A third spectrometer (UVIS channel) can work in the three observation modes covering the 200–650 nm UV-VIS spectral range. A second spectrometer, capable of performing nadir, limb, and solar occultation observations (LNO channel) covers the 2.3–3.8 μm IR spectral range. A first spectrometer is devoted to solar occultation observations (SO channel), operating in the 2.3–4.3 μm IR spectral range.
Led by the Royal Belgian Institute for Space Aeronomy (BIRA-IASB), NOMAD has been observing the Martian atmosphere since March 2018 (L S = 150° in MY34) through three channels operating in the ultraviolet-visible (UV-VIS), and infrared (IR) spectral ranges. The Nadir and Occultation for MArs Discovery (NOMAD) instrument is a suite of three high resolution spectrometers that was selected as part of the payload of the 2016 ExoMars Trace Gas Orbiter (TGO) mission. The analysis of NOMAD nadir data for MY34 and MY35 is performed in Section 4, where the results obtained over 1.5 MY of NOMAD acquisition are discussed and compared to previous studies and model predictions. Then, we describe the methodology of the study and derive the Frost and Clouds Index in Section 3. A brief description of the NOMAD instrument and of the nadir observations that we used in this study is presented in Section 2. For that reason, we define here a method aimed to identify H 2O ice clouds in NOMAD infrared nadir data, based on the characterization of the 2.7 μm ice absorption band. Given the peculiar mode of operations of the instrument for nadir observations, it is difficult to discern clouds from suspended dust and surface ice deposits. NOMAD is a suite of high spectral resolution instruments mainly dedicated to studying the Martian atmosphere trace gases and climatological processes. In this work, we investigate the information content of the ExoMars-TGO NOMAD infrared channel nadir dataset. We hence derive the infrared nadir channel sensitivity limit for the detection of these clouds. This is consistent with previous observations showing different physical properties between the two main Martian atmospheric structures and making the ACB less detectable in the infrared. Nevertheless, detections in the Aphelion Cloud Belt (ACB) are limited. FCI is sensitive to the Polar Hood clouds. We derive the Frost and Clouds Index (FCI), which is a good proxy for ice mapping, and obtain latitudinal-seasonal maps for water ice clouds. We take advantage of the strong water ice absorption band at 2.7 µm by selecting the diffraction orders 167, 168, and 169. In this study we present a method based on the investigation of nadir observations of the NOMAD infrared channel, acquired during Mars Years 34 and 35 (March 2018 to February 2021).
We demonstrate that when NOMAD is observing in nadir mode, i.e., when the line-of-sight points to the centre of Mars, it can be also exploited to detect ice. NOMAD is mainly dedicated to the study of trace atmospheric species taking advantage of a high-spectral resolution. Other than this I am absolutely In awe of this product at the moment.As part of the payload of the 2016 ExoMars Trace Gas Orbiter (TGO) mission, the Nadir and Occultation for MArs Discovery (NOMAD) suite instrument has been observing the Martian atmosphere since March 2018.
Also, the product may not go along well with dry skin beauties. The only thing I didn’t like much is the simple, silver coloured plastic packaging, which is actually not much of an issue though.