ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Boundary currents  (21)
  • American Meteorological Society  (20)
  • Dakar, Sénégal  (1)
  • ASLO (Association for the Sciences of Limnology and Oceanography)
  • 2015-2019  (21)
  • 1995-1999
Collection
Publisher
Years
Year
  • 1
    facet.materialart.
    Unknown
    Project “Protection of the Canary Current Large Marine Ecosystem” | Dakar, Sénégal
    Publication Date: 2021-01-30
    Description: La première réunion du Comité de Pilotage du projet CCLME qui s'est tenue à Dakar, au Sénégal, le 4 novembre 2010 s’était accordée sur l’établissement de six groupes de travail techniques afin d’aider le processus de développement d'une Analyse Diagnostique Transfrontalière (ADT) et l'élaboration d'un Plan d'Action Stratégique (PAS) pour le CCLME. La réunion a également adopté leurs termes de référence. En outre, il a été convenu que le projet CCLME et les pays participants contribueraient au soutien et au renforcement des deux groupes de travail du COPACE sur l'évaluation des stocks des ressources démersales et pélagiques. La première réunion du Groupe de Travail sur les changements climatiques s'est tenue à Saly, au Sénégal, du 11 au 13 mai 2011. Les membres du groupe de travail ont été nommés par les pays membres et les institutions partenaires du CCLME. L'objectif global de la réunion était pour le groupe de travail de se mettre d'accord sur les grandes lignes d'un document sur les impacts du changement climatique et les stratégies d'adaptation et d'atténuation pour le CCLME, d’ identifier des activités de projets potentiels pour traiter des questions de changement climatique identifiées, d'attribuer des responsabilités au sein du groupe et de s'entendre sur un plan de travail pour la période 2011-2012 en tenant compte de la date prévue pour l’adoption de l’ADT (novembre 2012). Mme Isabelle Niang, coordonnatrice régionale du projet « Adaptation aux Changements Climatiques et Côtiers en Afrique de l’Ouest (ACCC), a été élue Présidente du groupe de travail. Les représentants des pays participants et des partenaires du CCLME ont présenté les principales questions liées au changement climatique, les principales activités entreprises pour y répondre, les questions qui restent à traiter et les stratégies proposées pour minimiser les effets négatifs du changement climatique sur les ressources et les écosystèmes marins en fonction de l'avis de leur pays ou de leur organisation. Deux groupes de travail ont été formés afin d'identifier les questions prioritaires et leurs causes et de recommander des domaines d'intervention relatifs aux impacts du changement climatique sur les ressources marines vivantes et sur la biodiversité, les habitats et la qualité de l'eau dans la zone du CCLME. Les groupes de travail ont défini un certain nombre de domaines prioritaires d'intervention nécessitant des fonds supplémentaires. Il s’agit des besoins de systèmes d'observation améliorés; d’une analyse et de la modélisation des données existantes; de la cartographie de la vulnérabilité des zones prioritaires pour le CCLME; de l’examen et du renforcement des Plans d'Action Nationaux pour l’Adaptation (PANA) en ce qui concerne la pêche ; de la restauration de la mangrove/des sources d'énergie alternatives. La réunion a également convenu d'un projet de plan pour le document sur les impacts du changement climatique et les stratégies d'adaptation et d'atténuation pour le CCLME ainsi que d'un plan de travail 2011-2012 pour le groupe de travail, avec des responsabilités définies.
