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Interhemispheric differences in seasonal cycles of tropospheric ozone in the marine boundary layer: Observation‐model comparisons
Author(s) -
Derwent Richard G.,
Parrish David D.,
Galbally Ian E.,
Stevenson David S.,
Doherty Ruth M.,
Young Paul J.,
Shallcross Dudley E.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd024836
Subject(s) - southern hemisphere , climatology , northern hemisphere , environmental science , tropospheric ozone , atmospheric sciences , climate model , troposphere , inflow , boundary layer , annual cycle , climate change , geology , oceanography , physics , thermodynamics
Marine boundary layer ozone seasonal cycles have been quantified by fitting the sum of two sine curves through monthly detrended observations taken at three stations: Mace Head, Ireland, and Trinidad Head, California, in the Northern Hemisphere and Cape Grim, Tasmania, in the Southern Hemisphere. The parameters defining the sine curve fits at these stations have been compared with those from a global Lagrangian chemistry‐transport model and from 14 Atmospheric Chemistry Coupled Climate Model Intercomparison Project chemistry‐climate models. Most models substantially overestimated the long‐term average ozone levels at Trinidad Head, while they performed much better for Mace Head and Cape Grim. This led to an underestimation of the observed (North Atlantic inflow‐North Pacific inflow) difference. The models generally underpredicted the magnitude of the fundamental term of the fitted seasonal cycle, most strongly at Cape Grim. The models more accurately reproduced the observed second harmonic terms compared to the fundamental terms at all stations. Significant correlations have been identified between the errors in the different models' estimates of the seasonal cycle parameters; these correlations may yield further insights into the causes of the model‐measurement discrepancies.