ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in [citation], doi:[doi]. Morrow, R., Fu, L., Ardhuin, F., Benkiran, M., Chapron, B., Cosme, E., d'Ovidio, F., Farrar, J. T., Gille, S. T., Lapeyre, G., Le Traon, P., Pascual, A., Ponte, A., Qiu, B., Rascle, N., Ubelmann, C., Wang, J., & Zaron, E. D. Global observations of fine-scale ocean surface topography with the surface water and ocean topography (SWOT) mission. Frontiers in Marine Science, 6(232),(2019), doi:10.3389/fmars.2019.00232.
    Description: The future international Surface Water and Ocean Topography (SWOT) Mission, planned for launch in 2021, will make high-resolution 2D observations of sea-surface height using SAR radar interferometric techniques. SWOT will map the global and coastal oceans up to 77.6∘ latitude every 21 days over a swath of 120 km (20 km nadir gap). Today’s 2D mapped altimeter data can resolve ocean scales of 150 km wavelength whereas the SWOT measurement will extend our 2D observations down to 15–30 km, depending on sea state. SWOT will offer new opportunities to observe the oceanic dynamic processes at scales that are important in the generation and dissipation of kinetic energy in the ocean, and that facilitate the exchange of energy between the ocean interior and the upper layer. The active vertical exchanges linked to these scales have impacts on the local and global budgets of heat and carbon, and on nutrients for biogeochemical cycles. This review paper highlights the issues being addressed by the SWOT science community to understand SWOT’s very precise sea surface height (SSH)/surface pressure observations, and it explores how SWOT data will be combined with other satellite and in situ data and models to better understand the upper ocean 4D circulation (x, y, z, t) over the next decade. SWOT will provide unprecedented 2D ocean SSH observations down to 15–30 km in wavelength, which encompasses the scales of “balanced” geostrophic eddy motions, high-frequency internal tides and internal waves. This presents both a challenge in reconstructing the 4D upper ocean circulation, or in the assimilation of SSH in models, but also an opportunity to have global observations of the 2D structure of these phenomena, and to learn more about their interactions. At these small scales, ocean dynamics evolve rapidly, and combining SWOT 2D SSH data with other satellite or in situ data with different space-time coverage is also a challenge. SWOT’s new technology will be a forerunner for the future altimetric observing system, and so advancing on these issues today will pave the way for our future.
    Description: The authors were mostly funded through the NASA Physical Oceanography Program and the CNES/TOSCA programs for the SWOT and OSTST Science teams. AnP acknowledges support from the Spanish Research Agency and the European Regional Development Fund (Award No. CTM2016-78607-P). AuP acknowledges support from the ANR EQUINOx (ANR-17-CE01-0006-01).
    Keywords: Ocean mesoscale circulation ; Satellite altimetry ; SAR-interferometry ; Tides and internal tides ; Calibration-validation
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2018-06-01
    Description: In a recent study, O’Neill et al. analyzed the divergence of surface winds above the northwest Atlantic. In the time mean, a band of convergence is found, overlying the southern flank of the Gulf Stream. To quantify the impact of synoptic storms, the authors proposed to compare the time-mean divergence with the divergence averaged in the absence of rain. In the resulting conditional-average field, divergence was found to be positive nearly everywhere. O'Neill et al. concluded that this absence of convergence precludes the Ekman-balanced mass adjustment to be responsible for the atmospheric response above the Gulf Stream. Using a simplistic toy model as well as a numerical simulation representative of a storm track, we show that the absence of negative divergence values purely results from the correlation between rain and convergence: the conditional average based on the absence of rain necessarily implies a shift toward positive divergence values. In consequence, we argue that conditional statistics (based on the absence of rain or removing extreme values in the divergence field), as produced by O’Neill et al., do not allow conclusions on the mechanisms underlying the atmospheric response to the Gulf Stream. They nevertheless highlight the essential role of synoptic storms in shaping the divergence field in instantaneous fields.
    Print ISSN: 0022-4928
    Electronic ISSN: 1520-0469
    Topics: Geography , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2017-12-01
    Print ISSN: 0894-8755
    Electronic ISSN: 1520-0442
    Topics: Geography , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2000-11-01
    Print ISSN: 0167-2789
    Electronic ISSN: 1872-8022
    Topics: Physics
    Published by Elsevier
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2002-09-01
    Print ISSN: 1054-1500
    Electronic ISSN: 1089-7682
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Molecular Diversity Preservation International
    Publication Date: 2017-02-16
    Electronic ISSN: 2311-5521
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2010-06-01
    Description: Upper-tropospheric Rossby wave–breaking processes are examined in coupled ocean–atmosphere simulations of the Last Glacial Maximum (LGM) and of the modern era. LGM statistics of the Northern Hemisphere in winter, computed from the Paleoclimate Modeling Intercomparison Project Phase II (PMIP2) dataset, are compared with those from preindustrial simulations and from the 40-yr ECMWF Re-Analysis (ERA-40). Particular attention is given to the role of wave-breaking events in the North Atlantic Oscillation (NAO) for each simulation. Anticyclonic (AWB) and cyclonic (CWB) wave-breaking events during LGM are shown to be less and more frequent, respectively, than in the preindustrial climate, especially in the Pacific. This is consistent with the slight equatorward shift of the eddy-driven jets in the LGM runs. The most remarkable feature of the simulated LGM climate is that it presents much weaker latitudinal fluctuations of the eddy-driven jets. This is accompanied by less dispersion in the wave-breaking events. A physical interpretation is provided in terms of the fluctuations of the low-level baroclinicity at the entrance of the storm tracks. The NAO in the preindustrial simulations and in ERA-40 is characterized by strong latitudinal fluctuations of the Atlantic eddy-driven jet as well as by significant changes in the nature of the wave breaking. During the positive phase, the eddy-driven jet moves to the north with more AWB events than usual and is well separated from the subtropical African jet. The negative phase exhibits a more equatorward Atlantic jet and more CWB events. In contrast, the LGM NAO is less well marked by the latitudinal vacillation of the Atlantic jet and for some models this property disappears entirely. The LGM NAO corresponds more to acceleration–deceleration or extension–retraction of the Atlantic jet. The hemispheric point of view of the Arctic Oscillation exhibits similar changes.
