Project Rationale
The aim of this project is to assess the role of climate variability in driving Antarctic Ice Sheet changes by combing new observations of ice, ocean and atmosphere.
The Antarctic Ice Sheet has been losing mass at an accelerating rate, contributing >1 cm to global sea-level rise since the 1970s, [1]. This mass loss is associated with acceleration and retreat of marine-terminating glaciers. In turn, the retreat of these glaciers has been mostly associated with rapid basal melting at their floating terminus (ice shelves) by warm ocean waters.
Superimposed on this multidecadal trend are interannual fluctuations in glacier velocities and ice-shelf basal melting that vary spatially across Antarctica [1,2]. Such fluctuations can result in periods of enhanced glacial loss alternated with periods of stability. In the Amundsen Sea, these fluctuations have been linked to wind-driven variability of oceanic coastal circulation [3]. Interannual wind (and consequently glacial melting) variability in the Amundsen Sea is influenced by climate forcing through atmospheric teleconnections from the tropical Pacific [3] (i.e. El-Nino Southern Oscillation, ENSO). Other modes of climate variability, such as the Southern Annular Mode (SAM), also cause changes in ocean circulation around Antarctica. However, at continental scale, it remains uncertain how climate variability influences the behaviour of Antarctic glaciers and ice shelves. This project will fill this important knowledge gap.
Methodology
The candidate will combine pan-Antarctic estimates of ice sheet, ocean and atmospheric changes since the 1990s to develop a multi-disciplinary project. The following datasets will be used:
Ice Sheet: satellite-derived estimates of: 1) ice shelf melting, and 2) surface velocity of outlet glaciers around Antarctica.
Ocean: 1) satellite-derived sea surface height in the Southern Ocean (including recently-developed under sea ice measurements), allowing to detect changes in ocean circulation. 2) most recent compilation of in situ observations in the Southern Ocean
Atmosphere: Reanalysis products (e.g., EMCWF ERA5).
Climate Indices: e.g., ENSO (El-Nino Southern Oscillation), SAM (Southern Annular Mode)
The project will combine these different datasets using a statistical approach (e.g. coherence, Maximum Covariance and Principal Component Analysis) to detect coherent changes in the atmospheric-ocean-ice system. Physical interpretation will be essential to extract the mechanisms responsible for causing temporal changes in the ice shelves and outlet glaciers. Moreover, the candidate may use available circumpolar Southern Ocean models to gain further insight into the physical processes causing ocean variability near Antarctic glaciers.
The outcome of this project will provide new evidence of the role of climate variability in driving Antarctica’s contribution to sea-level rise. This project will be relevant to international research programmes such as SCAR’s (Scientific Committee on Antarctic Research) INSTANT (https://www.scar-instant.org).
Training
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and based at the National Oceanography Centre Southampton. Specific training will include:
• Processing and analysis of multi-disciplinary observational datasets.
• Understanding of a range of ice, ocean and atmospheric processes.
• Opportunities to attend national/international conferences to disseminate the candidate’s results and to broaden their scientific network.
• Opportunities to take part in fieldwork, including a cruise in the Southern Ocean.
• Opportunities to visit co-supervisors at the University of Leeds (UK), BAS (UK) and CSIRO (Australia).
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