Radiative transfer in the lower stratosphere due to the 9.6 micron band of ozone

Precise numerical calculations of the flux divergence due to narrow regions of the ozone 9.6 micron band were made, using the relative strengths and positions of the spectral lines calculated by Kaplan, Migeotte and Neven (1956). The absolute line strength was estimated on the basis of Walshaw's (1957) laboratory measurements. Spectral models or Curtis's approximation were not used, but Lorentz shapes and uniform widths were assumed for all lines. Calculations up to a height of 33 km were made for two ozone ascents of Brewer and Milford (1960). The atmospheric heating rates obtained for narrow regions of the band were then combined to estimate the heating rate by the whole band with results in qualitative agreement with, though nearly twice as great as those of Plass (1956a). The effect of the radiative temperature of the atmosphere below the ozone layer (whether of ground or cloud top) appears to be great. The radiative heating by ozone in the 10‐20 km region is 0·2 or 0·3 degrees C per day for a ground temperature of 10°C, but may disappear altogether, if cloud is present just below the tropopause. Using a larger computer, the procedure could be extended to cover the whole band, thereby avoiding the approximate extrapolation employed in this paper. The procedure could be applied to any absorption band, and is flexible to permit the use of any desired pressure and temperature dependence of the shape, width and strength of the spectral lines; results from it might serve as a standard against which conclusions reached by approximate methods can be checked.