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  • 1
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    MeRMEED cruise and mooring data - Vertical microstructure, CTD, vessel mounted ADCP, moored ADCP (2020)
    PANGAEA
    Details
    Publication Date: 2024-04-20
    Description: Cruise data collected across three separate cruises MeRMEED-1 (WS16336; 1-7 December 2016), MeRMEED-2 (WS17305; 31 October - 10 November 2017) and MeRMEED-3 (WS18066; 4-16 March 2018). All cruises were aboard the R/V F. G. Walton Smith. Cruise region: 76.5W-77.2W, 26.15N-26.8N. Cruises consisted of zonal tethered vertical microstructure profiler (VMP) and vessel mounted acoustic Doppler current profiler (ADCP) surveys, yielding sections of the turbulent dissipation rate (units: W/kg) and zonal and meridional velocity (units: m/s). The VMP used was the tethered Rockland Scientific International VMP-2000, and the ADCP was a vessel-mounted RDI 75 kHz Ocean Surveyor ADCP configured and run through the University of Hawai'i Data Acquisition System (UHDAS) software suite. The VMP was also mounted with a CTD (conductivity-temperature-depth) sensor package, including SBE-3 and SBE-4 sensors. The CTD data was processed according to the manufacturer specifications, using recommended values for the cell thermal mass coefficients (alpha=0.03 and beta=7.0). Files are named as follows: WSxxxxx_CTD.mat, WSxxxxx_vmp_all.mat and WSxxxxx_os75nb.nc for CTD, VMP and ADCP data respectively. Mooring-based data is from two 75 kHz ADCPs, one upward facing and the other downward facing, mounted at approximately 700 m on the RAPID/MOCHA (Rapid Climate Change / Meridional Overturning Circulation and Heat flux Array) mooring WB1 at 76.8W and 26.5N. This configuration gave full depth meridional and zonal velocity profiles (units: m/s) in a water depth of approximately 1300 m. The data spanned December 2015 to March 2017. The data are binned in 16 m depth bins and are bin averaged into 1 hour time bins. File name: WB1_adcp_UV_1hr.mat.
    Keywords: Binary Object; cruise; CT; Event label; MeRMEED-1; MeRMEED-2; MeRMEED-3; mesoscale eddy; MOOR; Mooring; RAPID-MOCHA_WB1; Turbulent dissipation; Underway cruise track measurements; velocity; Walton Smith; WS16336; WS16336-track; WS17305; WS17305-track; WS18066; WS18066-track
    Type: Dataset
    Format: text/tab-separated-values, 10 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Monitoring the Atlantic meridional overturning circulation (2011)
    Elsevier
    In:  Deep Sea Research Part II: Topical Studies in Oceanography, 58 (17-18). pp. 1744-1753.
    Details
    Publication Date: 2020-08-05
    Description: The rapid climate change programme (RAPID) has established a prototype system to continuously observe the strength and structure of the Atlantic meridional overturning circulation (MOC) at 26.5 degrees N. Here we provide a detailed description of the RAPID-MOC monitoring array and how it has evolved during the first four deployment years, as well as an overview of the main findings so far. The RAPID-MOC monitoring array measures: (1) Gulf Stream transport through Florida Strait by cable and repeat direct velocity measurements; (2) Ekman transports by satellite scatterometer measurements; (3) Deep Western Boundary Currents by direct velocity measurements; (4) the basin wide interior baroclinic circulation from moorings measuring vertical profiles of density at the boundaries and on either side of the Mid-Atlantic Ridge; and (5) barotropic fluctuations using bottom pressure recorders. The array became operational in late March 2004 and is expected to continue until at least 2014. The first 4 years of observations (April 2004-April 2008) have provided an unprecedented insight into the MOC structure and variability. We show that the zonally integrated meridional flow tends to conserve mass, with the fluctuations of the different transport components largely compensating at periods longer than 10 days. We take this as experimental confirmation of the monitoring strategy, which was initially tested in numerical models. The MOC at 26.5 degrees N is characterised by a large variability even on timescales as short as weeks to months. The mean maximum MOC transport for the first 4 years of observations is 18.7 Sv with a standard deviation of 4.8 Sv. The mechanisms causing the MOC variability are not yet fully understood. Part of the observed MOC variability consists of a seasonal cycle, which can be linked to the seasonal variability of the wind stress curl close to the African coast. Close to the western boundary, fluctuations in the Gulf Stream and in the North Atlantic Deep Water (NADW) coincide with bottom pressure variations at the western margin, thus suggesting a barotropic compensation. Ongoing and future research will put these local transport variations into a wider spatial and climatic context. (C) 2011 Elsevier Ltd. All rights reserved.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.dsr2.2010.10.056
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Atlantic Meridional Overturning Circulation: Observed Transport and Variability (2019)
    Frontiers
    In:  Frontiers in Marine Science, 6 . Art.Nr. 260.
