Effect of apodization on the retrieval of geophysical parameters from fourier-transform spectrometers.

The problem of the effect of apodization on the retrieval of geophysical parameters from infrared radiances recorded by Fourier transform spectrometers has been analytically and numerically addressed. Exploiting a matrix representation of apodization, we first derive a general analytical expression for the apodized covariance matrix and then show that apodization, when properly applied, has no effect on retrievals. The methodology has been applied to investigate the effect of Gaussian apodization on the Infrared Atmospheric Sounding Interferometer currently under development at the laboratories of the French Space Agency.