Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes
The aerosol direct radiative effect (ADRE) is defined as the change in the solar radiation flux, F, due to aerosol scattering and absorption. The difficulty in determining ADRE stems mainly from the need to estimate F without aerosols, F0, with either radiative transfer modeling and knowledge of the...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00044967 2023-05-15T13:06:32+02:00 Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes Huttunen, J. Arola, A. Myhre, G. Lindfors, A. V. Mielonen, T. Mikkonen, S. Schafer, J. S. Tripathi, S. N. Wild, M. Komppula, M. Lehtinen, K. E. J. 2014-06 electronic https://doi.org/10.5194/acp-14-6103-2014 https://noa.gwlb.de/receive/cop_mods_00044967 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044587/acp-14-6103-2014.pdf https://acp.copernicus.org/articles/14/6103/2014/acp-14-6103-2014.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-14-6103-2014 https://noa.gwlb.de/receive/cop_mods_00044967 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044587/acp-14-6103-2014.pdf https://acp.copernicus.org/articles/14/6103/2014/acp-14-6103-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/acp-14-6103-2014 2022-02-08T22:39:48Z The aerosol direct radiative effect (ADRE) is defined as the change in the solar radiation flux, F, due to aerosol scattering and absorption. The difficulty in determining ADRE stems mainly from the need to estimate F without aerosols, F0, with either radiative transfer modeling and knowledge of the atmospheric state, or regression analysis of radiation data down to zero aerosol optical depth (AOD), if only F and AOD are observed. This paper examines the regression analysis method by using modeled surface data products provided by the Aerosol Robotic Network (AERONET). We extrapolated F0 by two functions: a straight linear line and an exponential nonlinear decay. The exponential decay regression is expected to give a better estimation of ADRE with a few percent larger extrapolated F0 than the linear regression. We found that, contrary to the expectation, in most cases the linear regression gives better results than the nonlinear. In such cases the extrapolated F0 represents an unrealistically low water vapor column (WVC), resulting in underestimation of attenuation caused by the water vapor, and hence too large F0 and overestimation of the magnitude of ADRE. The nonlinear ADRE is generally 40–50% larger in magnitude than the linear ADRE due to the extrapolated F0 difference. Since for a majority of locations, AOD and WVC have a positive correlation, the extrapolated F0 with the nonlinear regression fit represents an unrealistically low WVC, and hence too large F0. The systematic underestimation of F0 with the linear regression is compensated by the positive correlation between AOD and water vapor, providing the better result. Article in Journal/Newspaper Aerosol Robotic Network Niedersächsisches Online-Archiv NOA Atmospheric Chemistry and Physics 14 12 6103 6110 |
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Niedersächsisches Online-Archiv NOA |
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English |
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article Verlagsveröffentlichung Huttunen, J. Arola, A. Myhre, G. Lindfors, A. V. Mielonen, T. Mikkonen, S. Schafer, J. S. Tripathi, S. N. Wild, M. Komppula, M. Lehtinen, K. E. J. Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
topic_facet |
article Verlagsveröffentlichung |
description |
The aerosol direct radiative effect (ADRE) is defined as the change in the solar radiation flux, F, due to aerosol scattering and absorption. The difficulty in determining ADRE stems mainly from the need to estimate F without aerosols, F0, with either radiative transfer modeling and knowledge of the atmospheric state, or regression analysis of radiation data down to zero aerosol optical depth (AOD), if only F and AOD are observed. This paper examines the regression analysis method by using modeled surface data products provided by the Aerosol Robotic Network (AERONET). We extrapolated F0 by two functions: a straight linear line and an exponential nonlinear decay. The exponential decay regression is expected to give a better estimation of ADRE with a few percent larger extrapolated F0 than the linear regression. We found that, contrary to the expectation, in most cases the linear regression gives better results than the nonlinear. In such cases the extrapolated F0 represents an unrealistically low water vapor column (WVC), resulting in underestimation of attenuation caused by the water vapor, and hence too large F0 and overestimation of the magnitude of ADRE. The nonlinear ADRE is generally 40–50% larger in magnitude than the linear ADRE due to the extrapolated F0 difference. Since for a majority of locations, AOD and WVC have a positive correlation, the extrapolated F0 with the nonlinear regression fit represents an unrealistically low WVC, and hence too large F0. The systematic underestimation of F0 with the linear regression is compensated by the positive correlation between AOD and water vapor, providing the better result. |
format |
Article in Journal/Newspaper |
author |
Huttunen, J. Arola, A. Myhre, G. Lindfors, A. V. Mielonen, T. Mikkonen, S. Schafer, J. S. Tripathi, S. N. Wild, M. Komppula, M. Lehtinen, K. E. J. |
author_facet |
Huttunen, J. Arola, A. Myhre, G. Lindfors, A. V. Mielonen, T. Mikkonen, S. Schafer, J. S. Tripathi, S. N. Wild, M. Komppula, M. Lehtinen, K. E. J. |
author_sort |
Huttunen, J. |
title |
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
title_short |
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
title_full |
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
title_fullStr |
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
title_full_unstemmed |
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes |
title_sort |
effect of water vapor on the determination of aerosol direct radiative effect based on the aeronet fluxes |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/acp-14-6103-2014 https://noa.gwlb.de/receive/cop_mods_00044967 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044587/acp-14-6103-2014.pdf https://acp.copernicus.org/articles/14/6103/2014/acp-14-6103-2014.pdf |
genre |
Aerosol Robotic Network |
genre_facet |
Aerosol Robotic Network |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-14-6103-2014 https://noa.gwlb.de/receive/cop_mods_00044967 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00044587/acp-14-6103-2014.pdf https://acp.copernicus.org/articles/14/6103/2014/acp-14-6103-2014.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-14-6103-2014 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
14 |
container_issue |
12 |
container_start_page |
6103 |
op_container_end_page |
6110 |
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1766009720830689280 |