Numerical methods of band modeling and their application to atmospheric nitrous oxide

Four numerical methods useful for determining the band parameters of infrared transmittance models are presented. A double exponential function described by three absorber parameters and one spectral parameter is adopted as the transmittance model. The methods are compared for accuracy and convenience through an application to line-by-line and measured data for nitrous oxide (N2O) of 20-cm−1 resolution over a wide range of atmospheric conditions. Sufficient mathematical details are provided so that the methods may be easily adapted to other transmittance functions. One of these—the weighted average method—is shown to be clearly superior to the others.