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Atmospheric trace gas studies in Antarctica
Author(s) -
Cronn D. R.,
Schilling K. J.
Publication year - 1988
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/rg026i003p00497
Subject(s) - polar vortex , northern hemisphere , atmospheric sciences , trace gas , atmospheric circulation , environmental science , tropopause , troposphere , climatology , stratosphere , southern hemisphere , subsidence , snow , jet stream , geology , jet (fluid) , structural basin , paleontology , physics , geomorphology , thermodynamics
Atmospheric trace gas studies in Antarctica have led to an increased understanding of the global effects from anthropogenic emissions of various compounds. These studies have also contributed to the identification of various atmospheric circulation patterns and mixing mechanisms. Time trend analyses have revealed that although the atmospheric concentrations of F‐11, F‐12, CH 3 CCl 3 , and other halocarbons are still increasing, their rate of increase has slowed from peak increasing rates observed in the 1970s. For CO 2 , CO, and CH 4 , time trend analyses have also been used to analyze seasonal concentration cycles and to establish relationships between sources and sinks at various times throughout the year. Latitudinal gradient studies have generally revealed that for most compounds with significant anthropogenic sources, atmospheric concentrations are higher in the northern hemisphere than in the southern hemisphere. This is mainly a result of the overwhelming majority of anthropogenic sources existing in the northern hemisphere. Vertical concentration profiles in Antarctica are dependent upon the seasonal variations in circulation patterns associated with final warming and breakup of the polar vortex. Since final warming and breakup of the polar vortex may not always occur at the same time each year, profiles for a given time period from separate years may be different. Stratospheric‐tropospheric air exchange over Antarctica occurs primarily as a result of (1) general circulation patterns with subsidence over the polar regions, (2) stratospheric air injection in the vicinity of jet streams and injection from tropopause folding upstream of troughs, and (3) mountain waves of sufficient magnitude to displace air parcels across the tropopause.