Guidelines for the Japanese Enhanced Fujita Scale
In April 2016, the Japan Meteorological Agency (JMA) introduced the Japanese Enhanced Fujita Scale (JEF Scale) as an improvement on the Fujita Scale (F Scale) for tornado intensity rating. This page links to Guidelines for the Japanese Enhanced Fujita Scale.
JMA tornado countermeasures and the Japanese Enhanced Fujita Scale
JMA dispatches staff to sites damaged by tornadoes and other strong winds (except synoptic-scale winds such as typhoon-induced winds) to investigate damage, identify the related wind phenomenon and rate its intensity. In this context, the Agency introduced the Japanese Enhanced Fujita Scale (JEF Scale) for tornado intensity rating in April 2016.
The Fujita Scale (F Scale), which is used to estimate wind speed ranges based on damage intensity, is commonly used worldwide. However, it was originally developed in the United States and is characterized by a number of issues: it is not well suited to Japanese buildings and structures, only nine damage indicators can be used, and rating results give only ranges of wind speed.
To improve on the F Scale for correspondence to damage to Japanese buildings/structures and enable more accurate wind speed rating, JMA formulated the Japanese Enhanced Fujita Scale (JEF Scale) in collaboration with experts in related research fields such as wind engineering and meteorology.
JMA provides Hazardous Wind Potential Nowcasts, which analyze and predict the probability of hazardous winds such as tornadoes with a spatial resolution of 10 km and a one-hour lead time. When such nowcasts predict hazardous wind, a Hazardous Wind Watch is issued to warn of such phenomena within the next hour. (See References below.)
Tornado intensity ratings have been used to improve Hazardous Wind Potential Nowcasts, and results based on the Japanese Enhanced Fujita Scale are expected to contribute to further enhancement.
References
