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: 2017-01-05
    Description: Author Posting. © American Geophysical Union, 2008. 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 113 (2008): C00A02, doi:10.1029/2008JC004829.
    Description: Six Ice-Tethered Profilers (ITP), deployed in the central Canada Basin of the Arctic Ocean between 2004 and 2007, have provided detailed potential temperature and salinity measurements of a double-diffusive staircase at about 200–300 m depth. Individual layers in the staircase are of order 1 m in vertical height but appear to extend horizontally for hundreds of kilometers, with along-layer gradients of temperature and salinity tightly related. On the basis of laboratory-derived double-diffusive flux laws, estimated vertical heat fluxes through the staircase are in the range 0.05–0.3 W m−2, only about one tenth of the estimated mean surface mixed layer heat flux to the sea ice. It is thus concluded that the vertical transport of heat from the Atlantic Water in the central basin is unlikely to have a significant impact to the Canada Basin ocean surface heat budget. Icebreaker conductivity-temperature-depth data from the Beaufort Gyre Freshwater Experiment show that the staircase is absent at the basin periphery. Turbulent mixing that presumably disrupts the staircase might drive greater flux from the Atlantic Water at the basin boundaries and possibly dominate the regionally averaged heat flux.
    Description: Funding for construction and deployment of the prototype ITPs was provided by the National Science Foundation Oceanographic Technology and Interdisciplinary Coordination (OTIC) Program and Office of Polar Programs (OPP) under grant OCE-0324233. Continued support for the ITP field program and data analysis has been provided by the OPP Arctic Sciences Section under awards ARC-0519899, ARC-0631951, ARC-0713837, and internal WHOI funding.
    Keywords: Double-diffusion ; Canada basin ; Ice-Tethered Profiler
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2017-01-04
    Description: Author Posting. © American Meteorological Society, 2010. 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 Atmospheric and Oceanic Technology 27 (2010): 1936-1949, doi:10.1175/2010JTECHO772.1.
    Description: Four ice-tethered profilers (ITPs), deployed between 2006 and 2009, have provided year-round dissolved oxygen (DO) measurements from the surface mixed layer to 760-m depth under the permanent sea ice cover in the Arctic Ocean. These ITPs drifted with the permanent ice pack and returned 2 one-way profiles per day of temperature, salinity, and DO. Long-term calibration drift of the oxygen sensor can be characterized and removed by referencing to recently calibrated ship DO observations on deep isotherms. Observed changes in the water column time series are due to both drift of the ITP into different water masses and seasonal variability, driven by both physical and biological processes within the water column. Several scientific examples are highlighted that demonstrate the considerable potential for sustained ITP-based DO measurements to better understand the Arctic Ocean circulation patterns and biogeochemical processes beneath the sea ice.
    Description: The National Science Foundation Office of Polar Programs Arctic Sciences Section under Awards ARC-0519899, ARC-0856479, and ARC-0806306 provided funding.
    Keywords: Profilers ; Ice shelves ; Arctic
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2017-01-04
    Description: Author Posting. © American Meteorological Society, 2007. 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 37 (2007): 1066–1076, doi:10.1175/JPO3032.1.
    Description: A 50-day time series of high-resolution temperature in the deepest layers of the Canada Basin in the Arctic Ocean indicates that the deep Canada Basin is a dynamically active environment, not the quiet, stable basin often assumed. Vertical motions at the near-inertial (tidal) frequency have amplitudes of 10– 20 m. These vertical displacements are surprisingly large considering the downward near-inertial internal wave energy flux typically observed in the Canada Basin. In addition to motion in the internal-wave frequency band, the measurements indicate distinctive subinertial temperature fluctuations, possibly due to intrusions of new water masses.
    Keywords: Arctic ; Ocean dynamics ; Ship observations
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2017-01-04
    Description: Author Posting. © American Meteorological Society, 2005. 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 35 (2005): 1489–1493, doi:10.1175/JPO2765.1.
    Description: The Arctic Ocean likely impacts global climate through its effect on the rate of deep-water formation and the subsequent influence on global thermohaline circulation. Here, the renewal of the deep waters in the isolated Canadian Basin is quanitified. Using hydraulic theory and hydrographic observations, the authors calculate the magnitude of this renewal where circumstances have thus far prevented direct measurements. A volume flow rate of Q = 0.25 ± 0.15 Sv (Sv ≡ 106 m3s−1) from the Eurasian Basin to the Canadian Basin via a deep gap in the dividing Lomonosov Ridge is estimated. Deep-water renewal time estimates based on this flow are consistent with 14C isolation ages. The flow is sufficiently large that it has a greater impact on the Canadian Basin deep water than either the geothermal heat flux or diffusive fluxes at the deep-water boundaries.
