100 RIN 1625-AA08 Special Local Regulation; Long Beach Regatta, Powerboat Race, Atlantic Ocean, Long Beach, NY AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed...

  2. Ecological Condition of Coastal Ocean Waters Along the U.S. Mid-Atlantic Bight: 2006

    EPA Science Inventory

    This report presents the results of an assessment of ecological condition in coastal-ocean waters of the U.S. mid-Atlantic Bight (MAB), along the U.S. continental shelf from Cape Cod, MA and Nantucket Shoals to the northeast to Cape Hatteras to the south, based on sampling conduc...

  3. Satellite-derived coastal ocean and estuarine salinity in the Mid-Atlantic

    NASA Astrophysics Data System (ADS)

    Geiger, Erick F.; Grossi, Matthew D.; Trembanis, Arthur C.; Kohut, Josh T.; Oliver, Matthew J.

    2013-07-01

    Coastal salinity is a basic oceanographic property that is not routinely estimated by satellites. Efforts to measure ocean salinity from space are designed for large scale open ocean environments, not coastal regions. In the Mid-Atlantic coastal ocean, salinity is critical for understanding circulation patterns, river plumes, and transport, which in turn impact the status of the ecosystem. However, the spatial and temporal coverage of in situ salinity measurements in this region are sparse and do not synoptically capture salinity in the coastal ocean. We compiled ˜2 million salinity records from four regional research vessels between the years 2003-2008 and found ˜9 thousand salinity records that could be adequately matched to MODIS-Aqua data. We show that the spectral shape of water-leaving radiance and sea surface temperature are most correlated with in situ salinity. Four neural network models designed to predict salinity were developed for the Mid-Atlantic coastal region and three of its major estuaries (Hudson, Delaware, and Chesapeake). Our models predict salinity with RMS errors between 1.40psu and 2.29psu, which are much less than the null model ranges (4.87-10.08psu) and the natural range of the system (0-32psu). Seasonal climatologies for the Chesapeake, Delaware, and Mid-Atlantic regions based on these models are fresher than the existing NODC climatologies. We also found significant freshening trends in the Mid-Atlantic over a 6 year period.

  4. 77 FR 27120 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-09

    ..., Virginia Beach, VA in the Federal Register (76 FR 13519). We received one comment on the proposed rule. No... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY:...

  5. 77 FR 13519 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ..., 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking....

  6. The diversity of cyanomyovirus populations along a North–South Atlantic Ocean transect

    PubMed Central

    Jameson, Eleanor; Mann, Nicholas H; Joint, Ian; Sambles, Christine; Mühling, Martin

    2011-01-01

    Viruses that infect the marine cyanobacterium Prochlorococcus have the potential to impact the growth, productivity, diversity and abundance of their hosts. In this study, changes in the microdiversity of cyanomyoviruses were investigated in 10 environmental samples taken along a North–South Atlantic Ocean transect using a myoviral-specific PCR-sequencing approach. Phylogenetic analyses of 630 viral g20 clones from this study, with 786 published g20 sequences, revealed that myoviral populations in the Atlantic Ocean had higher diversity than previously reported, with several novel putative g20 clades. Some of these clades were detected throughout the Atlantic Ocean. Multivariate statistical analyses did not reveal any significant correlations between myoviral diversity and environmental parameters, although myoviral diversity appeared to be lowest in samples collected from the north and south of the transect where Prochlorococcus diversity was also lowest. The results were correlated to the abundance and diversity of the co-occurring Prochlorococcus and Synechococcus populations, but revealed no significant correlations to either of the two potential host genera. This study provides evidence that cyanophages have extremely high and variable diversity and are distributed over large areas of the Atlantic Ocean. PMID:21633395

  7. Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States

    USGS Publications Warehouse

    McCabe, G.J.; Palecki, M.A.; Betancourt, J.L.

    2004-01-01

    More than half (52%) of the spatial and temporal variance in multidecadal drought frequency over the conterminous United States is attributable to the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). An additional 22% of the variance in drought frequency is related to a complex spatial pattern of positive and negative trends in drought occurrence possibly related to increasing Northern Hemisphere temperatures or some other unidirectional climate trend. Recent droughts with broad impacts over the conterminous U.S. (1996, 1999-2002) were associated with North Atlantic warming (positive AMO) and north-eastern and tropical Pacific cooling (negative PDO). Much of the long-term predictability of drought frequency may reside in the multidecadal behavior of the North Atlantic Ocean. Should the current positive AMO (warm North Atlantic) conditions persist into the upcoming decade, we suggest two possible drought scenarios that resemble the continental-scale patterns of the 1930s (positive PDO) and 1950s (negative PDO) drought.

