Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts
Geometric effects induced by the underlying terrain slope or by tilt errors of the radiation sensors lead to an erroneous measurement of snow or ice albedo. Consequently, artificial diurnal albedo variations in the order of 1–20 % are observed. The present paper proposes a general method to correct...
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2016
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00013673 2023-05-15T18:32:32+02:00 Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts Weiser, Ursula Olefs, Marc Schöner, Wolfgang Weyss, Gernot Hynek, Bernhard 2016-04 electronic https://doi.org/10.5194/tc-10-775-2016 https://noa.gwlb.de/receive/cop_mods_00013673 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013629/tc-10-775-2016.pdf https://tc.copernicus.org/articles/10/775/2016/tc-10-775-2016.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-10-775-2016 https://noa.gwlb.de/receive/cop_mods_00013673 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013629/tc-10-775-2016.pdf https://tc.copernicus.org/articles/10/775/2016/tc-10-775-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/tc-10-775-2016 2022-02-08T22:55:30Z Geometric effects induced by the underlying terrain slope or by tilt errors of the radiation sensors lead to an erroneous measurement of snow or ice albedo. Consequently, artificial diurnal albedo variations in the order of 1–20 % are observed. The present paper proposes a general method to correct tilt errors of albedo measurements in cases where tilts of both the sensors and the slopes are not accurately measured or known. We demonstrate that atmospheric parameters for this correction model can either be taken from a nearby well-maintained and horizontally levelled measurement of global radiation or alternatively from a solar radiation model. In a next step the model is fitted to the measured data to determine tilts and directions of sensors and the underlying terrain slope. This then allows us to correct the measured albedo, the radiative balance and the energy balance. Depending on the direction of the slope and the sensors a comparison between measured and corrected albedo values reveals obvious over- or underestimations of albedo. It is also demonstrated that differences between measured and corrected albedo are generally highest for large solar zenith angles. Article in Journal/Newspaper The Cryosphere Niedersächsisches Online-Archiv NOA The Cryosphere 10 2 775 790 |
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article Verlagsveröffentlichung Weiser, Ursula Olefs, Marc Schöner, Wolfgang Weyss, Gernot Hynek, Bernhard Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
topic_facet |
article Verlagsveröffentlichung |
description |
Geometric effects induced by the underlying terrain slope or by tilt errors of the radiation sensors lead to an erroneous measurement of snow or ice albedo. Consequently, artificial diurnal albedo variations in the order of 1–20 % are observed. The present paper proposes a general method to correct tilt errors of albedo measurements in cases where tilts of both the sensors and the slopes are not accurately measured or known. We demonstrate that atmospheric parameters for this correction model can either be taken from a nearby well-maintained and horizontally levelled measurement of global radiation or alternatively from a solar radiation model. In a next step the model is fitted to the measured data to determine tilts and directions of sensors and the underlying terrain slope. This then allows us to correct the measured albedo, the radiative balance and the energy balance. Depending on the direction of the slope and the sensors a comparison between measured and corrected albedo values reveals obvious over- or underestimations of albedo. It is also demonstrated that differences between measured and corrected albedo are generally highest for large solar zenith angles. |
format |
Article in Journal/Newspaper |
author |
Weiser, Ursula Olefs, Marc Schöner, Wolfgang Weyss, Gernot Hynek, Bernhard |
author_facet |
Weiser, Ursula Olefs, Marc Schöner, Wolfgang Weyss, Gernot Hynek, Bernhard |
author_sort |
Weiser, Ursula |
title |
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
title_short |
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
title_full |
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
title_fullStr |
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
title_full_unstemmed |
Correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
title_sort |
correction of broadband snow albedo measurements affected by unknown slope and sensor tilts |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-775-2016 https://noa.gwlb.de/receive/cop_mods_00013673 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013629/tc-10-775-2016.pdf https://tc.copernicus.org/articles/10/775/2016/tc-10-775-2016.pdf |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-10-775-2016 https://noa.gwlb.de/receive/cop_mods_00013673 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013629/tc-10-775-2016.pdf https://tc.copernicus.org/articles/10/775/2016/tc-10-775-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-10-775-2016 |
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The Cryosphere |
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10 |
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2 |
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775 |
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790 |
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1766216641465548800 |