    Description: The First CCLME Project Steering Committee Meeting that was held in Dakar, Senegal, the 4th of November 2010, agreed on the establishment of six CCLME technical working groups to assist the development process of a Transboundary Diagnostic Analysis (TDA) and the elaboration of a Strategic Action Plan (SAP) for the CCLME. The meeting also adopted their terms of references. In addition, it was agreed that the CCLME project and the participating countries would contribute to the maintenance and strengthening of two CECAF working groups on stock assessment of demersal and pelagic resources. The First Meeting of the Climate Change Working Group was held in Saly, Senegal from 11th to 13th of May 2011. The members of the working group had been nominated by the CCLME participating countries and partner institutions. The overall aim of the meeting was for the working group to agree on the outline of a document on climate change impacts and adaptation and mitigation strategies for the CCLME, to identify suitable potential project activities to address identified climate change issues, to assign responsibilities within the group and to agree on a work plan for the period 2011-2012 taking into consideration the expected date for the adoption of the TDA (November 2012). Ms Isabelle Niang, Regional coordinator of the project “Adaptation to Climate and Coastal Change in West Africa” (ACCC), was elected Chairperson of the working group. The CCLME participating countries and the partner representatives presented the main climate change issues, the main activities undertaken to address them, issues that remain to be addressed and suggested strategies to minimize negative effects of climate change on marine resources and ecosystems according to the view of their country or organization. Two groups were formed in order to identify priority issues and their causes and recommended domains of intervention regarding climate change impacts on marine living resources; and on biodiversity, habitat and water quality in the CCLME area. The working groups defined a number of priority areas of intervention in need of additional funds. These focused on the need for improved observation systems; further analysis and modelling of existing data; vulnerability mapping in priority areas for the CCLME; review and strengthening of National Adaptation Plans of Action (NAPAs) with regards to fisheries; and mangrove restoration / alternative energy sources. The meeting also agreed on a draft outline for the document on climate change impacts and adaptation and mitigation strategies for the CCLME as well as a 2011-2012 work plan for the working group with responsibilities assigned.
    Description: Fonds pour l’Environnement Mondial (FEM); co-financement despays participants et d’autres partenaires. Les partenaires actuels sont: l’Agence Française de Développement (AFD), la Commission Sous-Régionale des Pêches (CSRP), le projet EAF-Nansen, l’Administration Nationale des Océans et de l’Atmosphère (NOAA) des États-Unis d’Amérique, le Programme Régional de Conservation de la Zone Côtière et Marine en Afrique de l’Ouest (PRCM), l’Agence Suédoise de Coopération Internationale au Développement (SIDA) et WageningenInternational.
    Description: L’Organisation des Nations Unies pour l’alimentation et l’agriculture (FAO) et le Programme des Nations Unies pour l’Environnement (PNUE) sont les agences FEM pour la réalisation du projet CCLME. CCLME ou Canary Current Large Marine Ecosystem
    Description: Published
    Description: changement climatique
    Description: frontière
    Description: ressource pélagique
    Description: ressource demersale
    Description: mangrove
    Description: dégradation
    Description: sédimentation
    Description: eau
    Keywords: Changement climatique ; Climatic changes ; Boundary currents ; Pelagic fisheries ; Demersal fisheries ; Water resources ; Salinity ; Sedimentation ; Reefs (coral) ; Habitat degradation
    Repository Name: AquaDocs
    Type: Report , Not Known
    Format: 60pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 2127-2140, doi:10.1175/JPO-D-18-0035.1.
    Description: Shipboard hydrographic and velocity measurements collected in summer 2014 are used to study the evolution of the freshwater coastal current in southern Greenland as it encounters Cape Farewell. The velocity structure reveals that the coastal current maintains its identity as it flows around the cape and bifurcates such that most of the flow is diverted to the outer west Greenland shelf, while a small portion remains on the inner shelf. Taking into account this inner branch, the volume transport of the coastal current is conserved, but the freshwater transport decreases on the west side of Cape Farewell. A significant amount of freshwater appears to be transported off the shelf where the outer branch flows adjacent to the shelfbreak circulation. It is argued that the offshore transposition of the coastal current is caused by the flow following the isobaths as they bend offshore because of the widening of the shelf on the west side of Cape Farewell. An analysis of the potential vorticity shows that the subsequent seaward flux of freshwater can be enhanced by instabilities of the current. This set of circumstances provides a pathway for the freshest water originating from the Arctic, as well as runoff from the Greenland ice sheet, to be fluxed into the interior Labrador Sea where it could influence convection in the basin.
    Description: Funding for this project was provided by the National Science Foundation under Grant OCE-1259618.
    Description: 2019-03-11
    Keywords: Boundary currents ; Coastal flows ; Instability ; Ocean circulation ; Potential vorticity ; Transport
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 45 (2015): 2913–2932, doi:10.1175/JPO-D-14-0179.1.
