Gravity waves off the Atlas Mountains

Gravity waves off the Atlas Mountains

18 December 2019 00:00 UTC

Gravity waves off the Atlas Mountains
Gravity waves off the Atlas Mountains

Interesting orographic cloud waves formed over the Atlas Mountains, and wider, in mid-December.

Last Updated

10 November 2020

Published on

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).

 Meteosat-11 Water Vapour 7.3µm channel, 18 December 00:00 UTC.
Figure 1: Meteosat-11 Water Vapour 7.3µm channel, 18 December 00:00 UTC.
 

The animation in Figure 2 is an extended view of the gravity waves in the water vapour imagery.

Figure 2: Meteosat-11 Water Vapour 7.3µm channel loop, 18 December 00:00–12:00 UTC

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.

 Synoptic overview through Meteosat-11 Airmass RGB product and wind streamlines at 500hPa, 18 December 00:00 UTC.
Figure 3: Synoptic overview through Meteosat-11 Airmass RGB product and wind streamlines at 500hPa, 18 December 00:00 UTC.