Open AccessAssessment of the breakup of the Antarctic polar vortex in two new chemistry‐climate models
Author(s) -
Hurwitz M. M.,
Newman P. A.,
Li F.,
Oman L. D.,
Morgenstern O.,
Braesicke P.,
Pyle J. A.
Publication year - 2010
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jd012788
Subject(s) - breakup , polar vortex , stratosphere , geopotential height , troposphere , vortex , climatology , atmospheric sciences , sudden stratospheric warming , polar night , geology , polar , northern hemisphere , climate model , ozone depletion , meteorology , southern hemisphere , environmental science , physics , climate change , oceanography , precipitation , mechanics , astronomy
Successful simulation of the breakup of the Antarctic polar vortex depends on the representation of tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses the vortex breakup in two new chemistry‐climate models (CCMs). The stratospheric version of the UK Chemistry and Aerosols model is able to reproduce the observed timing of the vortex breakup. Version 2 of the Goddard Earth Observing System (GEOS V2) model is typical of CCMs in that the Antarctic polar vortex breaks up too late; at 10 hPa, the mean transition to easterlies at 60°S is delayed by 12–13 days as compared with the ERA‐40 and National Centers for Environmental Prediction reanalyses. The two models' skill in simulating planetary wave driving during the October–November period accounts for differences in their simulation of the vortex breakup, with GEOS V2 unable to simulate the magnitude and tilt of geopotential height anomalies in the troposphere and thus underestimating the wave driving. In the GEOS V2 CCM the delayed breakup of the Antarctic vortex biases polar temperatures and trace gas distributions in the upper stratosphere in November and December.