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
  • Cambridge University Press
  • 2010-2014  (10,840)
  • 1955-1959  (2,155)
Collection
Keywords
Publisher
Years
Year
  • 1
    facet.materialart.
    Unknown
    On latency of multiple zonal jets in the oceans (2012)
    Cambridge University Press
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2011. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 686 (2011): 534-567, doi:10.1017/jfm.2011.345.
    Description: Most of the nearly zonal, multiple, alternating jets observed in the oceans are latent, that is, their amplitudes are weak relative to the ambient mesoscale eddies. Yet, relatively strong jets are often observed in dynamical simulations. To explore mechanisms controlling the degree of latency, we analyse solutions of an idealized, eddy-resolving and flat-bottom quasigeostrophic model, in which dynamically generated mesoscale eddies maintain and interact with a set of multiple zonal jets. We find that the degree of the latency is controlled primarily by the bottom friction: the larger the friction parameter, the more latent are the jets; and the degree of the latency is substantial for a realistic range of the oceanic bottom friction coefficient. This result not only provides a plausible explanation for the latency of the oceanic jets, but it may also be relevant to the prominent atmospheric multiple jets observed on giant gas planets, such as Jupiter. We hypothesize that these jets can be so strong because of the relative absence of the bottom friction. The mechanism controlling the latency in our solutions is understood in terms of the changes induced in the linear eigenmodes of the time–mean flow by varying the bottom friction coefficient; these changes, in turn, affect and modify the jets. Effects of large Reynolds numbers on the eddies, jets, and the latency are also discussed.
    Description: Funding was provided: for P.B. by NSF grants OCE 0725796 and OCE 0845150, for J.T.F. by NSF grant OCE 0845150, for I.K. by NSF grant OCE 0842834, and for S.K. by the University Research Fellowship from the Royal Society. S.K. also acknowledges support from the Mary Sears Grant from the Woods Hole Oceanographic Institution.
    Description: 2012-09-27
    Keywords: Geostrophic turbulence ; Quasi-geostrophic flows ; Waves in rotating fluids
    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)
  • 2
    facet.materialart.
    Unknown
    Chaotic advection in a steady, three-dimensional, Ekman-driven eddy (2014)
    Cambridge University Press
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2013. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 738 (2014): 143-183, doi:10.1017/jfm.2013.583.
    Description: We investigate and quantify stirring due to chaotic advection within a steady, three-dimensional, Ekman-driven, rotating cylinder flow. The flow field has vertical overturning and horizontal swirling motion, and is an idealization of motion observed in some ocean eddies. The flow is characterized by strong background rotation, and we explore variations in Ekman and Rossby numbers, E and Ro, over ranges appropriate for the ocean mesoscale and submesoscale. A high-resolution spectral element model is used in conjunction with linear analytical theory, weakly nonlinear resonance analysis and a kinematic model in order to map out the barriers, manifolds, resonance layers and other objects that provide a template for chaotic stirring. As expected, chaos arises when a radially symmetric background state is perturbed by a symmetry-breaking disturbance. In the background state, each trajectory lives on a torus and some of the latter survive the perturbation and act as barriers to chaotic transport, a result consistent with an extension of the KAM theorem for three-dimensional, volume-preserving flow. For shallow eddies, where E is O(1), the flow is dominated by thin resonant layers sandwiched between KAM-type barriers, and the stirring rate is weak. On the other hand, eddies with moderately small E experience thicker resonant layers, wider-spread chaos and much more rapid stirring. This trend reverses for sufficiently small E, corresponding to deep eddies, where the vertical rigidity imposed by strong rotation limits the stirring. The bulk stirring rate, estimated from a passive tracer release, confirms the non-monotonic variation in stirring rate with E. This result is shown to be consistent with linear Ekman layer theory in conjunction with a resonant width calculation and the Taylor–Proudman theorem. The theory is able to roughly predict the value of E at which stirring is maximum. For large disturbances, the stirring rate becomes monotonic over the range of Ekman numbers explored. We also explore variation in the eddy aspect ratio.
    Description: L.J.P., I.I.R., T.M.O. and P.W. have been supported on DOD (MURI) grant N000141110087, administered by the Office of Naval Research. I.I.R. and L.J.P. received additional support from Grant NSF-OCE-0725796 from the National Science Foundation.
