GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Adequacy of the ocean observation system for quantifying regional heat and freshwater storage and change (2019)
    Frontiers
    In:  Frontiers in Marine Science, 6 . Art.Nr. 416.
    Details
    Publication Date: 2022-01-31
    Description: Considerable advances in the global ocean observing system over the last two decades offers an opportunity to provide more quantitative information on changes in heat and freshwater storage. Variations in these storage terms can arise through internal variability and also the response of the ocean to anthropogenic climate change. Disentangling these competing influences on the regional patterns of change and elucidating their governing processes remains an outstanding scientific challenge. This challenge is compounded by instrumental and sampling uncertainties. The combined use of ocean observations and model simulations is the most viable method to assess the forced signal from noise and ascertain the primary drivers of variability and change. Moreover, this approach offers the potential for improved seasonal-to-decadal predictions and the possibility to develop powerful multi-variate constraints on climate model future projections. Regional heat storage changes dominate the steric contribution to sea level rise over most of the ocean and are vital to understanding both global and regional heat budgets. Variations in regional freshwater storage are particularly relevant to our understanding of changes in the hydrological cycle and can potentially be used to verify local ocean mass addition from terrestrial and cryospheric systems associated with contemporary sea level rise. This White Paper will examine the ability of the current ocean observing system to quantify changes in regional heat and freshwater storage. In particular we will seek to answer the question: What time and space scales are currently resolved in different regions of the global oceans? In light of some of the key scientific questions, we will discuss the requirements for measurement accuracy, sampling, and coverage as well as the synergies that can be leveraged by more comprehensively analysing the multi-variable arrays provided by the integrated observing system.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3389/fmars.2019.00416
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
    facet.materialart.
    Unknown
    Integrated Observations of Global Surface Winds, Currents, and Waves: Requirements and Challenges for the Next Decade (2019)
    Frontiers
    In:  Frontiers in Marine Science, 6 . Art.Nr. 425.
    Details
    Publication Date: 2022-01-31
    Description: Ocean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it outlines observational gaps that limit our current understanding of coupled processes that happen at the air-sea-ice interface. A significant challenge for the coming decade of wind, current, and wave observations will come in combining and interpreting measurements from (a) wave-buoys and high-frequency radars in coastal regions, (b) surface drifters and wave-enabled drifters in the open-ocean, marginal ice zones, and wave-current interaction “hot-spots,” and (c) simultaneous measurements of absolute surface currents, ocean surface wind vector, and directional wave spectrum from Doppler satellite sensors.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3389/fmars.2019.00425
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
    facet.materialart.
    Unknown
    The Southern Ocean Carbon Cycle 1985–2018: Mean, Seasonal Cycle, Trends, and Storage (2023)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2024-02-07
    Description: We assess the Southern Ocean CO2 uptake (1985–2018) using data sets gathered in the REgional Carbon Cycle Assessment and Processes Project Phase 2. The Southern Ocean acted as a sink for CO2 with close agreement between simulation results from global ocean biogeochemistry models (GOBMs, 0.75 ± 0.28 PgC yr−1) and pCO2-observation-based products (0.73 ± 0.07 PgC yr−1). This sink is only half that reported by RECCAP1 for the same region and timeframe. The present-day net uptake is to first order a response to rising atmospheric CO2, driving large amounts of anthropogenic CO2 (Cant) into the ocean, thereby overcompensating the loss of natural CO2 to the atmosphere. An apparent knowledge gap is the increase of the sink since 2000, with pCO2-products suggesting a growth that is more than twice as strong and uncertain as that of GOBMs (0.26 ± 0.06 and 0.11 ± 0.03 Pg C yr−1 decade−1, respectively). This is despite nearly identical pCO2 trends in GOBMs and pCO2-products when both products are compared only at the locations where pCO2 was measured. Seasonal analyses revealed agreement in driving processes in winter with uncertainty in the magnitude of outgassing, whereas discrepancies are more fundamental in summer, when GOBMs exhibit difficulties in simulating the effects of the non-thermal processes of biology and mixing/circulation. Ocean interior accumulation of Cant points to an underestimate of Cant uptake and storage in GOBMs. Future work needs to link surface fluxes and interior ocean transport, build long overdue systematic observation networks and push toward better process understanding of drivers of the carbon cycle. Key Points: - Ocean models and machine learning estimates agree on the mean Southern Ocean CO2 sink, but the trend since 2000 differs by a factor of two - REgional Carbon Cycle Assessment and Processes Project Phase 2 estimates a 50% smaller Southern Ocean CO2 sink for the same region and timeframe as RECCAP1 - Large model spread in summer and winter indicates that sustained efforts are required to understand driving processes in all seasons
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
    facet.materialart.
