MEASUREMENT OF ATMOSPHERIC AEROSOLS IN THE MARINE
BOUNDARY LAYER
Principal Investigator:
T. P. Carsey
Objective:
Determine processes controlling the chemical composition of
boundary layer marine
aerosols
Rationale:
The chemical composition of marine aerosols has been the subject
of a number of useful
investigations, including the evaluation of long-range transport
of anthropogenic
constituents on the chemistry of the remote marine boundary layer
(e.g., Whelpdale et
al., 1994; Galloway et al., 1992). an understanding of
gas-particle interactions (Ottley and
Harrison, 1992; Pszenny, 1992), and the possible effect on
primary productivity in the
sea surface waters (Michaels et al., 1993). The effort at
AOML/OCD has been aimed
as using size-segregated aerosol chemical data to answer question
concerning gas-to-
particle reactions and depositional effects on the ocean.
Method:
Size-segregated aerosol chemical data are obtained on open-ocean
ship cruises and
interpreted in the context of mesoscale meteorology via back
trajectories and related
chemical data. Aerosol samples are obtained with a six-stage
Sierra high-volume
cascade impactor or bulk sampler unit housed in identical
anodized aluminum shelters.
The equipment is usually mounted on a 10-m air sampling tower
approximately 20 m
above the water line of the NOAA research ship MALCOLM BALDRIGE.
The 50% cut
sizes (Dp50) for the cascade impactor as specified by the
manufacturer are 3.6, 1.5, 0.75,
0.48, and 0.24 um radius for impactor stages 1-5; stage 6
collects all aerosols < 0.24 um.
Samples are analyzed by ion chromatography for anions (SO4, NO3-, Cl-, MSA
[methane
sulfonic acid]) and cations (Na, K, NH4). In addition,
non-seasalt sulfate (nssSO4) and chloride deficit
(defCl-) are computed (Carsey et al., 1995)
Accomplishment:
1992 ASTEX / MAGE Cruise
The OCD atmospheric chemistry group helped organize and
participated in the NOAA
component of the IGAC-sponsored ASTEX/MAGE experiment in the
summer of 1992
aboard the R/V MALCOLM BALDRIGE (Hubert et al., 1994). The
concentrations of
nitrate, sulfate, and MSA ranged from 1-30, 5-150 and 0.25-3.0
nMol/m (resp). The
sulfate budget was found to be primarily influenced by
anthropogenic sulfur (Pszenny
et al., 1994; Carsey et al, 1994).
1993 North Atlantic Cruise
In 1993, OCD organized a cruise in the North Atlantic (Iceland to
Miami). The
accompanying graphic shows the concentration of non-seasalt
sulfate (nssSO4)
versus
time (Carsey et al., 1995). Chemical and aerosol results are
currently being prepared for
publication.
1995 Atlantic / Indian Ocean Cruise
Bulk Aerosol samples were obtained during the Miami-South Africa
stage of the 1995
Indian Ocean cruise and have been analyzed at AOML. Results are
currently being
processed. The bulk aerosol sampler aboard the MALCOLM BALDRIGE
has continued
to obtain bulk samples for subsequent analysis.
Key reference:
Carsey, T. P., M. L. Farmer, C. J. Fischer,
A. Mendez, A. A. Pszenny, V. Ross III, P.-Y.
Whung, M. Springer-Young, and M. P. Zetwo.
Atmospheric Chemistry
Measurements from the 1992 ASTEX/MAGE Cruise, 30-May-1992 through
21-July
1992, Cruise Number 91-126. NOAA Data Report ERL AOML-26, 1994.
Carsey, T. P., M. L. Farmer, C. J. Fischer,
A. Mendez, V. B. Ross, and M.
Springer-Young. Atmospheric Chemistry Measurements during Leg 4
(RITS) of the
1993 North Atlantic Cruise. NOAA Data Report (in press, 1995).
Galloway, J., J. Penner, C. Atherton, J. Prospero, H. Rodhe, R.
Artz, Y. Balkanski, H.
Bingemer, R. Broast, S. Bergermeister, G. Charmichael, J. Chang,
R. Charlson, S.
Cober, W. Ellis, Jr., C. Fischer, J. Hales, D. Hastie, T.
Iversen, D. Jacob, K. John, J.
Johnson, P. Kasibhatla, J. Langner, J. Lelieveld, H. Levy, II, F.
Lipschultz, J. Merrill, A.
Michaels, J. Miller, J. Moody, J. Pinto, A. Pszenny, P. Spiro, L.
Tarrason, S. Turner,
and D. Whelpdale, 1992. Global Biogeochem. Cyc. 6, 77-100.
Huebert, B. J., A. Pszenny, and B. Blomquist, 1994. The
ASTEX/MAGE experiment. J.
Geophys. Res. (submitted).
Michaels, A., D. Siegel, R. Johnson, A. Knap, and J. Galloway,
1993. Episodic inputs
of atmospheric nitrogen to the Sargasso Sea: contributions to
new production and
phytoplankton blooms. Global Biogeochem. Cyc. 7, 339-351.
Ottley, C., and R. Harrison, 1992. Atmosph. Env. 26A,
1689-1699.
Pszenny, A. A., 1992. Particle size distributions of
methanesulfonate in the tropical
Pacific marine boundary layer. J. Atm. Chem. 14, 273-284.
Pszenny, A. A., T. P. Carsey, P. Y. Whung, M.
P. Zetwo, M. L. Farmer, and C. J.
Fischer. Measurements of various chemical concentrations in
the marine boundary
layer during the 1992 ASTEX/MAGE experiment. Presented at the
1994 AGU Spring
Meeting, May 25, 1994 (Eos 75, 89, 1994).
Stunder, J., Artz, R., Rolph, G., Harris, J., and Merrill, J.,
1990. Summary of
meteorological conditions over the North Atlantic Ocean during
GCE/CASE/WATOX Global Biogeochem. Cyc. 4, 121-132.
Whelpdale, D. M., and J. N. Galloway, 1994. Sulfur and reactive
nitrogen oxide
fluxes in the North Atlantic atmosphere. Global Biogeochem.
Cyc. 8, 481-493, 1994.
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