ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
Filter
  • Buoyancy  (6)
  • Antarctica  (1)
  • American Meteorological Society  (7)
Collection
Keywords
Publisher
  • American Meteorological Society  (7)
Years
  • 1
    facet.materialart.
    Unknown
    Circulation induced by isolated dense water formation over closed topographic contours (2017)
    American Meteorological Society
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2017. 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 47 (2017): 2251-2265, doi:10.1175/JPO-D-17-0042.1.
    Description: The problem of localized dense water formation over a sloping bottom is considered for the general case in which the topography forms a closed contour. This class of problems is motivated by topography around islands or shallow shoals in which convection resulting from brine rejection or surface heat loss reaches the bottom. The focus of this study is on the large-scale circulation that is forced far from the region of surface forcing. The authors find that a cyclonic current is generated around the topography, in the opposite sense to the propagation of the dense water plume. In physical terms, this current results from the propagation of low sea surface height from the region of dense water formation anticyclonically along the topographic contours back to the formation region. This pressure gradient is then balanced by a cyclonic geostrophic flow. This basic structure is well predicted by a linear quasigeostrophic theory, a primitive equation model, and in rotating tank experiments. For sufficiently strong forcing, the anticyclonic circulation of the dense plume meets this cyclonic circulation to produce a sharp front and offshore advection of dense water at the bottom and buoyant water at the surface. This nonlinear limit is demonstrated in both the primitive equation model and in the tank experiments.
    Description: MAS was supported by the National Science Foundation under Grant OCE-1534618. Support for CC was given by the WHOI Ocean Climate Change Institute Proposal 27071273.
    Description: 2018-03-20
    Keywords: Bottom currents ; Buoyancy ; Ocean dynamics ; Density currents
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Laboratory experiments on the interaction of a buoyant coastal current with a canyon : application to the East Greenland Current (2010)
    American Meteorological Society
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Meteorological Society, 2009. 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 39 (2009): 1258-1271, doi:10.1175/2008JPO4028.1.
    Description: This paper presents a set of laboratory experiments focused on how a buoyant coastal current flowing over a sloping bottom interacts with a canyon and what controls the separation, if any, of the current from the upstream canyon bend. The results show that the separation of a buoyant coastal current depends on the current width W relative to the radius of curvature of the bathymetry ρc. The flow moved across the mouth of the canyon (i.e., separated) for W/ρc 〉 1, in agreement with previous results. The present study extends previous work by examining both slope-controlled and surface-trapped currents, and using a geometry specific to investigating buoyant current–canyon interaction. The authors find that, although bottom friction is important in setting the position of the buoyant front, the separation process driven by the inertia of the flow could overcome even the strongest bathymetric influence. Application of the laboratory results to the East Greenland Current (EGC), an Arctic-origin buoyant current that is observed to flow in two branches south of Denmark Strait, suggests that the path of the EGC is influenced by the large canyons cutting across the shelf, as the range of W/ρc in the ocean spans those observed in the laboratory. What causes the formation of a two-branched EGC structure downstream of the Kangerdlugssuaq Canyon (68°N, 32°W) is still unclear, but potential mechanisms are discussed.
    Description: This work was partially funded by NSF Grant OCE-0450658. DS also received support from the Academic Programs Office of the Woods Hole Oceanographic Institution, while CC had partial support from NSF OCE-0350891.
    Keywords: Coastal flows ; Buoyancy ; Currents ; Experimental design ; 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 ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    Impact of two plumes’ interaction on submarine melting of tidewater glaciers : a laboratory study (2016)
    American Meteorological Society
    Details
    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): 361–367, doi:10.1175/JPO-D-15-0171.1.
