Hemispheric Spectral Statistics of Available Potential Energy

Abstract

Analysis of hemispheric temperature variance data on five isobaric surfaces in terms of two-dimensional spectral decomposition shows that the available potential energy distributes with a slope in the neighborhood of ?3 for the scale range 14≤n≤25. Although this slope varies with pressure, indications are that the observations substantiate the expectations of geostrophic turbulence theory. The noted deviations from ?3 are discussed in terms of the distribution of energy in vertical modes which are not in the range in which ?3 statistics should be expected. Vertical scales necessary for a three-dimensional spectral representation are considered with regard to the Brunt-Väisälä frequency distribution.