New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches
International audience Arctic shrubs reduce surface albedo in winter when branches protrude above the snow. To calculate the albedo of those mixed surfaces, the branch area index (BAI) of Arctic shrubs needs to be known. Moreover, an exposedvegetation function is required to determine the BAI for pr...
Published in: | Journal of Hydrometeorology |
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Format: | Article in Journal/Newspaper |
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2020
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Online Access: | https://doi.org/10.1175/jhm-d-20-0012.1 https://hal.archives-ouvertes.fr/hal-03070673/file/128-BelkeJHM2020.pdf https://hal.archives-ouvertes.fr/hal-03070673 |
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fttriple:oai:gotriple.eu:10670/1.xxoob7 2023-05-15T13:10:26+02:00 New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches Belke-Brea, M Domine, Florent Boudreau, S Picard, G Barrere, M Arnaud, L Paradis, M Takuvik Joint International Laboratory ULAVAL-CNRS Université Laval Québec (ULaval)-Centre National de la Recherche Scientifique (CNRS) Fondation BNP-Paribas, NSERC, IPEV 2020-11-25 https://doi.org/10.1175/jhm-d-20-0012.1 https://hal.archives-ouvertes.fr/hal-03070673/file/128-BelkeJHM2020.pdf https://hal.archives-ouvertes.fr/hal-03070673 en eng HAL CCSD American Meteorological Society hal-03070673 doi:10.1175/jhm-d-20-0012.1 10670/1.xxoob7 https://hal.archives-ouvertes.fr/hal-03070673/file/128-BelkeJHM2020.pdf https://hal.archives-ouvertes.fr/hal-03070673 other Hyper Article en Ligne - Sciences de l'Homme et de la Société ISSN: 1525-755X EISSN: 1525-7541 Journal of Hydrometeorology Journal of Hydrometeorology, American Meteorological Society, 2020, 21, pp.2581 - 2594. ⟨10.1175/jhm-d-20-0012.1⟩ Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization envir geo Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2020 fttriple https://doi.org/10.1175/jhm-d-20-0012.1 2023-01-22T17:44:33Z International audience Arctic shrubs reduce surface albedo in winter when branches protrude above the snow. To calculate the albedo of those mixed surfaces, the branch area index (BAI) of Arctic shrubs needs to be known. Moreover, an exposedvegetation function is required to determine the BAI for protruding branches only. This study used a structural analysis of 30 Betula glandulosa shrubs, sampled near Umiujaq, northern Quebec, to (i) establish an allometric relationship between shrub height and BAI and (ii) determine a specific exposed-vegetation function for Arctic shrubs. The spectral albedo (400-1080 nm) of mixed surfaces was then simulated with the equations derived from this study and validated with in situ measured spectra. Shrubs were sampled from two sites, one along the coast and the other in a nearby valley. The shrub height-BAI relationship varied between both sites. BAI values of shrubs growing in the wind-sheltered valley were 30%-50% lower. The exposed-vegetation function obtained here differed from the linear functions found in the literature. The linear functions strongly overestimated the BAI of exposed branches. Albedo was well simulated with an accuracy of 3% when using an allometric relationship adapted to the environmental conditions of our study site. However, simulated albedo values were consistently higher than field measurements, probably because radiation absorbed by impurities and buried branches was neglected in the model. We conclude that specific exposed-vegetation and allometric equations need to be implemented in models to accurately simulate the albedo of mixed snow-shrub surfaces. Article in Journal/Newspaper albedo Arctic Umiujaq Unknown Arctic Umiujaq ENVELOPE(-76.549,-76.549,56.553,56.553) Journal of Hydrometeorology 21 11 2581 2594 |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
English |
topic |
Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization envir geo |
spellingShingle |
Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization envir geo Belke-Brea, M Domine, Florent Boudreau, S Picard, G Barrere, M Arnaud, L Paradis, M New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
topic_facet |
Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization envir geo |
description |
International audience Arctic shrubs reduce surface albedo in winter when branches protrude above the snow. To calculate the albedo of those mixed surfaces, the branch area index (BAI) of Arctic shrubs needs to be known. Moreover, an exposedvegetation function is required to determine the BAI for protruding branches only. This study used a structural analysis of 30 Betula glandulosa shrubs, sampled near Umiujaq, northern Quebec, to (i) establish an allometric relationship between shrub height and BAI and (ii) determine a specific exposed-vegetation function for Arctic shrubs. The spectral albedo (400-1080 nm) of mixed surfaces was then simulated with the equations derived from this study and validated with in situ measured spectra. Shrubs were sampled from two sites, one along the coast and the other in a nearby valley. The shrub height-BAI relationship varied between both sites. BAI values of shrubs growing in the wind-sheltered valley were 30%-50% lower. The exposed-vegetation function obtained here differed from the linear functions found in the literature. The linear functions strongly overestimated the BAI of exposed branches. Albedo was well simulated with an accuracy of 3% when using an allometric relationship adapted to the environmental conditions of our study site. However, simulated albedo values were consistently higher than field measurements, probably because radiation absorbed by impurities and buried branches was neglected in the model. We conclude that specific exposed-vegetation and allometric equations need to be implemented in models to accurately simulate the albedo of mixed snow-shrub surfaces. |
author2 |
Takuvik Joint International Laboratory ULAVAL-CNRS Université Laval Québec (ULaval)-Centre National de la Recherche Scientifique (CNRS) Fondation BNP-Paribas, NSERC, IPEV |
format |
Article in Journal/Newspaper |
author |
Belke-Brea, M Domine, Florent Boudreau, S Picard, G Barrere, M Arnaud, L Paradis, M |
author_facet |
Belke-Brea, M Domine, Florent Boudreau, S Picard, G Barrere, M Arnaud, L Paradis, M |
author_sort |
Belke-Brea, M |
title |
New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
title_short |
New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
title_full |
New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
title_fullStr |
New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
title_full_unstemmed |
New Allometric Equations for Arctic Shrubs and Their Application for Calculating the Albedo of Surfaces with Snow and Protruding Branches |
title_sort |
new allometric equations for arctic shrubs and their application for calculating the albedo of surfaces with snow and protruding branches |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://doi.org/10.1175/jhm-d-20-0012.1 https://hal.archives-ouvertes.fr/hal-03070673/file/128-BelkeJHM2020.pdf https://hal.archives-ouvertes.fr/hal-03070673 |
long_lat |
ENVELOPE(-76.549,-76.549,56.553,56.553) |
geographic |
Arctic Umiujaq |
geographic_facet |
Arctic Umiujaq |
genre |
albedo Arctic Umiujaq |
genre_facet |
albedo Arctic Umiujaq |
op_source |
Hyper Article en Ligne - Sciences de l'Homme et de la Société ISSN: 1525-755X EISSN: 1525-7541 Journal of Hydrometeorology Journal of Hydrometeorology, American Meteorological Society, 2020, 21, pp.2581 - 2594. ⟨10.1175/jhm-d-20-0012.1⟩ |
op_relation |
hal-03070673 doi:10.1175/jhm-d-20-0012.1 10670/1.xxoob7 https://hal.archives-ouvertes.fr/hal-03070673/file/128-BelkeJHM2020.pdf https://hal.archives-ouvertes.fr/hal-03070673 |
op_rights |
other |
op_doi |
https://doi.org/10.1175/jhm-d-20-0012.1 |
container_title |
Journal of Hydrometeorology |
container_volume |
21 |
container_issue |
11 |
container_start_page |
2581 |
op_container_end_page |
2594 |
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1766229830948356096 |