Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes
In this study, we compare equilibrium-line altitudes (ELAs) calculated using the area–altitude balance ratio (AABR) and the accumulation–area ratio (AAR) methods, with measured ELAs derived from direct field observations. We utilise a GIS toolbox to calculate the ELA for 64 extant glaciers by applyi...
Main Authors: | , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2022
|
Subjects: | |
Online Access: | https://e-space.mmu.ac.uk/628444/3/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibrium-line-altitudes.pdf |
id |
ftmanchuniv:oai:e-space.mmu.ac.uk:628444 |
---|---|
record_format |
openpolar |
spelling |
ftmanchuniv:oai:e-space.mmu.ac.uk:628444 2024-05-19T07:43:15+00:00 Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes Oien, Rachel P Rea, Brice R Spagnolo, Matteo Barr, Iestyn D Bingham, Robert G 2022-04 text https://e-space.mmu.ac.uk/628444/3/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibrium-line-altitudes.pdf en eng Cambridge University Press (CUP) https://e-space.mmu.ac.uk/628444/ https://www.cambridge.org/core/journals/journal-of-glaciology/article/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibriumline-altitudes/4D2276F8D72752981C290F49E92C4E0A 10.1017/jog.2021.100 https://e-space.mmu.ac.uk/628444/3/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibrium-line-altitudes.pdf Oien, Rachel P </view/creators/Oien=3ARachel_P=3A=3A.html>, Rea, Brice R </view/creators/Rea=3ABrice_R=3A=3A.html>, Spagnolo, Matteo </view/creators/Spagnolo=3AMatteo=3A=3A.html>, Barr, Iestyn D </view/creators/Barr=3AIestyn_D=3A=3A.html> and Bingham, Robert G </view/creators/Bingham=3ARobert_G=3A=3A.html> (2022) Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes. Journal of Glaciology, 68 (268). pp. 357-368. ISSN 0022-1430 cc_by_4 info:eu-repo/semantics/openAccess Article PeerReviewed 2022 ftmanchuniv 2024-05-01T00:02:39Z In this study, we compare equilibrium-line altitudes (ELAs) calculated using the area–altitude balance ratio (AABR) and the accumulation–area ratio (AAR) methods, with measured ELAs derived from direct field observations. We utilise a GIS toolbox to calculate the ELA for 64 extant glaciers by applying the AABR and AAR methods to DEMs and polygons of their geometry. The calculated ELAs (c-ELAs) are then compared to measured zero-net balance ELAs (znb-ELAs) obtained from mass-balance time series held by the WGMS for the same glaciers. The correlation between znb-ELAs and AABR (1.56)/AAR (0.58) c-ELAs is very strong, with an <jats:italic>r</jats:italic><jats:sup>2</jats:sup> = 0.99. The smallest median difference between znb-ELAs and c-ELAs (i.e. 65.5 m) is obtained when a globally representative AABR of 1.56 is used. When applied to palaeoglacier-climate applications, this difference translates to ~0.42°C, well within the uncertainty of palaeotemperature proxies used to determine mean summer temperature at the ELA. The more widely used mean AABR of 1.75 is shown to be statistically invalid due to the skewness of the dataset. On this basis, when calculating glacier ELAs, we recommend the use of a global AABR value of 1.56. Article in Journal/Newspaper Journal of Glaciology eSpace - Manchester Metropolitan University's Research Repository |
institution |
Open Polar |
collection |
eSpace - Manchester Metropolitan University's Research Repository |
op_collection_id |
ftmanchuniv |
language |
English |
description |
In this study, we compare equilibrium-line altitudes (ELAs) calculated using the area–altitude balance ratio (AABR) and the accumulation–area ratio (AAR) methods, with measured ELAs derived from direct field observations. We utilise a GIS toolbox to calculate the ELA for 64 extant glaciers by applying the AABR and AAR methods to DEMs and polygons of their geometry. The calculated ELAs (c-ELAs) are then compared to measured zero-net balance ELAs (znb-ELAs) obtained from mass-balance time series held by the WGMS for the same glaciers. The correlation between znb-ELAs and AABR (1.56)/AAR (0.58) c-ELAs is very strong, with an <jats:italic>r</jats:italic><jats:sup>2</jats:sup> = 0.99. The smallest median difference between znb-ELAs and c-ELAs (i.e. 65.5 m) is obtained when a globally representative AABR of 1.56 is used. When applied to palaeoglacier-climate applications, this difference translates to ~0.42°C, well within the uncertainty of palaeotemperature proxies used to determine mean summer temperature at the ELA. The more widely used mean AABR of 1.75 is shown to be statistically invalid due to the skewness of the dataset. On this basis, when calculating glacier ELAs, we recommend the use of a global AABR value of 1.56. |
format |
Article in Journal/Newspaper |
author |
Oien, Rachel P Rea, Brice R Spagnolo, Matteo Barr, Iestyn D Bingham, Robert G |
spellingShingle |
Oien, Rachel P Rea, Brice R Spagnolo, Matteo Barr, Iestyn D Bingham, Robert G Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
author_facet |
Oien, Rachel P Rea, Brice R Spagnolo, Matteo Barr, Iestyn D Bingham, Robert G |
author_sort |
Oien, Rachel P |
title |
Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
title_short |
Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
title_full |
Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
title_fullStr |
Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
title_full_unstemmed |
Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes |
title_sort |
testing the area–altitude balance ratio (aabr) and accumulation–area ratio (aar) methods of calculating glacier equilibrium-line altitudes |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
https://e-space.mmu.ac.uk/628444/3/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibrium-line-altitudes.pdf |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_relation |
https://e-space.mmu.ac.uk/628444/ https://www.cambridge.org/core/journals/journal-of-glaciology/article/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibriumline-altitudes/4D2276F8D72752981C290F49E92C4E0A 10.1017/jog.2021.100 https://e-space.mmu.ac.uk/628444/3/testing-the-areaaltitude-balance-ratio-aabr-and-accumulationarea-ratio-aar-methods-of-calculating-glacier-equilibrium-line-altitudes.pdf Oien, Rachel P </view/creators/Oien=3ARachel_P=3A=3A.html>, Rea, Brice R </view/creators/Rea=3ABrice_R=3A=3A.html>, Spagnolo, Matteo </view/creators/Spagnolo=3AMatteo=3A=3A.html>, Barr, Iestyn D </view/creators/Barr=3AIestyn_D=3A=3A.html> and Bingham, Robert G </view/creators/Bingham=3ARobert_G=3A=3A.html> (2022) Testing the area–altitude balance ratio (AABR) and accumulation–area ratio (AAR) methods of calculating glacier equilibrium-line altitudes. Journal of Glaciology, 68 (268). pp. 357-368. ISSN 0022-1430 |
op_rights |
cc_by_4 info:eu-repo/semantics/openAccess |
_version_ |
1799482967264854016 |