Splitting Supercell

Splitting SupercellIdealized Simulation

Diff_6th_opt

Presented By: Jeff Curtis, Jason Keeler, and Cody Fritz

S. Nesbitt – ATMS 597

Objective• To track a simulated mesocyclone and assess the

contribution of the terms in the vorticity tendency equation.

• To change the 6th-order numerical diffusion option to 1 and compare to control simulation.

Outline• Brief background on numerical diffusion

option.• Track of vorticity maximum.• Comparison of vorticity maximum at

1.5km (video available)• Comparison of average vorticity between

0-3km..• Comparison of reflectivity (dBZ) (video

available).• Difference plots for Stretching, tilting, and

solenoid terms.

Background• The 6th-order horizontal diffusion acts as a short-wave

numerical noise filter (Chapter 5 – WRF Users Guide).

• 3 options are available:• 0 = no 6th-order numerical diffusion• 1 = 6th-order numerical diffusion• 2 = 6th-order numerical diffusion but with the

prohibiting of up-gradient diffusion

Maximum Vorticity Location

Vorticity – 1.5 kmControl – 00:05 Diff_6th – 00:05

Control – 01:00 Diff_6th – 01:00

Vorticity – 1.5 km

Control – 02:00 Diff_6th – 02:00

Vorticity – 1.5 km

Control – 03:00 Diff_6th – 03:00

Vorticity – 1.5 km

Vorticity – Averaged 0-3kmControl – 00:05 Diff_6th – 00:05

Control – 01:00 Diff_6th – 01:00

Vorticity – Averaged 0-3km

Control – 02:00 Diff_6th – 02:00

Vorticity – Averaged 0-3km

Control – 03:00 Diff_6th – 03:00

Vorticity – Averaged 0-3km

dBZControl – 00:15 Diff_6th – 00:15

dBZControl – 01:00 Diff_6th – 01:00

dBZControl – 02:00 Diff_6th – 02:00

dBZControl – 03:00 Diff_6th – 03:00

Stretching Term

00:05

Difference between control and diff_6th

option

Stretching Term

01:00

Difference between control and diff_6th

option

Stretching Term

02:00

Difference between control and diff_6th

option

Stretching Term

03:00

Difference between control and diff_6th

option

Tilting Term

00:05

Difference between control and diff_6th

option

Tilting Term

01:00

Difference between control and diff_6th

option

Tilting Term

02:00

Difference between control and diff_6th

option

Tilting Term

03:00

Difference between control and diff_6th

option

Solenoid Term

00:05

Difference between control and diff_6th

option

Solenoid Term

01:00

Difference between control and diff_6th

option

Solenoid Term

02:00

Difference between control and diff_6th

option

Solenoid Term

03:00

Difference between control and diff_6th

option