    Unknown
    Abyssal connections of Antarctic Bottom Water in a Southern Ocean State Estimate (2013)
    Wiley-Blackwell
    Details
    Publication Date: 2013-04-21
    Description: [1]  Antarctic Bottom Water (AABW) is formed in a few locations around the Antarctic continent, each source with distinct temperature and salinity. After formation, the different AABW varieties cross the Southern Ocean and flow into the subtropical abyssal basins. It is shown here, using the analysis of Lagrangian trajectories within the Southern Ocean State Estimate (SOSE) model, that the pathways of the different sources of AABW have to a large extent amalgamated into one pathway by the time it reaches 31°S in the deep subtropical basins. The Antarctic Circumpolar Current appears to play an important role in the amalgamation, as 70% of the AABW completes at least one circumpolar loop before reaching the subtropical basins. This amalgamation of AABW pathways suggests that on decadal to centennial time scales, changes to properties and formation rates in any of the AABW source regions will be conveyed to all three subtropical abyssal basins.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Thermohaline structure in the California Current System : observations and modeling of spice variance (2012)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): C02008, doi:10.1029/2011JC007589.
    Description: Upper ocean thermohaline structure in the California Current System is investigated using sustained observations from autonomous underwater gliders and a numerical state estimate. Both observations and the state estimate show layers distinguished by the temperature and salinity variability along isopycnals (i.e., spice variance). Mesoscale and submesoscale spice variance is largest in the remnant mixed layer, decreases to a minimum below the pycnocline near 26.3 kg m−3, and then increases again near 26.6 kg m−3. Layers of high (low) meso- and submesoscale spice variance are found on isopycnals where large-scale spice gradients are large (small), consistent with stirring of large-scale gradients to produce smaller scale thermohaline structure. Passive tracer adjoint calculations in the state estimate are used to investigate possible mechanisms for the formation of the layers of spice variance. Layers of high spice variance are found to have distinct origins and to be associated with named water masses; high spice variance water in the remnant mixed layer has northerly origin and is identified as Pacific Subarctic water, while the water in the deeper high spice variance layer has southerly origin and is identified as Equatorial Pacific water. The layer of low spice variance near 26.3 kg m−3 lies between the named water masses and does not have a clear origin. Both effective horizontal diffusivity, κh, and effective diapycnal diffusivity, κv, are elevated relative to the diffusion coefficients set in the numerical simulation, but changes in κh and κv with depth are not sufficient to explain the observed layering of thermohaline structure.
    Description: We gratefully acknowledge funding from the Gordon and Betty Moore Foundation, the Coastal Ocean Currents Monitoring Project (COCMP), and NOAA. R. E. Todd was partially supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Cooperative Institute for the North Atlantic Region.
    Description: 2012-08-03
    Keywords: California Current System ; Adjoint model ; Glider ; Passive tracer ; Spice ; Thermohaline structure
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Production and analysis of a Southern Ocean state estimate (2006)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Master of Science in Physical Oceanography, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006
    Description: A modern general circulation model of the Southern Ocean with one-sixth of a degree resolution is optimized to the observed ocean in a weighted least squares sense. Convergence toward the state estimate solution is carried out by systematically adjusting the control variables (prescribed atmospheric state, initial conditions, and open northern boundary at 24.7°S) using the adjoint method. A cost function compares the model state to data from CTD synoptic sections, hydrographic climatology, satellite altimetry, and XBTs. Costs attributed to control variable perturbations ensure a physically realistic solution. An optimized solution is determined by the weights placed on the cost function terms. The state estimation procedure, along with the weights used, is described. A significant result is that the adjoint method is shown to work at eddy-permitting resolution in the highly-energetic Southern Ocean. At the time of the writing of this thesis the state estimate was not fully consistent with the observations. An analysis of the remaining misfit, as well as the mass transport in the preliminary state, is presented.
    Keywords: Ocean circulation
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
    Format: 4999959 bytes
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Spiraling pathways of global deep waters to the surface of the Southern Ocean (2017)
    Nature Publishing Group
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 8 (2017): 172, doi:10.1038/s41467-017-00197-0.
    Description: Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60–90 years.