    Description: 2014-12-05
    Keywords: Chaotic advection ; Geophysical and geological flows ; Ocean processes
    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
    Spillover from marine reserves and the replenishment of fished stocks (2010)
    Cambridge University Press
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Foundation for Environmental Conservation, 2009. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Environmental Conservation 36 (2009): 268-276, doi:10.1017/S0376892910000032.
    Description: No-take marine reserves are widely recognized as an effective conservation tool for protecting marine resources. Despite considerable empirical evidence that abundance and biomass of fished species increase within marine reserve boundaries, the potential for reserves to provide fisheries and conservation benefits to adjacent waters remains heavily debated. This paper uses statistical and population models to evaluate published empirical data on adult spillover from marine reserves and shows that spillover is a common phenomenon for species that respond positively to reserve protection, but at relatively small scales, detectable on average up to 800 m from reserve boundaries. At these small scales, local fisheries around reserves were likely unsustainable in 12 of 14 cases without the reserve, and spillover partially or fully offsets losses in catch due to reserve closure in the other two cases. For reserves to play a role in sustaining and replenishing larger-scale fished stocks, networks of reserves may be necessary, but as few exist this is difficult to evaluate. The results suggest reserves can simultaneously meet conservation objectives and benefit local fisheries adjacent to their boundaries.
    Description: Support was provided by a grant from the David and Lucille Packard Foundation to NCEAS for ecosystem-based management ofmarine systems, the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) funded by the David and Lucile Packard Foundation and the Gordon and Betty Moore Foundation (contribution number 348), the Sustainable Fisheries Group supported by the Paul G. Allen Family Foundation and the Bahamas Biocomplexity Project (US NSF Biocomplexity grantOCE-0119976) andUS EPA Science to Achieve Results (R832223).
    Keywords: Adult fish movement ; Fisheries ; Global ; Marine protected areas ; No-take reserves ; Spillover effect ; Synthesis
    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)
  • 4
    facet.materialart.
    Unknown
    Entrainment in two coalescing axisymmetric turbulent plumes (2014)
    Cambridge University Press
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2014. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 752 (2014): R2, doi:10.1017/jfm.2014.389.
    Description: A model of the total volume flux and entrainment occurring in two coalescing axisymmetric turbulent plumes is developed and compared with laboratory experiments. The dynamical evolution of the two plumes is divided into three regions. In region 1, where the plumes are separate, the entrainment in each plume is unaffected by the other plume, although the two plumes are drawn together due to the entrainment of ambient fluid between them. In region 2 the two plumes touch each other but are not yet merged. In this region the total entrainment is a function of both the dynamics of the touching plumes and the reduced surface area through which entrainment occurs. In region 3 the two plumes are merged and the entrainment is equivalent to that in a single plume. We find that the total volume flux after the two plumes touch and before they merge increases linearly with distance from the sources, and can be expressed as a function of the known total volume fluxes at the touching and merging heights. Finally, we define an ‘effective’ entrainment constant, αeff, as the value of α needed to obtain the same total volume flux in two independent plumes as that occurring in two coalescing plumes. The definition of αeff allows us to find a single expression for the development of the total volume flux in the three different dynamical regions. This single expression will simplify the representation of coalescing plumes in more complex models, such as in large-scale geophysical convection, in which plume dynamics are not resolved. Experiments show that the model provides an accurate measure of the total volume flux in the two coalescing plumes as they evolve through the three regions.
    Description: The authors gratefully acknowledge the National Science Foundation (grant OCE-0824636) and the Office of Naval Research (grant N00014-09-1-0844) for their support of the 2013 WHOI Geophysical Fluid Dynamics Summer School where this project was initiated. Support to C.C. was given by the National Science Foundation project OCE-1130008.
    Description: 2015-07-11
    Keywords: Mixing ; Plumes/thermals ; Turbulent mixing
    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)
  • 5
    facet.materialart.
    Unknown
    Direct numerical simulations of instability and boundary layer turbulence under a solitary wave (2013)
    Cambridge University Press
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2013. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 731 (2013): 545-578, doi:10.1017/jfm.2013.361 .
