Monthly and seasonal characteristics of optical properties and direct radiative forcing of secondary marine aerosols in the East Asian sea area
Abstract
Marine aerosols (primary and secondary) as well as atmospheric anthropogenic aerosols have a substantial impact on the Earth's radiative balance. Unlike the primary marine aerosol, the secondary marine aerosol is produced by the gas-to-particle conversion of dimethyl sulfide (DMS), emitted from the sea surface in the marine boundary layer. In this study, sea-to-air DMS flux (i.e., DMS emission) was estimated from sea surface DMS concentrations and transfer velocity in the East Asian sea area during 2013-2016, using satellite observations and modeling data. The DMS emission data was then used to estimate the optical properties (e.g., aerosol optical depth, AOD) and direct radiative forcing (DRF) of the DMS-derived aerosol (i.e., non-sea-salt (NSS) sulfate) in an aerosol optical model and a radiative transfer model, respectively. The monthly mean AODs at 550 nm for the DMS-derived sulfate during the study period were in the range of 0.02 to 0.13 (a mean of 0.04±0.06). The mean DRF estimated in the study was highest in the coastal sea near Shanghai followed by the Bohai Sea, whereas its lowest value occurred around the East Sea during the study period. This spatial distribution was similar to that of DMS flux. In addition, the forcing at the surface and top of the atmosphere, and in the atmosphere of the DMS-derived sulfate showed a maximum in December 2014 (approximately -41.1, -35.9, and +6.4 W m-2, respectively) and a minimum in March 2013 (-9.5, -8.4, +1.2 W m-2, respectively).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A11G2283C
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0315 Biosphere/atmosphere interactions;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0409 Bioavailability: chemical speciation and complexation;
- BIOGEOSCIENCESDE: 4801 Aerosols;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL