Vandaele Ann C, Willame Yannick, Depiesse Cédric, Thomas Ian R, Robert Séverine, Bolsée David, Patel Manish R, Mason Jon P, Leese Mark, Lesschaeve Stefan, Antoine Philippe, Daerden Frank, Delanoye Sofie, Drummond Rachel, Neefs Eddy, Ristic Bojan, Lopez-Moreno José-Juan, Bellucci Giancarlo, Team Nomad
Opt Express. 2015 Nov 16;23(23):30028-42. doi: 10.1364/OE.23.030028.
The NOMAD instrument has been designed to best fulfil the science objectives of the ExoMars Trace Gas Orbiter mission that will be launched in 2016. The instrument is a combination of three channels that cover the UV, visible and IR spectral ranges and can perform solar occultation, nadir and limb observations. In this series of two papers, we present the optical models representing the three channels of the instrument and use them to determine signal to noise levels for different observation modes and Martian conditions. In this first part, we focus on the UVIS channel, which will sound the Martian atmosphere using nadir and solar occultation viewing modes, covering the 200-650nm spectral range. High SNR levels (>1000) can easily be reached for wavelengths higher than 300nm both in solar occultation and nadir modes when considering binning. Below 300nm SNR are lower primarily because of the lower signal and the impact of atmospheric absorption.
NOMAD仪器的设计旨在最佳地实现将于2016年发射的ExoMars痕量气体轨道器任务的科学目标。该仪器由三个通道组成，覆盖紫外、可见光和红外光谱范围，可进行太阳掩星、天底和临边观测。在这两篇系列论文中，我们展示了代表该仪器三个通道的光学模型，并使用它们来确定不同观测模式和火星条件下的信噪比水平。在第一部分中，我们重点关注UVIS通道，它将使用天底和太阳掩星观测模式探测火星大气，覆盖200-650nm光谱范围。考虑到合并时，在太阳掩星和天底模式下，波长高于300nm时很容易达到高信噪比水平（>1000）。低于300nm时，信噪比主要较低，这是因为信号较低以及大气吸收的影响。
