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Carbonyl sulfide in the planetary boundary layer: Coastal and continental influences
Author(s) -
Commane R.,
Herndon S. C.,
Zahniser M. S.,
Lerner B. M.,
McManus J. B.,
Munger J. W.,
Nelson D. D.,
Wofsy S. C.
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50581
Subject(s) - carbonyl sulfide , biosphere , environmental science , atmospheric sciences , plume , carbon cycle , boundary layer , biogeochemical cycle , environmental chemistry , ecosystem , oceanography , sulfur , chemistry , ecology , meteorology , geology , geography , physics , organic chemistry , biology , thermodynamics
Measurements of carbonyl sulfide (OCS) have been proposed to provide a unique constraint on carbon assimilation by the biosphere that is independent of the influence of plant and soil respiration of CO 2 , but this constraint depends on a comprehensive understanding of the processes controlling OCS in the biosphere. We conducted a high‐resolution temporal and spatial survey of OCS and CO 2 mixing ratios during the California Nexus Experiment research cruise along the coast of California (U.S.) and into the Sacramento River Delta using a newly constructed compact quantum cascade laser spectrometer (precision for OCS of <8 pptv (pmol/mol) at 1 Hz). The temporal and spatial resolution of the measurements revealed a number of specific processes related to known sources and sinks. The observations demonstrate OCS uptake during daytime photosynthetic uptake of CO 2 , OCS depletion during nighttime forest respiration of CO 2 , and OCS emission from a freshwater marsh. OCS emission was observed in one anthropogenically influenced plume, but, overall, no correlation was observed between OCS and SO 2 , and the use of scaled SO 2 emission fields in global budgets of OCS should be reconsidered for areas with strict sulfur emission controls, such as California. The observations show that, in a homogeneous ecosystem on a local scale, OCS may be a proxy for CO 2 uptake. However, at larger scales that span heterogeneous environments, in order to confidently quantify any single process, competing processes must be either relatively small or well quantified.