Method for correcting the wavelength misalignment in measured ultraviolet spectra

A new method for correcting the wavelength misalignment in measured UV spec tra is presented. It is based on a comparison between measured irradiances and irradiances computed from a radiative transfer code for a set of given atmospheric and solar conditions (250 < Dobson units < 450, 30 degrees < so lar zenith angle < 75 degrees). Results of tests run with spectra recorded on a clear-sky day by two spectroradiometers in a French UV spectral networ k station are analyzed. Applying the method once reduces shift to less than 0.05 nm. The smoothing included in the method enables detection of aberran t irradiance values and then completion of an initial quality control of me asured spectra. A technique for assessing the instruments' slit function is also presented. The key algorithms needed to build a computer code based o n this method are given. (C) 2001 Optical Society of America.