MATRIX PARAMETERIZATION OF THE 15 MU-M CO2 BAND COOLING IN THE MIDDLEAND UPPER-ATMOSPHERE FOR VARIABLE CO2 CONCENTRATION

A matrix parameterization of the 15 mu m CO2 band radiative cooling in the middle and upper terrestrial atmosphere for both local thermodyna mic equilibrium (LTE) and non-LTE (NLTE) layers is proposed. For the a tmospheric region between similar to 13 and 85 km, matrix coefficients for CO2 concentrations of 150, 360, 540, and 720 ppm have been precal culated using a Line-by-line technique. A method for interpolation of the matrix coefficients for arbitrary CO2 concentration is suggested. In the layer between 85 and 110 km, where strong NLTE effects start to occur, a recurrence formula relating cooling rate values at two neigh boring altitude levels is used. To calculate the cooling rate above 11 0 km, a simple approach accounting for both the absorption of the radi ative flux formed below 110 km and the cooling-to-space terms is sugge sted. The accuracy of the parameterization is examined for different t emperature and CO2 profiles as well as for different atomic oxygen con centrations in the NLTE layer.