Exploring spatiotemporal patterns of surface mass balance in East Antarctica: Insights from Dronning Maud Land using airborne radar observations

The near-surface stratigraphy of ice sheets provides a unique archive of past specific surface mass balance (SMB), usually on the order of years to millennia. In the context of ongoing climate change, a warming atmosphere is expected to increase SMB over the East Antarctic plateau due to enhanced snowfall. However, the scarcity of observational data across this vast region complicates the quantification of recent SMB changes, contributing to uncertainties in future sea level projections.

In this study, we reconstruct SMB over the last millennium along 3,000 km of airborne radar profiles on the plateau in Dronning Maud Land, East Antarctica. Multiple internal reflection horizons in the firn column are traced in the ultra-wideband radar data. The flight lines overlap with firn core positions, which allow dating of the horizons and thus an interpretation of the data as a proxy for time-averaged SMB. More specifically, we cover decadal to centennial time intervals going back to the 12^th century. The spatial variability (coefficient of variation) reaches more than 120% of the mean value inferred at the firn cores.

For time periods prior to 1975, we find temporally and spatially stable SMB patterns that do not change significantly within our error estimates. After 1975, the data suggest an increase of specific SMB up to 30%. We use environmental information such as wind direction and surface slope to generate spatial SMB fields that highlight spatio-temporal SMB changes. We also present robust uncertainty estimates that will help refine sea level projections and improve our understanding of East Antarctica’s role in the global climate system.