ALBERT

Description: The Antarctic Peninsula has exhibited some of the most spectacular changes observed in glacial systems in recent decades. The events include disintegration of ice shelves, acceleration and thinning of glaciers, variations in the limits between glacier facies, and retreat of glacier fronts. However, due to the lack of both consistent systematic observations of the glacial systems and information on their boundary conditions, it is difficult to accurately predict the contribution of Antarctic Peninsula glaciers to sea level rise and further responses of these ice masses to climatic and oceanographic changes. In this context, the activities of the GLIMS Regional Center for the Antarctic Peninsula and its network of international collaborators are based on the use of various types of Earth observation imagery, mainly optical and radar data. Although a complete glacier inventory is still lacking, we present the results of changes in glacier frontal positions and boundaries of glacier facies as well as links to dynamical adjustments for various locations in the Antarctic Peninsula’s ice masses. Evaluation of Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) digital elevation models generated for the Antarctic Peninsula is also discussed.

Description: The Cordillera Darwin Icefield in Tierra del Fuego experienced important mass losses during the last decades. Yet it is difficult to associate the recent loss to atmospheric changes as in-situ observations of climatic conditions and glacier mass balances are scarce due to the difficult accessibility and the harsh weather conditions in that area. Under these challenging conditions, we investigate strategies for calibration of surface mass balance models in the Monte Sarmiento Massif, western Cordillera Darwin. This study aims to identify best practices for regional scale application as well as to assess the influence of melt-model complexity.Applied calibration strategies range from a local single-glacier calibration to a regional calibration with the inclusion of a snowdrift parametrization. Furthermore, we apply four models of different complexity ranging from an empirical degree-day model to a fully-fledged surface energy balance model. This way, we examine the model transferability in space, the benefit of including regional mass change observations as calibration constraint and the advantage of increasing melt-model complexity. In-situ measurements comprise ablation stakes, ice thickness surveys and meteorological records at one glacier. Satellite remote sensing provides surface velocity and geodetic elevation changes for the entire region. Performance of simulated surface mass balance is validated against geodetic mass changes and stake observations.Results show that spatially transferring mass balance models is challenging and can produce distinctly biased estimates. The use of remotely sensed regional observations can significantly improve model performance. Snowdrift has an important impact on the surface mass balance in the Cordillera Darwin.

Description: The South Shetland Islands (SSIs) region, located on the northern Antarctic Peninsula (AP), is influenced by different climatic configurations from regional (five atmospheric circulation patterns, sea ice extent-concentration and surface temperature) to global (Southern Annular Mode-SAM, El Niño-Southern Oscillation-ENSO and deep convection in the central tropical Pacific-CPAC) scales. However, few studies have been developed to assess the influence of these climatic conditions on the surface mass balance (SMB) of glaciers located in the SSIs. To fill this gap, we analyzed correlation between annual SMB, reconstituted with a physical surface energy balance model (COSIPY), and regional-global climate indices from 1970 to 2020. COSIPY was calibrated and validated with 19 years of annual SMB observations from three glaciers (Johnsons, Hurd and Bellinghausen), showing a good ability to capture inter-annual (R² = 71%) variability. Results showed a break in the annual SMB trend following the warming and cooling periods of the surface air temperature in the AP. In addition, our results indicated low dependence of the SMB with main global atmospheric variability (SAM, ENSO and CPAC) and high dependence with custom regional climate indices (Drake Passage, Amundsen–Bellingshausen and Weddell regions). This study highlights the Drake Passage as a key region that has the potential to influence the interannual variability of the SMB and other climate variables such as surface air temperature and snowfall in the SSIs. We suggest that future work should consider this region to better understand the past, present and future climate changes on the SSIs and surrounding areas.