Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory
Analysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different s...
Published in: | Journal of Glaciology |
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Main Authors: | , , , , , |
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Cambridge University Press
2019
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Online Access: | https://doi.org/10.1017/jog.2019.63 https://ora.ox.ac.uk/objects/uuid:262fe452-775e-4c65-ac8f-03a194ebc89f |
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ftuloxford:oai:ora.ox.ac.uk:uuid:262fe452-775e-4c65-ac8f-03a194ebc89f 2024-10-06T13:48:55+00:00 Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory Benn, D Jones, R Luckman, A Fürst, J Hewitt, I Sommer, C 2019-09-24 https://doi.org/10.1017/jog.2019.63 https://ora.ox.ac.uk/objects/uuid:262fe452-775e-4c65-ac8f-03a194ebc89f unknown Cambridge University Press doi:10.1017/jog.2019.63 https://ora.ox.ac.uk/objects/uuid:262fe452-775e-4c65-ac8f-03a194ebc89f https://doi.org/10.1017/jog.2019.63 info:eu-repo/semantics/openAccess CC Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND) Journal article 2019 ftuloxford https://doi.org/10.1017/jog.2019.63 2024-09-06T07:47:29Z Analysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different stages of the surge cycle. During quiescence (1936–1990), velocities were very low, and geothermal heat slowly built-up enthalpy at the bed. Measurable mass transfer and frictional heating began in 1990–2010, then positive frictional heating-velocity feedbacks caused gradual acceleration from 2010 to 2015. Rapid acceleration occurred in summer 2016, when extensive crevassing and positive air temperatures allowed significant surface to bed drainage. The surge front reached the terminus in October 2016, coincident with a drop in velocities. Ice plumes in the fjord are interpreted as discharge of large volumes of supercooled water from the bed. Surge termination was prolonged, however, indicating persistence of an inefficient drainage system. The observations closely match predictions of the theory, particularly build-up of enthalpy from geothermal and frictional heat, and surface meltwater, and the concomitant changes in ice-surface elevation and velocity. Additional characteristics of the surge reflect spatial processes not represented in the model, but can be explained with respect to enthalpy gradients. Article in Journal/Newspaper glacier Svalbard ORA - Oxford University Research Archive Svalbard Journal of Glaciology 65 253 717 731 |
institution |
Open Polar |
collection |
ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
unknown |
description |
Analysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different stages of the surge cycle. During quiescence (1936–1990), velocities were very low, and geothermal heat slowly built-up enthalpy at the bed. Measurable mass transfer and frictional heating began in 1990–2010, then positive frictional heating-velocity feedbacks caused gradual acceleration from 2010 to 2015. Rapid acceleration occurred in summer 2016, when extensive crevassing and positive air temperatures allowed significant surface to bed drainage. The surge front reached the terminus in October 2016, coincident with a drop in velocities. Ice plumes in the fjord are interpreted as discharge of large volumes of supercooled water from the bed. Surge termination was prolonged, however, indicating persistence of an inefficient drainage system. The observations closely match predictions of the theory, particularly build-up of enthalpy from geothermal and frictional heat, and surface meltwater, and the concomitant changes in ice-surface elevation and velocity. Additional characteristics of the surge reflect spatial processes not represented in the model, but can be explained with respect to enthalpy gradients. |
format |
Article in Journal/Newspaper |
author |
Benn, D Jones, R Luckman, A Fürst, J Hewitt, I Sommer, C |
spellingShingle |
Benn, D Jones, R Luckman, A Fürst, J Hewitt, I Sommer, C Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
author_facet |
Benn, D Jones, R Luckman, A Fürst, J Hewitt, I Sommer, C |
author_sort |
Benn, D |
title |
Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
title_short |
Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
title_full |
Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
title_fullStr |
Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
title_full_unstemmed |
Mass and enthalpy budget evolution during the surge of a polythermal glacier: A test of theory |
title_sort |
mass and enthalpy budget evolution during the surge of a polythermal glacier: a test of theory |
publisher |
Cambridge University Press |
publishDate |
2019 |
url |
https://doi.org/10.1017/jog.2019.63 https://ora.ox.ac.uk/objects/uuid:262fe452-775e-4c65-ac8f-03a194ebc89f |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
glacier Svalbard |
genre_facet |
glacier Svalbard |
op_relation |
doi:10.1017/jog.2019.63 https://ora.ox.ac.uk/objects/uuid:262fe452-775e-4c65-ac8f-03a194ebc89f https://doi.org/10.1017/jog.2019.63 |
op_rights |
info:eu-repo/semantics/openAccess CC Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND) |
op_doi |
https://doi.org/10.1017/jog.2019.63 |
container_title |
Journal of Glaciology |
container_volume |
65 |
container_issue |
253 |
container_start_page |
717 |
op_container_end_page |
731 |
_version_ |
1812177001812852736 |