16 Dec 2022
16 Dec 2022
Status: this preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).

The Far-Infrared Radiation Mobile Observation System for spectral characterisation of the atmospheric emission

Claudio Belotti1, Flavio Barbara2, Marco Barucci1, Giovanni Bianchini1, Francesco D'Amato1, Samuele Del Bianco2, Gianluca Di Natale1, Marco Gai2, Alessio Montori1, Filippo Pratesi1, Markus Rettinger3, Christian Rolf4, Ralf Sussmann3, Thomas Trickl3, Silvia Viciani1, Hannes Vogelman3, and Luca Palchetti1 Claudio Belotti et al.
  • 1National Institute of Optics, National Research Council, Florence, Italy
  • 2Institute of Applied Physics "Nello Carrara", National Research Council, Florence, Italy
  • 3Karlsruhe Institute of Technology (KIT), IMK-IFU, Garmisch-Partenkirchen, Germany
  • 4Forschungszentrum Jülich, IEK-7, Jülich, Germany

Abstract. The Far-Infrared Radiation Mobile Observation System (FIRMOS) is a Fourier transform spectroradiometer developed to support the Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) satellite mission by validating measurement methods and instrument design concepts, both in the laboratory and in field campaigns. FIRMOS is capable of measuring the downwelling spectral radiance emitted by the atmosphere in the spectral band from 100 to 1000 cm-1 (10–100 µm in wavelength), with a maximum spectral resolution of 0.25 cm-1. We describe the instrument design and its characterisation and discuss the geophysical products obtained by inverting the atmospheric spectral radiance measured during a campaign from the high-altitude location of Mount Zugspitze in Germany, beside the Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI), which is permanently installed at the site. Following the selection of clear-sky scenes, using a specific algorithm, the water vapour and temperature profiles were retrieved from the FIRMOS spectra by applying the Kyoto protocol and Informed Management of the Adaptation (KLIMA) code. The profiles were found in very good agreement with those provided by radiosondes and by the Raman lidar operating from the Zugspitze Schneefernerhaus station. In addition, the retrieval products were validated by comparing the retrieved Integrated Water Vapour values with those obtained from the E-AERI spectra. Finally, we found that the trends for the temperature, and the water vapour profiles over time were in good agreement with those provided by ERA5 reanalysis.

Claudio Belotti et al.

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1327', Anonymous Referee #1, 22 Jan 2023 reply

Claudio Belotti et al.

Data sets

FIRMOS - Technical Assistance for a Far-Infrared Radiation Mobile Observation System (EE9 Forum) Luca Palchetti, Marco Barucci, Claudio Belotti, Giovanni Bianchini, Bertrand Cluzet, Francesco D'Amato, Samuele Del Bianco, Gianluca Di Natale, Marco Gai, Dina Khordakova, Alessio Montori, Hilke Oetjen, Markus Rettinger, Christian Rolf, Dirk Schuettemeyer, Ralf Sussmann, Silvia Viciani, Hannes Vogelmann, Frank Gunther Wienhold

Claudio Belotti et al.


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Short summary
FIRMOS is a spectroradiometer measuring in the far-infrared, developed to support the preparation of the FORUM satellite mission. In this paper we describe the instrument, its data products and the results of the comparison with a suite of observations made from a high-altitude site during a field campaign, in winter 2018–19.