Assessing Greenhouse Gas Monitoring Capabilities Using SolAtmos End-to-End Simulator: Application to the Uvsq-Sat NG Mission

Cannelle Clavier (1, 2) , Mustapha Meftah (1) , Alain Sarkissian (1) , Frédéric Romand (2) , Odile Hembise Fanton d'Andon (2) , Antoine Mangin (2) , Slimane Bekki (1) , Pierre-Richard Dahoo (3) , Patrick H. M. Galopeau (3) , Franck Lefèvre (1) , Alain Hauchecorne (1) , Philippe Keckhut (1)

1 STRATO - LATMOS
2 ACRI-ST - Analytic and Computational Research, Inc. - Earth Sciences
3 HELIOS - LATMOS

Monitoring atmospheric concentrations of greenhouse gases (GHGs) like carbon diox- ide and methane in near real time and with good spatial resolution is crucial for enhancing our understanding of the sources and sinks of these gases. A novel approach can be proposed using a con- stellation of small satellites equipped with miniaturized spectrometers having a spectral resolution of a few nanometers. The objective of this study is to describe expected results that can be obtained with a single satellite named Uvsq-Sat NG. The SolAtmos end-to-end simulator and its three tools (IRIS, OptiSpectra, and GHGRetrieval) were developed to evaluate the performance of the spectrometer of the Uvsq-Sat NG mission, which focuses on measuring the main GHGs. The IRIS tool was imple- mented to provide Top-Of-Atmosphere (TOA) spectral radiances. Four scenes were analyzed (pine forest, deciduous forest, ocean, snow) combined with different aerosol types (continental, desert, maritime, urban). Simulated radiance spectra were calculated based on the wavelength ranges of the Uvsq-Sat NG, which spans from 1200 to 2000 nm. The OptiSpectra tool was used to determine optimal observational settings for the spectrometer, including Signal-to-Noise Ratio (SNR) and integration time. Data derived from IRIS and OptiSpectra served as input for our GHGRetrieval simulation tool, developed to provide greenhouse gas concentrations. The Levenberg–Marquardt algorithm was applied iteratively to ne-tune gas concentrations and model inputs, aligning observed transmittance functions with simulated ones under given environmental conditions. To estimate gas concentrations (CO2 , CH4 , O2 , H2 O) and their uncertainties, the Monte Carlo method was used. Based on this analysis, this study demonstrates that a miniaturized spectrometer onboard Uvsq-Sat NG is capable of observing different scenes by adjusting its integration time according to the wavelength. The expected precision for each measurement is of the order of a few ppm for carbon dioxide and less than 25 ppb for methane.

Mots clés: greenhouse gases; carbon dioxide; methane; earth observation; Uvsq-Sat NG; SolAtmos

Domaines: Climatologie

Cannelle Clavier, Mustapha Meftah, Alain Sarkissian, Frédéric Romand, Odile Hembise Fanton d'Andon, et al.. Assessing Greenhouse Gas Monitoring Capabilities Using SolAtmos End-to-End Simulator: Application to the Uvsq-Sat NG Mission. Remote Sensing, In press, ⟨10.3390/rs1010000⟩. ⟨insu-04550544v1⟩