    Details
    Publication Date: 2022-01-31
    Description: The Atlantic Meridional Overturning Circulation (AMOC) extends from the Southern Ocean to the northern North Atlantic, transporting heat northwards throughout the South and North Atlantic, and sinking carbon and nutrients into the deep ocean. Climate models indicate that changes to the AMOC both herald and drive climate shifts. Intensive trans-basin AMOC observational systems have been put in place to continuously monitor meridional volume transport variability, and in some cases, heat, freshwater and carbon transport. These observational programs have been used to diagnose the magnitude and origins of transport variability, and to investigate impacts of variability on essential climate variables such as sea surface temperature, ocean heat content and coastal sea level. AMOC observing approaches vary between the different systems, ranging from trans-basin arrays (OSNAP, RAPID 26 degrees N, 11 degrees S, SAMBA 34.5 degrees S) to arrays concentrating on western boundaries (e.g., RAPID WAVE, MOVE 16 degrees N). In this paper, we outline the different approaches (aims, strengths and limitations) and summarize the key results to date. We also discuss alternate approaches for capturing AMOC variability including direct estimates (e.g., using sea level, bottom pressure, and hydrography from autonomous profiling floats), indirect estimates applying budgetary approaches, state estimates or ocean reanalyses, and proxies. Based on the existing observations and their results, and the potential of new observational and formal synthesis approaches, we make suggestions as to how to evaluate a comprehensive, future-proof observational network of the AMOC to deepen our understanding of the AMOC and its role in global climate.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
    DOI: 10.3389/fmars.2019.00260
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Loop Current Variability as Trigger of Coherent Gulf Stream Transport Anomalies (2019)
    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 49 (8). pp. 2115-2132.
    Details
    Publication Date: 2022-01-31
    Description: Satellite observations and output from a high-resolution ocean model are used to investigate how the Loop Current in the Gulf of Mexico affects the Gulf Stream transport through the Florida Straits. We find that the expansion (contraction) of the Loop Current leads to lower (higher) transports through the Straits of Florida. The associated surface velocity anomalies are coherent from the southwestern tip of Florida to Cape Hatteras. A simple continuity-based argument can be used to explain the link between the Loop Current and the downstream Gulf Stream transport: as the Loop Current lengthens (shortens) its path in the Gulf of Mexico, the flow out of the Gulf decreases (increases). Anomalies in the surface velocity field are first seen to the southwest of Florida and within 4 weeks propagate through the Florida Straits up to Cape Hatteras and into the Gulf Stream Extension. In both the observations and the model this propagation can be seen as pulses in the surface velocities. We estimate that the Loop Current variability can be linked to a variability of several Sverdrups (1Sv = 10(6) m(3) s(-1)) through the Florida Straits. The exact timing of the Loop Current variability is largely unpredictable beyond a few weeks and its variability is therefore likely a major contributor to the chaotic/intrinsic variability of the Gulf Stream. However, the time lag between the Loop Current and the flow downstream of the Gulf of Mexico means that if a lengthening/shortening of the Loop Current is observed this introduces some predictability in the downstream flow for a few weeks.
    Type: Article , PeerReviewed
    Format: archive
    Format: text
    DOI: 10.1175/JPO-D-18-0236.1
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    OceanGliders: A Component of the Integrated GOOS (2019)
    Frontiers
    In:  Frontiers in Marine Science, 6 . Art.Nr. 422.
