TY - JOUR

T1 - Interhemispheric differences in seasonal cycles of tropospheric ozone in the marine boundary layer

T2 - observation - model comparisons

AU - Derwent, R. G.

AU - Parrish, David

AU - Galbally, Ian

AU - Stevenson, D. S.

AU - Doherty, R. M.

AU - Young, Paul John

AU - Shallcross, D. E.

N1 - ©2016. American Geophysical Union. All Rights Reserved.

PY - 2016/9/27

Y1 - 2016/9/27

N2 - 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.

AB - 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.

U2 - 10.1002/2016JD024836

DO - 10.1002/2016JD024836

M3 - Journal article

VL - 121

SP - 11075

EP - 11085

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 0747-7309

IS - 18

ER -