Tropical cyclone classification schemes

Tropical cyclones are officially ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.

Tropical cyclones that develop in the Northern Hemisphere are officially classified, by the warning centres on one of three intensity scales. Tropical cyclones or subtropical cyclones that exist, within the North Atlantic Ocean or the North-eastern Pacific Ocean, are classified as either tropical depressions or tropical storms. Should a system intensify further and become a hurricane, then it will be classified on the Saffir–Simpson hurricane wind scale, which is based on the estimated maximum sustained winds over a 1-minute period. In the Western Pacific, the Typhoon Committee uses four separate classifications for tropical cyclones that exist within the basin, which are based on the estimated maximum sustained winds over a 10-minute period.

The India Meteorological Department's scale uses 7 different classifications for systems, within the North Indian Ocean and are based on the systems estimated 3-minute maximum sustained winds. Tropical cyclones that develop in the Southern Hemisphere are only officially classified by the warning centres on off two scales, which are both based on 10-minute sustained wind speeds. The Australian tropical cyclone intensity scale which is used to classify systems, within the Australian or South Pacific tropical cyclone basins. The scale used to classify systems in the South-West Indian Ocean and is adapted by Meteo France, for use in various French territories, including New Caledonia and French Polynesia.

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