Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry
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 mode...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , , , |
Format: | Text |
Language: | English |
Published: |
2023
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-17-789-2023 https://tc.copernicus.org/articles/17/789/2023/ |
id |
ftcopernicus:oai:publications.copernicus.org:tc101521 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:tc101521 2023-05-15T16:28:39+02:00 Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry Smith, Benjamin E. Medley, Brooke Fettweis, Xavier Sutterley, Tyler Alexander, Patrick Porter, David Tedesco, Marco 2023-02-16 application/pdf https://doi.org/10.5194/tc-17-789-2023 https://tc.copernicus.org/articles/17/789/2023/ eng eng doi:10.5194/tc-17-789-2023 https://tc.copernicus.org/articles/17/789/2023/ eISSN: 1994-0424 Text 2023 ftcopernicus https://doi.org/10.5194/tc-17-789-2023 2023-02-20T17:22:55Z 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 measured surface-height differences directly with those predicted by three FD–SMB models: MARv3.5.11 (Modèle Atmosphérique Régional version 3.5.11) and GSFCv1.1 and GSFCv1.2 (the Goddard Space Flight Center FD–SMB models version 1.1 and 1.2). 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-dynamics-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 of the models (MARv3.5.11 and GSFCv1.1) systematically overpredict, by around a factor of 2, 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. The third model, GSFCv1.2, which has an updated ... Text Greenland ice core Ice Sheet Copernicus Publications: E-Journals Greenland The Cryosphere 17 2 789 808 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
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 measured surface-height differences directly with those predicted by three FD–SMB models: MARv3.5.11 (Modèle Atmosphérique Régional version 3.5.11) and GSFCv1.1 and GSFCv1.2 (the Goddard Space Flight Center FD–SMB models version 1.1 and 1.2). 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-dynamics-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 of the models (MARv3.5.11 and GSFCv1.1) systematically overpredict, by around a factor of 2, 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. The third model, GSFCv1.2, which has an updated ... |
format |
Text |
author |
Smith, Benjamin E. Medley, Brooke Fettweis, Xavier Sutterley, Tyler Alexander, Patrick Porter, David Tedesco, Marco |
spellingShingle |
Smith, Benjamin E. Medley, Brooke Fettweis, Xavier Sutterley, Tyler Alexander, Patrick Porter, David Tedesco, Marco Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
author_facet |
Smith, Benjamin E. Medley, Brooke Fettweis, Xavier Sutterley, Tyler Alexander, Patrick Porter, David Tedesco, Marco |
author_sort |
Smith, Benjamin E. |
title |
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
title_short |
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
title_full |
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
title_fullStr |
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
title_full_unstemmed |
Evaluating Greenland surface-mass-balance and firn-densification data using ICESat-2 altimetry |
title_sort |
evaluating greenland surface-mass-balance and firn-densification data using icesat-2 altimetry |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-789-2023 https://tc.copernicus.org/articles/17/789/2023/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice core Ice Sheet |
genre_facet |
Greenland ice core Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-17-789-2023 https://tc.copernicus.org/articles/17/789/2023/ |
op_doi |
https://doi.org/10.5194/tc-17-789-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
2 |
container_start_page |
789 |
op_container_end_page |
808 |
_version_ |
1766018332044034048 |