Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic
<p>The processes contributing to Arctic cold-season (November–April) sea salt aerosols (SSAs) remain uncertain. Observations from coastal Alaska suggest that emissions from open leads in sea ice, which are not included in climate models, may play a dominant role. Their Arctic-wide significance...
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Copernicus Publications
2025-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/25/4531/2025/acp-25-4531-2025.pdf |
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| author | E. J. Emme H. M. Horowitz H. M. Horowitz |
| author_facet | E. J. Emme H. M. Horowitz H. M. Horowitz |
| author_sort | E. J. Emme |
| collection | DOAJ |
| description | <p>The processes contributing to Arctic cold-season (November–April) sea salt aerosols (SSAs) remain uncertain. Observations from coastal Alaska suggest that emissions from open leads in sea ice, which are not included in climate models, may play a dominant role. Their Arctic-wide significance has not yet been quantified. Here, we create an emission parameterization of SSAs from leads by combining satellite data of lead area (the Advanced Microwave Scanning Radiometer–Earth Observation System (AMSR-E) product) and a chemical transport model (GEOS-Chem) to quantify pan-Arctic SSA emissions from leads during the cold season from 2002 to 2008 and to predict their impacts on atmospheric chemistry, evaluating the results of our simulated SSAs against in situ observations. The AMSR-E product detects large leads with certainty (<span class="inline-formula">></span> 3 km in size), and, hence, our study is limited to quantifying emissions from large leads. Lead emissions vary seasonally and interannually. Simulated total monthly SSA emissions increase by 1.1 %–1.8 % (<span class="inline-formula">≥</span>60° N latitude) and 5.6 %–7.5 % (<span class="inline-formula">≥75</span>° N) for the 2002–2008 cold seasons. SSA concentrations primarily increase at the location of leads, where standard model concentrations are low. GEOS-Chem overestimates SSA concentrations at Arctic sites compared to ground observations, even when lead emissions are not included, suggesting underestimation of SSA sinks and/or uncertainties in SSA emissions from blowing snow and the open ocean. Multi-year monthly mean surface bromine atom (Br) concentrations increase by 2.8 %–8.8 % due to SSAs from leads for the 2002–2008 cold seasons. Changes in ozone concentrations are negligible. While leads contribute <span class="inline-formula"><</span> 10 % to Arctic-wide SSA emissions in the years 2002–2008, these emissions occur in regions of low background aerosol concentrations. Leads may increase in frequency under future climate change, which could increase SSA emissions from leads.</p> |
| format | Article |
| id | doaj-art-356ca4a64e314cffb3ddb17deffd9e80 |
| institution | OA Journals |
| issn | 1680-7316 1680-7324 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj-art-356ca4a64e314cffb3ddb17deffd9e802025-08-20T02:18:35ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242025-04-01254531454510.5194/acp-25-4531-2025Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the ArcticE. J. Emme0H. M. Horowitz1H. M. Horowitz2Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USADepartment of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USADepartment of Atmospheric Science, University of Illinois Urbana-Champaign, Urbana, Illinois, USA<p>The processes contributing to Arctic cold-season (November–April) sea salt aerosols (SSAs) remain uncertain. Observations from coastal Alaska suggest that emissions from open leads in sea ice, which are not included in climate models, may play a dominant role. Their Arctic-wide significance has not yet been quantified. Here, we create an emission parameterization of SSAs from leads by combining satellite data of lead area (the Advanced Microwave Scanning Radiometer–Earth Observation System (AMSR-E) product) and a chemical transport model (GEOS-Chem) to quantify pan-Arctic SSA emissions from leads during the cold season from 2002 to 2008 and to predict their impacts on atmospheric chemistry, evaluating the results of our simulated SSAs against in situ observations. The AMSR-E product detects large leads with certainty (<span class="inline-formula">></span> 3 km in size), and, hence, our study is limited to quantifying emissions from large leads. Lead emissions vary seasonally and interannually. Simulated total monthly SSA emissions increase by 1.1 %–1.8 % (<span class="inline-formula">≥</span>60° N latitude) and 5.6 %–7.5 % (<span class="inline-formula">≥75</span>° N) for the 2002–2008 cold seasons. SSA concentrations primarily increase at the location of leads, where standard model concentrations are low. GEOS-Chem overestimates SSA concentrations at Arctic sites compared to ground observations, even when lead emissions are not included, suggesting underestimation of SSA sinks and/or uncertainties in SSA emissions from blowing snow and the open ocean. Multi-year monthly mean surface bromine atom (Br) concentrations increase by 2.8 %–8.8 % due to SSAs from leads for the 2002–2008 cold seasons. Changes in ozone concentrations are negligible. While leads contribute <span class="inline-formula"><</span> 10 % to Arctic-wide SSA emissions in the years 2002–2008, these emissions occur in regions of low background aerosol concentrations. Leads may increase in frequency under future climate change, which could increase SSA emissions from leads.</p>https://acp.copernicus.org/articles/25/4531/2025/acp-25-4531-2025.pdf |
| spellingShingle | E. J. Emme H. M. Horowitz H. M. Horowitz Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic Atmospheric Chemistry and Physics |
| title | Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic |
| title_full | Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic |
| title_fullStr | Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic |
| title_full_unstemmed | Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic |
| title_short | Impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the Arctic |
| title_sort | impacts of sea ice leads on sea salt aerosols and atmospheric chemistry in the arctic |
| url | https://acp.copernicus.org/articles/25/4531/2025/acp-25-4531-2025.pdf |
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