The distribution of sea-salt aerosol in the global troposphere

Murphy, Daniel M.; Froyd, Karl D.; Bian, Huisheng; Brock, Charles A.; Dibb, Jack E.; DiGangi, Joshua P.; Diskin, Glenn; Dollner, Maximillian; Kupc, Agnieszka; Scheuer, Eric M.; Schill, Gregory P.; Weinzierl, Bernadett; Williamson, Christina J.; Yu, Pengfei

We present the first data on the concentration of sea-salt aerosol throughout most of the depth of the troposphere and over a wide range of latitudes, which were obtained during the Atmospheric Tomography (ATom) mission. Sea-salt concentrations in the upper troposphere are very small, usually less than 10 ng per standard m3 (about 10 parts per trillion by mass) and often less than 1 ng m−3. This puts stringent limits on the contribution of sea-salt aerosol to halogen and nitric acid chemistry in the upper troposphere. Within broad regions the concentration of sea-salt aerosol is roughly proportional to water vapor, supporting a dominant role for wet scavenging in removing sea-salt aerosol from the atmosphere. Concentrations of sea-salt aerosol in the winter upper troposphere are not as low as in the summer and the tropics. This is mostly a consequence of less wet scavenging in the drier, colder winter atmosphere. There is also a source of sea-salt aerosol over pack ice that is distinct from that over open water. With a well-studied and widely distributed source, sea-salt aerosol provides an excellent test of wet scavenging and vertical transport of aerosols in chemical transport models.

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Murphy, Daniel M. / Froyd, Karl D. / Bian, Huisheng / et al: The distribution of sea-salt aerosol in the global troposphere. 2019. Copernicus Publications.

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