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Estimating the average time for inter‐continental transport of air pollutants
Author(s) -
Liu Junfeng,
Mauzerall Denise L.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl022619
Subject(s) - tracer , environmental science , atmospheric sciences , climatology , atmospheric circulation , meteorology , geology , physics , nuclear physics
We estimate the average time required for inter‐continental transport of atmospheric tracers based on simulations with the global chemical tracer model MOZART‐2 driven with NCEP meteorology. We represent the average transport time by a ratio of the concentration of two tracers with different lifetimes. We find that average transport times increase with tracer lifetimes. With tracers of 1‐ and 2‐week lifetimes the average transport time from East Asia (EA) to the surface of western North America (NA) in April is 2–3 weeks, approximately a half week longer than transport from NA to western Europe (EU) and from EU to EA. We develop an ‘equivalent circulation’ method to estimate a timescale which has little dependence on tracer lifetimes and obtain similar results to those obtained with short‐lived tracers. Our findings show that average inter‐continental transport times, even for tracers with short lifetimes, are on average 1–2 weeks longer than rapid transport observed in plumes.