A simple model for the interhemispheric coupling of the middle atmosphere circulation
2010 (English)In: Advances in Space Research, ISSN 0273-1177, Vol. 45, no 5, 661-668 p.Article in journal (Refereed) Published
The interhemispheric coupling of the middle atmosphere general circulation is characterized by a global anomaly pattern of the zonal-mean temperature. This pattern reflects an anomalous stratospheric and mesospheric residual circulation, in which a weaker (stronger) stratospheric winter circulation is linked to an upward (downward) shift of its upper mesospheric branch reaching from the summer to the winter pole. This phenomenon is robust in observational data and several middle atmosphere general circulation models. In the present study, the recently proposed mechanism of the interhemispheric coupling is unequivocally proven within the framework of a zonally symmetric model that excludes any additional effects due to resolved waves and non-zonally propagating gravity waves. Two simulations are conducted that differ in the strength of the polar vortex. A weaker polar vortex results in a downward shift of the winter mesospheric gravity wave drag. This leads to changes also in the summer upper mesosphere via a feedback solely between gravity wave breaking and the zonal-mean state. The accompanying temperature anomaly reproduces the pattern of the interhemispheric coupling. (C) 2009 COSPAR.
Place, publisher, year, edition, pages
Elsevier Ltd. , 2010. Vol. 45, no 5, 661-668 p.
Middle atmosphere transport circulation, Noctilucent clouds
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-49272DOI: 10.1016/j.asr.2009.11.001ISI: 000275561200007OAI: oai:DiVA.org:su-49272DiVA: diva2:379462
authorCount :22010-12-172010-12-132010-12-23Bibliographically approved