  8. Arctic and N Atlantic Crustal Thickness and Oceanic Lithosphere Distribution from Gravity Inversion

    NASA Astrophysics Data System (ADS)

    Kusznir, Nick; Alvey, Andy

    2014-05-01

    The ocean basins of the Arctic and N. Atlantic formed during the Mesozoic and Cenozoic as a series of distinct ocean basins, both small and large, leading to a complex distribution of oceanic crust, thinned continental crust and rifted continental margins. The plate tectonic framework of this region was demonstrated by the pioneering work of Peter Ziegler in AAPG Memoir 43 " Evolution of the Arctic-North Atlantic and the Western Tethys" published in 1988. The spatial evolution of Arctic Ocean and N Atlantic ocean basin geometry and bathymetry are critical not only for hydrocarbon exploration but also for understanding regional palaeo-oceanography and ocean gateway connectivity, and its influence on global climate. Mapping crustal thickness and oceanic lithosphere distribution represents a substantial challenge for the Polar Regions. Using gravity anomaly inversion we have produced comprehensive maps of crustal thickness and oceanic lithosphere distribution for the Arctic and N Atlantic region, We determine Moho depth, crustal basement thickness, continental lithosphere thinning and ocean-continent transition location using a 3D spectral domain gravity inversion method, which incorporates a lithosphere thermal gravity anomaly correction (Chappell & Kusznir 2008). Gravity anomaly and bathymetry data used in the gravity inversion are from the NGA (U) Arctic Gravity Project and IBCAO respectively; sediment thickness is from a new regional compilation. The resulting maps of crustal thickness and continental lithosphere thinning factor are used to determine continent-ocean boundary location and the distribution of oceanic lithosphere. Crustal cross-sections using Moho depth from the gravity inversion allow continent-ocean transition structure to be determined and magmatic type (magma poor, "normal" or magma rich). Our gravity inversion predicts thin crust and high continental lithosphere thinning factors in the Eurasia, Canada, Makarov, Podvodnikov and Baffin Basins

  9. Future change in ocean productivity: Is the Arctic the new Atlantic?

    NASA Astrophysics Data System (ADS)

    Yool, A.; Popova, E. E.; Coward, A. C.

    2015-12-01

    One of the most characteristic features in ocean productivity is the North Atlantic spring bloom. Responding to seasonal increases in irradiance and stratification, surface phytopopulations rise significantly, a pattern that visibly tracks poleward into summer. While blooms also occur in the Arctic Ocean, they are constrained by the sea-ice and strong vertical stratification that characterize this region. However, Arctic sea-ice is currently declining, and forecasts suggest this may lead to completely ice-free summers by the mid-21st century. Such change may open the Arctic up to Atlantic-style spring blooms, and do so at the same time as Atlantic productivity is threatened by climate change-driven ocean stratification. Here we use low and high-resolution instances of a coupled ocean-biogeochemistry model, NEMO-MEDUSA, to investigate productivity. Drivers of present-day patterns are identified, and changes in these across a climate change scenario (IPCC RCP 8.5) are analyzed. We find a globally significant decline in North Atlantic productivity (> -20%) by 2100, and a correspondingly significant rise in the Arctic (> +50%). However, rather than the future Arctic coming to resemble the current Atlantic, both regions are instead transitioning to a common, low nutrient regime. The North Pacific provides a counterexample where nutrients remain high and productivity increases with elevated temperature. These responses to climate change in the Atlantic and Arctic are common between model resolutions, suggesting an independence from resolution for key impacts. However, some responses, such as those in the North Pacific, differ between the simulations, suggesting the reverse and supporting the drive to more fine-scale resolutions. This article was corrected on 5 JAN 2016. See the end of the full text for details.

  10. Ocean-atmosphere interaction in the seasonal to decadal variations of tropical Atlantic climate

    NASA Astrophysics Data System (ADS)

    Okumura, Yuko

    The tropical Atlantic ocean and atmosphere display distinct seasonal cycles with considerable year-to-year variations superimposed. The present study investigates processes and mechanisms important for tropical Atlantic climate and its variability, using numerical models and observational data, with an emphasis on ocean-atmosphere interaction. For the seasonal cycle, topics of particular interest are the rapid development of the monsoon-cold tongue complex in boreal summer and the oceanic response to the secondary acceleration of equatorial easterly winds in November; for interannual-to-decadal variability, they are the effect of the November thermocline shoaling on the equatorial zonal mode and the atmospheric response to the meridional sea surface temperature (SST) dipole mode. Atmospheric model experiments indicate that interaction between the equatorial cold tongue and the West African monsoon is essential for the rapid seasonal transition from boreal spring to summer. Mechanisms are identified for the summertime acceleration of equatorial easterly wind, which contributes to rapid equatorial cooling by forcing upwelling and thermocline shoaling. Analysis of high-resolution satellite/in-situ data reveals the equatorial SST change associated with the November easterly wind acceleration and thermocline shoaling. This overlooked climatic feature is further shown to give rise to a new mode of tropical Atlantic variability---Atlantic Nino II---which resembles the boreal summer zonal mode but peaks in November--December, and is statistically independent of the preceding summer events. Atlantic Nino II significantly affects interannual rainfall variations in the coastal Congo-Angola region, and evolves into the meridional mode in the following spring, affecting rainfall variations in northeast Brazil. It thus fills an important climate predictability gap in time, during the season for which the local variability was otherwise poorly understood. The atmospheric model