Calibration of the NOMAD-UVIS data

Journal
Date Issued
2022
Author(s)
Willame, Yannick
•
Depiesse, Cédric
•
Mason, Jonathon P.
•
Thomas, Ian R.
•
Patel, Manish R.
•
Hathi, Brijen
•
Leese, Mark R.
•
Bolsée, David
•
Wolff, Michael J.
•
Trompet, Loïc
•
Vandaele, Ann Carine
•
Piccialli, Arianna
•
Aoki, Shohei
•
Ristic, Bojan
•
Neefs, Eddy
•
Beeckman, Bram
•
Berkenbosch, Sophie
•
Clairquin, Roland
•
Mahieux, Arnaud
•
Pereira, Nuno
•
Robert, Séverine
•
Viscardy, Sébastien
•
Wilquet, Valérie
•
Daerden, Frank
•
Lopez-Moreno, José Juan
•
DOI
Abstract
The Ultraviolet and VIsible Spectrometer (UVIS), covering the 200-650 nm range, is one of three spectrometers that comprise the NOMAD instrument on the ExoMars 2016 Trace Gas Orbiter (TGO). UVIS can operate in solar occultation, nadir and limb viewing mode and was designed to monitor ozone and aerosols in the Martian atmosphere. Here, we describe the calibration procedure to convert the UVIS raw data into a calibrated data product ready for scientific exploitation. The calibration includes the CCD offset and dark current subtraction, the wavelength assignment, the noise identification and removal, the smearing removal, and the radiance or transmittance conversion. A straylight correction, critical for some parts of the UVIS spectral range, is also applied during the data reduction process, which is described in more detail in two companion papers [Mason et al., 2022; Depiesse et al., In prep] corresponding to two different and independent methods giving consistent results. The solar occultation observations are converted into transmittance and are therefore self-calibrating, while nadir and limb measurements require an absolute radiometric calibration. A comparison with coincident nadir MRO/MARCI measurements is provided as a final validation and generally shows a ±10% agreement on the radiances measured by both instruments.
Volume
218
Start page
105504
Uri
Url
Issn Identifier
0032-0633
Ads BibCode
2022P&SS..21805504W
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

YWillame Calibration NOMAD UVIS.pdf

Description
PDF editoriale
Size

6.84 MB

Format

Adobe PDF

Checksum (MD5)

6299e46b69ee4e2a5cb09a20936b97b5