Small spurious features are present in data from the Mariner 9 Infrared Int
erferometer Spectrometer (IRIS). These represent a low amplitude replicatio
n of the spectrum with a doubled wavenumber scale. This replication arises
principally from an internal reflection of the interferogram at the input w
indow. An algorithm is provided to correct for the effect, which is at the
2% level. We believe that the small error in the uncorrected spectra does n
ot materially affect previous results; however, it may be significant for s
ome future studies at short wavelengths. The IRIS spectra are also affected
by a coding error in the original calibration that results in only positiv
e radiances. This reduces the effectiveness of averaging spectra to improve
the signal to noise ratio at small signal levels. (C) 2000 Elsevier Scienc
e Ltd. All rights reserved.