Update on CO2 and temperature profiles retrievals from NOMAD-SO on board ExoMars TGO
- 1Royal Belgian Institute for Space Aeronomy, Belgium
- 2University of Namur, Belgium
- 3NASA Goddard Space Flight Center, USA
- 4University of Colorado, Boulder, USA
- 5Instituto de Astrofísica de Andalucía, CSIC, Spain
- 6Institute for Space Astrophysics and Planetology, Italy
- 7Open University, UK
- 8American University, Washington DC, USA
- 9Japan Aerospace Exploration Agency, Japan
- *A full list of authors appears at the end of the abstract
- The SO channel of the NOMAD instrument
The NOMAD-SO channel [1] is an infrared spectrometer working in the 2.2 to 4.3 µm spectral range (2200-4500 cm-1) and started to perform solar occultation measurement on April 21, 2018. The instrument is composed of an echelle grating coupled to an Acousto-Optical Tunable Filter for the diffraction order selection. As TGO is on a quasi-circular orbit at around 400 km of altitude, it performs one orbit every two hours. During a solar occultation measurement, SO scans six diffraction orders each second. These diffraction orders are recorded on four bins leading to a vertical sampling lower than one km. The calibration of the SO channel is described in [2] and is still being fine-tuned.
- CO2 density and temperature profiles retrievals
Several diffraction orders probe different altitude ranges as they contain CO2 lines with different intensities that appear and saturate at different altitudes. Correct temperature profiles are necessary for the retrieval of several species and the profiles have to be carefully retrieved as their inversion is very sensitive to noise. We use the following retrieval scheme:
For each solar occultation measurement, we derive a slant column profile of CO2 using ASIMUT-ALVL [3]. ASIMUT is a radiative transfer program developed at BIRA-IASB and uses the Optimal Estimation Method for regularization [4]. The GEM-Mars GCM provides the a priori profiles of CO2 local density, pressure and temperature. We then apply an iterated Tikhonov regularization to derive a regularized local density profile using an improved version of the algorithm described in [5]. This method requires the selection of a regularization parameter to reduce as much as possible the presence of noise in the profile while keeping the real variations. This retrieval scheme allows a fine-tuning of the reguralization parameter. We finally apply the hydrostatic equilibrium equation to derive the temperature profiles [6]. We derived the NOMAD-SO CO2 and temperature profiles for MY34 and 35.
The NOMAD Science Team PI: Vandaele, Ann Carine; Co-PIs: Lopez Moreno, Jose Juan; Bellucci, Giancarlo; Patel, Manish; Altieri, Francesca; Aoki, Shohei; Bauduin, Sophie; Bolsée, David; Carrozzo, Giacomo; Clancy, Todd; Cloutis, Edward; Crismani, Matteo; Daerden, Frank; Da Pieve, Fabiana; D'Aversa, Emiliano; Depiesse, Cédric; Erwin, Justin; Etiope, Giuseppe; Fedorova, Anna; Funke, Bernd; Fussen, Didier; Garcia-Comas, Maia; Gérard, Jean-Claude; Gkouvelis, Leo; Giuranna, Marco; Gonzalez-Galindo, Francisco; Hewson, Will; Holmes, James; Hubert, Benoît; Ignatiev, Nicolai; Kaminski, Jacek; Karatekin, Ozgur; Kasaba, Yasumasa; Kass, David, Kleinböhl, Armin; Lanciano, Orietta; Lefèvre, Franck; Lewis, Stephen; Liuzzi, Giulano; López-Puertas, Manuel; López-Valverde, Miguel; Mahieux, Arnaud; Mason, Jon; Mège, Daniel; Mumma, Mike; Nakagawa, Hiromu, Neary, Lori; Neefs, Eddy; Novak, Rob; Oliva, Fabrizio; Piccialli, Arianna; Renotte, Etienne; Ritter, Birgit; Robert, Severine; Rosenblatt, Pascal; Schmidt, Frédéric; Schneider, Nick; Sindoni, Giuseppe; Smith, Michael D.; Teanby, Nicholas A.; Thiemann, Ed; Thomas, Ian; Trokhimovskiy, Alexander; Vander Auwera, Jean; Villanueva, Geronimo; Viscardy, Sébastien; Whiteway, Jim; Willame, Yannick; Wilquet, Valérie; Wolff, Michael; Wolkenberg, Paulina; Yelle, Roger The NOMAD Technical Team Alonso-Rodrigo, Gustavo; Aparicio del Moral, Beatriz; Barzin, Pascal; Beeckman, Bram; BenMoussa, Ali; Berkenbosch, Sophie; Biondi, David; Bonnewijn, Sabrina; Candini, Gian Paolo; Clairquin, Roland; Cubas, Javier; Giordanengo, Boris; Gissot, Samuel; Gomez, Alejandro; Hathi, Brijen; Jeronimo Zafra, Jose; Leese, Mark; Maes, Jeroen;Mazy, Emmanuel; Mazzoli, Alexandra; Meseguer, Jose; Morales, Rafael; Orban, Anne; Pastor-Morales, M; Perez-grande, Isabel; Queirolo, Claudio; Ristic, Bojan; Rodriguez Gomez, Julio; Saggin, Bortolino; Samain, Valérie; Sanz Andres, Angel; Sanz, Rosario; Sellers, Graham; Simar, Juan-Felipe; Thibert, Tanguy; Trompet, Loïc
How to cite: Trompet, L., Vandaele, A. C., Aoki, S., Erwin, J., Thomas, I., Piccialli, A., Daerden, F., Neary, L., Villanueva, G., Liuzzi, G., Crismani, M., Lopez-Valverde, M. A., Ristic, B., Lopez-Moreno, J. J., Bellucci, G., and Patel, M. and the NOMAD team: Update on CO2 and temperature profiles retrievals from NOMAD-SO on board ExoMars TGO, European Planetary Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-216, https://doi.org/10.5194/epsc2021-216, 2021.
