Breaking gravity waves

For the gravity wave breaking:

Default run-temperature:

The wave breaking after the model runs after 1 day, especially near the tropopause (400 K theta line)

brunt_vaisala_frequency_squared:

What if I increase the horizontal pole-to-equator temperature gradient? (increase the temperature difference bewteen the pole and equator by 10 K):

The isentropes of 400 K near the tropapause tend to overfold (curve) at lower height, means that the gravity waves tend to break at lower altitude. 

What if I decrease the horizontal temperature gradient?

(decrease the temperature difference by 10 K)

It is interesting that the fold (curve) of the potential temperature is less evident, which means that the gravity wave breaking is also strongly dampened after the temperature gradient is weakened. Background baroclinity has a strong control on the gravity wave breaking.

(2) Modify parameter B (Jet half-width parameter)

The parameter B determines the strength of Jet stream in horizontal direction.

Additionally,

increase the vertical scale of jet stream!

The stronger jet stream will lead the wave being able to propagate to higher altitude (>20 km).

(3) Modify KK (Jet width parameter)

Test:

a. KK = 3.0 (default)

b. KK = 2.5 ---> (x)

c. KK = 3.5 ---> (x)

d. KK = 2.0 ---> (x)

e. KK = 2.9 ---> (x)

For the squall line:

We have total 5 experiments, including one control run and 4 sensitivity runs.

Control run: everything is default.

Sensitivity run1: change the bubble perturbation temperature (pert_dtheta) from 3d (default) to 8d (Gus)

Sensitivity run2: change the number of bubble (pert_num) from 9 (default) to 18 (Shu-Hsuan)

Sensitivity run3: change both the number of bubble and the bubble perturbation temperature (Li)

Sensitivity run4: change the bubble perturbation temperature, the bubble number and the sponge layer w-damping coefficient (0.2 => 0.4) (Po Ju). 

In general, I think sensitivity run1, 2 and 3 will make the squall line becomes stronger and longer, while sensitivity run4 will slow down the squall line but also makes it a little weaker. 

Purpose of the test: how the MPAS simulates stronger squall line

(1) Control Run

(2) change the bubble perturbation temperature (pert_dtheta): 3 --> 8

(3) change the number of bubble (pert_num): 9 --> 18

(4) change number of bubble and perturbation temperature: (pert_dtheta: 3--> 8), (pert_num: 9-->18)

(5) change number of bubble, perturbation temperature, and w-damping coefficient: (pert_dtheta: 3--> 8), (pert_num: 9-->18), (w-damping: 0.2 --> 0.4)

(1) Control Run

(2) change the bubble perturbation temperature (pert_dtheta): 3 --> 8

(3) change the number of bubble (pert_num): 9 --> 18

(4) change number of bubble and perturbation temperature: (pert_dtheta: 3--> 8), (pert_num: 9-->18)

(5) change number of bubble, perturbation temperature, and max w-damping coefficient: (pert_dtheta: 3--> 8), (pert_num: 9-->18),                              (w-damping: 0.2 --> 0.4)