Abstract
Marine cloud brightening (MCB) is proposed to offset global warming by emitting sea salt aerosols to the tropical marine boundary layer, which increases aerosol and cloud albedo. Sea salt aerosol is the main source of tropospheric reactive chlorine (Cly) and bromine (Bry). The effects of additional sea salt on atmospheric chemistry have not been explored. We simulate sea salt aerosol injections for MCB under two scenarios (212–569 Tg/a) in the GEOS-Chem global chemical transport model, only considering their impacts as a halogen source. Globally, tropospheric Cly and Bry increase (20–40%), leading to decreased ozone (−3 to −6%). Consequently, OH decreases (−3 to −5%), which increases the methane lifetime (3–6%). Our results suggest that the chemistry of the additional sea salt leads to minor total radiative forcing compared to that of the sea salt aerosol itself (~2%) but may have potential implications for surface ozone pollution in tropical coastal regions.
Original language | English |
---|---|
Article number | e2019GL085838 |
Number of pages | 16 |
Journal | Geophysical Research Letters |
Volume | 47 |
Issue number | 4 |
Early online date | 29 Jan 2020 |
DOIs | |
Publication status | Published - 28 Feb 2020 |
Bibliographical note
© 2020 American Geophysical Union. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.Keywords
- geoengineering
- atmospheric chemistry
- sea salt aerosols
- reactive halogens
- marine cloud brightening