    Details
    Publication Date: 2022-01-31
    Description: The OceanGliders program started in 2016 to support active coordination and enhancement of global glider activity. OceanGliders contributes to the international efforts of the Global Ocean Observation System (GOOS) for Climate, Ocean Health, and Operational Services. It brings together marine scientists and engineers operating gliders around the world: (1) to observe the long-term physical, biogeochemical, and biological ocean processes and phenomena that are relevant for societal applications; and, (2) to contribute to the GOOS through real-time and delayed mode data dissemination. The OceanGliders program is distributed across national and regional observing systems and significantly contributes to integrated, multi-scale and multi-platform sampling strategies. OceanGliders shares best practices, requirements, and scientific knowledge needed for glider operations, data collection and analysis. It also monitors global glider activity and supports the dissemination of glider data through regional and global databases, in real-time and delayed modes, facilitating data access to the wider community. OceanGliders currently supports national, regional and global initiatives to maintain and expand the capabilities and application of gliders to meet key global challenges such as improved measurement of ocean boundary currents, water transformation and storm forecast.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.3389/fmars.2019.00422
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    The evolution of the North Atlantic Meridional Overturning Circulation since 1980 (2022)
    Nature Research
    Details
    Publication Date: 2024-02-07
    Description: The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the climate through its transport of heat in the North Atlantic Ocean. Decadal changes in the AMOC, whether through internal variability or anthropogenically forced weakening, therefore have wide-ranging impacts. In this Review, we synthesize the understanding of contemporary decadal variability in the AMOC, bringing together evidence from observations, ocean reanalyses, forced models and AMOC proxies. Since 1980, there is evidence for periods of strengthening and weakening, although the magnitudes of change (5–25%) are uncertain. In the subpolar North Atlantic, the AMOC strengthened until the mid-1990s and then weakened until the early 2010s, with some evidence of a strengthening thereafter; these changes are probably linked to buoyancy forcing related to the North Atlantic Oscillation. In the subtropics, there is some evidence of the AMOC strengthening from 2001 to 2005 and strong evidence of a weakening from 2005 to 2014. Such large interannual and decadal variability complicates the detection of ongoing long-term trends, but does not preclude a weakening associated with anthropogenic warming. Research priorities include developing robust and sustainable solutions for the long-term monitoring of the AMOC, observation–modelling collaborations to improve the representation of processes in the North Atlantic and better ways to distinguish anthropogenic weakening from internal variability.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Global Oceans (2021)
    AMS (American Meteorological Society)
    Details
    Publication Date: 2024-02-08
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Climate-Relevant Ocean Transport Measurements in the Atlantic and Arctic Oceans (2021)
    Oceanography Society
    Details
    Publication Date: 2024-04-08
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    Global Oceans (2020)
    AMS (American Meteorological Society)
    Details
    Publication Date: 2024-04-08
    Description: State of the climate in 2019
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
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    Rapid mixing and exchange of deep-ocean waters in an abyssal boundary current. (2019)
    National Academy of Sciences
    Details
    Publication Date: 2022-10-26
    Description: Author Posting. © National Academy of Sciences, 2019. This article is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 116(27), (2019): 13233-13238, doi: 10.1073/pnas.1904087116.
    Description: The overturning circulation of the global ocean is critically shaped by deep-ocean mixing, which transforms cold waters sinking at high latitudes into warmer, shallower waters. The effectiveness of mixing in driving this transformation is jointly set by two factors: the intensity of turbulence near topography and the rate at which well-mixed boundary waters are exchanged with the stratified ocean interior. Here, we use innovative observations of a major branch of the overturning circulation—an abyssal boundary current in the Southern Ocean—to identify a previously undocumented mixing mechanism, by which deep-ocean waters are efficiently laundered through intensified near-boundary turbulence and boundary–interior exchange. The linchpin of the mechanism is the generation of submesoscale dynamical instabilities by the flow of deep-ocean waters along a steep topographic boundary. As the conditions conducive to this mode of mixing are common to many abyssal boundary currents, our findings highlight an imperative for its representation in models of oceanic overturning.
    Description: The DynOPO project is supported by the UK Natural Environment Research Council (grants NE/K013181/1 and NE/K012843/1) and the US National Science Foundation (grants OCE-1536453 and OCE-1536779). A.C.N.G. acknowledges the support of the Royal Society and the Wolfson Foundation. S.L. acknowledges the support of award NA14OAR4320106 from the National Oceanic and Atmospheric Administration, US Department of Commerce. The statements, findings, conclusions, and recommendations are those of the authors, and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration, or the US Department of Commerce. We are grateful to the scientific party, crew, and technicians on the RRS James Clark Ross for their hard work during data collection.
    Description: 2019-12-18
    Keywords: Ocean mixing ; Overturning circulation ; Submesoscale instabilities ; Turbulence
    Repository Name: Woods Hole Open Access Server
    Type: Article
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    PAPER (OA)
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