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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Online Access: | https://hal.science/hal-03070673 https://hal.science/hal-03070673/document https://hal.science/hal-03070673/file/128-BelkeJHM2020.pdf https://doi.org/10.1175/jhm-d-20-0012.1 |
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ftinsu:oai:HAL:hal-03070673v1 2023-06-18T03:35:42+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)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Fondation BNP-Paribas, NSERC, IPEV 2020-11-25 https://hal.science/hal-03070673 https://hal.science/hal-03070673/document https://hal.science/hal-03070673/file/128-BelkeJHM2020.pdf https://doi.org/10.1175/jhm-d-20-0012.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/jhm-d-20-0012.1 hal-03070673 https://hal.science/hal-03070673 https://hal.science/hal-03070673/document https://hal.science/hal-03070673/file/128-BelkeJHM2020.pdf doi:10.1175/jhm-d-20-0012.1 info:eu-repo/semantics/OpenAccess ISSN: 1525-755X EISSN: 1525-7541 Journal of Hydrometeorology https://hal.science/hal-03070673 Journal of Hydrometeorology, 2020, 21, pp.2581 - 2594. ⟨10.1175/jhm-d-20-0012.1⟩ Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2020 ftinsu https://doi.org/10.1175/jhm-d-20-0012.1 2023-06-05T22:07:15Z 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 Institut national des sciences de l'Univers: HAL-INSU Arctic Umiujaq ENVELOPE(-76.549,-76.549,56.553,56.553) Journal of Hydrometeorology 21 11 2581 2594 |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization [SDE]Environmental Sciences |
spellingShingle |
Arctic Vegetation Radiative forcing Shortwave radiation Snow cover Parameterization [SDE]Environmental Sciences 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 [SDE]Environmental Sciences |
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)-Institut national des sciences de l'Univers (INSU - CNRS)-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://hal.science/hal-03070673 https://hal.science/hal-03070673/document https://hal.science/hal-03070673/file/128-BelkeJHM2020.pdf https://doi.org/10.1175/jhm-d-20-0012.1 |
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 |
ISSN: 1525-755X EISSN: 1525-7541 Journal of Hydrometeorology https://hal.science/hal-03070673 Journal of Hydrometeorology, 2020, 21, pp.2581 - 2594. ⟨10.1175/jhm-d-20-0012.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/jhm-d-20-0012.1 hal-03070673 https://hal.science/hal-03070673 https://hal.science/hal-03070673/document https://hal.science/hal-03070673/file/128-BelkeJHM2020.pdf doi:10.1175/jhm-d-20-0012.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
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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1769009791614582784 |