West Antarctic mass trends and driving processes from 2003 until present from a Bayesian hierarchical model approach

Abstract:

West Antarctica, encompassing the Amundsen Sea Embayment and Antarctic Peninsula, has undergone rapid changes in mass balance over the last two decades, evidenced through observations of grounding line retreat and increases in ice sheet velocity. The collapse of the Larsen A and B ice shelves in the Antarctic Peninsula exemplify the rapidity of the grounded ice sheet response and provide potential analogues for future ice sheet response to ice shelf collapse in other regions of Antarctica. Better understanding of the processes driving these changes require long-term continuous monitoring from multiple observation approaches.

The topography and geometry of this region makes it challenging to assess its mass balance. Conventional pulse limited satellite altimetry suffers from data loss over regions of mountainous topography, whereas the coarse spatial resolution of GRACE (~300 km) is unable to resolve small scale changes over outlet glaciers and is susceptible to signal leakage. Conversely, datasets such as stereo-image DEM differencing and laser altimetry from Operation Ice Bridge provide localised observations of these challenging regions but are limited in their wider spatial coverage and temporal resolution. As a result, it is difficult to integrate these diverse observations to provide a single reconciled mass balance estimate, in addition to the contribution of each driving process.

To resolve this, we have developed an optimised Bayesian hierarchical model to specifically investigate this region. It incorporates an improved and more diverse range of observations including CryoSat-2 swath altimetry, stereo-image DEM differencing and NASA Operation Ice Bridge laser altimetry. We will present results from the regionally optimised model from 2003 until present, including basin-scale mass trends and changes in spatial latent processes at an annual resolution. Additionally, we will discuss future opportunities, such as the extension of the technique into the next decade.