Noble Gases and Helium Isotopes During Ocean2ice: Processes and Variability of Ocean Heat Transport Toward Ice Shelves in the Amundsen Sea

University Of Rhode Island, Kingston RI

Investigators

Abstract

Ice shelf mass balance is controlled by net surface accretion (precipitation minus ablation and surface melt terms), calving and basal melt along the underside of the ice shelf cavity, which is in contact with a warming ocean. Estimating the rate of basal melt is the most challenging term in this balance because it is difficult to directly observe, but is also sensitive to changes in ocean temperature and other ocean-atmospheric processes such as the sea ice cycle. This project will join the Ocean2ice program, a UK led effort to integrate state of the art instrumentation, chemical analysis and modeling with the goal of improving the dynamical representation of ice shelf mas balance processes in Antarctic circulation models. In the Amundsen Sea, the shoaling warm Circumpolar Deep Water (CDW) and surficial glacial meltwater are two important diagnostic and prognostic terms in the ice shelf mass balance. By measuring the distribution of these water masses, using a suite of their distinct inert gas tracers ? 3He, 4He, Ne, Ar, Kr and Xe - together with their change over time, estimates of basal melt rates of some of the large West Antarctic ice shelves (e.g. Pine Island Glacier) are to be made. Greenland and the West Antarctic Ice Sheets together represent potentially more than a 10 m of increase in mean (global) sea surface height. How fast glacial mobilization rates may increase is of considerable societal importance.