The vertical distribution of the Venus NO nightglow: Limb profiles inversion and one-dimensional modeling

Abstract

International audienceUltraviolet (UV) spectra of the δ (190-240 nm) and γ (225-270 nm) bands of the nitric oxide (NO) molecule have been measured on the nightside of the atmosphere of Venus with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express (VEX). Excited NO molecules on the nightside of the planet are created by radiative recombination of O(3P) and N(4S) atoms. The atoms are produced by photodissociation of CO2 and N2 molecules on the dayside and then transported on the nightside by the global circulation. We analyze all nightside limb profiles obtained since 2006 and provide a statistical study of the nitric oxide airglow layer and its variability. We also apply a spatial deconvolution and an Abel inversion method to the limb profiles to retrieve and quantify the volume emission rate distribution and its dependence on several factors. We also show that about 10% of the limb profiles exhibits a secondary peak located above or below the main airglow peak. Furthermore, a one-dimensional chemical-diffusive model is used to simultaneously model the globally averaged NO and O2(a1Δg) airglow vertical distributions using CO2 and O density profiles rooted in VIRTIS and SPICAV observation

Storms on Venus: Lightning-induced chemistry and predicted products

“…These were detected by the International Ultraviolet Explorer (IUE) and the Pioneer Venus UV instrument as well as by the SPICAV instrument onboard Venus Express (Stiepen et al, 2012(Stiepen et al, , 2013. Another reaction is combination of excited state N atoms with CO 2 to form NO (below).…”

Variability of the nitric oxide nightglow at Venus during solar minimum

“…In 2012, Stiepen et al . [] published results from a statistical study of the NO airglow based on a larger data set for the Northern Hemisphere from Gérard et al . [].…”

“…Analyses derived from the Venus Express data [ Gérard et al ., ; Royer et al ., ; Stiepen et al ., ] have shown that the NO emission peaks at a mean altitude of 113 km, with the NO airglow being observed in the 95 to 132 km range. The limb brightness was found to range between 5 kR and 540 kR and the scale height to be about 8 km.…”

“…Both data sets are thus complementary. In 2012,Stiepen et al [2012] published results from a statistical study of the NO airglow based on a larger data set for the Northern Hemisphere fromGérard et al [2008]. A second study fromStiepen et al [2013] focused on nadir observations made by SPICAV.…”

Modeling VIRTIS/VEX O2(a1∆g) nightglow profiles affected by the propagation of gravity waves in the Venus upper mesosphere

“…In all these cases, the measured horizontal wavelengths and phase velocities have been demonstrated to be comparable with GWs propagating at the considered altitudes [ Peralta et al ., , ]. Occasional secondary peaks, probably induced by GW propagations, were also observed above the main peak of the NO nightglow from SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) data [ Stiepen et al ., ]. The effect of planetary waves in the O 2 nightglow intensity fluctuation was investigated by Hoshino et al .…”