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gfdl's home page > gfdl on-line bibliography > 1994: Proceedings of the Fifth COSPAR Colloquium, Pergamon Press, 751-757
Modelling middle atmosphere interannual variability
| Hamilton, K., 1994: Modelling middle atmosphere interannual variability. In Proceedings of the Fifth COSPAR Colloquium, Pergamon Press, 751-757. |
| Abstract: The GFDL "SKYHI" general circulation model is designed to perform comprehensive simulations of the dynamics of the global troposphere, stratosphere and mesosphere. In the version considered here the primitive equations are discretized on a grid with 3° horizontal resolution and 40 levels between the ground and the mesopause. A control simulation of over twenty years duration was performed using a climatological annual cycle of sea surface temperature. The interannual variability of the stratospheric circulation in this model has some impressively realistic features. In particular the simulated variance of monthly mean zonal mean temperature and wind in the extratropical Northern Hemisphere agrees fairly well with observations. The major deficiency is the absence of a realistic quasi-biennial oscillation (QBO) in the simulated winds in the tropical lower stratosphere. |
| The model has also been run through a large number of boreal winter simulations with the mean flow in the tropical lower stratosphere arbitrarily modified to be appropriate for different extremes of the QBO. The effects of these modifications on the simulated circulation in both the tropical and extratropical middle atmosphere was then examined. The model results are consistent with the observed tendency for the polar vortex to be weaker (stronger) when the QBO is in its easterly (westerly) phase. |