Validated transmittance band model for SO_2 in the infrared

A band model is presented for the calculation of atmospheric molecular transmittance through sulfur dioxide (SO2) in the infrared region. It consists of a well-established double-exponential function defined by three absorber-dependent parameters and a single spectrally dependent parameter. The parameters are determined by an optimal numerical procedure which incorporates a mixture of line-by-line calculated transmittance data and laboratory measurements. The developing data are degraded to 20-cm−1 resolution spectral averages repeated at 5-cm−1 intervals for easy adaptability with the lowtran code. A diurnally and seasonally averaged mixing ratio profile for SO2 is proposed for use with the thirty-three layer standard atmosphere models. The proposed band model reproduces the developing data with an average rms error of 2.37%.