Chemistry of dimethyl sulfide in the equatorial Pacific atmosphere

1996 ◽  
Vol 23 (7) ◽  
pp. 741-744 ◽  
Author(s):  
A. R. Bandy ◽  
D. C. Thornton ◽  
B. W. Blomquist ◽  
S. Chen ◽  
T. P. Wade ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Equatorial Pacific

scholarly journals Free troposphere as a major source of CCN for the equatorial pacific boundary layer: long-range transport and teleconnections

2013 ◽  
Vol 13 (15) ◽  
pp. 7511-7529 ◽  
Author(s):  
A. D. Clarke ◽  
S. Freitag ◽  
R. M. C. Simpson ◽  
J. G. Hudson ◽  
S. G. Howell ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Long Range ◽  
Dimethyl Sulfide ◽  
Large Fraction ◽  
Equatorial Pacific ◽  
Long Range Transport ◽  
Quasi Equilibrium ◽  
Free Troposphere ◽  
Inter Tropical Convergence Zone ◽  
Range Transport

Abstract. Airborne aerosol measurements in the central equatorial Pacific during PASE (Pacific Atmospheric Sulfur Experiment) revealed that cloud condensation nuclei (CCN) activated in marine boundary layer (MBL) clouds were strongly influenced by entrainment from the free troposphere (FT). About 65% entered at sizes effective as CCN in MBL clouds, while ~25% entered the MBL too small to activate but subsequently grew via gas to particle conversion. The remaining ~10% were inferred to be sea salt aerosol. FT aerosols at low carbon monoxide (CO) mixing ratios (< 63 ppbv) were mostly volatile at 360 °C with a number mode peak of around 30–40 nm dry diameter and tended to be associated with cloud outflow from distant (3000 km or more) deep convection. Higher CO concentrations were commonly associated with trajectories from South America and the Amazon region (ca. ~10 000 km away) and occurred in layers indicative of combustion sources (biomass burning season) partially scavenged by precipitation. These had number modes near 60–80 nm dry diameter with a large fraction of CCN.2 (those activated at 0.2% supersaturation and representative of MBL clouds) prior to entrainment into the MBL. Flight averaged concentrations of CCN.2 were similar for measurements near the surface, below the inversion and in the FT just above the inversion, confirming that subsidence and entrainment of FT aerosol strongly influenced MBL CCN.2. Concurrent flight-to-flight variations of CCN.2 at all altitudes below 3 km also imply MBL CCN.2 concentrations were in quasi-equilibrium with the FT over a 2–3 day timescale. The observed FT transport over thousands of kilometers indicates teleconnections between MBL CCN and cloud-scavenged sources of both natural and/or residual combustion origin. Nonetheless, in spite of its importance, this source of CCN number is not well represented in most current models and is generally not detectable by satellite because of the low aerosol scattering in such layers as a result of cloud scavenging. In addition, our measurements confirm nucleation in the MBL was not evident during PASE and argue against a localized linear relation in the MBL between dimethyl sulfide (DMS) and CCN suggested by the CLAW hypothesis. However, when the FT is not impacted by long-range transport, sulfate aerosol derived from DMS pumped aloft in the ITCZ (Inter-Tropical Convergence Zone) can provide a source of CCN to the boundary layer via FT teleconnections involving more complex non-linear processes.

Chemical and hydrographic measurements from the Equatorial Pacific during boreal spring 1992

1992 ◽  
Author(s):  
M.F. LAMB, ◽  
J.C. HENDEE, ◽  
R. WANNINKHOF, ◽  
R.A. FEELY, ◽  
F.J. MILLERO, ◽  
...  
Keyword(s):  
Equatorial Pacific ◽  
Boreal Spring

Microbial Origins and Consequences of Dimethyl Sulfide

2012 ◽  
Vol 7 (4) ◽  
pp. 181-185 ◽  
Author(s):  
Andrew W. B. Johnston ◽  
Andrew R. J. Curson ◽  
Jonathan D. Todd
Keyword(s):  
Dimethyl Sulfide

USING MARINE SEDIMENT TO DETERMINE PALEOCLIMATE IN THE EQUATORIAL PACIFIC: COCOS RIDGE ODP SITE 1242

2016 ◽  
Author(s):  
Leah H. Joseph ◽  
◽  
James S. Coble ◽  
Jesse E. Hart ◽  
Gabriel R. Haug
Keyword(s):  
Marine Sediment ◽  
Equatorial Pacific
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