Mesoscale modeling of Venus’ bow-shape waves. (arXiv:1902.07010v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lefevre_M/0/1/0/all/0/1">Maxence Lefèvre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spiga_A/0/1/0/all/0/1">Aymeric Spiga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lebonnois_S/0/1/0/all/0/1">Sébastien Lebonnois</a>
The Akatsuki instrument LIR measured an unprecedented wave feature at the top
of Venusian cloud layer. Stationary bow-shape waves of thousands of kilometers
large lasting several Earth days have been observed over the main equatorial
mountains. Here we use for the first time a mesoscale model of the Venus’s
atmosphere with high-resolution topography and fully coupled interactive
radiative transfer computations. Mountain waves resolved by the model form
large-scale bow shape waves with an amplitude of about 1.5 K and a size up to
several decades of latitude similar to the ones measured by the Akatsuki
spacecraft. The maximum amplitude of the waves appears in the afternoon due to
an increase of the near-surface stability. Propagating vertically the waves
encounter two regions of low static stability, the mixed layer between
approximately 18 and 30 km and the convective layer between 50 and 55 km. Some
part of the wave energy can pass through these regions via wave tunneling.
These two layers act as wave filter, especially the deep atmosphere layer. The
encounter with these layers generates trapped lee waves propagating
horizontally. No stationary waves is resolved at cloud top over the polar
regions because of strong circumpolar transient waves, and a thicker deep
atmosphere mixed layer that filters most the mountain waves
The Akatsuki instrument LIR measured an unprecedented wave feature at the top
of Venusian cloud layer. Stationary bow-shape waves of thousands of kilometers
large lasting several Earth days have been observed over the main equatorial
mountains. Here we use for the first time a mesoscale model of the Venus’s
atmosphere with high-resolution topography and fully coupled interactive
radiative transfer computations. Mountain waves resolved by the model form
large-scale bow shape waves with an amplitude of about 1.5 K and a size up to
several decades of latitude similar to the ones measured by the Akatsuki
spacecraft. The maximum amplitude of the waves appears in the afternoon due to
an increase of the near-surface stability. Propagating vertically the waves
encounter two regions of low static stability, the mixed layer between
approximately 18 and 30 km and the convective layer between 50 and 55 km. Some
part of the wave energy can pass through these regions via wave tunneling.
These two layers act as wave filter, especially the deep atmosphere layer. The
encounter with these layers generates trapped lee waves propagating
horizontally. No stationary waves is resolved at cloud top over the polar
regions because of strong circumpolar transient waves, and a thicker deep
atmosphere mixed layer that filters most the mountain waves
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