On the Energy Exchange between the Baroclinic and Barotropic Components of Atmospheric Flow

The energy conversion between the vertical shear flow and the vertical mean flow has been computed using atmospheric data from the isobaric surfaces: 850, 700, 500, 300, and 200 mb. I n comparison with carlier calculations based on a smaller vertical resolution (2 levels) and a smaller sample, it is found that the new calculations give larger numerical values in better agreement with the results of numerical experiments concerning the gencral circulation of the atmosphere. The energy transformation has bcen computed in the wave number regime, and it is found that the medium-scale waves a,rc responsible for the major portion of the transformation. The amounts of energy in the baroclinic component (the vertical shear flow) and the barotropic component (the vertical mean flow) have bccn computed as a function of wave number. It is found that thc kinctic encrgy in thc barotropic component is about 2.6 times the kinctic energy in the baroclinic component. The partitioning of the kinetic energy bctween the zonal flow and the eddies is such that the eddies contain more encrgy than the zonal flow. This result applies for the vertical shear flow as well as the vertical mean flow and is in contrast to thc results obtaincd from numerical experiments regarding the general circulation. The present computations include only the encrgy calculations which would be present in a quasi-non-divergent model. L:Ltcr calculations will provide estimates of the remaining term of the energy conversion.