Characterization of fine resolution field spectrometers using solar Fraunhofer lines and atmospheric absorption features

• Published in: Applied optics. Optical technology and biomedical optics 2010-05, Vol.49 (15), p.2858
• Main Authors: Meroni, Michele, Busetto, Lorenzo, Guanter, Luis, Cogliati, Sergio, Crosta, Giovanni Franco, Migliavacca, Mirco, Panigada, Cinzia, Rossini, Micol, Colombo, Roberto
• Format: Article
• Language: English
• Subjects: Algorithms; Atmosphere - chemistry; Environmental Monitoring - instrumentation; Environmental Monitoring - methods; Equipment Design; Equipment Failure Analysis; Refractometry; Solar Energy; Spectrum Analysis - instrumentation; Spectrum Analysis - methods
• ISSN: 2155-3165
• DOI: 10.1364/AO.49.002858

The accurate spectral characterization of high-resolution spectrometers is required for correctly computing, interpreting, and comparing radiance and reflectance spectra acquired at different times or by different instruments. In this paper, we describe an algorithm for the spectral characterization of field spectrometer data using sharp atmospheric or solar absorption features present in the measured data. The algorithm retrieves systematic shifts in channel position and actual full width at half-maximum (FWHM) of the instrument by comparing data acquired during standard field spectroscopy measurement operations with a reference irradiance spectrum modeled with the MODTRAN4 radiative transfer code. Measurements from four different field spectrometers with spectral resolutions ranging from 0.05 to 3.5nm are processed and the results validated against laboratory calibration. An accurate retrieval of channel position and FWHM has been achieved, with an average error smaller than the instrument spectral sampling interval.