THE PROBABILITY DENSITY DISTRIBUTION OF THE PLANETARY-SCALE ATMOSPHERIC WAVE AMPLITUDE REVISITED

The investigation for evidence of multiple statistical flow regimes in the amplitude of the planetary-scale waves presented earlier by Hanse n and Sutera is revisited. A methodology for generating Monte Carlo te sts of the statistical significance of univariate probability density estimates of temporally correlated time series is proposed and applied to a 42-winter time series of the amplitude of the planetary-scale wa ves. The statistical significance of bimodality in the planetary wave amplitude can be established from a 28-winter dataset as well as the 4 2-winter dataset, but not from the 16-winter dataset originally used b y Hansen and Sutera. Corroboration of this result is found from compar able analysis of an extended general circulation model integration and from examination of the results of other independent observational st udies. Several analysis schemes find flow regimes with a similar patte rn that features large amplitudes in the planetary-scale waves.