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Lifetime dependent flux into the lowermost stratosphere for idealized trace gases of surface origin
Author(s) -
Holzer Mark,
Polvani Lorenzo M.
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.50657
Subject(s) - stratosphere , tropopause , flux (metallurgy) , trace gas , atmospheric sciences , troposphere , isentropic process , environmental science , climatology , extratropical cyclone , northern hemisphere , physics , chemistry , mechanics , geology , organic chemistry
The flux of idealized trace gases across the thermal tropopause is quantified as a function of their chemical lifetime using the Model of Atmospheric Transport and Chemistry (MATCH) driven by National Centers for Environmental Prediction (NCEP) reanalyses. The flux is computed in the limit of instant stratospheric chemical loss, and tropospheric chemistry is idealized as decay with a constant lifetime, τ c . Emissions are idealized as time independent, with either a generic anthropogenic pattern or a uniform ocean source. We find that the globally averaged flux into the stratosphere normalized by surface emissions is ∼1% for τ c = 8 days and ∼30% for τ c ∼ 140 days, slowly approaching the long‐lived limit of balance between stratospheric sinks and surface sources. The qualitative τ c dependence of the globally averaged flux is captured by a simple one‐dimensional model. The flux patterns computed with MATCH for the NCEP reanalyses are insensitive to τ c and reveal preferred pathways into the stratosphere: The divergent circulation feeding isentropic cross‐tropopause transport, storm tracks in the winter hemisphere, and isentropic transport to high latitudes.