Assessing the retrieval of cloud properties from radiation measurements over snow and ice
Abstract We critically review and improve a simple method to extract year‐round records of cloud optical thickness from radiation measurements made by automatic weather stations (AWSs) over snow and ice surfaces. A ‘longwave‐equivalent cloudiness’, N ε , obtained from longwave radiation measurements...
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crwiley:10.1002/joc.2114 2024-06-02T07:57:26+00:00 Assessing the retrieval of cloud properties from radiation measurements over snow and ice Kuipers Munneke, P. Reijmer, C. H. van den Broeke, M. R. 2011 http://dx.doi.org/10.1002/joc.2114 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.2114 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.2114 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor International Journal of Climatology volume 31, issue 5, page 756-769 ISSN 0899-8418 1097-0088 journal-article 2011 crwiley https://doi.org/10.1002/joc.2114 2024-05-03T11:27:40Z Abstract We critically review and improve a simple method to extract year‐round records of cloud optical thickness from radiation measurements made by automatic weather stations (AWSs) over snow and ice surfaces. A ‘longwave‐equivalent cloudiness’, N ε , obtained from longwave radiation measurements, is combined with the effective cloud optical thickness, τ, from shortwave data, to obtain consistent, year‐round information on cloud properties. The method is applied to radiation data from six AWSs in Dronning Maud Land, Antarctica, and the ablation area of the West‐Greenland ice sheet. The good correlation between daily‐mean N ε and τ for all locations (0.77 < r < 0.94) shows that shortwave radiative properties of clouds can be inferred using longwave radiation even in the absence of solar radiation itself. An error analysis shows that retrievals of τ are sensitive to the quality of the input data, but accurate to about 21% for hourly values, 11% for daily means, and about 6% for monthly means. As three applications of the method presented above, we discuss the influence of clouds on the radiation budget (Application I), the relation between cloud cover and broadband albedo (Application II) at the six AWS locations, and we demonstrate the possibility to detect trends in τ in longer data series (Application III). About one‐third of the attenuation of solar radiation by clouds is compensated by multiple reflections between the high‐albedo surface and the cloud base (Application I). Cloudy‐sky surface albedo is higher than the clear‐sky albedo for snow surfaces but not for ice (Application II): over snow surfaces, clouds deplete near‐infrared (IR) radiation and thus increase the broadband albedo. Ice surfaces have a much lower albedo for visible radiation, weakening this enrichment of visible radiation and thus the increase of broadband albedo. The method is used to detect a trend in τ of − 0.40 ± 0.15 y −1 in the 1995–2004 time series from Neumayer, Antarctica (Application III). Copyright © 2010 Royal ... Article in Journal/Newspaper Antarc* Antarctica Dronning Maud Land Greenland Ice Sheet Wiley Online Library Dronning Maud Land Greenland Neumayer International Journal of Climatology 31 5 756 769 |
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Open Polar |
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Wiley Online Library |
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English |
description |
Abstract We critically review and improve a simple method to extract year‐round records of cloud optical thickness from radiation measurements made by automatic weather stations (AWSs) over snow and ice surfaces. A ‘longwave‐equivalent cloudiness’, N ε , obtained from longwave radiation measurements, is combined with the effective cloud optical thickness, τ, from shortwave data, to obtain consistent, year‐round information on cloud properties. The method is applied to radiation data from six AWSs in Dronning Maud Land, Antarctica, and the ablation area of the West‐Greenland ice sheet. The good correlation between daily‐mean N ε and τ for all locations (0.77 < r < 0.94) shows that shortwave radiative properties of clouds can be inferred using longwave radiation even in the absence of solar radiation itself. An error analysis shows that retrievals of τ are sensitive to the quality of the input data, but accurate to about 21% for hourly values, 11% for daily means, and about 6% for monthly means. As three applications of the method presented above, we discuss the influence of clouds on the radiation budget (Application I), the relation between cloud cover and broadband albedo (Application II) at the six AWS locations, and we demonstrate the possibility to detect trends in τ in longer data series (Application III). About one‐third of the attenuation of solar radiation by clouds is compensated by multiple reflections between the high‐albedo surface and the cloud base (Application I). Cloudy‐sky surface albedo is higher than the clear‐sky albedo for snow surfaces but not for ice (Application II): over snow surfaces, clouds deplete near‐infrared (IR) radiation and thus increase the broadband albedo. Ice surfaces have a much lower albedo for visible radiation, weakening this enrichment of visible radiation and thus the increase of broadband albedo. The method is used to detect a trend in τ of − 0.40 ± 0.15 y −1 in the 1995–2004 time series from Neumayer, Antarctica (Application III). Copyright © 2010 Royal ... |
format |
Article in Journal/Newspaper |
author |
Kuipers Munneke, P. Reijmer, C. H. van den Broeke, M. R. |
spellingShingle |
Kuipers Munneke, P. Reijmer, C. H. van den Broeke, M. R. Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
author_facet |
Kuipers Munneke, P. Reijmer, C. H. van den Broeke, M. R. |
author_sort |
Kuipers Munneke, P. |
title |
Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
title_short |
Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
title_full |
Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
title_fullStr |
Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
title_full_unstemmed |
Assessing the retrieval of cloud properties from radiation measurements over snow and ice |
title_sort |
assessing the retrieval of cloud properties from radiation measurements over snow and ice |
publisher |
Wiley |
publishDate |
2011 |
url |
http://dx.doi.org/10.1002/joc.2114 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.2114 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.2114 |
geographic |
Dronning Maud Land Greenland Neumayer |
geographic_facet |
Dronning Maud Land Greenland Neumayer |
genre |
Antarc* Antarctica Dronning Maud Land Greenland Ice Sheet |
genre_facet |
Antarc* Antarctica Dronning Maud Land Greenland Ice Sheet |
op_source |
International Journal of Climatology volume 31, issue 5, page 756-769 ISSN 0899-8418 1097-0088 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/joc.2114 |
container_title |
International Journal of Climatology |
container_volume |
31 |
container_issue |
5 |
container_start_page |
756 |
op_container_end_page |
769 |
_version_ |
1800740590678179840 |