Publication Abstracts

Smith et al. 2023, accepted

Smith, B.E., B. Medley, X. Fettweis, T. Sutterley, P. Alexander, D. Porter, and M. Tedesco, 2023: Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry. The Cryosphere, accepted.

Surface-mass-balance (SMB) and firn-densification (FD) models are widely used in altimetry studies as a tool to separate atmospheric-driven from ice-dynamics-driven ice-sheet mass changes, and to partition observed volume changes into ice-mass changes and firn-air-content changes. Until now, SMB models have been principally validated based on comparison with ice core and weather-station data, or comparison with widely separated flight radar-survey flight lines. Firn-densification models have been primarily validated based on their ability to match net densification over decades, as recorded in firn cores, and the short-term time-dependent component of densification has rarely been evaluated at all. The advent of systematic ice-sheet-wide repeated ice-surface-height measurements from ICESat-2 (the Ice Cloud, and land Elevation Satellite, 2) allows us to measure the net surface-height change of the Greenland ice sheet at quarterly resolution, and compare the surface height changes directly with those predicted by three FD/SMB models. By segregating the data by season and elevation, and based on the timing and magnitude of modelled processes in areas where we expect minimal ice-dynamic-driven height changes, we investigate the models' accuracy in predicting atmospherically-driven height changes. We find that while all three models do well in predicting the large seasonal changes in the low-elevation parts of the ice sheet where melt rates are highest, two models systematically overpredict, by around a factor of two, the magnitude of height changes in the high-elevation parts of the ice sheet, particularly those associated with melt events. This overprediction seems to be associated with the melt sensitivity of the models in the high-elevation part of the ice sheet, and third model, which has an updated high-elevation melt parameterization, avoids this overprediction.

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BibTeX Citation

  author={Smith, B. E. and Medley, B. and Fettweis, X. and Sutterley, T. and Alexander, P. and Porter, D. and Tedesco, M.},
  title={Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry},
  journal={The Cryosphere},

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RIS Citation

ID  - sm04200y
AU  - Smith, B. E.
AU  - Medley, B.
AU  - Fettweis, X.
AU  - Sutterley, T.
AU  - Alexander, P.
AU  - Porter, D.
AU  - Tedesco, M.
PY  - 2023
TI  - Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry
JA  - The Cryosphere
ER  -

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