Identifying Glacial Meltwater in the Amundsen Sea

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

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Abstract

Abstract
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 09:41
Last Modified: 17 Jun 2016 09:41
URI: https://ueaeprints.uea.ac.uk/id/eprint/59385
DOI:

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