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Satellite observations of atmosphere-ice-ocean interactions around Antarctica

  • Author(s): Adusumilli, Susheel
  • Advisor(s): Fricker, Helen A
  • et al.
Abstract

Ongoing increases in global sea level, projected to continue through the 21st century, have widespread impacts on coastal communities and infrastructure. Uncertainties in model projections of Antarctic Ice Sheet mass represent a major contribution to uncertainties in projected sea level rise. Many modelling studies have identified the important role of climate variability in driving ice sheet change; however, there have not been sufficient observational studies on the impact of this variability on the ice sheet.

The Antarctic Ice Sheet is vast, and remote; therefore, satellites are the only feasible instruments with which we can measure changes in ice mass. In particular, satellite radar and laser altimeter measurements of changes in ice sheet height are a valuable tool to monitor changes in mass of both grounded ice and floating ice shelves. In this dissertation, we use satellite altimetry together with other ancillary datasets to identify the influences of variability in atmospheric and oceanic conditions on ice sheet mass.

We demonstrate of how satellite radar altimetry data can be used to identify the climate drivers ice shelf change during 1994–2016 in the Antarctic Peninsula, a region that has changed rapidly during that period. In the western Antarctic Peninsula, the rates of ocean-driven basal melting exceeded values required to maintain constant mass. Extending this analysis to all Antarctic ice shelves, we find large interannual variability in the total volume flux of freshwater due to basal melting exported into the Southern Ocean, with the highest values occurring during the late 2000s from ice shelves in West Antarctica. Finally, we demonstrate how laser altimetry can be used to monitor large changes in snowfall at seasonal time scales over the grounded portion of the West Antarctic Ice Sheet during the 2019.

The results described in this dissertation together highlight the value of satellite altimetry in observing variability in ice sheet mass at seasonal to interannual time scales. We expect that they will help improve model projections of sea level rise through a better understanding of the processes driving ice sheet change, and by providing improved constraints on the current state of the atmosphere-ice-ocean system.

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