Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo
Albedo is a key variable in the response of glaciers to climate. In Iceland, large albedo variations of the ice caps may be caused by the deposition of volcanic ash (tephra). Sparse in situ measurements are insufficient to characterize the spatial variation of albedo over the ice caps due to their l...
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Online Access: | https://hdl.handle.net/20.500.11815/334 https://doi.org/10.3390/rs9050399 |
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ftopinvisindi:oai:opinvisindi.is:20.500.11815/334 2024-09-15T18:04:01+00:00 Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo Gascoin, Simon Guðmundsson, Sverrir Adalgeirsdottir, Gudfinna Pálsson, Finnur Schmidt, Louise Berthier, Etienne Björnsson, Helgi Jarðvísindastofnun (HÍ) Institute of Earth Sciences (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland 2017-04-25 399 https://hdl.handle.net/20.500.11815/334 https://doi.org/10.3390/rs9050399 en eng MDPI AG Remote Sensing;9(5) Gascoin S, Guðmundsson S, Aðalgeirsdóttir G, Pálsson F, Schmidt L, Berthier E, Björnsson H. Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo. Remote Sensing. 2017; 9(5):399. doi:10.3390/rs9050399 2072-4292 https://hdl.handle.net/20.500.11815/334 Remote Sensing doi:10.3390/rs9050399 info:eu-repo/semantics/openAccess Glacier Albedo Volcanic eruption Jöklar Eldgos info:eu-repo/semantics/article 2017 ftopinvisindi https://doi.org/20.500.11815/33410.3390/rs9050399 2024-07-09T03:01:56Z Albedo is a key variable in the response of glaciers to climate. In Iceland, large albedo variations of the ice caps may be caused by the deposition of volcanic ash (tephra). Sparse in situ measurements are insufficient to characterize the spatial variation of albedo over the ice caps due to their large size. Here we evaluated the latest MCD43 MODIS albedo product (collection 6) to monitor albedo changes over the Icelandic ice caps using albedo measurements from ten automatic weather stations on Vatnajökull and Langjökull. Furthermore, we examined the influence of the albedo variability within MODIS pixels by comparing the results with a collection of Landsat scenes. The results indicate a good ability of the MODIS product to characterize the seasonal and interannual albedo changes with correlation coefficients ranging from 0.47 to 0.90 (median 0.84) and small biases ranging from −0.07 to 0.09. The root-mean square errors (RMSE) ranging from 0.08 to 0.21, are larger than that from previous studies, but we did not discard the retrievals flagged as bad quality to maximize the amount of observations given the frequent cloud obstruction in Iceland. We found a positive but non-significant relationship between the RMSE and the subpixel variability as indicated by the standard deviation of the Landsat albedo within a MODIS pixel (R = 0.48). The summer albedo maps and time series computed from the MODIS product show that the albedo decreased significantly after the 2010 Eyjafjallajökull and 2011 Grímsvötn eruptions on all the main ice caps except the northernmost Drangajökull. A strong reduction of the summer albedo by up to 0.6 is observed over large regions of the accumulation areas. These data can be assimilated in an energy and mass balance model to better understand the relative influence of the volcanic and climate forcing to the ongoing mass losses of Icelandic ice caps. We greatly thank Crystal Schaaf and Qingsong Sun from University of Massachusetts Boston for providing us MCD43A V006 data before the official ... Article in Journal/Newspaper Drangajökull Eyjafjallajökull glacier Iceland Langjökull Vatnajökull Opin vísindi (Iceland) Remote Sensing 9 5 399 |
institution |
Open Polar |
collection |
Opin vísindi (Iceland) |
op_collection_id |
ftopinvisindi |
language |
English |
topic |
Glacier Albedo Volcanic eruption Jöklar Eldgos |
spellingShingle |
Glacier Albedo Volcanic eruption Jöklar Eldgos Gascoin, Simon Guðmundsson, Sverrir Adalgeirsdottir, Gudfinna Pálsson, Finnur Schmidt, Louise Berthier, Etienne Björnsson, Helgi Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
