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Revisiting the hemispheric asymmetry in midlatitude ozone changes following the Mount Pinatubo eruption: A 3‐D model study
Author(s) -
Dhomse S. S.,
Chipperfield M. P.,
Feng W.,
Hossaini R.,
Mann G. W.,
Santee M. L.
Publication year - 2015
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 - 10.1002/2015gl063052
Subject(s) - ozone depletion , middle latitudes , stratosphere , atmospheric sciences , climatology , ozone , environmental science , chemical transport model , asymmetry , aerosol , geology , troposphere , meteorology , physics , quantum mechanics
Following the eruption of Mount Pinatubo, satellite and in situ measurements showed a large enhancement in stratospheric aerosol in both hemispheres, but significant midlatitude column O 3 depletion was observed only in the north. We use a three‐dimensional chemical transport model to determine the mechanisms behind this hemispheric asymmetry. The model, forced by European Centre for Medium‐Range Weather Forecasts ERA‐Interim reanalyses and updated aerosol surface area density, successfully simulates observed large column NO 2 decreases and the different extents of ozone depletion in the two hemispheres. The chemical ozone loss is similar in the Northern (NH) and Southern Hemispheres (SH), but the contrasting role of dynamics increases the depletion in the NH and decreases it in the SH. The relevant SH dynamics are not captured as well by earlier ERA‐40 reanalyses. Overall, the smaller SH column O 3 depletion can be attributed to dynamical variability and smaller SH background lower stratosphere O 3 concentrations.