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  • 1
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    Modelled surface mass balance and firn elevation change on Antarctic ice shelves, 2003-2008 (2012)
    PANGAEA
    Details
    Publication Date: 2023-01-13
    Type: Dataset
    Format: application/zip, 10.9 kBytes
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Corrected ICESat altimetry data, surface mass balance, and firn elevation change on Antarctic ice shelves (2012)
    PANGAEA
    Details
    Publication Date: 2023-02-24
    Description: Accurate prediction of global sea-level rise requires that we understand the cause of recent, widespread and intensifying glacier acceleration along Antarctic ice-sheet coastal margins. Floating ice shelves buttress the flow of grounded tributary glaciers and their thickness and extent are particularly susceptible to changes in both climate and ocean forcing. Recent ice-shelf collapse led to retreat and acceleration of several glaciers on the Antarctic Peninsula. However, the extent and magnitude of ice-shelf thickness change, its causes and its link to glacier flow rate are so poorly understood that its influence on the future of the ice sheets cannot yet be predicted. Here we use satellite laser altimetry and modelling of the surface firn layer to reveal for the first time the circum-Antarctic pattern of ice-shelf thinning through increased basal melt. We deduce that this increased melt is the primary driver of Antarctic ice-sheet loss, through a reduction in buttressing of the adjacent ice sheet that has led to accelerated glacier flow. The highest thinning rates (~7 m/a) occur where warm water at depth can access thick ice shelves via submarine troughs crossing the continental shelf. Wind forcing could explain the dominant patterns of both basal melting and the surface melting and collapse of Antarctic ice shelves, through ocean upwelling in the Amundsen and Bellingshausen Seas and atmospheric warming on the Antarctic Peninsula. This implies that climate forcing through changing winds influences Antarctic Ice Sheet mass balance, and hence global sea-level, on annual to decadal timescales.
    Keywords: ice2sea
    Type: Dataset
    Format: application/zip, 2 datasets
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    DATA PANGAEA
  • 3
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    Corrected ICESat altimetry data for Antarctic ice shelves with links to shapefiles (2012)
    PANGAEA
    In:  British Antarctic Survey, Cambridge
    Details
    Publication Date: 2023-02-24
    Keywords: Area/locality; File name; File size; ice2sea; LATITUDE; LONGITUDE; Polar stereographic projection, X; Polar stereographic projection, Y; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 72 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 4
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    Antarctic Pacific sector ice-shelf height anomaly for 1994-2017 from satellite radar altimetry
    PANGAEA
    In:  Supplement to: Paolo, Fernando S; Padman, Laurie; Fricker, Helen; Adusumilli, S; Howard, S; Siegfried, M R (2018): Response of Pacific-sector Antarctic ice shelves to the El Niño/Southern Oscillation. Nature Geoscience, 11, 121-126, https://doi.org/10.1038/s41561-017-0033-0
    Details
    Publication Date: 2023-05-12
    Description: Satellite observations over the past two decades have revealed increasing loss of grounded ice in West Antarctica, associated with floating ice shelves that have been thinning. Thinning reduces an ice shelf's ability to restrain grounded-ice discharge, yet our understanding of the climate processes that drive mass changes is limited. Here, we use ice-shelf height data from four satellite altimeter missions (1994-2017) to show a direct link between ice-shelf height variability in the Antarctic Pacific sector and changes in regional atmospheric circulation driven by the El Niño/Southern Oscillation. This link is strongest from the Dotson to Ross ice shelves and weaker elsewhere. During intense El Niño years, height increase by accumulation exceeds the height decrease by basal melting, but net ice-shelf mass declines as basal ice loss exceeds ice gain by lower-density snow. Our results demonstrate a substantial response of Amundsen Sea ice shelves to global and regional climate variability, with rates of change in height and mass on interannual timescales that can be comparable to the longer-term trend, and with mass changes from surface accumulation offsetting a significant fraction of the changes in basal melting. This implies that ice-shelf height and mass variability will increase as interannual atmospheric variability increases in a warming climate.
