The spectroscopic parameters that are used when fitting a generated spectrum to a measurement come from large catalogues of measurements and calculations, such as HITRAN or the JPL catalogue. Thousands of these numbers are looked up and used by a radiative transfer model when calculating the transmission of electromagnetic energy through the atmosphere.

In an inversion process where the radiative transfer model describes how atmospheric gas concentrations are related to a measurement, the “background parameters” like those looked up in catalogues are assumed (or hoped) to be well known. I will give a short presentation on how sensitive inversions can be to uncertainties and errors in the spectroscopic parameters and how they cause biases in a data set.