    Description: V.T., L.D.T., and M.R.M. were supported by NSF OCE-1357072. A.K.M., H.F.D., and W.W. were supported by the RGCM program of the US Department of Energy under Contract DE-SC0012457. J.L.S. acknowledges NSF’s Southern Ocean Carbon and Climate Observations and Modeling project under NSF PLR-1425989, which partially supported L.D.T. and M.R.M. as well. C.O.D was supported by the National Aeronautics and Space Administration (NASA) under Award NNX14AL40G and by the Princeton Environmental Institute Grand Challenge initiative. A.R.G. was supported by a Climate and Global Change Postdoctoral Fellowship from the National Oceanic and Atmospheric Administration (NOAA). S.M.G. acknowledges the ongoing support of NOAA/GFDL for high-end ocean and climate-modeling activities. J.W. acknowledges support from NSF OCE-1234473.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    The Southern Ocean meridional overturning circulation as diagnosed from an eddy permitting state estimate (2008)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publication Date: 2022-05-25
    Description: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2008
    Description: A modern general circulation model of the Southern Ocean with one-sixth of a degree resolution is optimized to the observed ocean in a weighted least squares sense. Convergence to the state estimate solution is carried out by systematically adjusting the control variables (atmospheric state and initial conditions) using the adjoint model. A cost function compares the model state to in situ observations (Argo float profiles, CTD synoptic sections, SEaOS instrument mounted seal profiles, and XBTs), altimetric observations (ENVISAT, GEOSAT, Jason, TOPEX/Poseidon), and other data sets (e.g. infrared and microwave radiometer observed sea surface temperature and NSIDC sea-ice concentration). Costs attributed to control variable perturbations ensure a physically realistic solution. The state estimate is found to be largely consistent with the individual observations, as well as with integrated fluxes inferred from previous static inverse models. The transformed Eulerian mean formulation is an elegant way to theorize about the Southern Ocean. Current researchers utilizing this framework, however, have been making assumptions that render their theories largely irrelevant to the actual ocean. It is shown that theories of the overturning circulation must include the effect of pressure forcing. This is true in the most buoyant waters, where pressure forcing overcomes eddy and wind forcing to balance a poleward geostrophic transport and allows the buoyancy budget to be closed. Pressure forcing is also lowest order at depth. Indeed, the Southern Ocean’s characteristic multiple cell overturning is primarily in geostrophic balance. Several other aspects of the Southern Ocean circulation are also investigated in the thesis, including an analysis of the magnitude and variability of heat, salt, and volume inter-basin transports.
    Description: This work was supported by CalTech - Jet Propulsion Lab contract #1205624 (Global Oceans Dynamics and Transports). Support for my first 2 years in the MITWHOI Joint Program came from NSF awards #OCE-9901654 (Research in Linear and Nonlinear Waves and Ocean Circulation Theory). I was also supported for two months by NSF awards #OCE-0223434.
    Keywords: Ocean circulation ; Ocean temperature
    Repository Name: Woods Hole Open Access Server
    Type: Thesis
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Polar Ocean Observations: A Critical Gap in the Observing System and Its Effect on Environmental Predictions From Hours to a Season (2019)
    In:  EPIC3Frontiers in Marine Science, 6(429), ISSN: 2296-7745
    Details
    Publication Date: 2020-05-15
    Description: There is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. Oceanographic predictions in the Antarctic are also important, both to support Antarctic operations and also to help elucidate processes governing sea ice and ice shelf stability. However, a significant gap exists in the ocean observing system in polar regions, compared to most areas of the global ocean, hindering the reliability of ocean and sea ice forecasts. This gap can also be seen from the spread in ocean and sea ice reanalyses for polar regions which provide an estimate of their uncertainty. The reduced reliability of polar predictions may affect the quality of various applications including search and rescue, coupling with numerical weather and seasonal predictions, historical reconstructions (reanalysis), aquaculture and environmental management including environmental emergency response. Here, we outline the status of existing near-real time ocean observational efforts in polar regions, discuss gaps, and explore perspectives for the future. Specific recommendations include a renewed call for open access to data, especially real-time data, as a critical capability for improved sea ice and weather forecasting and other environmental prediction needs. Dedicated efforts are also needed to make use of additional observations made as part of the Year of Polar Prediction (YOPP; 2017–2019) to inform optimal observing system design. To provide a polar extension to the Argo network, it is recommended that a network of ice-borne sea ice and upper-ocean observing buoys be deployed and supported operationally in ice-covered areas together with autonomous profiling floats and gliders (potentially with ice detection capability) in seasonally ice covered seas. Finally, additional efforts to better measure and parameterize surface exchanges in polar regions are much needed to improve coupled environmental prediction.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    DASSO: a data assimilation system for the Southern Ocean that utilizes both sea-ice concentration and thickness observations (2021)
    In:  EPIC3Journal of Glaciology, 67(266), pp. 1235-1240
    Details
    Publication Date: 2021-12-28
    Description: To improve Antarctic sea-ice simulations and estimations, an ensemble-based Data Assimilation System for the Southern Ocean (DASSO) was developed based on a regional sea ice–ocean coupled model, which assimilates sea-ice thickness (SIT) together with sea-ice concentration (SIC) derived from satellites. To validate the performance of DASSO, experiments were conducted from 15 April to 14 October 2016. Generally, assimilating SIC and SIT can suppress the overestimation of sea ice in the model-free run. Besides considering uncertainties in the operational atmospheric forcing data, a covariance inflation procedure in data assimilation further improves the simulation of Antarctic sea ice, especially SIT. The results demonstrate the effectiveness of assimilating sea-ice observations in reconstructing the state of Antarctic sea ice, but also highlight the necessity of more reasonable error estimation for the background as well as the observation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...