    Description: Idealized laboratory experiments investigate the glacier–ocean boundary dynamics near a vertical glacier in a two-layer stratified fluid. Discharge of meltwater runoff at the base of the glacier (subglacial discharge) enhances submarine melting. In the laboratory, the effect of multiple sources of subglacial discharge is simulated by introducing freshwater at freezing temperature from two point sources at the base of an ice block representing the glacier. The buoyant plumes of cold meltwater and subglacial discharge water entrain warm ambient water, rise vertically, and interact within a layer of depth H2 if the distance between the sources x0 is smaller than H2α/0.35, where α is the entrainment constant. The plume water detaches from the glacier face at the interface between the two layers and/or at the free surface, as confirmed by previous numerical studies and field observations. A plume model is used to explain the observed nonmonotonic dependence of submarine melting on the sources’ separation. The distance between the two sources influences the entrainment of warm water in the plumes and consequently the amount of submarine melting and the final location of the meltwater within the water column. Two interacting plumes located very close together are observed to melt approximately half as much as two independent plumes. The inclusion, or parameterization, of the dynamics regulating multiple plumes’ interaction is therefore necessary for a correct estimate of submarine melting. Hence, the distribution and number of sources of subglacial discharge may play an important role in glacial melt rates and fjord stratification and circulation.
    Description: Support to C.C. was given by the NSF Project OCE-1130008 and OCE-1434041. V.M.G. received support from the “Gori” Fellowship.
    Description: 2016-07-01
    Keywords: Geographic location/entity ; Glaciers ; Circulation/ Dynamics ; Buoyancy ; Entrainment ; Ocean dynamics ; Small scale processes ; Models and modeling ; Laboratory/physical models
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Dynamics of three-dimensional turbulent wall plumes and implications for estimates of submarine glacier melting (2018)
    American Meteorological Society
    Details
    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):1941-1950, doi:10.1175/JPO-D-17-0194.1.
    Description: Subglacial discharges have been observed to generate buoyant plumes along the ice face of Greenland tidewater glaciers. These plumes have been traditionally modeled using classical plume theory, and their characteristic parameters (e.g., velocity) are employed in the widely used three-equation melt parameterization. However, the applicability of plume theory for three-dimensional turbulent wall plumes is questionable because of the complex near-wall plume dynamics. In this study, corrections to the classical plume theory are introduced to account for the presence of a wall. In particular, the drag and entrainment coefficients are quantified for a three-dimensional turbulent wall plume using data from direct numerical simulations. The drag coefficient is found to be an order of magnitude larger than that for a boundary layer flow over a flat plate at a similar Reynolds number. This result suggests a significant increase in the melting estimates by the current parameterization. However, the volume flux in a wall plume is found to be one-half that of a conical plume that has 2 times the buoyancy flux. This finding suggests that the total entrainment (per unit area) of ambient water is the same and that the plume scalar characteristics (i.e., temperature and salinity) can be predicted reasonably well using classical plume theory.
    Description: This work was supported by the Linné FLOW Centre at KTH and the Academy of Finland Center of Excellence Programme Grant 307331 (author Ezhova) and by VR Swedish Research Council GrantVR2014-5001 (author Brandt). Support to author Cenedese was given by NSF Project OCE-1434041.
    Description: 2019-02-27
    Keywords: Buoyancy ; Entrainment ; Turbulence
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    Impact of a localized source of subglacial discharge on the heat flux and submarine melting of a tidewater glacier : a laboratory study (2016)
    American Meteorological Society
    Details
    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): 3155-3163, doi:10.1175/JPO-D-16-0123.1.
    Description: Idealized laboratory experiments have been conducted in a two-layer stratified fluid to investigate the leading-order dynamics that control submarine melting and meltwater export near a vertical ice–ocean interface as a function of subglacial discharge. In summer, the discharge of surface runoff at the base of a glacier (subglacial discharge) generates strong buoyant plumes that rise along the glacier front entraining ambient water along the way. The entrainment enhances the heat transport toward the glacier front and hence the submarine melt rate increases with the subglacial discharge rate. In the laboratory, the effect of subglacial discharge is simulated by introducing freshwater at freezing temperature from a point source at the base of an ice block representing the glacier. The circulation pattern observed both with and without subglacial discharge resembles those observed in previous observational and numerical studies. Buoyant plumes rise vertically until they find either their neutrally buoyant level or the free surface. Hence, the meltwater can deposit within the interior of the water column and not entirely at the free surface, as confirmed by field observations. The heat budget in the tank, calculated following a new framework, gives estimates of submarine melt rate that increase with the subglacial discharge and are in agreement with the directly measured submarine melting. This laboratory study provides the first direct measurements of submarine melt rates for different subglacial discharges, and the results are consistent with the predictions of previous theoretical and numerical studies.
