On One Estimate of the Boundary of the Rossby Regime Zone in the Atmosphere

Abstract

A two-zone model of the atmospheric circulation over the hemisphere is considered. The geographic latitude φ of the boundary between the Rossby circulation regime zone at middle and high latitudes and the Hadley circulation regime zone at low latitudes serves as a model variable. The closeness between the actual and reference (exponential) air-mass distribution over the hemisphere, with respect to Ertel’s modified potential vorticity (MPV), is accounted for. The informational entropy of the statistical MPV distribution in the hemispheric atmosphere and the informational entropy of the eddy regime in the basic storm-track zone are used to determine a statistically (climatically) equilibrium value of φ. The question of atmospheric blocking over the hemisphere is considered using the proposed statistical–dynamical model.