Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment
-
Published:2018-04-26
Issue:8
Volume:18
Page:5861-5877
-
ISSN:1680-7324
-
Container-title:Atmospheric Chemistry and Physics
-
language:en
-
Short-container-title:Atmos. Chem. Phys.
Author:
Smith Murray J., Walker Carolyn F.ORCID, Bell Thomas G.ORCID, Harvey Mike J.ORCID, Saltzman Eric S., Law Cliff S.ORCID
Abstract
Abstract. Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the
Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in
February–March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean.
Three distinct phytoplankton blooms were studied with oceanic DMS
concentrations as high as 25 nmol L−1. Measurements of DMS fluxes were
made using two independent methods: the eddy covariance (EC) technique using
atmospheric pressure chemical ionization–mass spectrometry (API-CIMS) and
the gradient flux (GF) technique from an autonomous catamaran platform.
Catamaran flux measurements are relatively unaffected by airflow distortion
and are made close to the water surface, where gas gradients are largest. Flux
measurements were complemented by near-surface hydrographic measurements to
elucidate physical factors influencing DMS emission. Individual DMS fluxes
derived by EC showed significant scatter and, at times, consistent departures
from the Coupled Ocean–Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the
two flux methods was carried out to separate instrumental effects from
environmental effects and showed good agreement with a regression slope of
0.96 (r2= 0.89). A period of abnormal downward atmospheric heat
flux enhanced near-surface ocean stratification and reduced turbulent
exchange, during which GF and EC transfer velocities showed good agreement
but modelled COAREG values were significantly higher. The transfer velocity
derived from near-surface ocean turbulence measurements on a spar buoy
compared well with the COAREG model in general but showed less variation.
This first direct comparison between EC and GF fluxes of DMS provides
confidence in compilation of flux estimates from both techniques, as well as in
the stable periods when the observations are not well predicted by the COAREG
model.
Funder
National Institute of Water and Atmospheric Research Division of Atmospheric and Geospace Sciences
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference62 articles.
1. Andreae, M. O. and Crutzen, P. J.: Atmospheric aerosols: Biogeochemical
sources and role in atmospheric chemistry, Science, 276, 1052–1058, https://doi.org/10.1126/science.276.5315.1052, 1997. 2. Bell, T. G.: DMS Data Selection, available at: http://saga.pmel.noaa.gov/dms/select.php, last access: 11 April 2018. 3. Bell, T. G., De Bruyn, W., Miller, S. D., Ward, B., Christensen, K. H., and
Saltzman, E. S.: Air–sea dimethylsulfide (DMS) gas transfer in the North
Atlantic: evidence for limited interfacial gas exchange at high wind speed,
Atmos. Chem. Phys., 13, 11073–11087,
https://doi.org/10.5194/acp-13-11073-2013, 2013. 4. Bell, T. G., De Bruyn, W., Marandino, C. A., Miller, S. D., Law, C. S.,
Smith, M. J., and Saltzman, E. S.: Dimethylsulfide gas transfer coefficients
from algal blooms in the Southern Ocean, Atmos. Chem. Phys., 15, 1783–1794,
https://doi.org/10.5194/acp-15-1783-2015, 2015. 5. Bell, T. G., Landwehr, S., Miller, S. D., de Bruyn, W. J., Callaghan, A. H.,
Scanlon, B., Ward, B., Yang, M., and Saltzman, E. S.: Estimation of
bubble-mediated air–sea gas exchange from concurrent DMS and CO2 transfer
velocities at intermediate–high wind speeds, Atmos. Chem. Phys., 17,
9019–9033, https://doi.org/10.5194/acp-17-9019-2017, 2017.
Cited by
14 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|