The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic

Understanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent ch...

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Main Authors: H. Struthers, A. M. L. Ekman, P. Glantz, T. Iversen, A. Kirkevåg, E. M. Mårtensson, Ø. Seland, E. D. Nilsson
Format: Article
Language:English
Published: Copernicus Publications 2011-04-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/11/3459/2011/acp-11-3459-2011.pdf
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author H. Struthers
A. M. L. Ekman
P. Glantz
T. Iversen
A. Kirkevåg
E. M. Mårtensson
Ø. Seland
E. D. Nilsson
author_facet H. Struthers
A. M. L. Ekman
P. Glantz
T. Iversen
A. Kirkevåg
E. M. Mårtensson
Ø. Seland
E. D. Nilsson
author_sort H. Struthers
collection DOAJ
description Understanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent change in radiative balance is examined. A set of idealized climate model simulations were performed to quantify the radiative effects of changes in sea salt aerosol emissions induced by prescribed changes in sea ice extent. The model was forced using sea ice concentrations consistent with present day conditions and projections of sea ice extent for 2100. Sea salt aerosol emissions increase in response to a decrease in sea ice, the model results showing an annual average increase in number emission over the polar cap (70–90° N) of 86 × 10<sup>6</sup> m<sup>−2</sup> s<sup>−1</sup> (mass emission increase of 23 μg m<sup>−2</sup> s<sup>−1</sup>). This in turn leads to an increase in the natural aerosol optical depth of approximately 23%. In response to changes in aerosol optical depth, the natural component of the aerosol direct forcing over the Arctic polar cap is estimated to be between −0.2 and −0.4 W m<sup>−2</sup> for the summer months, which results in a negative feedback on the system. The model predicts that the change in first indirect aerosol effect (cloud albedo effect) is approximately a factor of ten greater than the change in direct aerosol forcing although this result is highly uncertain due to the crude representation of Arctic clouds and aerosol-cloud interactions in the model. This study shows that both the natural aerosol direct and first indirect effects are strongly dependent on the surface albedo, highlighting the strong coupling between sea ice, aerosols, Arctic clouds and their radiative effects.
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spelling doaj.art-a473ba5299f543748b1a86de5648a8dd2022-12-22T00:26:11ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-04-011173459347710.5194/acp-11-3459-2011The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the ArcticH. StruthersA. M. L. EkmanP. GlantzT. IversenA. KirkevågE. M. MårtenssonØ. SelandE. D. NilssonUnderstanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent change in radiative balance is examined. A set of idealized climate model simulations were performed to quantify the radiative effects of changes in sea salt aerosol emissions induced by prescribed changes in sea ice extent. The model was forced using sea ice concentrations consistent with present day conditions and projections of sea ice extent for 2100. Sea salt aerosol emissions increase in response to a decrease in sea ice, the model results showing an annual average increase in number emission over the polar cap (70–90° N) of 86 × 10<sup>6</sup> m<sup>−2</sup> s<sup>−1</sup> (mass emission increase of 23 μg m<sup>−2</sup> s<sup>−1</sup>). This in turn leads to an increase in the natural aerosol optical depth of approximately 23%. In response to changes in aerosol optical depth, the natural component of the aerosol direct forcing over the Arctic polar cap is estimated to be between −0.2 and −0.4 W m<sup>−2</sup> for the summer months, which results in a negative feedback on the system. The model predicts that the change in first indirect aerosol effect (cloud albedo effect) is approximately a factor of ten greater than the change in direct aerosol forcing although this result is highly uncertain due to the crude representation of Arctic clouds and aerosol-cloud interactions in the model. This study shows that both the natural aerosol direct and first indirect effects are strongly dependent on the surface albedo, highlighting the strong coupling between sea ice, aerosols, Arctic clouds and their radiative effects.http://www.atmos-chem-phys.net/11/3459/2011/acp-11-3459-2011.pdf
spellingShingle H. Struthers
A. M. L. Ekman
P. Glantz
T. Iversen
A. Kirkevåg
E. M. Mårtensson
Ø. Seland
E. D. Nilsson
The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
Atmospheric Chemistry and Physics
title The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
title_full The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
title_fullStr The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
title_full_unstemmed The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
title_short The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic
title_sort effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the arctic
url http://www.atmos-chem-phys.net/11/3459/2011/acp-11-3459-2011.pdf
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