Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations.
The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiativ...
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ftunivbergen:oai:bora.uib.no:11250/2754994 2023-05-15T16:21:29+02:00 Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. Djoumna, G. Mernild, Jacob Sebastian Haugaard Holland, D.M. 2021 application/pdf https://hdl.handle.net/11250/2754994 https://doi.org/10.3389/feart.2020.616105 eng eng Frontiers urn:issn:2296-6463 https://hdl.handle.net/11250/2754994 https://doi.org/10.3389/feart.2020.616105 cristin:1880462 Frontiers in Earth Science. 2021, 8, 616105 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2021 Djoumna, Mernild and Holland. 616105 Frontiers in Earth Science 8 Journal article Peer reviewed 2021 ftunivbergen https://doi.org/10.3389/feart.2020.616105 2023-03-14T17:40:26Z The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation data. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG, 66.3290°N, 38.1460°W) and Jakobshavn Isbræ(JI, 69.2220°N, 49.8150°W) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is about 50.0 W m−2 larger than at JI. Cloud metrics derived at the two sites reveal partly cloudy conditions were frequent (42 and 65% of the period at HG and JI) with a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction. CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 ± 7.4 W m−2 and 1.9±15.1 W m−2 at JI and HG. CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates. publishedVersion Article in Journal/Newspaper glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ University of Bergen: Bergen Open Research Archive (BORA-UiB) Greenland Jakobshavn Isbræ ENVELOPE(-49.917,-49.917,69.167,69.167) Frontiers in Earth Science 8 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
The surface radiation budget is an essential component of the total energy exchange between the atmosphere and the Earth’s surface. Measurements of radiative fluxes near/on ice surfaces are sparse in the polar regions, including on the Greenland Ice Sheet (GrIS), and the effects of cloud on radiative fluxes are still poorly studied. In this work, we assess the impacts of cloud on radiative fluxes using two metrics: the longwave-equivalent cloudiness, derived from long-wave radiation measurements, and the cloud transmittance factor, obtained from short-wave radiation data. The metrics are applied to radiation data from two automatic weather stations located over the bare ground near the ice front of Helheim (HG, 66.3290°N, 38.1460°W) and Jakobshavn Isbræ(JI, 69.2220°N, 49.8150°W) on the GrIS. Comparisons of meteorological parameters, surface radiation fluxes, and cloud metrics show significant differences between the two sites. The cloud transmittance factor is higher at HG than at JI, and the incoming short-wave radiation in the summer at HG is about 50.0 W m−2 larger than at JI. Cloud metrics derived at the two sites reveal partly cloudy conditions were frequent (42 and 65% of the period at HG and JI) with a high dependency on the wind direction. The total cloud radiative effect (CREnet) generally increases during melt season at the two stations due to long-wave CRE enhancement by cloud fraction. CREnet decreases from May to June and increases afterward, due to the strengthened short-wave CRE. The annually averaged CREnet were 3.0 ± 7.4 W m−2 and 1.9±15.1 W m−2 at JI and HG. CREnet estimated from AWS indicates that clouds cool the JI and HG during melt season at different rates. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Djoumna, G. Mernild, Jacob Sebastian Haugaard Holland, D.M. |
spellingShingle |
Djoumna, G. Mernild, Jacob Sebastian Haugaard Holland, D.M. Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
author_facet |
Djoumna, G. Mernild, Jacob Sebastian Haugaard Holland, D.M. |
author_sort |
Djoumna, G. |
title |
Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
title_short |
Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
title_full |
Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
title_fullStr |
Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
title_full_unstemmed |
Meteorological conditions and cloud effects on surface radiation balance near Helheim glacier and Jakobshavn isbræ (Greenland)using ground-based observations. |
title_sort |
meteorological conditions and cloud effects on surface radiation balance near helheim glacier and jakobshavn isbræ (greenland)using ground-based observations. |
publisher |
Frontiers |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2754994 https://doi.org/10.3389/feart.2020.616105 |
long_lat |
ENVELOPE(-49.917,-49.917,69.167,69.167) |
geographic |
Greenland Jakobshavn Isbræ |
geographic_facet |
Greenland Jakobshavn Isbræ |
genre |
glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ |
genre_facet |
glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ |
op_source |
616105 Frontiers in Earth Science 8 |
op_relation |
urn:issn:2296-6463 https://hdl.handle.net/11250/2754994 https://doi.org/10.3389/feart.2020.616105 cristin:1880462 Frontiers in Earth Science. 2021, 8, 616105 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no Copyright 2021 Djoumna, Mernild and Holland. |
op_doi |
https://doi.org/10.3389/feart.2020.616105 |
container_title |
Frontiers in Earth Science |
container_volume |
8 |
_version_ |
1766009492951007232 |