Model evaluation of marine primary organic aerosol emission schemes 1North Carolina State University, Raleigh, NC, USA
21 Sep 2012
2Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
3School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland
*now at: NASA Ames Research Center, Moffett Field, CA, USA
Received: 23 April 2012 – Published in Atmos. Chem. Phys. Discuss.: 23 May 2012 Abstract. In this study, several marine primary organic aerosol (POA) emission schemes
have been evaluated using the GEOS-Chem chemical transport model in order to
provide guidance for their implementation in air quality and climate models.
These emission schemes, based on varying dependencies of chlorophyll a
concentration ([chl a]) and 10 m wind speed (U10), have large
differences in their magnitude, spatial distribution, and seasonality. Model
comparison with weekly and monthly mean values of the organic aerosol mass
concentration at two coastal sites shows that the source function exclusively
related to [chl a] does a better job replicating surface observations.
Sensitivity simulations in which the negative U10 and positive [chl a]
dependence of the organic mass fraction of sea spray aerosol are enhanced
show improved prediction of the seasonality of the marine POA concentrations.
A top-down estimate of submicron marine POA emissions based on the
parameterization that compares best to the observed weekly and monthly mean
values of marine organic aerosol surface concentrations has a global average
emission rate of 6.3 Tg yr−1. Evaluation of existing marine POA source
functions against a case study during which marine POA contributed the major
fraction of submicron aerosol mass shows that none of the existing
parameterizations are able to reproduce the hourly-averaged observations. Our
calculations suggest that in order to capture episodic events and short-term
variability in submicron marine POA concentration over the ocean, new source
functions need to be developed that are grounded in the physical processes
unique to the organic fraction of sea spray aerosol.
Revised: 16 August 2012 – Accepted: 02 September 2012 – Published: 21 September 2012
Citation: Gantt, B., Johnson, M. S., Meskhidze, N., Sciare, J., Ovadnevaite, J., Ceburnis, D., and O'Dowd, C. D.: Model evaluation of marine primary organic aerosol emission schemes, Atmos. Chem. Phys., 12, 8553-8566, doi:10.5194/acp-12-8553-2012, 2012.