    Description: The oceanic deep circulation is shared between concentrated deep western boundary currents (DWBCs) and broader interior pathways, a process that is sensitive to seafloor topography. This study investigates the spreading and deepening of Denmark Strait overflow water (DSOW) in the western subpolar North Atlantic using two ° eddy-resolving Atlantic simulations, including a passive tracer injected into the DSOW. The deepest layers of DSOW transit from a narrow DWBC in the southern Irminger Sea into widespread westward flow across the central Labrador Sea, which remerges along the Labrador coast. This abyssal circulation, in contrast to the upper levels of overflow water that remain as a boundary current, blankets the deep Labrador Sea with DSOW. Farther downstream after being steered around the abrupt topography of Orphan Knoll, DSOW again leaves the boundary, forming cyclonic recirculation cells in the deep Newfoundland basin. The deep recirculation, mostly driven by the meandering pathway of the upper North Atlantic Current, leads to accumulation of tracer offshore of Orphan Knoll, precisely where a local maximum of chlorofluorocarbon (CFC) inventory is observed. At Flemish Cap, eddy fluxes carry ~20% of the tracer transport from the boundary current into the interior. Potential vorticity is conserved as the flow of DSOW broadens at the transition from steep to less steep continental rise into the Labrador Sea, while around the abrupt topography of Orphan Knoll, potential vorticity is not conserved and the DSOW deepens significantly.
    Description: This work is supported by ONR Award N00014-09-1-0587, the NSF Physical Oceanography Program, and NASA Ocean Surface Topography Science Team Program.
    Description: 2016-06-01
    Keywords: Circulation/ Dynamics ; Abyssal circulation ; Boundary currents ; Ocean circulation ; Ocean dynamics ; Potential vorticity ; Topographic effects
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 573-590, doi:10.1175/JPO-D-17-0206.1.
    Description: Motivated by the proximity of the Northern Recirculation Gyre and the deep western boundary current in the North Atlantic, an idealized model is used to investigate how recirculation gyres and a deep flow along a topographic slope interact. In this two-layer quasigeostrophic model, an unstable jet imposed in the upper layer generates barotropic recirculation gyres. These are maintained by an eddy-mean balance of potential vorticity (PV) in steady state. The authors show that the topographic slope can constrain the northern recirculation gyre meridionally and that the gyre’s adjustment to the slope leads to increased eddy PV fluxes at the base of the slope. When a deep current is present along the topographic slope in the lower layer, these eddy PV fluxes stir the deep current and recirculation gyre waters. Increased proximity to the slope dampens the eddy growth rate within the unstable jet, altering the geometry of recirculation gyre forcing and leading to a decrease in overall eddy PV fluxes. These mechanisms may shape the circulation in the western North Atlantic, with potential feedbacks on the climate system.
    Description: We gratefully acknowledge an AMS graduate fellowship (IALB) and U.S. National Science Foundation Grants OCE-1332667 and 1332834 (IALB and JMT).
    Description: 2018-09-06
    Keywords: Boundary currents ; Meridional overturning circulation ; Mesoscale processes ; Ocean circulation ; Potential vorticity ; Quasigeostrophic models
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 739-748, doi:10.1175/JPO-D-17-0089.1.
    Description: McDougall and Ferrari have estimated the global deep upward diapycnal flow in the boundary layer overlying continental slopes that must balance both downward diapycnal flow in the deep interior and the formation of bottom water around Antarctica. The decrease of perimeter of isopycnal surfaces with depth and the observed decay with height above bottom of turbulent dissipation in the deep ocean play a key role in their estimate. They argue that because the perimeter of seamounts increases with depth, the net effect of mixing around seamounts is to produce net downward diapycnal flow. While this is true along much of a seamount, it is shown here that diapycnal flow of the densest water around the seamount is upward, with buoyancy being transferred from water just above. The same is true for midocean ridges, whose perimeter is constant with depth. It is argued that mixing around seamounts and especially midocean ridges contributes positively to the global deep overturning circulation, reducing the amount of turbulence demanded over the continental slopes to balance the buoyancy budget for the bottom and deep water.
    Description: This work was supported by National Science Foundation Grant OCE- 1232962.
    Description: 2018-09-29
    Keywords: Abyssal circulation ; Boundary currents ; Buoyancy ; Diapycnal mixing ; Mass fluxes/transport ; Ocean circulation
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 2457-2475, doi:10.1175/JPO-D-17-0186.1.
