This page describes a numerical simulation of gravity waves generated by an idealized
thunderstorm over Jacksonville, Florida. The thunderstorm parameters are modifications
to those used by Heale et al. (2020) for their study of wave filtering and ultimate
breaking for various climatological conditions. In particular, in Heale's work,
the thunderstom has
a radially-symmetric Gaussian distribution in the horizontal plane with standard
deviation 8 km and cosine distribution in the vertical with wavelength 11.25 km. It
also has a cosine variation in time (one cycle) with period 20 minutes. Here we
used the same thunderstorm dimensions but increased its amplitude by a factor of 4 and
increased its duration to 30 minutes.

Computational Domain

The mesh is clustered in both horizontal directions in order to achieve
500 x 500 meter spacing over the center 60 x 60 km region.
Very weak stretching is used so that the resolution
is still ~500 x 500 m over the entire grid. The domain
extends to an altitude of 64 km and uses uniform vertical spacing of 250 m.
A total of 340 x 340 x 256 mesh points are used. Sponge layers are used
on all external boundaries in order to absorb outgoing waves.

Wind and Thermodynamic Profiles

The mean winds and temperature profile are taken from radiosonde data, on
June 15 2018, from a launch site in Jacksonville, Florida.
The data reach an altitude of slightly more than 30 km. The profiles
were then extended to higher altitudes using polynomial curve fits. Three
scenerios are considered, one having increasing easterly winds aloft (Case A),
a second having nearly constant weak easterly winds aloft (Case B), and a third
having increasing westerly winds aloft (Case C). The meridional winds were
set to zero above 30 km and the temperature was taken from climatology.
Plots of various profiles for the three cases are shown below. Note that each
profile is resampled on the 250m mesh spacing.

Results

Animation of u' in the xz plane at the position y = 0 km

Case A

Case B

Case C

Animation of vorticity magnitude in the xz plane at the position y = 0 km

Case A

Case B

Case C

Animation of u' in the xy plane at the position z = 20 km

Cases A, B, and C are virtually identical at this altitude

Animation of vorticity magnitude in the xy plane at the position z = 20 km

Cases A, B, and C are virtually identical at this altitude

Animation of u' in the xy plane at the position z = 30 km

Cases A, B, and C are very similar at this altitude

Animation of vorticity magnitude in the xy plane at the position z = 30 km

Cases A, B, and C are very similar at this altitude

Animation of u' in the xy plane at the position z = 50 km

Case A

Case B

Case C

Animation of vorticity magnitude in the xy plane at the position z = 50 km