The National Centre for Polar and Ocean Research (NCPOR) recently predicted an increase in the expansion of the boundaries of the Amery Ice Shelf (AIS), one of the largest glacier drainage basins in the world, located on the east coast of Antarctica. This prediction is based on extensive satellite observations over a 16-year period and is expected to provide valuable insights into changes in oceanic and atmospheric conditions. The AIS dynamics and mass balance are crucial in understanding the global climate scenario.
Understanding Ice Shelves
Ice shelves – floating sheets of ice – play a pivotal role in maintaining glacier stability. They act as connectors between glaciers and landmasses. Their importance can be gauged by various parameters such as the ice sheet mass balance, sea stratification and bottom water formation, which collectively work in harmony to balance a glacier.
The ice sheet mass balance of a glacier refers to the delicate equilibrium between the mass-gain from snow deposition and mass-loss due to melting. Sea stratification refers to the process in which different layers of water with varying properties – salinity, oxygenation, density, temperature – form barriers prohibiting watermixing. The deep-ocean bottom water is formed when surface water cools and sinks at high latitudes.
Key Points Description
The NCPOR’s predictions draw upon a 16-year-long satellite-based observation that covered an impressive area of 60,000 sq. km across the AIS. The study aims to analyse AIS extension and understand the influence of ocean atmospheric forcing in East Antarctica.
Expansion of AIS
According to the predictions, a 24% increase in the expansion of AIS boundaries is expected by 2021 and another 24% expansion by 2026 from its 2016 positions. The study also noted a spatio-temporal change in the ice shelf, as demonstrated by the extension of the Prydz, Mackenzie and the Sandefjord Bays, which form part of the AIS.
Significance
Given the global warming scenario, the study sheds light on the advancement in the predicted ice shelf extent, future dynamics of ocean heat fluctuation, and anticipated shifts in Antarctic Amery ice shelf mass. It was observed that a critical cooling of the Sea Surface Temperature (SST) has led to an 88% advancement of the ice shelf over the past 15 years. Such changes are expected to significantly contribute to climate variability.
