Enter the MLCAPE and the wind speed difference between the density-weighted 0-6km mean wind and the lowest 500 m mean wind into the Bulk Richardson Number Calculator. The calculator will evaluate the Bulk Richardson Number. 

Bulk Richardson Number Formula

The following two example problems outline the steps and information needed to calculate the Bulk Richardson Number.

BRN = MLCAPE / (.5*U^2)

Variables:

  • BRN is the Bulk Richardson Number ( )
  • MLCAPE is the MLCAPE 
  • U is the wind speed difference between the density-weighted 0-6km mean wind and the lowest 500 m mean wind. 

To calculate the Bulk Richardson number, divide the MLCAPE by the wind speed difference between the density-weighted 0-6km win and lowest 500m mean wind squared divide by 2.

How to Calculate Bulk Richardson Number?

The following steps outline how to calculate the Bulk Richardson Number.


  1. First, determine the MLCAPE. 
  2. Next, determine the wind speed difference between the density weighted 0-6km mean wind and the lowest 500 m mean wind. 
  3. Next, gather the formula from above = BRN = MLCAPE / (.5*U^2).
  4. Finally, calculate the Bulk Richardson Number.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

MLCAPE = 5

wind speed difference between the density weighted 0-6km mean wind and the lowest 500 m mean wind = 20

BRN = MLCAPE / (.5*U^2) = ?