    Description: A significant amount of research effort has been made to understand the boundary layer instability and the generation and evolution of turbulence subject to periodic/oscillatory flows. However, little is known about bottom boundary layers driven by highly transient and intermittent free-stream flow forcing, such as solitary wave motion. To better understand the nature of the instability mechanisms and turbulent flow characteristics subject to solitary wave motion, a large number of direct numerical simulations are conducted. Different amplitudes of random initial fluctuating velocity field are imposed. Two different instability mechanisms are observed within the range of Reynolds number studied. The first is a short-lived, nonlinear, long-wave instability which is observed during the acceleration phase, and the second is a broadband instability that occurs during the deceleration phase. Transition from a laminar to turbulent state is observed to follow two different breakdown pathways: the first follows the sequence of $K$-type secondary instability of a near-wall boundary layer at comparatively lower Reynolds number and the second one follows a breakdown path similar to that of free shear layers. Overall characteristics of the flow are categorized into four regimes as: (i) laminar; (ii) disturbed laminar; (iii) transitional; and (iv) turbulent. Our categorization into four regimes is consistent with earlier works. However, this study is able to provide more specific definitions through the instability characteristics and the turbulence breakdown process.
    Description: This study is supported by National Science Foundation (CMMI-1135026; OCE- 1130217; OCE-1131016).
    Description: 2014-08-28
    Keywords: Coastal engineering ; Solitary waves ; Turbulent flows
    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)
  • 6
    facet.materialart.
    Unknown
    Finger puzzles (2012)
    Cambridge University Press
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2012. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 692 (2012): 1-4, doi:10.1017/jfm.2011.468.
    Description: Salt fingers are a form of double-diffusive convection that can occur in a wide variety of fluid systems, ranging from stellar interiors and oceans to magma chambers. Their amplitude has long been difficult to quantify, and a variety of mechanisms have been proposed. Radko & Smith (J. Fluid Mech., this issue, vol. 692, 2012, pp. 5–27) have developed a new theory that balances the basic growth rate with that of secondary instabilities that act on the finite amplitude fingers. Their approach promises a way forward for computationally challenging systems with vastly different scales of decay for momentum, heat and dissolved substances.
    Description: 2013-01-24
    Keywords: Double diffusive convection ; Instability ; Ocean processes
    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)
  • 7
    facet.materialart.
    Unknown
    Nonlinear stratified spindown over a slope (2014)
    Cambridge University Press
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2013. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 726 (2013): 371-403, doi:10.1017/jfm.2013.231.
    Description: Nonlinear stratified spindown of an along-isobath current over an insulated slope is shown to develop asymmetries in the vertical circulation and vertical relative vorticity field. During spindown, cyclonic vorticity is weakened to a greater extent than anticyclonic vorticity near the boundary because of buoyancy advection. As a consequence, Ekman pumping is weakened over Ekman suction. Momentum advection can weaken Ekman pumping and strengthen Ekman suction. Time-dependent feedback between the geostrophic flow and the frictional secondary circulation induces asymmetry in cyclonic and anticyclonic vorticity away from the boundary. Buoyancy advection over a slope can modify the secondary circulation such that anticyclonic vorticity decays faster than cyclonic vorticity outside the boundary layer. In contrast, momentum advection can cause cyclonic vorticity to spin down faster than anticyclonic vorticity. A scaling and analytical solutions are derived for when buoyancy advection over a slope can have a more significant impact than momentum advection on these asymmetries. In order to test this scaling and analytical solutions, numerical experiments are run in which both buoyancy and momentum advection are active. These solutions are contrasted with homogeneous or stratified spindown over a flat bottom, in which momentum advection controls the asymmetries. These results are applied to ocean currents over continental shelves and slopes.
    Description: 2014-06-05
    Keywords: Geophysical flows ; 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 ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    Climate change appraisal in the EU: current trends and future challenges (2010)
    Cambridge University Press
    In:  Making Climate Change Work for Us
    Details
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    CITATION PIK
  • 9
    facet.materialart.
    Unknown
    Information from Paleoclimate Archives (2014)
    Cambridge University Press
    In:  Climate Change 2013: The Physical Science Basis
    Details
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    CITATION PIK
  • 10
    facet.materialart.
    Unknown
    Learning to adapt: re-framing climate change adaptation (2010)
    Cambridge University Press
    In:  Making Climate Change Work for Us
    Details
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    CITATION PIK
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...