Intercontinental source attribution of ozone pollution at western U.S. sites using an adjoint method
Article first published online: 6 JUN 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 11, June 2009
How to Cite
2009), Intercontinental source attribution of ozone pollution at western U.S. sites using an adjoint method, Geophys. Res. Lett., 36, L11810, doi:10.1029/2009GL037950., , , , , and (
- Issue published online: 6 JUN 2009
- Article first published online: 6 JUN 2009
- Manuscript Accepted: 5 MAY 2009
- Manuscript Revised: 23 APR 2009
- Manuscript Received: 27 FEB 2009
- intercontinental transport;
- ozone pollution;
- adjoint model
 We use the GEOS-Chem chemical transport model and its adjoint to quantify source contributions to ozone pollution at two adjacent sites on the U.S. west coast in spring 2006: Mt. Bachelor Observatory (MBO) at 2.7 km altitude and Trinidad Head (TH) at sea level. The adjoint computes the sensitivity of ozone concentrations at the receptor sites to ozone production rates at 2° × 2.5° resolution over the history of air parcels reaching the site. MBO experiences distinct Asian ozone pollution episodes; most of the ozone production in these episodes takes place over East Asia with maxima over northeast China and southern Japan, adding to a diffuse background production distributed over the extratropical northern hemisphere. TH shows the same Asian origins for ozone as MBO but no distinct Asian pollution episodes. We find that transpacific pollution plumes transported in the free troposphere are diluted by a factor of 3 when entrained into the boundary layer, explaining why these plumes are undetectable in U.S. surface air.