Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation
The low spatial resolution of GRACE causes leakage, where signals in one location spread out into nearby regions. Because of this leakage, using simple techniques such as basin averages may result in an incorrect estimate of the true mass change in a region. A fairly simple least squares inversion t...
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Digital Commons @ University of South Florida
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Online Access: | https://digitalcommons.usf.edu/msc_facpub/1414 https://doi.org/10.1093/gji/ggt091 |
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ftusouthflorida:oai:digitalcommons.usf.edu:msc_facpub-2404 2023-07-30T04:02:02+02:00 Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation Bonin, Jennifer Chambers, Don 2013-01-01T08:00:00Z https://digitalcommons.usf.edu/msc_facpub/1414 https://doi.org/10.1093/gji/ggt091 unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/msc_facpub/1414 doi:10.1093/gji/ggt091 https://doi.org/10.1093/gji/ggt091 Marine Science Faculty Publications Time-series analysis Inverse theory Satellite gravity Time variable gravity Arctic region Life Sciences article 2013 ftusouthflorida https://doi.org/10.1093/gji/ggt091 2023-07-13T21:01:59Z The low spatial resolution of GRACE causes leakage, where signals in one location spread out into nearby regions. Because of this leakage, using simple techniques such as basin averages may result in an incorrect estimate of the true mass change in a region. A fairly simple least squares inversion technique can be used to more specifically localize mass changes into a pre-determined set of basins of uniform internal mass distribution. However, the accuracy of these higher resolution basin mass amplitudes has not been determined, nor is it known how the distribution of the chosen basins affects the results. We use a simple ‘truth’ model over Greenland as an example case, to estimate the uncertainties of this inversion method and expose those design parameters which may result in an incorrect high-resolution mass distribution. We determine that an appropriate level of smoothing (300–400 km) and process noise (0.30 cm2 of water) gets the best results. The trends of the Greenland internal basins and Iceland can be reasonably estimated with this method, with average systematic errors of 3.5 cm yr−1 per basin. The largest mass losses found from GRACE RL04 occur in the coastal northwest (−19.9 and −33.0 cm yr−1) and southeast (−24.2 and −27.9 cm yr−1), with small mass gains (+1.4 to +7.7 cm yr−1) found across the northern interior. Acceleration of mass change is measurable at the 95 per cent confidence level in four northwestern basins, but not elsewhere in Greenland. Due to an insufficiently detailed distribution of basins across internal Canada, the trend estimates of Baffin and Ellesmere Islands are expected to be incorrect due to systematic errors caused by the inversion technique. Article in Journal/Newspaper Arctic Baffin Greenland Iceland University of South Florida St. Petersburg: Digital USFSP Arctic Canada Greenland Geophysical Journal International 194 1 212 229 |
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Open Polar |
collection |
University of South Florida St. Petersburg: Digital USFSP |
op_collection_id |
ftusouthflorida |
language |
unknown |
topic |
Time-series analysis Inverse theory Satellite gravity Time variable gravity Arctic region Life Sciences |
spellingShingle |
Time-series analysis Inverse theory Satellite gravity Time variable gravity Arctic region Life Sciences Bonin, Jennifer Chambers, Don Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
topic_facet |
Time-series analysis Inverse theory Satellite gravity Time variable gravity Arctic region Life Sciences |
description |
The low spatial resolution of GRACE causes leakage, where signals in one location spread out into nearby regions. Because of this leakage, using simple techniques such as basin averages may result in an incorrect estimate of the true mass change in a region. A fairly simple least squares inversion technique can be used to more specifically localize mass changes into a pre-determined set of basins of uniform internal mass distribution. However, the accuracy of these higher resolution basin mass amplitudes has not been determined, nor is it known how the distribution of the chosen basins affects the results. We use a simple ‘truth’ model over Greenland as an example case, to estimate the uncertainties of this inversion method and expose those design parameters which may result in an incorrect high-resolution mass distribution. We determine that an appropriate level of smoothing (300–400 km) and process noise (0.30 cm2 of water) gets the best results. The trends of the Greenland internal basins and Iceland can be reasonably estimated with this method, with average systematic errors of 3.5 cm yr−1 per basin. The largest mass losses found from GRACE RL04 occur in the coastal northwest (−19.9 and −33.0 cm yr−1) and southeast (−24.2 and −27.9 cm yr−1), with small mass gains (+1.4 to +7.7 cm yr−1) found across the northern interior. Acceleration of mass change is measurable at the 95 per cent confidence level in four northwestern basins, but not elsewhere in Greenland. Due to an insufficiently detailed distribution of basins across internal Canada, the trend estimates of Baffin and Ellesmere Islands are expected to be incorrect due to systematic errors caused by the inversion technique. |
format |
Article in Journal/Newspaper |
author |
Bonin, Jennifer Chambers, Don |
author_facet |
Bonin, Jennifer Chambers, Don |
author_sort |
Bonin, Jennifer |
title |
Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
title_short |
Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
title_full |
Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
title_fullStr |
Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
title_full_unstemmed |
Uncertainty Estimates of a GRACE Inversion Modelling Technique Over Greenland Using a Simulation |
title_sort |
uncertainty estimates of a grace inversion modelling technique over greenland using a simulation |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2013 |
url |
https://digitalcommons.usf.edu/msc_facpub/1414 https://doi.org/10.1093/gji/ggt091 |
geographic |
Arctic Canada Greenland |
geographic_facet |
Arctic Canada Greenland |
genre |
Arctic Baffin Greenland Iceland |
genre_facet |
Arctic Baffin Greenland Iceland |
op_source |
Marine Science Faculty Publications |
op_relation |
https://digitalcommons.usf.edu/msc_facpub/1414 doi:10.1093/gji/ggt091 https://doi.org/10.1093/gji/ggt091 |
op_doi |
https://doi.org/10.1093/gji/ggt091 |
container_title |
Geophysical Journal International |
container_volume |
194 |
container_issue |
1 |
container_start_page |
212 |
op_container_end_page |
229 |
_version_ |
1772812765542481920 |