Premium
Modeling VIRTIS/VEX O 2 ( a 1∆ g ) nightglow profiles affected by the propagation of gravity waves in the Venus upper mesosphere
Author(s) -
Altieri F.,
Migliorini A.,
Zasova L.,
Shakun A.,
Piccioni G.,
Bellucci G.
Publication year - 2014
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2013je004585
Subject(s) - airglow , venus , gravity wave , physics , middle latitudes , atmospheric sciences , amplitude , gravitational wave , mesosphere , geophysics , atmospheric wave , wavelength , geology , stratosphere , astrophysics , optics , astrobiology
In this work we describe a model of the perturbation of the O 2 ( a 1 Δ g ) nightglow limb profiles by the action of gravity waves (GWs) propagating in the Venus' upper atmosphere. Data have been acquired by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on board the European Space Agency mission Venus Express (VEX). The high variability observed in the shape of the O 2 ( a 1 Δ g ) nightglow limb profiles between 80 and 120 km, often characterized by the presence of a double peak, suggests the occurrence of GWs at the considered altitudes. In order to model and derive the GWs properties, we apply to Venus a well‐known theory used to study terrestrial density fluctuations induced by the GWs propagation. The retrieved vertical wavelengths and amplitudes of the waves at the O 2 ( a 1 Δ g ) layer altitude (~100 km) are of the order of 7–16 km and 3–14% respectively, complying with wave amplitude threshold for dynamical instability in the majority of the fitted cases. Temperature fluctuations would exceed 40% at higher altitudes (115–120 km) thus inducing either wave breaking or dissipation. Intrinsic horizontal phase velocities are expected to vary in the range 32 m/s and 85 m/s. GWs are detected in a wide range of latitudes from the midlatitudes up to the polar regions, and we cannot exclude existence of the sources of different nature. This study also confirms the high variability induced by the action of GW propagation in the airglow profiles of the terrestrial planets and points out the need for future missions to couple simultaneous complementary GW detection techniques in order to better constrain GW properties and understand their impact on the Venus general circulation.