Absorption Spectra of Martian Dust Simulants

Abstract

Understanding the Martian climate requires a detailed characterization of the optical properties of Martian dust as it is a ubiquitous component of the atmosphere. The continued improvement of Martian atmosphere observations motivates measurements of terrestrial simulants under controlled conditions to support field studies and computational modeling. This investigation demonstrates an in situ method to entrain and directly measure the absorption spectrum of six Martian dust simulants using photoacoustic spectroscopy. Measured size distributions and absorption cross sections (C abs) are used in Mie theory calculations to retrieve the effective imaginary component of the refractive index (k eff) of each sample while constraining the real component to n = 1.5, the refractive index of silica. The weakly absorbing simulants have k eff values ranging between 0.002 and 0.03 at a wavelength of 500 nm that are correlated with the mass fraction of iron oxides.

Effect of the Net Charges Carried by Dust on Martian Atmospheric Temperature

“…investigate the local and global effects of radiatively active water ice clouds, and the results show that they contribute to reducing temperature biases between model and observations throughout the northern spring and summer (Madeleine et al., 2012). Thanks to numerous Mars exploration missions in the last two decades (Gebhardt & Abuelgasim, 2019), many improvements have been made in the understanding of the radiative properties of Martian dust (Razafindrambinina et al., 2022). However, even with updated optical properties of dust, particle size and opacity of dust, and the effects of radiatively active water‐ice clouds into the consideration, discrepancies between the results of models and observations have remained (Stcherbinine et al., 2020).…”