topic_facet |
Glacier Albedo Volcanic eruption Jöklar Eldgos |
description |
Albedo is a key variable in the response of glaciers to climate. In Iceland, large albedo variations of the ice caps may be caused by the deposition of volcanic ash (tephra). Sparse in situ measurements are insufficient to characterize the spatial variation of albedo over the ice caps due to their large size. Here we evaluated the latest MCD43 MODIS albedo product (collection 6) to monitor albedo changes over the Icelandic ice caps using albedo measurements from ten automatic weather stations on Vatnajökull and Langjökull. Furthermore, we examined the influence of the albedo variability within MODIS pixels by comparing the results with a collection of Landsat scenes. The results indicate a good ability of the MODIS product to characterize the seasonal and interannual albedo changes with correlation coefficients ranging from 0.47 to 0.90 (median 0.84) and small biases ranging from −0.07 to 0.09. The root-mean square errors (RMSE) ranging from 0.08 to 0.21, are larger than that from previous studies, but we did not discard the retrievals flagged as bad quality to maximize the amount of observations given the frequent cloud obstruction in Iceland. We found a positive but non-significant relationship between the RMSE and the subpixel variability as indicated by the standard deviation of the Landsat albedo within a MODIS pixel (R = 0.48). The summer albedo maps and time series computed from the MODIS product show that the albedo decreased significantly after the 2010 Eyjafjallajökull and 2011 Grímsvötn eruptions on all the main ice caps except the northernmost Drangajökull. A strong reduction of the summer albedo by up to 0.6 is observed over large regions of the accumulation areas. These data can be assimilated in an energy and mass balance model to better understand the relative influence of the volcanic and climate forcing to the ongoing mass losses of Icelandic ice caps. We greatly thank Crystal Schaaf and Qingsong Sun from University of Massachusetts Boston for providing us MCD43A V006 data before the official ... |
author2 |
Jarðvísindastofnun (HÍ) Institute of Earth Sciences (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland |
format |
Article in Journal/Newspaper |
author |
Gascoin, Simon Guðmundsson, Sverrir Adalgeirsdottir, Gudfinna Pálsson, Finnur Schmidt, Louise Berthier, Etienne Björnsson, Helgi |
author_facet |
Gascoin, Simon Guðmundsson, Sverrir Adalgeirsdottir, Gudfinna Pálsson, Finnur Schmidt, Louise Berthier, Etienne Björnsson, Helgi |
author_sort |
Gascoin, Simon |
title |
Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
title_short |
Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
title_full |
Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
title_fullStr |
Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
title_full_unstemmed |
Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo |
title_sort |
evaluation of modis albedo product over ice caps in iceland and impact of volcanic eruptions on their albedo |
publisher |
MDPI AG |
publishDate |
2017 |
url |
https://hdl.handle.net/20.500.11815/334 https://doi.org/10.3390/rs9050399 |
genre |
Drangajökull Eyjafjallajökull glacier Iceland Langjökull Vatnajökull |
genre_facet |
Drangajökull Eyjafjallajökull glacier Iceland Langjökull Vatnajökull |
op_relation |
Remote Sensing;9(5) Gascoin S, Guðmundsson S, Aðalgeirsdóttir G, Pálsson F, Schmidt L, Berthier E, Björnsson H. Evaluation of MODIS Albedo Product over Ice Caps in Iceland and Impact of Volcanic Eruptions on Their Albedo. Remote Sensing. 2017; 9(5):399. doi:10.3390/rs9050399 2072-4292 https://hdl.handle.net/20.500.11815/334 Remote Sensing doi:10.3390/rs9050399 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/20.500.11815/33410.3390/rs9050399 |
container_title |
Remote Sensing |
container_volume |
9 |
container_issue |
5 |
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399 |
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1810441506676277248 |