Revised Estimates of Recent Mass Loss Rates for Penny Ice Cap, Baffin Island, Based on Elevation Changes Modified for Firn Densification
In this study, we update NASA Airborne Topographic Mapper (ATM) altimetry elevation changes across Penny Ice Cap (Baffin Island, Canada) to assess total changes in ice mass from 2005-2014, relative to 1995-2000. We use the ATM L1B elevation dataset from which we extract the elevation every 10 m alon...
| Main Authors: | , , , , |
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| Format: | Dataset |
| Language: | unknown |
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Canadian Cryospheric Information Network
2019
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.21963/13106 https://www.polardata.ca/pdcsearch/PDCSearch.jsp?doi_id=13106 |
| Summary: | In this study, we update NASA Airborne Topographic Mapper (ATM) altimetry elevation changes across Penny Ice Cap (Baffin Island, Canada) to assess total changes in ice mass from 2005-2014, relative to 1995-2000. We use the ATM L1B elevation dataset from which we extract the elevation every 10 m along a line of best fit for the 2005, 2013 and 2014 data sets. The changes in elevation (dh/dt) between 2005-2013 and 2013-2014 are calculated, then extrapolated to the entire ice cap using least-squares linear regression of dh/dt against the altimetry elevation. Dual-frequency GPS measurements and temporal changes in ice core density profiles are used to calculate firn densification and ice dynamics to isolate the component of elevation change due to surface mass balance. A Trimble R7 dGPS receiver is used with a minimum 20 minute occupation time per stake (accuracy: ± 0.09 m horizontally and ± 0.10 m vertically). We use data from ice or firn cores collected in 1995, 2010 and 2013 near the summit of the ice cap. The densification rate is calculated from the change in thickness of near-surface firn layers down to a depth equivalent to 5 m w.e. Envisat satellite imagery and ground-penetrating radar data are used to delineate the areas impacted by firn densification. These data are compared to annual in situ mass balance data collected between 2006-2014 at stakes along three survey lines during spring (~April), totalling 140 measurements at elevations ranging from 71-1822 m a.s.l. |
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