Sea spray as an obscured source for marine cloud nuclei
Xu, W.; Ovadnevaite, J.; Fossum, K.N.; Lin, C.; Huang, R.-J.; Ceburnis, D.; O'Dowd, C. (2022). Sea spray as an obscured source for marine cloud nuclei. Nature Geoscience 15(4): 282-286. https://dx.doi.org/10.1038/s41561-022-00917-2
In: Nature Geoscience. Nature Publishing Group: London. ISSN 1752-0894; e-ISSN 1752-0908, more
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| Authors | | Top |
- Xu, W.
- Ovadnevaite, J.
- Fossum, K.N.
- Lin, C.
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- Huang, R.-J.
- Ceburnis, D.
- O'Dowd, C.
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| Abstract |
Sea spray aerosols (SSAs) make up a substantial proportion of aerosols in the global atmosphere and, especially when considering marine haze and cloud layers, can have a large impact on cloud formation and atmospheric radiative balance. Although SSA has the highest cloud condensation nuclei (CCN) activation potential, the majority of its population, residing in sub-micrometre sizes, are often obscured by non-sea-spray CCN. Quantification of SSA-derived CCN is fundamental in understanding the radiative budget. Recent approaches to estimate the sub-micrometre SSA employed a free-monomodal lognormal analysis that depicts the global oceanic CCN population comprising less than 30% SSA. Here we derive SSA distributions from a unique five-year dataset of aerosol microphysics and hygroscopicity (water uptake ability) over Atlantic waters. This approach utilizes the distinctive ultra-high hygroscopicity signature of inorganic sea salt and is able to identify the sub-micrometre sea spray down to 35 nm diameter with high time and size resolution. In stark contrast to previous studies, the hygroscopicity coupled multimodal fitting analysis yields SSA-derived CCN as much as 500% in excess of estimates produced using the free-monomodal approach. Our results suggest the contribution of SSA to global CCN, particularly Aitken mode SSA, has probably been overlooked. |
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