    Print ISSN: 0894-8755
    Electronic ISSN: 1520-0442
    Topics: Geography , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2017-05-24
    Description: The statistical properties of turbulent fluids depend on how local the energy transfers among scales are, i.e. whether the energy transfer at some given scale is due to the eddies at that particular scale, or to eddies at larger (non-local) scale. This locality in the energy transfers may have consequences for the relative dispersion of passive particles. In this paper, we consider a class of generalized two-dimensional flows (produced by the so-called α-turbulence models), theoretically possessing different properties in terms of locality of energy transfers. It encompasses the standard barotropic quasi-geostrophic (QG) and the surface quasi-geostrophic (SQG) models as limiting cases. The relative dispersion statistics are examined, both as a function of time and as a function of scale, and compared to predictions based on phenomenological arguments assuming the locality of the cascade. We find that the dispersion statistics follow the predicted values from local theories, as long as the parameter is α small enough (dynamics close to that of the SQG model), for sufficiently small initial pair separations. In contrast, non-local dispersion is observed for the QG model, a robust result when looking at relative displacement probability distributions. However, we point out that spectral energy transfers do have a non-local contribution for models with different values of α, including the SQG case. This indicates that locality/non-locality of the turbulent cascade may not always imply locality/non-locality in the relative dispersion of particles and that the self-similar nature of the turbulent cascade is more appropriate for determining the relative dispersion locality. © 2017 Cambridge University Press.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2012-03-30
    Description: The authors undertake a detailed analysis of the influence of water vapor condensation and latent heat release upon the evolution of the baroclinic instability. The framework consists in a two-layer rotating shallow-water model with moisture coupled to dynamics through mass exchange between the layers due to condensation/precipitation. The model gives all known in literature models of this kind as specific limits. It is fully nonlinear and ageostrophic. The reference state is a baroclinic Bickley jet. The authors first study its “dry” linear instability and then use the most unstable mode to initialize high-resolution numerical simulations of the life cycle of the instability in nonprecipitating (moisture being a passive tracer) and precipitating cases. A new-generation well-balanced finite-volume scheme is used in these simulations. The evolution in the nonprecipitating case follows the standard cyclonic wave-breaking life cycle of the baroclinic instability, which is reproduced with a high fidelity. In the precipitating case, the onset of condensation significantly increases the growth rate of the baroclinic instability at the initial stages due to production of available potential energy by the latent heat release. Condensation occurs in frontal regions and wraps up around the cyclone, which is consistent with the moist cyclogenesis theory and observations. Condensation induces a clear-cut cyclone–anticyclone asymmetry. The authors explain the underlying mechanism and show how it modifies the equilibration of the flow at the late stages of the saturation of the instability. In spite of significant differences in the evolution, only weak differences in various norms of the perturbations remain between precipitating and nonprecipitating cases at the end of the saturation process.
    Print ISSN: 0022-4928
    Electronic ISSN: 1520-0469
    Topics: Geography , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2012-06-01
    Description: The combined effects of the deformation (horizontal stretching and shearing) and nonlinearities on the beta drift of midlatitude cyclones are studied using a barotropic quasigeostrophic model on the beta plane. It is found that, without any background flow, a cyclonic vortex moves more rapidly northward when it is initially strongly stretched along a mostly north–south direction. This meridional stretching is more efficient at forming an anticyclone to the east of the cyclone through Rossby wave radiation. The cyclone–anticyclone couple then forms a nonlinear vortex dipole that propagates mostly northward. The case of a cyclone embedded in uniformly sheared zonal flows is then studied. A cyclone evolving in an anticyclonic shear is stretched more strongly, develops a stronger anticyclone, and moves faster northward than a cyclone embedded in a cyclonic shear, which remains almost isotropic. Similar results are found in the general case of uniformly sheared nonzonal flows. The evolution of cyclones is also investigated in the case of a more realistic meandering jet whose relative vorticity gradient creates an effective beta and whose deformation field is spatially varying. A statistical study reveals a strong correlation among the cyclone’s stretching, the anticyclone strength, and the velocity toward the jet center. These different observations agree with the more idealized cases. Finally, these results provide a rationale for the existence of preferential zones for the jet-crossing phase: that is, the phase when a cyclone crosses a jet from its anticyclonic to its cyclonic side.
    Print ISSN: 0022-4928
    Electronic ISSN: 1520-0469
    Topics: Geography , Geosciences , Physics
    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...