Radiative Generation of Eddy Available Potential Energyin Extratropical Cyclones

Abstract

Calculations for eight cyclonic storm situations give rates of infrared radiative generation of eddy availablepotential energy that, in these cases, were an order of magnitude less than the rates of frictional dissipation,and so suggest that this mode of energy generation within such systems may not be as significant as haspreviously been postulated. The calculations further showed that the relationships of the existing cloud and thermal patterns approximately maximized the rates of generation in the maturing and later stages of extratropical cyclones. In contrast, the relationships of the respective patterns in earlier stages, or at the latitudes of secondarydevelopments, often led, at least in the cases studied, to rates of generation which were significantly belowtheir possible maxima. These differences in the degree of optimization of energy generation arose fromdifferences in the typical flow and thermal patterns.