Can SMOS Ocean Salinity Data Detect a Link Between Increasing Antarctic Sea Ice Extent and Freshwater Flux from Basal Melting of Antarctic ice shelves?
Degree GrantorUniversity of Canterbury
Degree LevelPostgraduate Certificate
Degree NamePostgraduate Certificate in Antarctic Studies
The drivers behind the observed trend of increasing Antarctic sea ice extent are not yet well understood, though several potential drivers have been identified, such as the increased input of freshwater into the Southern Ocean due to basal melting of ice shelves around Antarctica. Previous studies have found seasonal links between the growth and decay of sea ice and the minimum and maximum input of freshwater from basal melting of ice shelves. A variety of observation and measurement techniques have been used to quantify freshwater input from basal melting, and remote sensing techniques have been recognised as an important opportunity for large-scale monitoring of the surface freshwater balance both in the Southern Ocean and globally. In this study, data products from the European Space Agency’s Soil Moisture Ocean Salinity (SMOS) mission are investigated to highlight the strengths and weaknesses of ocean salinity data in detecting salinity and freshwater trends around the Antarctic continent and adjacent to the ice shelves. Several limitations were noted for both data products, including the rejection of data during pre-processing stages due to sea ice presence, land contamination, and too few data measurements. The reliability of data adjacent to the continent and sea ice is therefore substantially reduced, and would benefit from additional investigation into lower-level, unfiltered data that retains the rejected gridpoints, whether this is available through SMOS or a similar mission such as the National Aeronautics and Space Administration (NASA)’s Aquarius mission. However, initial analyses of Level 3 data demonstrated seasonal patterns that correspond with modelled projections of minimum and maximum freshwater input from basal melting of ice shelves, and indicating that there could be a role for remote sensing in monitoring these patterns and, in conjunction with direct measurements, exploring more closely whether freshwater flux from basal melting of ice shelves is a significant driver of increasing seasonal Antarctic sea ice extent. It is vital that biases in SMOS data be addressed, or alternative data sought, to determine the extent to which remote sensing can contribute to this research goal.