    Description: A subpolar marginal sea, like the Nordic seas, is a transition zone between the temperature-stratified subtropics (the alpha ocean) and the salinity-stratified polar regions (the beta ocean). An inflow of Atlantic Water circulates these seas as a boundary current that is cooled and freshened downstream, eventually to outflow as Deep and Polar Water. Stratification in the boundary region is dominated by a thermocline over the continental slope and a halocline over the continental shelves, separating Atlantic Water from Deep and Polar Water, respectively. A conceptual model is introduced for the circulation and water mass transformation in a subpolar marginal sea to explore the potential interaction between the alpha and beta oceans. Freshwater input into the shelf regions has a slight strengthening effect on the Atlantic inflow, but more prominently impacts the water mass composition of the outflow. This impact of freshwater, characterized by enhancing Polar Water outflow and suppressing Deep Water outflow, is strongly determined by the source location of freshwater. Concretely, perturbations in upstream freshwater sources, like the Baltic freshwater outflow into the Nordic seas, have an order of magnitude larger potential to impact water mass transports than perturbations in downstream sources like the Arctic freshwater outflow. These boundary current dynamics are directly related to the qualitative stratification in transition zones and illustrate the interaction between the alpha and beta oceans.
    Description: This research was supported by the Research Council of Norway project NORTH. Support for the publication was provided by the University of Bergen. Ocean Outlook has supported a research visit for EL to Woods Hole Oceanographic Institute where much of the current work has been carried out. Support forMAS was provided by the National Science Foundation Grant OCE-1558742.
    Keywords: Continental shelf/slope ; Baroclinic flows ; Boundary currents ; Buoyancy ; Freshwater ; Thermohaline circulation
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 45 (2015): 1410–1425, doi:10.1175/JPO-D-14-0192.1.
    Description: The west-to-east crossover of boundary currents has been seen in mean circulation schemes from several past models of the Red Sea. This study investigates the mechanisms that produce and control the crossover in an idealized, eddy-resolving numerical model of the Red Sea. The authors also review the observational evidence and derive an analytical estimate for the crossover latitude. The surface buoyancy loss increases northward in the idealized model, and the resultant mean circulation consists of an anticyclonic gyre in the south and a cyclonic gyre in the north. In the midbasin, the northward surface flow crosses from the western boundary to the eastern boundary. Numerical experiments with different parameters indicate that the crossover latitude of the boundary currents changes with f0, β, and the meridional gradient of surface buoyancy forcing. In the analytical estimate, which is based on quasigeostrophic, β-plane dynamics, the crossover is predicted to lie at the latitude where the net potential vorticity advection (including an eddy component) is zero. Various terms in the potential vorticity budget can be estimated using a buoyancy budget, a thermal wind balance, and a parameterization of baroclinic instability.
    Description: This work is supported by Award USA 00002, KSA 00011, and KSA 00011/02 made by King Abdullah University of Science and Technology (KAUST), by National Science Foundation Grants OCE0927017, OCE1154641, and OCE85464100, and by the Woods Hole Oceanographic Institution Academic Program Office.
    Description: 2015-11-01
    Keywords: Circulation/ Dynamics ; Boundary currents ; Buoyancy ; Ocean circulation ; Ocean dynamics
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 45 (2015): 1822–1842, doi:10.1175/JPO-D-14-0147.1.
    Description: Influences of time-dependent precipitation on water mass transformation and heat budgets in an idealized marginal sea are examined using theoretical and numerical models. The equations proposed by Spall in 2012 are extended to cases with time-dependent precipitation whose form is either a step function or a sinusoidal function. The theory predicts the differences in temperature and salinity between the convective water and the boundary current as well as the magnitudes of heat fluxes into the marginal sea and across the sea surface. Moreover, the theory reveals that there are three inherent time scales: relaxation time scales for temperature and salinity and a precipitation time scale. The relaxation time scales are determined by a steady solution of the theoretical model with steady precipitation. The relaxation time scale for temperature is always smaller than that for salinity as a result of not only the difference in the form of fluxes at the surface but also the variation in the eddy transport from the boundary current. These three time scales and the precipitation amplitude determine the strength of the ocean response to changes in precipitation and the phase relation between precipitation, changes in salinity and temperature, and changes in heat fluxes. It is demonstrated that the theoretical predictions agree qualitatively well with results from the eddy-resolving numerical model. This demonstrates the fundamental role of mesoscale eddies in the ocean response to time-dependent forcing and provides a framework with which to assess the extent to which observed variability in marginal sea convection and water mass transformation are consistent with an external forcing by variations in precipitation.