    Description: Financial support was provided to P. Winsor from NSF OPP- 0352628.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2017-01-04
    Description: Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24 no. 3 (2011): 126–135, doi:10.5670/oceanog.2011.64.
    Description: Ice-Tethered Profilers (ITPs), first deployed in fall 2004, have significantly increased the number of high-quality upper-ocean water-property observations available from the central Arctic. This article reviews the instrument technology and provides a status report on performance, along with several examples of the science that ITPs and companion instrumentation support.
    Description: Initial development of the ITP concept was supported by the Cecil H. and Ida M. Green Technology Innovation Program at the Woods Hole Oceanographic Institution. Funding for construction and deployment of the prototype ITPs was provided by the National Science Foundation Oceanographic Technology and Interdisciplinary Coordination (OTIC) Program and Office of Polar Programs (OPP) under Grant OCE-0324233. Continued support has been provided by the OPP Arctic Sciences Section under Awards ARC-0519899, ARC-0631951, ARC-0856479, and internal WHOI funding, including the James M. and Ruth P. Clark Initiative for Arctic Research.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2017-01-04
    Description: Author Posting. © American Meteorological Society, 2014. 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 44 (2014): 1306–1328, doi:10.1175/JPO-D-12-0191.1.
    Description: The ice–ocean system is investigated on inertial to monthly time scales using winter 2009–10 observations from the first ice-tethered profiler (ITP) equipped with a velocity sensor (ITP-V). Fluctuations in surface winds, ice velocity, and ocean velocity at 7-m depth were correlated. Observed ocean velocity was primarily directed to the right of the ice velocity and spiraled clockwise while decaying with depth through the mixed layer. Inertial and tidal motions of the ice and in the underlying ocean were observed throughout the record. Just below the ice–ocean interface, direct estimates of the turbulent vertical heat, salt, and momentum fluxes and the turbulent dissipation rate were obtained. Periods of elevated internal wave activity were associated with changes to the turbulent heat and salt fluxes as well as stratification primarily within the mixed layer. Turbulent heat and salt fluxes were correlated particularly when the mixed layer was closest to the freezing temperature. Momentum flux is adequately related to velocity shear using a constant ice–ocean drag coefficient, mixing length based on the planetary and geometric scales, or Rossby similarity theory. Ekman viscosity described velocity shear over the mixed layer. The ice–ocean drag coefficient was elevated for certain directions of the ice–ocean shear, implying an ice topography that was characterized by linear ridges. Mixing length was best estimated using the wavenumber of the beginning of the inertial subrange or a variable drag coefficient. Analyses of this and future ITP-V datasets will advance understanding of ice–ocean interactions and their parameterizations in numerical models.
    Description: Support for this study and the overall ITP program was provided by the National Science Foundation and Woods Hole Oceanographic Institution. Support for S. Cole was partially though the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Devonshire Foundation.
    Description: 2014-11-01
    Keywords: Geographic location/entity ; Arctic ; Sea ice ; Circulation/ Dynamics ; Ekman pumping/transport ; Internal waves ; Turbulence ; Atm/Ocean Structure/ Phenomena ; Oceanic mixed layer
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2016-09-23
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Philosophical Transactions of the Royal Society A 373 (2015): 20140160, doi:10.1098/rsta.2014.0160.
    Description: Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability.
    Description: Support was provided by US National Science Foundation PLR 1313614, 1203720, 1107277 and 0856531 to A.P., PLR-0804017 to D.D. and by the HYCOM consortium (no. N00014-09-1-0587) to D.D.
    Keywords: Arctic climate variability ; Circulation regimes ; Freshwater and heat content
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2017-06-02
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Biogeosciences 121 (2016): 675-717, doi:10.1002/2015JG003140.
    Description: The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean's thermohaline circulation. We here assess the system's key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and storage) of freshwater components within the Arctic Ocean; and (3) the release and export of freshwater components into the bordering convective domains of the North Atlantic. We then examine physical, chemical, or biological processes which are influenced or constrained by the local quantities and geochemical qualities of freshwater; these include stratification and vertical mixing, ocean heat flux, nutrient supply, primary production, ocean acidification, and biogeochemical cycling. Internal to the Arctic the joint effects of sea ice decline and hydrological cycle intensification have strengthened coupling between the ocean and the atmosphere (e.g., wind and ice drift stresses, solar radiation, and heat and moisture exchange), the bordering drainage basins (e.g., river discharge, sediment transport, and erosion), and terrestrial ecosystems (e.g., Arctic greening, dissolved and particulate carbon loading, and altered phenology of biotic components). External to the Arctic freshwater export acts as both a constraint to and a necessary ingredient for deep convection in the bordering subarctic gyres and thus affects the global thermohaline circulation. Geochemical fingerprints attained within the Arctic Ocean are likewise exported into the neighboring subarctic systems and beyond. Finally, we discuss observed and modeled functions and changes in this system on seasonal, annual, and decadal time scales and discuss mechanisms that link the marine system to atmospheric, terrestrial, and cryospheric systems.
