ICESat laser altimetry over small mountain glaciers
Using sparsely glaciated southern Norway as a case study, we assess the potential and limitations of ICESat laser altimetry for analysing regional glacier elevation change in rough mountain terrain. Differences between ICESat GLAS elevations and reference elevation data are plotted over time to deri...
Published in: | The Cryosphere |
---|---|
Main Authors: | , |
Format: | Text |
Language: | English |
Published: |
2018
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-10-2129-2016 https://tc.copernicus.org/articles/10/2129/2016/ |
id |
ftcopernicus:oai:publications.copernicus.org:tc49147 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:tc49147 2023-05-15T16:21:54+02:00 ICESat laser altimetry over small mountain glaciers Treichler, Désirée Kääb, Andreas 2018-09-27 application/pdf https://doi.org/10.5194/tc-10-2129-2016 https://tc.copernicus.org/articles/10/2129/2016/ eng eng doi:10.5194/tc-10-2129-2016 https://tc.copernicus.org/articles/10/2129/2016/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-10-2129-2016 2020-07-20T16:23:59Z Using sparsely glaciated southern Norway as a case study, we assess the potential and limitations of ICESat laser altimetry for analysing regional glacier elevation change in rough mountain terrain. Differences between ICESat GLAS elevations and reference elevation data are plotted over time to derive a glacier surface elevation trend for the ICESat acquisition period 2003–2008. We find spatially varying biases between ICESat and three tested digital elevation models (DEMs): the Norwegian national DEM, SRTM DEM, and a high-resolution lidar DEM. For regional glacier elevation change, the spatial inconsistency of reference DEMs – a result of spatio-temporal merging – has the potential to significantly affect or dilute trends. Elevation uncertainties of all three tested DEMs exceed ICESat elevation uncertainty by an order of magnitude, and are thus limiting the accuracy of the method, rather than ICESat uncertainty. ICESat matches glacier size distribution of the study area well and measures small ice patches not commonly monitored in situ. The sample is large enough for spatial and thematic subsetting. Vertical offsets to ICESat elevations vary for different glaciers in southern Norway due to spatially inconsistent reference DEM age. We introduce a per-glacier correction that removes these spatially varying offsets, and considerably increases trend significance. Only after application of this correction do individual campaigns fit observed in situ glacier mass balance. Our correction also has the potential to improve glacier trend significance for other causes of spatially varying vertical offsets, for instance due to radar penetration into ice and snow for the SRTM DEM or as a consequence of mosaicking and merging that is common for national or global DEMs. After correction of reference elevation bias, we find that ICESat provides a robust and realistic estimate of a moderately negative glacier mass balance of around −0.36 ± 0.07 m ice per year. This regional estimate agrees well with the heterogeneous but overall negative in situ glacier mass balance observed in the area. Text glacier Copernicus Publications: E-Journals Norway The Cryosphere 10 5 2129 2146 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Using sparsely glaciated southern Norway as a case study, we assess the potential and limitations of ICESat laser altimetry for analysing regional glacier elevation change in rough mountain terrain. Differences between ICESat GLAS elevations and reference elevation data are plotted over time to derive a glacier surface elevation trend for the ICESat acquisition period 2003–2008. We find spatially varying biases between ICESat and three tested digital elevation models (DEMs): the Norwegian national DEM, SRTM DEM, and a high-resolution lidar DEM. For regional glacier elevation change, the spatial inconsistency of reference DEMs – a result of spatio-temporal merging – has the potential to significantly affect or dilute trends. Elevation uncertainties of all three tested DEMs exceed ICESat elevation uncertainty by an order of magnitude, and are thus limiting the accuracy of the method, rather than ICESat uncertainty. ICESat matches glacier size distribution of the study area well and measures small ice patches not commonly monitored in situ. The sample is large enough for spatial and thematic subsetting. Vertical offsets to ICESat elevations vary for different glaciers in southern Norway due to spatially inconsistent reference DEM age. We introduce a per-glacier correction that removes these spatially varying offsets, and considerably increases trend significance. Only after application of this correction do individual campaigns fit observed in situ glacier mass balance. Our correction also has the potential to improve glacier trend significance for other causes of spatially varying vertical offsets, for instance due to radar penetration into ice and snow for the SRTM DEM or as a consequence of mosaicking and merging that is common for national or global DEMs. After correction of reference elevation bias, we find that ICESat provides a robust and realistic estimate of a moderately negative glacier mass balance of around −0.36 ± 0.07 m ice per year. This regional estimate agrees well with the heterogeneous but overall negative in situ glacier mass balance observed in the area. |
format |
Text |
author |
Treichler, Désirée Kääb, Andreas |
spellingShingle |
Treichler, Désirée Kääb, Andreas ICESat laser altimetry over small mountain glaciers |
author_facet |
Treichler, Désirée Kääb, Andreas |
author_sort |
Treichler, Désirée |
title |
ICESat laser altimetry over small mountain glaciers |
title_short |
ICESat laser altimetry over small mountain glaciers |
title_full |
ICESat laser altimetry over small mountain glaciers |
title_fullStr |
ICESat laser altimetry over small mountain glaciers |
title_full_unstemmed |
ICESat laser altimetry over small mountain glaciers |
title_sort |
icesat laser altimetry over small mountain glaciers |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-10-2129-2016 https://tc.copernicus.org/articles/10/2129/2016/ |
geographic |
Norway |
geographic_facet |
Norway |
genre |
glacier |
genre_facet |
glacier |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-10-2129-2016 https://tc.copernicus.org/articles/10/2129/2016/ |
op_doi |
https://doi.org/10.5194/tc-10-2129-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
5 |
container_start_page |
2129 |
op_container_end_page |
2146 |
_version_ |
1766009878601531392 |