Base Cases: 

Tropopause test (Wandi Yu)

Test 1: L120, change the tropopause from 20 km to 10 km:

• crashes due to negative moisture layer depth near the model top 

Test 2: change tau of the Rayleigh fraction layer from 5 to 2.5: 

• crashes due to the same reason 

Test 3: change tau from 5 into 10:

• success 

interesting features: 

1. why doesn't the gravity wave break right above the tropopause @ 10 km? 

• might be an issue of not enough vertical resolution, can test by adding the vertical layers 

2. then why does the gravity wave break @ 25 km?

• might dut to the vertical wind shear, can test by adjusting the wind filed settings 

Lapse rate in troposphere & stratosphere 

Test 1: L120, double the lapse rate in troposphere and stratosphere

• crashes due to negative moisture layer depth near the surface

Test 2:  double se_nsplit:

• success 

Lapse rate in stratosphere 

Test 1: L120, double the lapse rate in only stratosphere 

• crashes due to negative mositure layer depth near the model top

Test 2:  change tau from 5 to 10:

• success 

CTL vs. blocky mountain (Jishi Zhang)

the flow behavior changed a lot in this case, like the zonal and vertical winds. The stronger insteability is also reflected in the Froude number near the foot of the mountain, and the stronger u wind shear in the lower layers. If we futher double the height of this blocky mountain, which basically lowers the Froude number further, we got crash, which is great

Laplacian Sponge Layer Removal (Giacomo Giuliani)

 Test 1: Removal of both sponge layers (Laplacian Diffusion and Rayleigh Friction)

• doesn't crash, but numerical noise in the stratosphere

Test 2:  Removal of Laplacian layer and Strengthening of Rayleigh layer (changes: tau = 2 → 5 days, layer depth = 15. → 20. km):

• crashes due to negative moisture layer depth near the model top 

Test 3: Strengthening of Rayleigh layer  and upgrade physics coupling from 30 to 10 mins (ATM_NCPL=144):

• success 

Effect of Adding Diffusion