Alkyl nitrates, nonmethane hydrocarbons, and halocarbon gases over the equatorial Pacific Ocean during Saga 3

Journal Article · Mon Sep 20 04:00:00 EDT 1993 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/93JD01005· OSTI ID:83365

Atlas, E; Pollock, W; Greenberg, J; Heidt, L ^[1]; Thompson, A M ^[2]

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1. National Center for Atmospheric Research, Boulder, CO (United States)
2. NASA Goddard Space Flight Center, Greenbelt, MD (United States)

The third joint Soviet-American Gases and Aerosols (SAGA 3) experiment was a research cruise conducted aboard the Akademik Korolev in February and March 1990. The cruise covered a region of the equatorial Pacific Ocean from 15{degrees}N to 10{degrees}S latitude and 144{degrees} to 165{degrees}W longitude. On this cruise the authors collected samples for the measurement of alkyl nitrates (RONO{sub 2}), nonmethane hydrocarbons (NMHC) and several halocarbon gases. Though there are few data available for comparison in this region of the marine boundary layer, the mixing ratios of the trace gases measured are within the range of prior measurements in the remote atmosphere. Latitudinal gradients were found for trace gases with predominantly anthropogenic sources, e.g., methylene chloride, tetrachloroethylene, and acetylene; higher concentrations in the North Pacific atmosphere decreased slowly across the Equator to the South Pacific. More stable gases, e.g. methyl chloride and methyl bromide, had no pronounced variation across the equator. A biogenic source of two organobromine compounds, bromoform and dibromochloromethane, was indicated by maximum mixing ratios of these species over the equator where indicators of biological productivity (e.g., chlorophyll) in the surface ocean water also maximized. Alkyl nitrates were found at levels higher than predicted from steady state calculations based on measured mixing ratios of hydrocarbons and NO. The measured levels of RONO{sub 2} suggest long-range transport as one mechanism contributing to elevated concentrations of alkyl nitrates in the remote troposphere. However, the distributions of C{sub 2} and C{sub 3} alkyl nitrates over the equator were similar to the organobromine gases. This distribution suggests a possible oceanic source for alkyl nitrates to the atmosphere. 47 refs., 8 figs., 8 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 83365
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: D9 Vol. 98; ISSN 0148-0227; ISSN JGREA2
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACETYLENE
BROMOFORM
ECOLOGICAL CONCENTRATION
EMISSION
EQUATOR
METHYL BROMIDE
METHYL CHLORIDE
METHYLENE CHLORIDE
PACIFIC OCEAN
SPATIAL DISTRIBUTION