GB/T 40243-2021.Tornado intensity scale.
1 Scope
GB/T 40243 specifies the identification rules and intensity classification of tornadoes.
GB/T 40243 applies to the monitoring, early warning, identification, rating and scientific research of tornadoes.
2 Normative references
This document has no normative references.
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Tornado
Tornado
A rapidly rotating column of air extending from the base of a cumuliform cloud to the land or water surface.
Note: It often appears as a funnel-shaped cloud body.
3.2
Funnel cloud
A cloud extending downward from a cumuliform cloud, usually in the shape of a funnel and accompanied by a rotating air column.
Note: This rotating air column is a tornado when it touches the ground.
3.3
Convective storm
A weather system composed of cumulonimbus clouds.
Note: It is often accompanied by thunder and lightning, strong winds, heavy precipitation, and sometimes hail, downbursts, and even tornadoes.
3.4
​​ Gust wind speed
The maximum instantaneous wind speed on the ground at a certain moment caused by a tornado (3s average wind speed).
3.5
Radial velocity
The component of the wind vector along the radar radial direction.
Note: It is also called Doppler velocity in Doppler weather radar observations.
3.6
Tornado vortex signature; TVS
The radial velocity characteristics of the vortex airflow near the center of a tornado on a Doppler weather radar.
Note: It is usually cyclonic, manifested as strong cyclonic tangential velocity pairs between adjacent azimuth pixels on the radar radial velocity field.
3.7
Mesocyclone
A cyclonic vortex with a horizontal diameter of 2km~10km that appears in a convective storm.
This document specifies the identification rules and intensity classification of tornadoes. This document is applicable to the monitoring, early warning, identification, rating and scientific research of tornadoes.

ICS07.060
CCS A 47
National Standard of the People's Republic of China
GB/T 40243—2021
Tornado intensity level
Tornado intensity scale
Released on 2021-05-21
State Administration for Market Regulation
National Standardization Administration
Implementation on 2021-12-01bzxz.net
GB/T40243—2021
Normative referenced documents
Terms and definitions
4 Tornado identification
5 Classification
Appendix A (informative) Wind speed lookup table based on disaster indicators and disaster damage degree Reference literature
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GB/T40243—2021
This document is drafted in accordance with the provisions of GB/T 1.1.2020 Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents.
Please note that some contents of this document may involve patents. The issuing agency of this document does not assume the responsibility of identifying patents. This document was issued by the China Meteorological Administration.
This document is under the jurisdiction of the National Meteorological Disaster Prevention and Mitigation Standardization Technical Committee (SA/1C345). The drafting units of this document are: China Meteorological Science Academy, National Meteorological Center, and Foshan Tornado Research Center. The main drafters of this document: Yao Pin, Liang Xudong, Sun Jisong, Zheng Yongguang, Zhou Yanliang, Li Cailing, Cai Kanglong, Li Zhaoming, rrKaeerkAca-
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1 Scope
Tornado intensity level
This document specifies the identification rules and intensity level classification of tornadoes. This document is applicable to the monitoring, early warning, identification, level assessment and scientific research of tornadoes. 2 Normative references
This document has no normative references
3 Terms and definitions
The following terms and definitions apply to this document: 3.1
Tornado
tornado
A rapidly rotating air column extending from the base of cumuliform clouds over land or water. Note: It often appears as a clear bucket-shaped cloud body.
Funnel cloud
Funnel cloud
Developed from cumuliform cloud, it is a cloud with a funnel shape and accompanied by a rotating air column. Note: when the rotating air column touches the ground, it is a tornado. 3.3
Convective storm
convective storm
A weather system composed of cumulonimbus
Note: often accompanied by lightning, strong winds, heavy rainfall, and sometimes ice caps, downhill flash floods and tornadoes. 3.4
Gust wind speed
gust wind speed
The maximum instantaneous wind speed on the ground at a certain moment caused by a tornado (3: average wind speed). 3.5
radial velocit.
Radial velocity
The component of wind speed along the path,
Note: It is also called Doppler velocity in Doppler weather observation. 3.6
tornadic vortex signature: The radial velocity characteristics of the vortex airflow near the center of a tornado on the Doppler weather observation, GB/T40243—2021
Note: It is usually cyclonic, manifested as a strong cyclonic directional velocity pair between adjacent azimuth negative images in the directional velocity field. 3.7
Mesocyclone
mesocyclone
A cyclonic vortex with a horizontal diameter of 2km10km that appears in a convective storm1
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GB/T40243—2021
Disaster Surveydamagesurvey
Investigation, evidence collection, assessment and analysis of the site of the disaster and the weather scene to determine whether a tornado disaster has occurred and to determine the extent of the damage, scope of impact and intensity level. 4 Tornado Identification
4.1 Overview
After a suspected tornado report appears, refer to the following steps to carry out tornado identification as soon as possible. The identification of historical cases can be referenced.
