Processes controlling the distribution of aerosol particles in the lower marine boundary layer during the First Aerosol Characterization Experiment (ACE 1)
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Authors
Bates, Timothy S.
Kapustin, Vladimir N.
Quinn, Patricia K.
Covert, David S.
Coffman, Derek J.
Mari, Celine
Durkee, Philip A.
De Bruyn, Warren J.
Saltzman, Eric S.
Subjects
Advisors
Date of Issue
1998-07-20
Date
Publisher
American Geophysical Union
Language
Abstract
The goals of the International Global Atmospheric Chemistry (IGAC) Program's First Aerosol Characterization Experiment (ACE 1) are to determine and understand the properties and controlling factors of the aerosol in the remote marine atmosphere that are relevant to radiative forcing and climate. A key question in terms of this goal and the overall biogeochemical sulfur cycle is what factors control the formation, growth, and evolution of particles in the marine boundary layer (MBL). To address this question, simultaneous measurements of dimethylsulfide (DMS), sulfur dioxide (SO2), the aerosol chemical mass size distribution, and the aerosol number size distribution from 5 to 10,000 nm diameter were made on the
National Oceanic and Atmospheric Administration (NOAA) ship Discoverer. From these data we conclude that the background MBL aerosol during ACE I often was composed of four distinct modes: an ultrafine (UF) mode (Dp = 5-20 nm), an Aitken mode (Dp = 20-80 nm), an accumulation mode (Dp = 80-300 nm), and a coarse mode (Dp > 300 nm). The presence of UF mode particles in the MBL could be explained by convective mixing between the free troposphere (FT) and the MBL associated with cloud pumping and subsidence following cold frontal passages. There was no evidence of major new particle production in the MBL. Oceanic emissions of DMS appeared to contribute to the growth of Aitken and accumulation mode particles. Coarse mode particles were comprised primarily of sea salt. Although these particles result from turbulence at the air-sea interface, the instantaneous wind speed accounted for only one third of the variance in the coarse mode number concentration in this region.
Type
Article
Description
Series/Report No
Department
Meteorology
Organization
Naval Postgraduate School (U.S.)
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NPS Report Number
Sponsors
This research was funded by the Aerosol Project of the NOAA Climate and Global Change Program.
Funder
Format
15 p.
Citation
Journal of Geophysical Research, Vol. 103, No. D13, Pp. 16,369-16,383, July 20, 1998
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.