The importance of temporal collocation for the evaluation of aerosol models with observations
It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We assess the errors incurred due to ignoring temporal sampling and show that they are of similar magnitude as (but smaller than) ac...
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2016
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00043956 2023-05-15T13:06:27+02:00 The importance of temporal collocation for the evaluation of aerosol models with observations Schutgens, N. A. J. Partridge, D. G. Stier, P. 2016-01 electronic https://doi.org/10.5194/acp-16-1065-2016 https://noa.gwlb.de/receive/cop_mods_00043956 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043576/acp-16-1065-2016.pdf https://acp.copernicus.org/articles/16/1065/2016/acp-16-1065-2016.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-16-1065-2016 https://noa.gwlb.de/receive/cop_mods_00043956 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043576/acp-16-1065-2016.pdf https://acp.copernicus.org/articles/16/1065/2016/acp-16-1065-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/acp-16-1065-2016 2022-02-08T22:40:19Z It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We assess the errors incurred due to ignoring temporal sampling and show that they are of similar magnitude as (but smaller than) actual model errors (20–60 %). Using temporal sampling from remote-sensing data sets, the satellite imager MODIS (MODerate resolution Imaging Spectroradiometer) and the ground-based sun photometer network AERONET (AErosol Robotic NETwork), and three different global aerosol models, we compare annual and monthly averages of full model data to sampled model data. Our results show that sampling errors as large as 100 % in AOT (aerosol optical thickness), 0.4 in AE (Ångström Exponent) and 0.05 in SSA (single scattering albedo) are possible. Even in daily averages, sampling errors can be significant. Moreover these sampling errors are often correlated over long distances giving rise to artificial contrasts between pristine and polluted events and regions. Additionally, we provide evidence that suggests that models will underestimate these errors. To prevent sampling errors, model data should be temporally collocated to the observations before any analysis is made. We also discuss how this work has consequences for in situ measurements (e.g. aircraft campaigns or surface measurements) in model evaluation. Although this study is framed in the context of model evaluation, it has a clear and direct relevance to climatologies derived from observational data sets. Article in Journal/Newspaper Aerosol Robotic Network Niedersächsisches Online-Archiv NOA Atmospheric Chemistry and Physics 16 2 1065 1079 |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
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English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Schutgens, N. A. J. Partridge, D. G. Stier, P. The importance of temporal collocation for the evaluation of aerosol models with observations |
topic_facet |
article Verlagsveröffentlichung |
description |
It is often implicitly assumed that over suitably long periods the mean of observations and models should be comparable, even if they have different temporal sampling. We assess the errors incurred due to ignoring temporal sampling and show that they are of similar magnitude as (but smaller than) actual model errors (20–60 %). Using temporal sampling from remote-sensing data sets, the satellite imager MODIS (MODerate resolution Imaging Spectroradiometer) and the ground-based sun photometer network AERONET (AErosol Robotic NETwork), and three different global aerosol models, we compare annual and monthly averages of full model data to sampled model data. Our results show that sampling errors as large as 100 % in AOT (aerosol optical thickness), 0.4 in AE (Ångström Exponent) and 0.05 in SSA (single scattering albedo) are possible. Even in daily averages, sampling errors can be significant. Moreover these sampling errors are often correlated over long distances giving rise to artificial contrasts between pristine and polluted events and regions. Additionally, we provide evidence that suggests that models will underestimate these errors. To prevent sampling errors, model data should be temporally collocated to the observations before any analysis is made. We also discuss how this work has consequences for in situ measurements (e.g. aircraft campaigns or surface measurements) in model evaluation. Although this study is framed in the context of model evaluation, it has a clear and direct relevance to climatologies derived from observational data sets. |
format |
Article in Journal/Newspaper |
author |
Schutgens, N. A. J. Partridge, D. G. Stier, P. |
author_facet |
Schutgens, N. A. J. Partridge, D. G. Stier, P. |
author_sort |
Schutgens, N. A. J. |
title |
The importance of temporal collocation for the evaluation of aerosol models with observations |
title_short |
The importance of temporal collocation for the evaluation of aerosol models with observations |
title_full |
The importance of temporal collocation for the evaluation of aerosol models with observations |
title_fullStr |
The importance of temporal collocation for the evaluation of aerosol models with observations |
title_full_unstemmed |
The importance of temporal collocation for the evaluation of aerosol models with observations |
title_sort |
importance of temporal collocation for the evaluation of aerosol models with observations |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-1065-2016 https://noa.gwlb.de/receive/cop_mods_00043956 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043576/acp-16-1065-2016.pdf https://acp.copernicus.org/articles/16/1065/2016/acp-16-1065-2016.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-16-1065-2016 https://noa.gwlb.de/receive/cop_mods_00043956 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043576/acp-16-1065-2016.pdf https://acp.copernicus.org/articles/16/1065/2016/acp-16-1065-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-16-1065-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
2 |
container_start_page |
1065 |
op_container_end_page |
1079 |
_version_ |
1766006313329885184 |