ENERGETICS OF THE MIDDLE ATMOSPHERE - THEORY AND OBSERVATION REQUIREMENTS

This paper presents an overview of the significant advances which have been made over the past three years in the understanding of the energy budget of the mesosphere and lower thermosphere. Recent calculations of key heat source terms are presented and compared. Observation requirements to further the understanding are also presented. In particular, the ozone concentration is shown to be of considerable importance to the mesospheric heat budget through absorption of solar ultraviolet radiation and participation in exothermic reactions. Two techniques by which ozone may be determined from space-based instruments employing infrared emission sensing are also reviewed and compared. Very accurate knowledge of the departure from local thermodynamic equilibrium in the observed emission features is required to reliably determine the ozone concentration.