How the Historical Data Is Processed
Turbli's historical database is built from the forecasts provided by the following agencies:
- NOAA: Graphical Turbulence Guidance forecast
- UK Met Office: Cumulonimbus cloud (thunderstorms) forecast
At Turbli, the forecast hours of 6, 12, 18 and 24 UTC are archived every day since the 1st of November 2021 (prior to 2024, only the 6 and 12 UTC hours were saved). The spatial resolution of the archived forecasts is 0.5 degrees in latitude and longitude, which corresponds to about 25 km (15.5 miles) in distance.
In the turbulence forecasts, the altitudes saved go from 10,000 ft to 44,000 ft (prior to 2024, less altitude levels were saved). The turbulence strength is in units of eddy dissipation rate (edr). This is the standard unit used by NOAA, and it corresponds to the rate at which the energy of turbulent structures is dissipated by viscous forces. High dissipation means that turbulence is also being generated at high rates.
In the thunderstorm forecasts, we save data on the base elevation, top elevation, and extent of the thunderstorm clouds. Thunderstorm clouds are particularly dangerous for flight operations due to their strong upward and downward currents
Routes and airports rankings
Every year, we do a ranking of the most turbulent flight routes and most turbulent airports in the world. For a detailed description on how this is made, please refer to the specific page on how the yearly rankings are made.
Country rankings
Every month, we do a ranking of the countries with most turbulence and most thunderstorm activity.
To do this, every point of the archived forecasts is assigned a country or ocean location. Such an assignment is based on the boundaries given by the Natural Earth database. No action is taken to correct disputed or conflict zones, and no political views are implied from such a decision. Countries smaller than about 80x80 km are removed from the historical data handling since the quality of the weather statistics drawn from these would be low. This includes city-states such as Luxembourg or Singapore and small islands such as Malta, Saint Helena, etc.
Overseas territories are added separately when it's considered that they can be under a very different weather system than the rest of the country. Examples are Alaska, Hawaii and Puerto Rico for the US; the French Polynesia and New Caledonia for France; etc. Large countries such as China or Russia are indeed under many different weather patterns as well, but these are not split into different zones.
In the monthly turbulence rankings, turbulence is evaluated between altitudes of 23,500 to 41,000 ft (7,200 to 12,500 m), since these are the most common range of cruising altitudes for commercial aviation.
In the monthly thunderstorm rankings, the height presented in the tables is between the cloud base to cloud top, not the height at which the cloud is located. The area cover is computed as the percentage of country or ocean area covered by thunderstorm clouds. Areas with thunderstorm clouds smaller than 500 m in height are considered to be in the early developing stage and categorized as no thunderstorm clouds.
Copyright
The rankings and historical data presented in Turbli are copyrighted but can be used in the media as long as you adhere to our Terms Of Use.
Disclaimer
Please read our Disclaimer regarding the usage of the historical or other data presented in Turbli.