GB/T 40239-2021.Meteorological grades for urban snow hazard.
1 Scope
GB/T 40239 specifies the classification of meteorological grades for urban snow disasters and the calculation of indexes.
GB/T 40239 is applicable to the classification of meteorological grades for urban snow disasters and risk assessment.
2 Normative references
This document has no normative references.
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Snowfall
During a certain period of time, the depth of solid snowfall that falls from the sky to the ground after melting without evaporation, infiltration or loss and accumulates on the horizontal surface.
Note: The unit is millimeter (mm), with 1 decimal place.
3.2
Daily snowfall
The accumulated snowfall in one day.
Note 1: The unit is millimeter (mm), with one decimal place.
Note 2: One day usually refers to 08:00 to 08:00 or 20:00 to 20:00 Beijing time.
3..3
Number of consecutive days with snow fall
The accumulated number of days with consecutive daily snowfall (3.2) not less than 0.1 mm.
3.4
​​ Maximum daily snowfall
The maximum value of daily snowfall (3.2) in the consecutive days with snowfall.
Note: The unit is millimeter (mm), with one decimal place.
3.5
Accumulated snowfall
The cumulative value of daily snowfall (3.2) in consecutive snowfall days.
Note: The unit is millimeter (mm), rounded to 1 decimal place.
3.6
Snow depth
The vertical depth from the snow surface to the underlying surface.
Note: The unit is centimeter (cm). ||
tt||[Source: GB/T 35229-2017, 3.1]
This document specifies the classification of urban snow disaster meteorological levels and index calculation. This document is applicable to the classification of urban snow disaster meteorological levels, risk assessment, etc.

ICS 07.060
CCS A 47
National Standard of the People's Republic of China
GB/T40239—2021
Meteorological grades for urban snow hazard
Meteorological grades for urban snow hazard2021-05-21Issued
State Administration for Market Regulation
National Administration of Standardization
Implementation on 2021-12-01
GB/T 40239—2021
Normative referenced documents
Terms and definitions
Grade classification
Index calculation
Appendix A (Normative)
References·
Regional division
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This document is in accordance with GB/T 1.1
2020 Standardization Work Guidelines
Drafting.
This document is proposed by the China Meteorological Administration.
GB/T-40239—2021
Part 1: Structure and Drafting Rules for Standardization Documents This document is under the jurisdiction of the National Meteorological Disaster Prevention and Disaster Standardization Technical Committee (SAC/TC345). The unit of this document is: Heilongjiang Meteorological Bureau. The main drafters of this document are: Zhao Na, Ma Guozhong, Wu Yan, Guan Ming, Qi Feng, Sun Qi, Zhang Yue, Zhao Ning I
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1 Scope
Urban snowstorm meteorological level
This document defines the classification of urban snowstorm meteorological levels and index calculation. This document is applicable to the classification of urban snowstorm meteorological levels, risk assessment, etc. 2 Normative references
This document has no normative references.
3 Terms and definitions
The following terms and definitions apply to this document. 3.1
Snowfall
snowfall
GB/T 40239—2021
The depth of solid snowfall that falls from the sky to the ground after melting without evaporation, infiltration, or loss on the horizontal surface during a certain period of time.
Note: The unit is old meter (mm). Take 1 decimal place. 3.2
daily snowfall
Daily snowfall
The accumulated snowfall in a day.
Note 1: Single letter is mm, 1 decimal place
Note 2: A day usually refers to 08:00 to 08:00 or 20:00 to 20:00 Beijing time the next day. 3.3
Number of consecutive days with snowfall The accumulated number of consecutive days with snowfall equivalent (3.2) not less than 0.1 mm. 3.4
Maximum daily snowfall
maximum daily snowfall
The maximum value of snowfall (3.2) in the number of consecutive snowfalls Note: The unit is mm, 1 decimal place. 3.5
Accumulated snowfall
aecumulaled snowfall
The cumulative value of the snowfall in consecutive snowfalls (3.2). Note: The unit is millimeter (mm), rounded to one decimal place. 3.6
snowdepth
The vertical depth from the snow surface to the bottom. Note: The unit is centimeter (cm).
[Source: GB/T35229
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GB/T40239—2021
Wind speedwind speed
The horizontal distance moved by air per unit time. Note: The unit is meter per second (m/s). Take one decimal place. [Source: GB/21984-2017, 2.12, modified] 3.8
DailymaximumwindspeedDailymaximumwindspeedThe maximum value of the average wind speed within any 10 minutes in a day. Note 1: The unit is meter per second (m/s), take one decimal place. Note 2: The zone of III refers to 08:00 to 08:00 or 20:00 to 120:00 in Beijing time. 3.9
Dailyminimumairtemperature
The lowest temperature in a day.
Note 1: The unit is degrees Celsius (T), and values ​​below degrees are negative. Note 2: Zone III usually refers to 08:00 to 08:00 or 20:00 to 20:00 in Beijing time. 3.10
Relative humidityrelative humidity
The ratio of the actual water vapor in the air (e) to the saturated water vapor at the current temperature (E). Note: Expressed as a percentage (%)
LSource: GB/219812017.2.10
Daily minimum relative humidity
dailyminimumrelativehumiclityThe lowest value of the relative humidity of the air during the day,
Note 1: Expressed as a percentage (hing).
Note 2: -Day usually refers to 08:00 Beijing time, 8:00 the next day or 20:00 Beijing time, 20:00 the next day, 3.12
urban Snowhazard
Urban snow disaster
Snowstorms in cities are events that cause varying degrees of damage to the lives and health of urban residents, urban buildings and facilities, and production and social activities in all walks of life in cities.
