Gravity waves off the Atlas Mountains
18 December 2019 00:00 UTC
Interesting orographic cloud waves formed over the Atlas Mountains, and wider, in mid-December.
10 November 2020
17 December 2019
By Ivan Smiljanic (CGI)
The following gravity waves, that were also related to severe turbulence, formed in a cloud-free area over Algeria. They formed along the circular motion of the air masses in the system, and were detected using the water vapour signal in the SEVIRI 7.3µm channel, blue, in places less organised, wavy formations in Figure 1.
The most intense wave formation can be seen over the highest orography areas, along the air mass advection path (e.g. south of the Atlas mountains).
The animation in Figure 2 is an extended view of the gravity waves in the water vapour imagery.
Figure 3 reveals the synoptic forcing on the wider scale, responsible for intense wind advection behind, and around upper level cold front that passed over Tunisia on 18 December. The Meteosat-11 Airmass RGB is overlaid with wind streamlines at 500hPa, roughly the height at which the 7.3µm channel is most sensitive.
