Open AccessAircraft measurements of the latitudinal, vertical, and seasonal variations of NMHCs, methyl nitrate, methyl halides, and DMS during the First Aerosol Characterization Experiment (ACE 1)
Author(s) -
Blake Nicola J.,
Blake Donald R.,
Wingenter Oliver W.,
Sive Barkley C.,
Kang Chang Hee,
Thornton Donald C.,
Bandy Alan R.,
Atlas Elliot,
Flocke Frank,
Harris Joyce M.,
Rowland F. Sherwood
Publication year - 1999
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jd900238
Subject(s) - dimethyl sulfide , troposphere , southern hemisphere , aerosol , environmental science , mixing ratio , atmospheric sciences , methyl iodide , northern hemisphere , dimethylsulfoniopropionate , nitrate , trace gas , oceanography , climatology , geology , chemistry , meteorology , geography , phytoplankton , nutrient , sulfur , organic chemistry , medicinal chemistry
Canister sampling for the determination of atmospheric mixing ratios of nonmethane hydrocarbons (NMHCs), selected halocarbons, and methyl nitrate was conducted aboard the National Center for Atmospheric Research (NCAR) C‐130 aircraft over the Pacific and Southern Oceans as part of the First Aerosol Characterization Experiment (ACE 1) during November and December 1995. A latitudinal profile, flown from 76°N to 60°S, revealed latitudinal gradients for most trace gases. NMHC and halocarbon gases with predominantly anthropogenic sources, including ethane, ethyne, and tetrachloroethene, exhibited significantly higher mixing ratios in the northern hemisphere at all altitudes. Methyl chloride exhibited its lowest mixing ratios at the highest northern hemisphere latitudes, and the distributions of methyl nitrate and methyl iodide were consistent with tropical and subtropical oceanic sources. Layers containing continental air characteristic of aged biomass burning emissions were observed above about 3 km over the remote southern Pacific and near New Zealand between approximately 19°S and 43°S. These plumes originated from the west, possibly from fires in southern Africa. The month‐long intensive investigation of the clean marine southern midlatitude troposphere south of Australia revealed decreases in the mixing ratios of ethane, ethyne, propane, and tetrachloroethene, consistent with their seasonal mixing ratio cycle. By contrast, increases in the average marine boundary layer concentrations of methyl iodide, methyl nitrate, and dimethyl sulfide (DMS) were observed as the season progressed to summer conditions. These increases were most appreciable in the region south of 44°S over Southern Ocean waters characterized as subantarctic and polar, indicating a seasonal increase in oceanic productivity for these gases.