The influence of the quasi-biennial oscillation on the troposphere in winter in a hierarchy of models. Part I: Simplified dry gcms

Chaim I. Garfinkel, Dennis L. Hartmann

Research output: Contribution to journalArticlepeer-review

Abstract

A dry primitive equation model is used to explain how the quasi-biennial oscillation (QBO) of the tropical stratosphere can influence the troposphere, even in the absence of tropical convection anomalies and a variable stratospheric polar vortex. QBO momentum anomalies induce a meridional circulation to maintain thermal wind balance. This circulation includes zonal wind anomalies that extend from the equatorial stratosphere into the subtropical troposphere. In the presence of extratropical eddies, the zonalwind anomalies are intensified and extend downward to the surface. The tropospheric response differs qualitatively between integrations in which the subtropical jet is strong and integrations in which the subtropical jet is weak. While fluctuation- dissipation theory provides a guide to predicting the response in some cases, significant nonlinearity in others, particularly those designed to model the midwinter subtropical jet of the North Pacific, prevents its universal application. When the extratropical circulation is made zonally asymmetric, the response to the QBO is greatest in the exit region of the subtropical jet. The dry model is able to simulate much of the Northern Hemisphere wintertime tropospheric response to the QBO observed in reanalysis datasets and in long time integrations of the Whole Atmosphere Community Climate Model (WACCM).

Original languageAmerican English
Pages (from-to)1273-1289
Number of pages17
JournalJournals of the Atmospheric Sciences
Volume68
Issue number6
DOIs
StatePublished - Jun 2011
Externally publishedYes

Keywords

  • Coupled models
  • General circulation models
  • Quasibiennial oscillation
  • Troposphere
  • Winter/cool season

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Fingerprint

Dive into the research topics of 'The influence of the quasi-biennial oscillation on the troposphere in winter in a hierarchy of models. Part I: Simplified dry gcms'. Together they form a unique fingerprint.

Cite this