    Description: Support to C. C. was given by the NSF project OCE- 1130008 and OCE-1434041. M. G. received support from the ‘‘Gori’’ Fellowship.
    Description: 2017-04-07
    Keywords: Glaciers ; Buoyancy ; Density currents ; Turbulence ; Laboratory/physical models
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    A laboratory study of iceberg side melting in vertically sheared flows (2018)
    American Meteorological Society
    Details
    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): 1367-1373, doi:10.1175/JPO-D-17-0185.1.
    Description: An earlier study indicates that the side melting of icebergs subject to vertically homogeneous horizontal velocities is controlled by two distinct regimes, which depend on the melt plume behavior and produce a nonlinear dependence of side melt rate on velocity. Here, we extend this study to consider ice blocks melting in a two-layer vertically sheared flow in a laboratory setting. It is found that the use of the vertically averaged flow speed in current melt parameterizations gives an underestimate of the submarine side melt rate, in part because of the nonlinearity of the dependence of the side melt rate on flow speed but also because vertical shear in the horizontal velocity profile fundamentally changes the flow splitting around the ice block and consequently the velocity felt by the ice surface. An observational record of 90 icebergs in a Greenland fjord suggests that this effect could produce an average underestimate of iceberg side melt rates of 21%.
    Description: A. F. was supported by NA14OAR4320106 from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. C. C. was supported by NSF OCE-1658079 and F. S. was supported by NSF OCE-1657601 and NSF PLR-1743693.
    Description: 2018-12-12
    Keywords: Ocean ; Antarctica ; Arctic ; Laboratory/physical models ; Parameterization
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Dynamics of a turbulent buoyant plume in a stratified fluid : an idealized model of subglacial discharge in Greenland fjords (2017)
    American Meteorological Society
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Meteorological Society, 2017. 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 47 (2017): 2611-2630, doi:10.1175/JPO-D-16-0259.1.
    Description: This study reports the results of large-eddy simulations of an axisymmetric turbulent buoyant plume in a stratified fluid. The configuration used is an idealized model of the plume generated by a subglacial discharge at the base of a tidewater glacier with an ambient stratification typical of Greenland fjords. The plume is discharged from a round source of various diameters and characteristic stratifications for summer and winter are considered. The classical theory for the integral parameters of a turbulent plume in a homogeneous fluid gives accurate predictions in the weakly stratified lower layer up to the pycnocline, and the plume dynamics are not sensitive to changes in the source diameter. In winter, when the stratification is similar to an idealized two-layer case, turbulent entrainment and generation of internal waves by the plume top are in agreement with the theoretical and numerical results obtained for turbulent jets in a two-layer stratification. In summer, instead, the stratification is more complex and turbulent entrainment by the plume top is significantly reduced. The subsurface layer in summer is characterized by a strong density gradient and the oscillating plume generates internal waves that might serve as an indicator of submerged plumes not penetrating to the surface.
    Description: This work was supported by Linné FLOW Centre at KTH and the Academy of Finland Centre of Excellence program (Grant 307331) (E. E.) and VR Swedish Research Council, Outstanding Young Researcher Award, Grant VR 2014-5001 (L. B.). Support to C. C. was given by the NSF Project OCE-1434041.
    Description: 2018-04-26
    Keywords: Buoyancy ; Internal waves ; Turbulence ; Jets ; Oscillations ; Large eddy simulations
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected 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...