    Description: This work was initiated at the 2013 WHOI Geophysical Fluid Dynamics Summer Program, which was supported by the National Science Foundation and the Office of Naval Research. This work was also supported by Grant-in-Aid for Research Fellow (25·8466) of the Ministry of Education, Culture, Sports and Technology (MEXT), Japan, the Program for Leading Graduate Schools, MEXT, Japan (YY), and by the National Science Foundation Grant OCE-1232389 (MAS).
    Description: 2016-01-01
    Keywords: Circulation/ Dynamics ; Boundary currents ; Deep convection ; Eddies ; Ocean dynamics ; Atm/Ocean Structure/ Phenomena ; Precipitation
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 327–348, doi:10.1175/JPO-D-15-0112.1.
    Description: Potential vorticity structure in two segments of the North Atlantic’s western boundary current is examined using concurrent, high-resolution measurements of hydrography and velocity from gliders. Spray gliders occupied 40 transects across the Loop Current in the Gulf of Mexico and 11 transects across the Gulf Stream downstream of Cape Hatteras. Cross-stream distributions of the Ertel potential vorticity and its components are calculated for each transect under the assumptions that all flow is in the direction of measured vertically averaged currents and that the flow is geostrophic. Mean cross-stream distributions of hydrographic properties, potential vorticity, and alongstream velocity are calculated for both the Loop Current and the detached Gulf Stream in both depth and density coordinates. Differences between these mean transects highlight the downstream changes in western boundary current structure. As the current increases its transport downstream, upper-layer potential vorticity is generally reduced because of the combined effects of increased anticyclonic relative vorticity, reduced stratification, and increased cross-stream density gradients. The only exception is within the 20-km-wide cyclonic flank of the Gulf Stream, where intense cyclonic relative vorticity results in more positive potential vorticity than in the Loop Current. Cross-stream gradients of mean potential vorticity satisfy necessary conditions for both barotropic and baroclinic instability within the western boundary current. Instances of very low or negative potential vorticity, which predispose the flow to various overturning instabilities, are observed in individual transects across both the Loop Current and the Gulf Stream.
    Description: Glider operations in the Gulf Stream were supported by the National Science Foundation under Grant OCE-0220769. Glider operations in the Gulf of Mexico were supported by BP. R.E.T. was supported by the Penzance Endowed Fund in Support of Assistant Scientists and the Independent Research and Development Program at WHOI.
    Description: 2016-07-01
    Keywords: Geographic location/entity ; North Atlantic Ocean ; Circulation/ Dynamics ; Boundary currents ; Potential vorticity ; Atm/Ocean Structure/ Phenomena ; Boundary currents
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2014. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 44 (2014): 3033–3053, doi:10.1175/JPO-D-13-0227.1.
    Description: The East Greenland Current (EGC) had long been considered the main pathway for the Denmark Strait overflow (DSO). Recent observations, however, indicate that the north Icelandic jet (NIJ), which flows westward along the north coast of Iceland, is a major separate pathway for the DSO. In this study a two-layer numerical model and complementary integral constraints are used to examine various pathways that lead to the DSO and to explore plausible mechanisms for the NIJ’s existence. In these simulations, a westward and NIJ-like current emerges as a robust feature and a main pathway for the Denmark Strait overflow. Its existence can be explained through circulation integrals around advantageous contours. One such constraint spells out the consequences of overflow water as a source of low potential vorticity. A stronger constraint can be added when the outflow occurs through two outlets: it takes the form of a circulation integral around the Iceland–Faroe Ridge. In either case, the direction of overall circulation about the contour can be deduced from the required frictional torques. Some effects of wind stress forcing are also examined. The overall positive curl of the wind forces cyclonic gyres in both layers, enhancing the East Greenland Current. The wind stress forcing weakens but does not eliminate the NIJ. It also modifies the sign of the deep circulation in various subbasins and alters the path by which overflow water is brought to the Faroe Bank Channel, all in ways that bring the idealized model more in line with observations. The sequence of numerical experiments separates the effects of wind and buoyancy forcing and shows how each is important.
    Description: This study has been supported by National Science Foundation (OCE0927017 and ARC1107412).
    Description: 2015-06-01
    Keywords: Circulation/ Dynamics ; Boundary currents ; Channel flows ; Meridional overturning circulation ; Ocean circulation ; Topographic effects
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...