Identifying Glacial Meltwater in the Amundsen Sea

Biddle, Louise (2016) Identifying Glacial Meltwater in the Amundsen Sea. Doctoral thesis, University of East Anglia.

Download (60MB) | Preview


    Pine Island Ice Shelf (PIIS), in the Amundsen Sea, is losing mass due to warm ocean
    waters melting the ice from below. The glacial meltwater appears as a warmer and
    more saline water mass (with lower O2 concentration) than theWinterWater. Tracing
    meltwater pathways from ice shelves is important for identifying the regions most
    affected by the increased input of this water type.
    Water mass characteristics (temperature, salinity, O2 concentration) are used to
    calculate glacial meltwater fractions (MW). The observations from the Amundsen
    Sea show a plume of MW travelling away from PIIS along ¾ = 27.7 kg m¡3, out to
    the continental shelf edge. We investigate the reliability of the interpretation of the
    observations as a signature of MW.
    Physical and biological processes can affect the calculated apparentMWby causing
    variations in the water mass characteristics. In theWeddell Sea, iceberg meltwater
    was found to enhance biological productivity. In the Amundsen Sea, the biological
    productivity was seen to artificially decrease the apparentMWsignature. We analyse
    the effects of these processes on the reliability of the calculated meltwater fractions
    using a modified one-dimensional ocean model. The model simulates the effects of
    an increase in sea ice production and an influx of Lower CDW, as well as biological
    activity. These processes are found to result in an observation that can conventionally
    be interpreted as a meltwater signature, similar to the plume observed at the continental
    shelf edge.
    Recommendations are made to improve the reliability of MW calculations, including
    the identification of a ‘pseudo’-CDW endpoint and to increase the uncertainty
    associated with the O2 concentrations. A meltwater pathway leading to the
    west of PIIS, along the coastline, is observed. This has implications for water mass
    characteristics further to the west and ultimately AABW formation in the Ross Sea.

    Item Type: Thesis (Doctoral)
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    Depositing User: Vailele Chittock
    Date Deposited: 17 Jun 2016 10:41
    Last Modified: 17 Jun 2016 10:41

    Actions (login required)

    View Item