A multi-season investigation of glacier surface roughness lengths through in situ and remote observation
The roughness length values for momentum, temperature, and water vapour are key inputs to the bulk aerodynamic method for estimating turbulent heat flux. Measurements of site-specific roughness length are rare for glacier surfaces, and substantial uncertainty remains in the values and ratios commonl...
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Copernicus Publications
2019
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Online Access: | https://doi.org/10.5194/tc-13-1051-2019 https://doaj.org/article/8549e57ccfac4cb8960de9a32a2efc7f |
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ftdoajarticles:oai:doaj.org/article:8549e57ccfac4cb8960de9a32a2efc7f 2023-05-15T18:32:27+02:00 A multi-season investigation of glacier surface roughness lengths through in situ and remote observation N. Fitzpatrick V. Radić B. Menounos 2019-04-01T00:00:00Z https://doi.org/10.5194/tc-13-1051-2019 https://doaj.org/article/8549e57ccfac4cb8960de9a32a2efc7f EN eng Copernicus Publications https://www.the-cryosphere.net/13/1051/2019/tc-13-1051-2019.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-13-1051-2019 1994-0416 1994-0424 https://doaj.org/article/8549e57ccfac4cb8960de9a32a2efc7f The Cryosphere, Vol 13, Pp 1051-1071 (2019) Environmental sciences GE1-350 Geology QE1-996.5 article 2019 ftdoajarticles https://doi.org/10.5194/tc-13-1051-2019 2022-12-30T21:10:08Z The roughness length values for momentum, temperature, and water vapour are key inputs to the bulk aerodynamic method for estimating turbulent heat flux. Measurements of site-specific roughness length are rare for glacier surfaces, and substantial uncertainty remains in the values and ratios commonly assumed when parameterising turbulence. Over three melt seasons, eddy covariance observations were implemented to derive the momentum and scalar roughness lengths at several locations on two mid-latitude mountain glaciers. In addition, two techniques were developed in this study for the remote estimation of momentum roughness length, utilising lidar-derived digital elevation models with a 1×1 m resolution. Seasonal mean momentum roughness length values derived from eddy covariance observations at each location ranged from 0.7 to 4.5 mm for ice surfaces and 0.5 to 2.4 mm for snow surfaces. From one season to the next, mean momentum roughness length values over ice remained relatively consistent at a given location (0–1 mm difference between seasonal mean values), while within a season, temporal variability in momentum roughness length over melting snow was found to be substantial ( > an order of magnitude). The two remote techniques were able to differentiate between ice and snow cover and return momentum roughness lengths that were within 1–2 mm ( ≪ an order of magnitude) of the in situ eddy covariance values. Changes in wind direction affected the magnitude of the momentum roughness length due to the anisotropic nature of features on a melting glacier surface. Persistence in downslope wind direction on the glacier surfaces, however, reduced the influence of this variability. Scalar roughness length values showed considerable variation (up to 2.5 orders of magnitude) between locations and seasons and no evidence of a constant ratio with momentum roughness length or each other. Of the tested estimation methods, the Andreas (1987) surface renewal model returned scalar roughness lengths closest to those derived from ... Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles Andreas ENVELOPE(-60.729,-60.729,-64.008,-64.008) The Cryosphere 13 3 1051 1071 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 N. Fitzpatrick V. Radić B. Menounos A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
The roughness length values for momentum, temperature, and water vapour are key inputs to the bulk aerodynamic method for estimating turbulent heat flux. Measurements of site-specific roughness length are rare for glacier surfaces, and substantial uncertainty remains in the values and ratios commonly assumed when parameterising turbulence. Over three melt seasons, eddy covariance observations were implemented to derive the momentum and scalar roughness lengths at several locations on two mid-latitude mountain glaciers. In addition, two techniques were developed in this study for the remote estimation of momentum roughness length, utilising lidar-derived digital elevation models with a 1×1 m resolution. Seasonal mean momentum roughness length values derived from eddy covariance observations at each location ranged from 0.7 to 4.5 mm for ice surfaces and 0.5 to 2.4 mm for snow surfaces. From one season to the next, mean momentum roughness length values over ice remained relatively consistent at a given location (0–1 mm difference between seasonal mean values), while within a season, temporal variability in momentum roughness length over melting snow was found to be substantial ( > an order of magnitude). The two remote techniques were able to differentiate between ice and snow cover and return momentum roughness lengths that were within 1–2 mm ( ≪ an order of magnitude) of the in situ eddy covariance values. Changes in wind direction affected the magnitude of the momentum roughness length due to the anisotropic nature of features on a melting glacier surface. Persistence in downslope wind direction on the glacier surfaces, however, reduced the influence of this variability. Scalar roughness length values showed considerable variation (up to 2.5 orders of magnitude) between locations and seasons and no evidence of a constant ratio with momentum roughness length or each other. Of the tested estimation methods, the Andreas (1987) surface renewal model returned scalar roughness lengths closest to those derived from ... |
format |
Article in Journal/Newspaper |
author |
N. Fitzpatrick V. Radić B. Menounos |
author_facet |
N. Fitzpatrick V. Radić B. Menounos |
author_sort |
N. Fitzpatrick |
title |
A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
title_short |
A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
title_full |
A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
title_fullStr |
A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
title_full_unstemmed |
A multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
title_sort |
multi-season investigation of glacier surface roughness lengths through in situ and remote observation |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-1051-2019 https://doaj.org/article/8549e57ccfac4cb8960de9a32a2efc7f |
long_lat |
ENVELOPE(-60.729,-60.729,-64.008,-64.008) |
geographic |
Andreas |
geographic_facet |
Andreas |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 13, Pp 1051-1071 (2019) |
op_relation |
https://www.the-cryosphere.net/13/1051/2019/tc-13-1051-2019.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-13-1051-2019 1994-0416 1994-0424 https://doaj.org/article/8549e57ccfac4cb8960de9a32a2efc7f |
op_doi |
https://doi.org/10.5194/tc-13-1051-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
3 |
container_start_page |
1051 |
op_container_end_page |
1071 |
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1766216571421720576 |