Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations
We combine in situ measurements of sea salt aerosols (SS) from open ocean cruises and ground-based stations together with aerosol optical depth (AOD) observations from MODIS and AERONET, and the GEOS-Chem global chemical transport model to provide new constraints on SS emissions over the world'...
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ftdoajarticles:oai:doaj.org/article:df76f714e3b842798685d4edc8b5431f 2023-05-15T17:36:37+02:00 Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations L. Jaeglé P. K. Quinn T. S. Bates B. Alexander J.-T. Lin 2011-04-01T00:00:00Z https://doi.org/10.5194/acp-11-3137-2011 https://doaj.org/article/df76f714e3b842798685d4edc8b5431f EN eng Copernicus Publications http://www.atmos-chem-phys.net/11/3137/2011/acp-11-3137-2011.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-11-3137-2011 1680-7316 1680-7324 https://doaj.org/article/df76f714e3b842798685d4edc8b5431f Atmospheric Chemistry and Physics, Vol 11, Iss 7, Pp 3137-3157 (2011) Physics QC1-999 Chemistry QD1-999 article 2011 ftdoajarticles https://doi.org/10.5194/acp-11-3137-2011 2022-12-31T00:36:36Z We combine in situ measurements of sea salt aerosols (SS) from open ocean cruises and ground-based stations together with aerosol optical depth (AOD) observations from MODIS and AERONET, and the GEOS-Chem global chemical transport model to provide new constraints on SS emissions over the world's oceans. We find that the GEOS-Chem model using the Gong (2003) source function overestimates cruise observations of coarse mode SS mass concentrations by factors of 2–3 at high wind speeds over the cold waters of the Southern, North Pacific and North Atlantic Oceans. Furthermore, the model systematically underestimates SS over the warm tropical waters of the Central Pacific, Atlantic, and Indian Oceans. This pattern is confirmed by SS measurements from a global network of 15 island and coastal stations. The model discrepancy at high wind speeds (>6 m s −1 ) has a clear dependence on sea surface temperature (SST). We use the cruise observations to derive an empirical SS source function depending on both wind speed and SST. Implementing this new source function in GEOS-Chem results in improved agreement with in situ observations, with a decrease in the model bias from +64% to +33% for the cruises and from +32% to −5% for the ground-based sites. We also show that the wind speed-SST source function significantly improves agreement with MODIS and AERONET AOD, and provides an explanation for the high AOD observed over the tropical oceans. With the wind speed-SST formulation, global SS emissions show a small decrease from 5200 Mg yr −1 to 4600 Mg yr −1 , while the SS burden decreases from 9.1 to 8.5 mg m −2 . The spatial distribution of SS, however, is greatly affected, with the SS burden increasing by 50% in the tropics and decreasing by 40% at mid- and high-latitudes. Our results imply a stronger than expected halogen source from SS in the tropical marine boundary layer. They also imply stronger radiative forcing of SS in the tropics and a larger response of SS emissions to climate change than previously thought. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Indian Pacific Atmospheric Chemistry and Physics 11 7 3137 3157 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 L. Jaeglé P. K. Quinn T. S. Bates B. Alexander J.-T. Lin Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
We combine in situ measurements of sea salt aerosols (SS) from open ocean cruises and ground-based stations together with aerosol optical depth (AOD) observations from MODIS and AERONET, and the GEOS-Chem global chemical transport model to provide new constraints on SS emissions over the world's oceans. We find that the GEOS-Chem model using the Gong (2003) source function overestimates cruise observations of coarse mode SS mass concentrations by factors of 2–3 at high wind speeds over the cold waters of the Southern, North Pacific and North Atlantic Oceans. Furthermore, the model systematically underestimates SS over the warm tropical waters of the Central Pacific, Atlantic, and Indian Oceans. This pattern is confirmed by SS measurements from a global network of 15 island and coastal stations. The model discrepancy at high wind speeds (>6 m s −1 ) has a clear dependence on sea surface temperature (SST). We use the cruise observations to derive an empirical SS source function depending on both wind speed and SST. Implementing this new source function in GEOS-Chem results in improved agreement with in situ observations, with a decrease in the model bias from +64% to +33% for the cruises and from +32% to −5% for the ground-based sites. We also show that the wind speed-SST source function significantly improves agreement with MODIS and AERONET AOD, and provides an explanation for the high AOD observed over the tropical oceans. With the wind speed-SST formulation, global SS emissions show a small decrease from 5200 Mg yr −1 to 4600 Mg yr −1 , while the SS burden decreases from 9.1 to 8.5 mg m −2 . The spatial distribution of SS, however, is greatly affected, with the SS burden increasing by 50% in the tropics and decreasing by 40% at mid- and high-latitudes. Our results imply a stronger than expected halogen source from SS in the tropical marine boundary layer. They also imply stronger radiative forcing of SS in the tropics and a larger response of SS emissions to climate change than previously thought. |
format |
Article in Journal/Newspaper |
author |
L. Jaeglé P. K. Quinn T. S. Bates B. Alexander J.-T. Lin |
author_facet |
L. Jaeglé P. K. Quinn T. S. Bates B. Alexander J.-T. Lin |
author_sort |
L. Jaeglé |
title |
Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
title_short |
Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
title_full |
Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
title_fullStr |
Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
title_full_unstemmed |
Global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
title_sort |
global distribution of sea salt aerosols: new constraints from in situ and remote sensing observations |
publisher |
Copernicus Publications |
publishDate |
2011 |
url |
https://doi.org/10.5194/acp-11-3137-2011 https://doaj.org/article/df76f714e3b842798685d4edc8b5431f |
geographic |
Indian Pacific |
geographic_facet |
Indian Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Atmospheric Chemistry and Physics, Vol 11, Iss 7, Pp 3137-3157 (2011) |
op_relation |
http://www.atmos-chem-phys.net/11/3137/2011/acp-11-3137-2011.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-11-3137-2011 1680-7316 1680-7324 https://doaj.org/article/df76f714e3b842798685d4edc8b5431f |
op_doi |
https://doi.org/10.5194/acp-11-3137-2011 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
11 |
container_issue |
7 |
container_start_page |
3137 |
op_container_end_page |
3157 |
_version_ |
1766136166694780928 |