Putting Constraints on the Life Cycle of Reactive Organic Carbon based on Ecosystem Scale Flux Measurements
Vortragender: Dr. Thomas Karl, National Center for Atmospheric Research, Boulder, CO, USADo. 27.10.2011 (17:00-18:30)
eingeladen von Andreas Held.
Large quantities of volatile organic compounds (VOC) enter the
atmosphere. The annual production of VOC (600 -2000 TgC/a) likely
exceeds that of methane and CO (~500 TgC/a each). Together these gases
fuel tropospheric chemistry. Oxidation of VOC leads to the formation
of aerosol via complex organic chemistry in the gas and aerosol phase
thereby modulating the oxidation capacity of the atmosphere. It is
currently believed that a large fraction of VOC originates from
biogenic sources (e.g. >80%). The life cycle of organic carbon is
ultimately controlled by emission and deposition processes at the
surface. Uncertainties in budgets of VOC and potential ramifications
for organic aerosol production in the atmosphere will be discussed
based on a synthesis of direct VOC flux measurements performed in a
range of different ecosystems. These direct flux measurements will be
used to address some outstanding questions concerning (1) the amount
of reactive biogenic organic aerosol precursors, (2) the magnitude of
deposition processes and (3) the lifetime of reactive biogenic organic
aerosol precursors in the atmosphere.
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