Richardson Number | Ellrod Index | Interval Values of Ellrod Index | Turbulence CAPE Index

Atmospheric Turbulence

Richardson Number

The Richardson number is the ratio of buoyancy and flow shear terms. It is expressed by a dimensionless number between 0 and 10. In aviation the Richardson Number can be used to assess atmospheric turbulence. This is also referred to as Clear Air Turbulence (CAT). Values below unity indicate significant turbulence.

richardson_number_<level>:idx

Available levels: 100hPa, 300hPa, 500hPa

Examples:

• Show Richardson Number for the entire globe:
  
  

  

• Current situation:
  https://api.meteomatics.com/2023-09-21T06:00:00Z/richardson_number_500hPa:idx/global:1,1/html_map

Ellrod Index

The Ellrod Index is designed to detect regions of Clear-Air-Turbulence (CAT) in the atmosphere. It is computed based on horizontal deformation of air parcels and vertical wind shear. The unit is s^-2.

• Especially suitable to detect turbulence near the jet stream; at upper level troughs and ridges, and the exit region of a jet
• Does NOT account for low level turbulence due to thunderstorms, mountain ranges, etc.

Range	Meaning
0-2	smooth conditions
2-9	light turbulence
9-20	moderate turbulence
20-36	severe turbulence
> 36	extreme turbulence

turbulence_ellrod_<level>:s2

Available levels (global): 950hPa, 925hPa, 900hPa, 850hPa, 800hPa, 700hPa, 500hPa, 300hPa, 250hPa, 200hPa, 150hPa, 100hPa, 70hPa, 50hPa, 10hPa
Available flight levels (global): FL20 - FL900 (continuously)

Examples:

• Ellrod Index at 700 hPa around the globe:
  
  

  

• Current situation:
  https://api.meteomatics.com/2023-09-21T06:00:00Z/turbulence_ellrod_700hPa:s2/global:0.5,0.5/html_map

Interval Values of Ellrod Index

Gives the mean, maximum or minimum ellrod index at the indicated flight level over the indicated duration.

turbulence_ellrod_<measure>_<level>_<interval>:s2

Available flight levels: FL20 - FL900 (continuously)

Available measures: mean, min, max

Available intervals: 1h, 3h, 6h, 12h, 24h

Examples

• Create a time series for the maximum ellrod index at FL100 for Los Angeles using 3 hour intervals.
  
  

  

• Current situation:
  https://api.meteomatics.com/2023-09-21T00:00:00Z--2023-09-24T00:00:00Z:PT3H/turbulence_ellrod_max_FL100_3h:s2/34.0522,118.2437/html?source=mix

Turbulence CAPE Index

Turbulence index incorporating CAPE. The index is computed for the total atmospheric column and not for single layers. This index allows for checking if turbulence is present. The values range from 0 (no turbulence expected) to 1 (turbulence expected)

turbulence_cape:m23s

Examples:

• Shown is the turbulence CAPE for the entire globe:
  
  

  

• Current situation:
  https://api.meteomatics.com/2023-09-21T06:00:00Z/turbulence_cape:m23s/global:1,1/html_map