Determination of the TROPOMI-SWIR instrument spectral response function
Richard M. van Hees1,Paul J. J. Tol1,Sidney Cadot1,2,Matthijs Krijger1,3,Stefan T. Persijn5,Tim A. van Kempen1,Ralph Snel1,4,Ilse Aben1,and Ruud W. M. Hoogeveen1Richard M. van Hees et al.Richard M. van Hees1,Paul J. J. Tol1,Sidney Cadot1,2,Matthijs Krijger1,3,Stefan T. Persijn5,Tim A. van Kempen1,Ralph Snel1,4,Ilse Aben1,and Ruud W. M. Hoogeveen1
Received: 05 Dec 2017 – Discussion started: 15 Dec 2017 – Revised: 25 May 2018 – Accepted: 18 Jun 2018 – Published: 04 Jul 2018
Abstract. The Tropospheric Monitoring Instrument (TROPOMI) is the single instrument on board the ESA Copernicus Sentinel-5 Precursor satellite. TROPOMI is a nadir-viewing imaging spectrometer with bands in the ultraviolet and visible, the near infrared and the shortwave infrared (SWIR). An accurate instrument spectral response function (ISRF) is required in the SWIR band where absorption lines of CO, methane and water vapor overlap. In this paper, we report on the determination of the TROPOMI-SWIR ISRF during an extensive on-ground calibration campaign. Measurements are taken with a monochromatic light source scanning the whole detector, using the spectrometer itself to determine the light intensity and wavelength. The accuracy of the resulting ISRF calibration key data is well within the requirement for trace-gas retrievals. Long-term in-flight monitoring of SWIR ISRF is achieved using five on-board diode lasers.
