(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985
Photogrammetric reanalysis of 1985 aerial photos has revealed substantial submarine melting of the floating ice tongue of Jakobshavn Isbrae, west Greenland. The thickness of the floating tongue determined from hydrostatic equilibrium tapers from ~940 m near the grounding zone to ~600 m near the term...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.817300 2024-09-15T18:09:36+00:00 (Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 Motyka, Roman J Truffer, Martin Fahnestock, Mark Mortensen, John Rysgaard, Søren Howat, Ian M LATITUDE: 69.130000 * LONGITUDE: -49.560000 * DATE/TIME START: 1984-07-24T00:00:00 * DATE/TIME END: 1984-07-24T00:00:00 2011 text/tab-separated-values, 10 data points https://doi.pangaea.de/10.1594/PANGAEA.817300 https://doi.org/10.1594/PANGAEA.817300 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.817300 https://doi.org/10.1594/PANGAEA.817300 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Motyka, Roman J; Truffer, Martin; Fahnestock, Mark; Mortensen, John; Rysgaard, Søren; Howat, Ian M (2011): Submarine melting of the 1985 Jakobshavn Isbræ floating tongue and the triggering of the current retreat. Journal of Geophysical Research, 116(F1), F01007, https://doi.org/10.1029/2009JF001632 Aerial photography AERP DATE/TIME Date/time end Ice loss International Polar Year (2007-2008) IPY Jacobshavn_Isbrae Location Melt rate submarine Standard deviation Surface ablation West Greenland dataset 2011 ftpangaea https://doi.org/10.1594/PANGAEA.81730010.1029/2009JF001632 2024-07-24T02:31:32Z Photogrammetric reanalysis of 1985 aerial photos has revealed substantial submarine melting of the floating ice tongue of Jakobshavn Isbrae, west Greenland. The thickness of the floating tongue determined from hydrostatic equilibrium tapers from ~940 m near the grounding zone to ~600 m near the terminus. Feature tracking on orthophotos shows speeds on the July 1985 ice tongue to be nearly constant (~18.5 m/d), indicating negligible dynamic thinning. The thinning of the ice tongue is mostly due to submarine melting with average rates of 228 ± 49 m/yr (0.62 ± 0.13 m/d) between the summers of 1984 and 1985. The cause of the high melt rate is the circulation of warm seawater (thermal forcing of up to 4.2°C) beneath the tongue with convection driven by the substantial discharge of subglacial freshwater from the grounding zone. We believe that this buoyancy-driven convection is responsible for a deep channel incised into the sole of the floating tongue. A dramatic thinning, retreat, and speedup began in 1998 and continues today. The timing of the change is coincident with a 1.1°C warming of deep ocean waters entering the fjord after 1997. Assuming a linear relationship between thermal forcing and submarine melt rate, average melt rates should have increased by ~25% (~57 m/yr), sufficient to destabilize the ice tongue and initiate the ice thinning and the retreat that followed. Dataset Greenland International Polar Year IPY Jakobshavn PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-49.560000,-49.560000,69.130000,69.130000) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
Aerial photography AERP DATE/TIME Date/time end Ice loss International Polar Year (2007-2008) IPY Jacobshavn_Isbrae Location Melt rate submarine Standard deviation Surface ablation West Greenland |
spellingShingle |
Aerial photography AERP DATE/TIME Date/time end Ice loss International Polar Year (2007-2008) IPY Jacobshavn_Isbrae Location Melt rate submarine Standard deviation Surface ablation West Greenland Motyka, Roman J Truffer, Martin Fahnestock, Mark Mortensen, John Rysgaard, Søren Howat, Ian M (Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
topic_facet |
Aerial photography AERP DATE/TIME Date/time end Ice loss International Polar Year (2007-2008) IPY Jacobshavn_Isbrae Location Melt rate submarine Standard deviation Surface ablation West Greenland |
description |
Photogrammetric reanalysis of 1985 aerial photos has revealed substantial submarine melting of the floating ice tongue of Jakobshavn Isbrae, west Greenland. The thickness of the floating tongue determined from hydrostatic equilibrium tapers from ~940 m near the grounding zone to ~600 m near the terminus. Feature tracking on orthophotos shows speeds on the July 1985 ice tongue to be nearly constant (~18.5 m/d), indicating negligible dynamic thinning. The thinning of the ice tongue is mostly due to submarine melting with average rates of 228 ± 49 m/yr (0.62 ± 0.13 m/d) between the summers of 1984 and 1985. The cause of the high melt rate is the circulation of warm seawater (thermal forcing of up to 4.2°C) beneath the tongue with convection driven by the substantial discharge of subglacial freshwater from the grounding zone. We believe that this buoyancy-driven convection is responsible for a deep channel incised into the sole of the floating tongue. A dramatic thinning, retreat, and speedup began in 1998 and continues today. The timing of the change is coincident with a 1.1°C warming of deep ocean waters entering the fjord after 1997. Assuming a linear relationship between thermal forcing and submarine melt rate, average melt rates should have increased by ~25% (~57 m/yr), sufficient to destabilize the ice tongue and initiate the ice thinning and the retreat that followed. |
format |
Dataset |
author |
Motyka, Roman J Truffer, Martin Fahnestock, Mark Mortensen, John Rysgaard, Søren Howat, Ian M |
author_facet |
Motyka, Roman J Truffer, Martin Fahnestock, Mark Mortensen, John Rysgaard, Søren Howat, Ian M |
author_sort |
Motyka, Roman J |
title |
(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
title_short |
(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
title_full |
(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
title_fullStr |
(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
title_full_unstemmed |
(Table 1) Annual melt rates of the South Branch of Jacobshavn Isbrae between July 1984-1985 |
title_sort |
(table 1) annual melt rates of the south branch of jacobshavn isbrae between july 1984-1985 |
publisher |
PANGAEA |
publishDate |
2011 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.817300 https://doi.org/10.1594/PANGAEA.817300 |
op_coverage |
LATITUDE: 69.130000 * LONGITUDE: -49.560000 * DATE/TIME START: 1984-07-24T00:00:00 * DATE/TIME END: 1984-07-24T00:00:00 |
long_lat |
ENVELOPE(-49.560000,-49.560000,69.130000,69.130000) |
genre |
Greenland International Polar Year IPY Jakobshavn |
genre_facet |
Greenland International Polar Year IPY Jakobshavn |
op_source |
Supplement to: Motyka, Roman J; Truffer, Martin; Fahnestock, Mark; Mortensen, John; Rysgaard, Søren; Howat, Ian M (2011): Submarine melting of the 1985 Jakobshavn Isbræ floating tongue and the triggering of the current retreat. Journal of Geophysical Research, 116(F1), F01007, https://doi.org/10.1029/2009JF001632 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.817300 https://doi.org/10.1594/PANGAEA.817300 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1594/PANGAEA.81730010.1029/2009JF001632 |
_version_ |
1810447167832195072 |