Title
Natural sea-salt emissions moderate the climate forcing of anthropogenic nitrate
Author
Chen, Y.
Cheng, Y.
Ma, N.
Wei, C.
Ran, L.
Wolke, R.
Gross, J.
Wang, Q.
Pozzer, A.
van der Gon, H.A.C.D.
Spindler, G.
Lelieveld, J.
Tegen, I.
Su, H.
Wiedensohler, A.
Publication year
2020
Abstract
Natural sea-salt aerosols, when interacting with anthropogenic emissions, can enhance the formation of particulate nitrate. This enhancement has been suggested to increase the direct radiative forcing of nitrate, called the "massenhancement effect". Through a size-resolved dynamic mass transfer modeling approach, we show that interactions with sea salt shift the nitrate from sub-to super-micron-sized particles ("redistribution effect"), and hence this lowers its efficiency for light extinction and reduces its lifetime. The redistribution effect overwhelms the mass-enhancement effect and significantly moderates nitrate cooling; e.g., the nitrateassociated aerosol optical depth can be reduced by 10 %-20% over European polluted regions during a typical seasalt event, in contrast to an increase by ∼ 10% when only accounting for the mass-enhancement effect. Global model simulations indicate significant redistribution over coastal and offshore regions worldwide. Our study suggests a strong buffering by natural sea-salt aerosols that reduces the climate forcing of anthropogenic nitrate, which had been expected to dominate the aerosol cooling by the end of the century. Comprehensive considerations of this redistribution effect foster better understandings of climate change and nitrogen deposition. © Author(s) 2020.
Subject
Aerosol
Aerosol composition
Anthropogenic source
Climate forcing
Nitrate
Optical depth
Particulate matter
Sea salt
Environment & Sustainability
Urbanisation
To reference this document use:
http://resolver.tudelft.nl/uuid:5d73489a-26e2-4faf-a177-98334b6dda27
DOI
https://doi.org/10.5194/acp-20-771-2020
TNO identifier
873517
Publisher
Copernicus GmbH
ISSN
1680-7316
Source
Atmospheric Chemistry and Physics, 20 (20), 771-786
Document type
article