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Title: Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation

Abstract

Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM5) with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7). Emissions of marine primary organic aerosols (POA), phytoplanktonproduced isoprene- and monoterpenes-derived secondary organic aerosols (SOA) and methane sulfonate (MS{sup -}) are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr{sup -1}, for the Gantt et al. (2011) and Vignati et al. (2010) emission parameterizations, respectively. Marine sources of SOA and particulate MS{sup -} (containing both sulfur and carbon atoms) contribute an additional 0.2 and 5.1 Tg yr{sup -1}, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ngm{sup -3}, with values up to 400 ngm{sup -3} over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM) with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2), both Gantt et al. (2011) and Vignati et al. (2010) formulations are ablemore » to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011) parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN). The largest increases (up to 20 %) in CCN (at a supersaturation (S) of 0.2 %) number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides diverse results with increases and decreases in the concentration of CCN over different parts of the ocean. The sign of the CCN change due to the addition of marine organics to seasalt aerosol is determined by the relative significance of the increase in mean modal diameter due to addition of mass, and the decrease in particle hygroscopicity due to compositional changes in marine aerosol. Based on emerging evidence for increased CCN concentration over biologically active surface ocean areas/periods, our study suggests that treatment of sea spray in global climate models (GCMs) as an internal mixture of marine organic aerosols and sea-salt will likely lead to an underestimation in CCN number concentration.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1031423
Report Number(s):
PNNL-SA-84328
Journal ID: ISSN 1680-7316; KP1703010; TRN: US201201%%598
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Atmospheric Chemistry and Physics
Additional Journal Information:
Journal Volume: 11; Journal Issue: 22; Journal ID: ISSN 1680-7316
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; AEROSOLS; ATOMS; CARBON; CLIMATE MODELS; CLIMATES; CLOUDS; CONDENSATION NUCLEI; DISTRIBUTION; EVALUATION; HYGROSCOPICITY; ISOPRENE; METHANE; MIXTURES; ORGANIC MATTER; PARTICULATES; SEAS; SULFONATES; SULFUR; SUPERSATURATION; global distribution; climate forcing; marine organic; aerosol model improvements; evaluation

Citation Formats

Meskhidze, N, Xu, J, Gantt, Brett, Zhang, Yang, Nenes, Athanasios, Ghan, Steven J, Liu, Xiaohong, Easter, Richard C, and Zaveri, Rahul A. Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation. United States: N. p., 2011. Web. doi:10.5194/acp-11-11689-2011.
Meskhidze, N, Xu, J, Gantt, Brett, Zhang, Yang, Nenes, Athanasios, Ghan, Steven J, Liu, Xiaohong, Easter, Richard C, & Zaveri, Rahul A. Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation. United States. https://doi.org/10.5194/acp-11-11689-2011
Meskhidze, N, Xu, J, Gantt, Brett, Zhang, Yang, Nenes, Athanasios, Ghan, Steven J, Liu, Xiaohong, Easter, Richard C, and Zaveri, Rahul A. 2011. "Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation". United States. https://doi.org/10.5194/acp-11-11689-2011.
@article{osti_1031423,
title = {Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation},
author = {Meskhidze, N and Xu, J and Gantt, Brett and Zhang, Yang and Nenes, Athanasios and Ghan, Steven J and Liu, Xiaohong and Easter, Richard C and Zaveri, Rahul A},
abstractNote = {Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM5) with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7). Emissions of marine primary organic aerosols (POA), phytoplanktonproduced isoprene- and monoterpenes-derived secondary organic aerosols (SOA) and methane sulfonate (MS{sup -}) are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr{sup -1}, for the Gantt et al. (2011) and Vignati et al. (2010) emission parameterizations, respectively. Marine sources of SOA and particulate MS{sup -} (containing both sulfur and carbon atoms) contribute an additional 0.2 and 5.1 Tg yr{sup -1}, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ngm{sup -3}, with values up to 400 ngm{sup -3} over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM) with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2), both Gantt et al. (2011) and Vignati et al. (2010) formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011) parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN). The largest increases (up to 20 %) in CCN (at a supersaturation (S) of 0.2 %) number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming marine organics are internally-mixed with sea-salt provides diverse results with increases and decreases in the concentration of CCN over different parts of the ocean. The sign of the CCN change due to the addition of marine organics to seasalt aerosol is determined by the relative significance of the increase in mean modal diameter due to addition of mass, and the decrease in particle hygroscopicity due to compositional changes in marine aerosol. Based on emerging evidence for increased CCN concentration over biologically active surface ocean areas/periods, our study suggests that treatment of sea spray in global climate models (GCMs) as an internal mixture of marine organic aerosols and sea-salt will likely lead to an underestimation in CCN number concentration.},
doi = {10.5194/acp-11-11689-2011},
url = {https://www.osti.gov/biblio/1031423}, journal = {Atmospheric Chemistry and Physics},
issn = {1680-7316},
number = 22,
volume = 11,
place = {United States},
year = {Wed Nov 23 00:00:00 EST 2011},
month = {Wed Nov 23 00:00:00 EST 2011}
}