4.2 Analyze meteorological data
Analyze meteorological data such as Doppler weather radar and ground observations. Under the premise that the occurrence of wind disasters is accompanied by the appearance of convective storms, determine the impact path of mesocyclones and/or tornado vortex characteristics. 4.3 Conduct disaster investigation
Perform according to the following requirements:
Quickly conduct disaster investigation along the impact path of mesocyclones and/or tornado vortex characteristics and in the affected areas, and record the degree of damage and distribution of disaster indicators:
Collect tornado funnel cloud image data (including photos and videos), visit the site and record the time, location, angle, personnel and other information of the shooting:
4.4 Determine the occurrence of a tornado
4.4.1 If there is funnel cloud image data, its authenticity should be verified based on its shooting information and combined with meteorological data. If the funnel cloud image data is authentic and reliable, it can be determined that a tornado has occurred. 4.4.2 If there is no funnel cloud image data, or if there is funnel cloud image data but its authenticity cannot be verified, the disaster survey should be based on the analysis of the distribution characteristics of the disaster indicators in combination with meteorological data. If the disaster characteristics of a tornado are consistent (the disaster is distributed in a narrow and long shape, and the fallen objects are characterized by convergence or rotation) and the path of influence of the mesocyclone and/or tornado vortex characteristics is consistent, it can be determined that a tornado has occurred. 4.4.3 If there is no funnel cloud image data and the disaster survey cannot be carried out: the meteorological data and related records should be referred to, and the possibility of a tornado occurring should be determined through expert consultation.
5 Classification
5.1 Based on the determination of the occurrence of a tornado, the maximum gust wind speed V.. at the time of its occurrence is used as an indicator to classify the intensity of a tornado into four levels: weak, moderate, strong, and super strong. See Table 1. 5.2 For major disasters, refer to the wind speed calculation table for disaster indicators and damage levels provided in Appendix A to calculate the gust wind speed caused by the tornado. The maximum gust wind speed calculated for all disasters is used as the basis for determining the intensity of the tornado. 5.3 The gust wind speed should be calculated based on the wind speed in Tables A.1 to A.4. Based on the expected wind speed, refer to the disaster indicators and their actual damaged conditions and make appropriate selections within the two wind speed ranges in Table A.1~~Table A12
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Tornado intensity level classification
Gust wind speed
38V=x48
GB/T40243—2021
Degree of disaster
Destructiveness
Note: Tornado intensity level and Improved Fujitn SccleEFScale) has the following pairing relationship: corresponding to FFA.FFI5
corresponding to FFO and below; medium
corresponding to bottom FFI strong
corresponding to FF2, FF3; super strong
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GB/T40243—2021
Appendix A
(Informative)
Wind speed lookup table based on disaster indicators and disaster damage degree Table A.1 Table A.1 gives the wind speed lookup table (civil buildings), wind speed lookup table (other buildings) wind speed calculation table (structures) and wind speed check table (trees).
Table A,1
Disaster indicators
Residential buildings with non-frame structures
(e.g. single-story houses with brick-concrete structures)
Residential buildings with reinforced concrete structures
(e.g. low-rise houses with reinforced concrete structures)Public buildings with non-frame structures
(e.g. shops with brick-concrete structures)
Public buildings with frame structures
(e.g. small public buildings with reinforced concrete structures)Wind speed calculation table (civil buildings)||tt ||Degree of damage
Minor possible damage
Minor damage to the building
Damage to the door and glass
Heavy damage to the roof
Complete collapse of the structure
Outer wall collapsed
Complete collapse of the building
Minor visible damage
Items slightly damaged
Preliminary severe damage
Glass of doors and windows broken
Complete roof||t t||Exterior wall seriously damaged
Building completely destroyed
Minor visible damage
Roof slightly damaged
Door and glass damaged
Heavily damaged
Roof completely tilted
Exterior wall collapsed
Building completely destroyed
Minor visible damage
Roof slightly damaged
Door and glass damaged
Heavily damaged
Building cladding damaged
Roof partition tilted
Building wall collapsed
Building seriously damaged
. Slight damage means the damaged area is less than or equal to 20%. Severe damage means the damaged area is more than 20%. -rrKaeerKAca-
Expected wind speed
Wind speed range
2:~-36
29--44| |tt||38--52
66--89
25~-37
24--36
32~-46
45--63
54~-71
32---49
35-~51
57--77
Disaster indicators
Metallic structure industrial buildings
(Example Such as steel structure factory buildings)
Metal structure agricultural buildings
(such as color steel plate material construction period)
Disaster indicators
Electric poles, transmission towers
(with transmission line connection)
Radio towers
Street lights, flagpoles
Wind speed calculation table (other buildings)
Degree of damage
Slightly visible damage
Deformation of roof panels|| tt||Bending of roof trusses
Collapse of rigid structure
Complete destruction of the building
Minor visible damage
Roof board material damaged
Door collapsed
Roof tilted
Building collapsed
Overall damage of the building
Complete destruction of the building
Expected wind speed
Wind speed calculation table (structure)
Degree of damage||tt| |Slightly visible tension
Broken wooden beams
Tilt of wooden supports
Broken non-wooden poles
Bent non-wooden poles
Falling metal towers
Slightly visible damage
Falling metal towers
Slightly visible damage
Bending of metal poles
Falling of metal poles
Including bending or breaking of metal or concrete + material poles. -riKacerKAca-
Expected wind speed
GB/T40243—2021
Wind speed range
24--37
35~-54
59--80
27~-11
30--46
Wind speed specification
35-~51
38--58
22--63
52--71
34--51
38--54
44--62
GB/T40243— 2021
Disaster indicators
Glossy wood
(such as poplar, birch, maple, etc.)