    Description: World Climate Research Program-Climate and Cryosphere (WCRP-CliC); Arctic Monitoring and Assessment Program (AMAP) International Arctic Science Committee (IASC); Norwegian Ministries of Environment and of Foreign Affairs; Swedish Secretariat for Environmental Earth System Sciences (SSEESS); Swedish Polar Research Secretariat; NSF Grant Numbers: OCE 1130008, 1249133, AON-1203473, AON-1338948, OCE 1434041; Polar Research Programme of the Norwegian Research Council Grant Number: 226415
    Keywords: Arctic ; Oceans ; Circulation ; Freshwater ; Carbon cycle ; Acidification
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2017-08-08
    Description: Author Posting. © American Geophysical Union, 2017. 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: Oceans 122 (2017): 980–994, doi:10.1002/2016JC012419.
    Description: The Arctic Ocean thermohaline stratification frequently exhibits a staircase structure overlying the Atlantic Water Layer that can be attributed to the diffusive form of double-diffusive convection. The staircase consists of multiple layers of O(1) m in thickness separated by sharp interfaces, across which temperature and salinity change abruptly. Through a detailed analysis of Ice-Tethered Profiler measurements from 2004 to 2013, the double-diffusive staircase structure is characterized across the entire Arctic Ocean. We demonstrate how the large-scale Arctic Ocean circulation influences the small-scale staircase properties. These staircase properties (layer thicknesses and temperature and salinity jumps across interfaces) are examined in relation to a bulk vertical density ratio spanning the staircase stratification. We show that the Lomonosov Ridge serves as an approximate boundary between regions of low density ratio (approximately 3–4) on the Eurasian side and higher density ratio (approximately 6–7) on the Canadian side. We find that the Eurasian Basin staircase is characterized by fewer, thinner layers than that in the Canadian Basin, although the margins of all basins are characterized by relatively thin layers and the absence of a well-defined staircase. A double-diffusive 4/3 flux law parametrization is used to estimate vertical heat fluxes in the Canadian Basin to be O(0.1) W m−2. It is shown that the 4/3 flux law may not be an appropriate representation of heat fluxes through the Eurasian Basin staircase. Here molecular heat fluxes are estimated to be between O(0.01) and O(0.1) W m−2. However, many uncertainties remain about the exact nature of these fluxes.
    Description: National Science Foundation Division of Polar Programs
    Description: 2017-08-08
    Keywords: Arctic Ocean ; Double-diffusion ; Atlantic Water
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2019-01-10
    Description: Author Posting. © American Geophysical Union, 2018. 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: Oceans 123 (2018): 4806-4819, doi:10.1029/2018JC014037.
    Description: Kinetic energy (KE) in the Arctic Ocean's Beaufort Gyre is dominated by the mesoscale eddy field that plays a central role in the transport of freshwater, heat, and biogeochemical tracers. Understanding Beaufort Gyre KE variability sheds light on how this freshwater reservoir responds to wind forcing and sea ice and ocean changes. The evolution and fate of mesoscale eddies relate to energy pathways in the ocean (e.g., the exchange of energy between barotropic and baroclinic modes). Mooring measurements of horizontal velocities in the Beaufort Gyre are analyzed to partition KE into barotropic and baroclinic modes and explore their evolution. We find that a significant fraction of water column KE is in the barotropic and the first two baroclinic modes. We explain this energy partitioning by quantifying the energy transfer coefficients between the vertical modes using the quasi‐geostrophic potential vorticity conservation equations with a specific background stratification observed in the Beaufort Gyre. We find that the quasi‐geostrophic vertical mode interactions uphold the persistence of KE in the first two baroclinic modes, consistent with observations. Our results explain the specific role of halocline structure on KE evolution in the gyre and suggest depressed transfer to the barotropic mode. This limits the capacity for frictional dissipation at the sea floor and suggests that energy dissipation via sea ice‐ocean drag may be prominent.
    Description: National Science Foundation Division of Polar Programs Grant Number: 1107623
    Description: 2019-01-10
    Keywords: Beaufort Gyre kinetic energy ; Mesoscale eddies ; Energy pathways ; Barotropic and baroclinic modes
    Repository Name: Woods Hole Open Access Server
    Type: Article
    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...