Brief communication: ICESat-2 reveals seasonal thickness change patterns of Greenland Ice Sheet outlet glaciers for the first time

• Main Authors: Taubenberger, Christian J., Felikson, Denis, Neumann, Thomas
• Format: Text
• Language: English
• Published: 2021
• Subjects: Greenland; glacier; Ice Sheet
• Online Access: https://doi.org/10.5194/tc-2021-181; https://tc.copernicus.org/preprints/tc-2021-181/

Dynamic changes of marine-terminating outlet glaciers are projected to be responsible for about half of future ice loss from the Greenland Ice Sheet. However, we lack a unified, process-based understanding that can explain the observed dynamic changes of all outlet glaciers. Many glaciers undergo seasonal dynamic thickness changes and classifying the patterns of seasonal thickness change can improve our understanding of the processes that drive glacier behavior. The Ice, Cloud and land Elevation Satellite (ICESat-2) provides the first space-based, seasonally repeating altimetry measurements of the ice sheets, allowing us to quantify near-termini seasonal dynamic thickness patterns of 34 outlet glaciers around the Greenland Ice Sheet. We classify the glaciers into seven common patterns of seasonal thickness change over a two-year period from 2019 to 2020. We find small groupings of neighboring glaciers with similar seasonal thickness change patterns but, within larger sectors of the ice sheet, seasonal thickness change patterns are heterogeneous. Comparing the seasonal thickness changes to average glacier ice flow speeds, we find that faster glaciers typically undergo patterns of spring and summer dynamic thickening, while slower glaciers exhibit a variety of thickness change patterns. Future studies can build upon our results by comparing seasonal dynamic thickness changes with external forcings, such as ocean temperature and meltwater runoff, and with other dynamic variables such as seasonal glacier velocity and terminus position changes.