Revealing a High Water Abundance in the Upper Mesosphere of Mars With ACS Onboard TGO

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Revealing a High Water Abundance in the Upper Mesosphere of Mars With ACS Onboard TGO

Geophysical Research Letters. 2021. Vol. 48. No. 10. Article e2021GL093411.

Belyaev D. A.

We present the first water vapor profiles encompassing the upper mesosphere of Mars, 100–120 km, far exceeding the maximum altitudes where remote sensing has been able to observe water to date. Our results are based on solar occultation measurements by Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO). The observed wavelength range around 2.7 μm possesses strong CO2 and H2O absorption lines allowing sensitive temperature and density retrievals. We report a maximum H2O mixing ratio varying from 10 to 50 ppmv at 100–120 km during the global dust storm (GDS) of Martian Year (MY) 34 and around southern summer solstice of MY 34 and 35. During other seasons water remains persistently below ∼2 ppmv. We claim that contributions of the MY34 GDS and perihelion periods into the projected hydrogen escape from Mars are nearly equivalent.

Gravity Wave Activity in the Martian Atmosphere at Altitudes 20-160 km From ACS/TGO Occultation Measurements

Starichenko E., Belyaev Denis A., JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 2021 Vol. 126 No. 8 Article e2021JE006899

The paper presents observations of gravity wave-induced temperature disturbances in the Martian atmosphere obtained with the mid-infrared (MIR) spectrometer, a channel of the Atmospheric Chemistry Suite instrument on board the Trace Gas Orbiter (ACS/TGO). Solar occultation measurements of a CO2 absorption band at 2.7 mu m were used for retrieving density and temperature profiles between ...

Added: November 28, 2022

Thermal Structure of the Middle and Upper Atmosphere of Mars From ACS/TGO CO2 Spectroscopy

Belyaev D. A., JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 2022 Vol. 127 No. 10 Article e2022JE007286

Temperature and density in the upper Martian atmosphere, above similar to 100 km, are key diagnostic parameters to study processes of the species' escape, investigate the impact of solar activity, model the atmospheric circulation, and plan spacecraft descent or aerobraking maneuvers. In this paper, we report vertical profiling of carbon dioxide (CO2) density and temperature ...

Added: November 28, 2022

Dust and dusty plasma effects in Schumann resonances on Mars: Comparison with Earth

Izvekova Y. N., Popel S. I., Izvekov O. Y., Icarus 2022 Vol. 371 Article 114717

Dust and dusty plasma play significant role in the atmosphere and ionosphere of Mars. Electrification in dust events such as dust devils and dust storms can presumably lead to electric fields large enough for discharges to take place and for existence of oscillations in the Schumann cavity. We discuss the role of dust and dusty ...

Added: September 29, 2021

High-resolution spectra of LiYF4:Ho3+ in a magnetic field

Boldyrev K., Попова М. Н., Optical Materials 2017 Vol. 63 P. 101–104

We report on the first high-resolution optical spectroscopy study of LiYF4:Ho in an external magnetic field. Peculiarities in the hyperfine structure of holmium spectral lines are discussed for the cases H||c and H⊥c (H = 0.53 and 0.87 T). The spectra reveal a strong interaction between crystal-field levels, mediated by Zeeman and hyperfine terms in the Hamiltonian. A ...

Added: February 8, 2019

Spectroscopy of f-f transitions, crystal-field calculations, and magnetic and quadrupole helix chirality in DyFe3(BO3)4

Boldyrev K., Попова М. Н., Чукалина Е. П. et al., Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 95 No. 12 P. 125131-1–125131-9

We present the results of temperature- and polarization-dependent high-resolution optical spectroscopy studies of DyFe3(BO3)4 performed in spectral ranges 40-300cm-1 and 3000-23000cm-1. The crystal-field (CF) parameters for the Dy3+ ions in the P3121 (P3221) phase of DyFe3(BO3)4 are obtained from calculations based on the analysis of the measured f-f transitions. Recently, quadrupole helix chirality and its ...

Added: February 8, 2019

Distribution function of random strains in an elastically anisotropic continuum and defect strengths of Tm3+ impurity ions in crystals with zircon structure

Boldyrev K., Малкин Б. З., Абишев Н. М. et al., Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 96 No. 1 P. 014116-1–014116-13

We construct a distribution function of the strain-tensor components induced by point defects in an elastically anisotropic continuum, which can be used to account quantitatively for many effects observed in different branches of condensed matter physics. Parameters of the derived six-dimensional generalized Lorentz distribution are expressed through the integrals computed over the array of strains. ...

Added: February 8, 2019