    Keywords: Antarctica; Antarctica_pacific; RADAR; Radar profile
    Type: Dataset
    Format: application/zip, 84.3 kBytes
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    DATA PANGAEA
  • 5
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    Intensification of Near‐Surface Currents and Shear in the Eastern Arctic Ocean (2020)
    AGU | Wiley
    Details
    Publication Date: 2023-02-08
    Description: A 15-year (2004–2018) record of mooring observations from the upper 50 m of the ocean in the eastern Eurasian Basin reveals increased current speeds and vertical shear, associated with an increasing coupling between wind, ice, and the upper ocean over 2004–2018, particularly in summer. Substantial increases in current speeds and shears in the upper 50 m are dominated by a two times amplification of currents in the semidiurnal band, which includes tides and wind-forced near-inertial oscillations. For the first time the strengthened upper ocean currents and shear are observed to coincide with weakening stratification. This coupling links the Atlantic Water heat to the sea ice, a consequence of which would be reducing regional sea ice volume. These results point to a new positive feedback mechanism in which reduced sea ice extent facilitates more energetic inertial oscillations and associated upper-ocean shear, thus leading to enhanced ventilation of the Atlantic Water.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean (2020)
    AMS (American Meterological Society)
    Details
    Publication Date: 2023-02-08
    Description: A 15-yr duration record of mooring observations from the eastern (〉70°E) Eurasian Basin (EB) of the Arctic Ocean is used to show and quantify the recently increased oceanic heat flux from intermediate-depth (~150–900 m) warm Atlantic Water (AW) to the surface mixed layer and sea ice. The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to 〉10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Oceanic Routing of Wind-Sourced Energy Along the Arctic Continental Shelves (2020)
    Frontiers
    Details
    Publication Date: 2023-02-08
    Description: Data from coastal tide gauges, oceanographic moorings, and a numerical model show that Arctic storm surges force continental shelf waves (CSWs) that dynamically link the circumpolar Arctic continental shelf system. These trains of barotropic disturbances result from coastal convergences driven by cross-shelf Ekman transport. Observed propagation speeds of 600−3000 km day–1, periods of 2−6 days, wavelengths of 2000−7000 km, and elevation maxima near the coast but velocity maxima near the upper slope are all consistent with theoretical CSW characteristics. Other, more isolated events are tied to local responses to propagating storm systems. Energy and phase propagation is from west to east: ocean elevation anomalies in the Laptev Sea follow Kara Sea anomalies by one day and precede Chukchi and Beaufort Sea anomalies by 4−6 days. Some leakage and dissipation occurs. About half of the eastward-propagating energy in the Kara Sea passes Severnaya Zemlya into the Laptev Sea. About half of the eastward-propagating energy from the East Siberian Sea passes southward through Bering Strait, while one quarter is dissipated locally in the Chukchi Sea and another quarter passes eastward into the Beaufort Sea. Likewise, CSW generation in the Bering Sea can trigger elevation and current speed anomalies downstream in the Northeast Chukchi Sea of 25 cm and 20 cm s–1, respectively. Although each event is ephemeral, the large number of CSWs generated annually suggest that they represent a non-negligible source of time-averaged energy transport and bottom stress-induced dissipative mixing, particularly near the outer shelf and upper slope. Coastal water level and landfast ice breakout event forecasts should include CSW effects and associated lag times from distant upstream winds.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Eastern Arctic Ocean Diapycnal Heat Fluxes through Large Double-Diffusive Steps (2019)
    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanograph, 49 (1). pp. 227-246.
    Details
    Publication Date: 2022-01-31
    Description: The diffusive layering (DL) form of double-diffusive convection cools the Atlantic Water (AW) as it circulates around the Arctic Ocean. Large DL steps, with heights of homogeneous layers often greater than 10 m, have been found above the AW core in the Eurasian Basin (EB) of the eastern Arctic. Within these DL staircases, heat and salt fluxes are determined by the mechanisms for vertical transport through the high-gradient regions (HGRs) between the homogeneous layers. These HGRs can be thick (up to 5 m and more) and are frequently complex, being composed of multiple small steps or continuous stratification. Microstructure data collected in the EB in 2007 and 2008 are used to estimate heat fluxes through large steps in three ways: using the measured dissipation rate in the large homogeneous layers; utilizing empirical flux laws based on the density ratio and temperature step across HGRs after scaling to account for the presence of multiple small DL interfaces within each HGR; and averaging estimates of heat fluxes computed separately for individual small interfaces (as laminar conductive fluxes), small convective layers (via dissipation rates within small DL layers), and turbulent patches (using dissipation rate and buoyancy) within each HGR. Diapycnal heat fluxes through HGRs evaluated by each method agree with each other and range from ~2 to ~8 W m−2, with an average flux of ~3–4 W m−2. These large fluxes confirm a critical role for the DL instability in cooling and thickening the AW layer as it circulates around the eastern Arctic Ocean.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1175/JPO-D-18-0080.1
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    Interannual changes of the floating ice shelf of Petermann Gletscher, North Greenland, from 2000 to 2012 (2014)
    Cambridge University Press
    Details
    Publication Date: 2014-07-21
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Published by Cambridge University Press on behalf of The International Glaciological Society (IGS).
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    PAPER CURRENT
  • 10
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    Seals map bathymetry of the Antarctic continental shelf (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 37 (2010): L21601, doi:10.1029/2010GL044921.
    Description: We demonstrate the first use of marine mammal dive-depth data to improve maps of bathymetry in poorly sampled regions of the continental shelf. A group of 57 instrumented elephant seals made on the order of 2 × 105 dives over and near the continental shelf on the western side of the Antarctic Peninsula during five seasons, 2005–2009. Maximum dive depth exceeded 2000 m. For dives made near existing ship tracks with measured water depths H〈700 m, ∼30% of dive depths were to the seabed, consistent with expected benthic foraging behavior. By identifying the deepest of multiple dives within small areas as a dive to the seabed, we have developed a map of seal-derived bathymetry. Our map fills in several regions for which trackline data are sparse, significantly improving delineation of troughs crossing the continental shelf of the southern Bellingshausen Sea.
    Description: This work was supported by: NASA grants NNG05GR58G, NNX06AD40G and NNG06GA69G to LP; ONR grant N00014‐05‐1‐ 0645 to DPC; NSF grants OPP‐0338101 to ESR, and ANT‐0440687 and ANT‐0523332 to DPC and MEG; and the U.S.‐AMLR program.
    Keywords: Antarctic continental shelf ; Bathymetry ; Seal dive depth
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Format: image/tiff
    Format: text/plain
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    PAPER (OA)
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