Coniferous wood
(such as pine, spruce, fir, etc.)
Wind speed table (trees)
Degree of damage
Thin branches broken
Thick branches broken
Roots uprooted
Tree roots broken
Bark peeling
Thin branches broken
Thick branches uprooted
Tree trunks broken
Bark peeling
Red branches refer to those with a diameter less than or equal to 2.5em. , thick branches refer to trees with a diameter of more than 2.5 cm1
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Periodic wind speed
Wind speed range
21--32
55--75
33--51
39~~57
2 Wind force level
GB/T28591—2012
GB/T 34301—2017
References
Technical Specifications for Tornado Disaster Investigation
GB/T352272017 Specifications for Ground Meteorological Observations Wind Direction and Speed ​​QX/T416—2018 Severe Convective Weather Grades
GB/T40243—2021
Atmospheric Science Name River Approval Committee. Atmospheric Science Terminology: Third Edition [M_]. Beijing: Science Press, 2009L6] Fan Wenjie, Yu Xiaoding. Spatial and Temporal Distribution Characteristics of Tornadoes in ChinaLJI (Xiang, 2015, (7): 793-805[7] Zheng Shuiguang, Zhu Wenjian, Yao Pin, et al. Wind Speed ​​Grade Standard and Intensity Estimation of Funing Tornado on June 23, 2016 (Part 1). Meteorological 2016.42(11):1289-1303
L8JAmerican Meteorological Socicty.Glossary of meteorology.https://glossary.amctsoc.org,wiki/welcome
9l Wind Seience and Engineering Center, Texas Tech University. A rerotnmendation for anenhancedl Fujita scale(EF scale), Revision 2. 2006. http://depts.ttu.cdu/nwi/pubs/fscale/efseale.jdf
Llo》 Edwards R. LaDue JG, Ferrec JT, cl al. Tornado intensity estimation: Past, prcscnt.and future[J].Bull Amer Meteor Soc, 2013.94:64l 653[ll] Meng Z, Yao D, Danmage survey, radar, and environment analyzes on the Firxi-Ever Doc-umentcd Tornado in Beijing during the heavy rainfall event of 21 July 2012LJ/.Wea Forccasting2014, 29: 702 724
I 12l Meng 7., Yao D. Bai L, et al. Wind estitnalion around the shipwreck of Orienlal Starbased on field damage surveys and radar observations[J]. Scicnce Bulletin, 20l6, 6l: 330 337[13_Bai I..,Meng Z. Hurng I., el al. An integrated danage, visual.and radar analysig of the2015 Foshan, Guangdong.EF3 Tornado in China produced by the landfalling typhoon Mujigac (2015)l.BullAmerMeteorSoc;2017.98:26192640[14] Meng 7.. Bai 1. , Zhang M, el al. The deadliest tortnado (EF4) in the past 40 yearx in China _IJ. Wea Forccasting+ 2018, 33:693-713-riKaeerKAca-
GB/T40243-2021
People's Republic of China
National Standard
Tornado Intensity Level
GB/T 40243—2021
Published and distributed by China Standard Stream Publishing House
No. 2, Hepingli West Street, Chaoyang District, Beijing (100029) No. 16, Sanhuahe North Street, Xicheng District, Beijing (100M6) Website: spc.org.cn
Service hotline: 400-168-0010
First edition in May 2021
No. 5: 155066·1-67713
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