The Fujita scale increase (EF-Scale ) assesses the intensity of tornadoes in the United States and Canada based on the damage it causes.
The Fujita scale was introduced in 1971 by Tetsuya Theodore Fujita, it began operating in the United States on February 1, 2007, followed by Canada on April 1, 2013. This scale has the same basic design as the original Fujita scale --six categories from zero to five, representing an increased level of damage. It was revised to reflect a better examination of the tornado damage survey, so as to align the wind speed closer to the associated storm damage. Better standardization and explain what was previously subjective and ambiguous, also added more types of structures and vegetation, expanded the extent of damage, and better accounts for variables such as differences in construction quality.
More recent scales were openly inaugurated by the National Weather Service at the American Meteorological Society conference in Atlanta on February 2, 2006. It was developed from 2000 to 2004 by the Fujita Scale Improvement Project from the Wind Science and Engineering Research Center at Texas Tech University, which brings together dozens meteorologists and civil engineers in addition to its own resources.
Like the Fujita scale, the Fujita scale Enhanced remains the scale of damage and is just a proxy for the actual wind speed. While wind velocities associated with registered damage have not undergone empirical analysis (such as physical or numerical modeling in detail) due to excessive costs, wind speed is obtained through expert elicitation processes based on various engineering studies since the 1970s as well. such as from the field experience of meteorologists and engineers. In addition to damage to structure and vegetation, radar data, photogrammetry, and cycloidal marks (circle patterns) may be used if available.
This scale is used for the first time in the United States a year after its public announcement when the central Florida section was hit by some tornadoes, the strongest being rated at EF3 on a new scale. It was used for the first time in Canada shortly after its application when a tornado developed near the city in Shelburne, Ontario on April 18, 2013, causing damage to EF1.
Video Enhanced Fujita scale
Parameter
The six categories for the EF scale are listed below, in order of increasing intensity. Although wind speed and photographic damage samples are updated, the description of the damage provided is from the Fujita scale, which is still more or less accurate. However, for actual EF scales in practice, the damage indicator (type of damaged structure) is mostly used in determining the intensity of the tornado.
Indicator of damage and level of damage
The current EF scale has 28 indicators of damage (DI), or type of structure and vegetation, each with varying degrees of damage (DoD). A greater degree of damage to the damage indicator corresponds to a higher wind speed. The links in the right column of the following table illustrate the extent of the damage for the damage indicator listed on each line.
Maps Enhanced Fujita scale
Difference from Fujita scale
The new scale takes into account the quality of construction and standardization of various types of structures. Wind speeds on the original scale are considered by meteorologists and engineers as too high, and engineering studies show that winds are slower than originally thought to cause levels of damage each. The old scale includes the F5 tornado as a wind speed of 261-318 mph (420-512 km/h), while the new scale registering EF5 as a tornado with winds above 200 mph (322 km/h) is found to be sufficient. to cause damage previously thought to be derived from the F5 wind speed range. None of the tornadoes recorded on or before January 31, 2007 will be re-categorized.
Basically, there is no functional difference in how to judge a tornado. Old ratings and new rankings are connected smoothly with linear formulas. The only difference is the adjusted wind speed, the measurement not used in the previous rank, and the description of the smoothed damage; this is to standardize the rankings and make it easier to rate tornadoes that attack multiple structures. Twenty-eight Damage Indicators (DI), with descriptions such as "double-width mobile homes" or "small malls", are used in conjunction with Degradation Dods to determine wind forecasts. Different structures, depending on their building materials and ability to survive with strong winds, have their own DI and DOD. Explanation of the damage and wind speed will also be ready to be updated as new information is learned.
Because the new system still uses actual tornado damage and similar damage rates for each category to estimate the wind speed of the storm, the National Weather Service states that the new scale is unlikely to cause an increase in the number of tornadoes classified as EF5. In addition, the upper limit of the wind speed range for EF5 is open - in other words, no predetermined maximum wind speed.
Ranking classification
For purposes such as the tornado climatology study, Fujita's enhanced scale rating can be grouped into classes.
Typically, the classic version always suggests EF4 and EF5 are the cruelest tornadoes.
The table shown on the right shows another variation of the tornado rating classification based on a specific area.
See also
References
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Edwards, Roger; J. G. LaDue; J. T. Ferree; K. Scharfenberg; C. Maier; W. L. Coulbourne (2013). "Estimated Tornado Intensity: Past, Present, and Future". Bull. Amer. Meteor. Soc . 94 (5): 641-53. Bibcode: 2013BAMS... 94..641E. doi: 10.1175/BAMS-D-11-00006.1.
External links
- National Oceanic and Atmospheric Administration
- NOAA National Weather Service Improves the Tornado Rating System in NOAA News
- Fujita Scale Improvement (EF Scale) in Hurricane Prediction Center
- EF-Scale Training at the National Weather Service (NWS) Warning Branch Warning Training
- Fujita Tornado Scale Improvement at National Climatic Data Center
- Tornado: Technical Oriented Perspective (NWS SR147)
- Guide to Conducting Windstorm Convection Surveys (NWS SR146)
- Fujita Scale Upgrade Project (Research Center for Wind Science and Engineering at Texas Tech University)
- Symposium on the Assessment of F-Scale Damage and Severe Weather Damage at the American Meteorological Society
- Guidelines for F-Scale Damage Assessment, MetEd, University Corporation for Atmospheric Research
- Report of the Mitigation Assessment Team: Tornado Midwest May 3, 1999 (Federal Emergency Management Agency)
Source of the article : Wikipedia
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