Urban snow hazard meteorological index
Urban snow hazard meteorological indexMeteorological evaluation index of the severity of urban snow disasters. Grade classification
According to the urban snow disaster meteorological index I (see Chapter 5), the urban disaster meteorological grade is divided into four levels: mild, moderate, severe and serious, see Table 1.
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Index range
5Index calculation
Table 1 Classification of urban snow disaster meteorological grades
Possible impact
GB/T 40239—2021
It has a certain impact on the operation of cities and social activities. It causes temporary blockage of urban traffic: affects people's normal activities, etc. It has a great impact on the operation of cities and social activities. Urban transportation is blocked: the operation of power and communication lines is affected, seriously affecting people's normal activities, etc.
It has a great impact on the operation of cities and social activities: urban transportation, railways, and civil aviation transportation are interrupted; the operation of urban power and communication lines is seriously affected: it is easy to cause the collapse of buildings and facilities: it is easy to cause casualties, etc. It has a great impact on the operation of cities and social activities, and the transportation, railways, and civil aviation transportation are interrupted, which is easy to cause the interruption of power and communication lines: it is very easy to cause the collapse of buildings and facilities: it is easy to cause casualties, etc. 5.1 Calculation method of index
Select the cumulative snowfall, the maximum daily snowfall, the snow depth, the number of consecutive snowfall days, the daily minimum temperature, the daily maximum wind speed, and the daily The minimum relative humidity and other seven meteorological elements are the components of the urban snowstorm meteorological index. The calculation of the urban snowstorm meteorological index is shown in formula (1). I=kIuIIII
Wherein:
Urban snowstorm meteorological index;
The component of the urban snowstorm meteorological index corresponding to the cumulative snowfall; The component of the urban snowstorm (phenomenon index corresponding to the maximum snowfall; The component of the urban snowstorm phenomenon index corresponding to the snow depth; The component of the urban snowstorm meteorological index corresponding to the number of consecutive snowfalls; The component of the urban snowstorm meteorological index corresponding to the daily minimum temperature; The component of the urban snowstorm meteorological index corresponding to the daily maximum wind speed: The component of the urban disaster meteorological index corresponding to the daily minimum relative humidity, 5.2I value requirements
...(1)
The regional type of the city should be determined according to the regional division in Appendix A, and the value should be selected from Table 2 according to the cumulative snowfall in the number of consecutive snowfall days.
Table 2 Components of urban snow disaster meteorological index corresponding to cumulative snowfall (1) Cumulative snowfall
[Class I area
Class II area
Cumulative snowfall
10.0-19.9
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20.0-29.9
10.0--19.9
30.0--39.9
20.0-29.9
GB/T 40239—2021
3 Requirements for the value of Irr
The regional type of the city should be determined according to the regional division in Appendix A, and the Ika value should be selected from Table 3 according to the maximum daily snowfall in the number of consecutive snowfalls.
Table 3 Components of the urban snowstorm meteorological index corresponding to the maximum daily snowfall (Iem) Maximum daily snowfallwww.bzxz.net
I-class area
II-class area
Maximum snowfall
5.4I value requirements
10.0---19.9
20.a.29.9
10.9--19.9
The regional type of the city should be determined according to the regional division in Appendix A, and the value should be selected from Table 4 according to the maximum snow depth in the number of consecutive snowfall days:
Class 1 area
Class Ⅱ area
Value requirements of ",
The component of the urban snow disaster meteorological index corresponding to the snow depth (I,) 9.5
10.0---19.
20.0---29.9
10.0~19.8
Select 1 value from Table 5 according to the number of consecutive snowfall days in the city. 30.0--39.9
20.0--29.9
40.9--49.9
30.9--39.9
Table 5 Components of the urban snowstorm meteorological index corresponding to the number of consecutive snowfall days (1N) Continuous snowfall needs Ⅱ effect
5.6I, the value requirement
should determine the regional type of the city according to the regional division of Appendix A, and select 1~values ​​from Table 6 according to the minimum daily minimum temperature in the number of consecutive snowfall days.
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【Class area
Class II area
The component of the urban snow disaster meteorological index corresponding to the daily minimum temperature (I1) Table 6
Daily minimum temperature
Daily low temperature
Requirements for the value of Iw
14.8--—10.0
8.3---7.0
GB/T40239—2021
-5.5--3.0
According to the maximum wind speed value in the number of continuous snowfalls in the city, select 1 from Table 7. The component of the urban snow disaster meteorological index corresponding to the maximum wind speed on the day (Iw) Table 7
Daily maximum wind speed range
Requirements for the value of I
3.4 --5.4
8.0--10.7
10.8--13.8
The regional type of the city should be determined according to the regional division in Appendix A. According to the minimum relative humidity in the continuous snowfall number, select the Im value from Table 8.
Table 8 Components of the urban snowstorm meteorological index corresponding to the daily minimum relative humidity (Il) Daily minimum relative humidity
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GB/T40239—2021
Appendix A
(Normative)
Regional division
Based on the average number of snowfall days in my country over the years and the underground distribution of light snow, moderate snow, heavy snow and blizzard Characteristics, the country is divided into two categories of regions, see Table A.1.
Regional division
Class I regions
Class II regions
Heilongjiang Province, Gulin Province, Qianning Province, Inner Mongolia Baizhi District, Xin Uyghur Baizhi District, Tibet Baizhi District, Qinghai Province, Gansu Province, Ningzong Nationality Baizhi District, Shaanxi Province, Shanxi Province, Hebei Province, Beijing, Tianyang City, Shanghai, Jiangsu Province, Zhejiang Province, Anhui Province, Jiangxi Province, Shandong Province, Heshi Province, Hunan Province, Hubei Province, Chongqing City, Sichuan Province, Guizhou Province, Yunnan Province, Guangxi Zhuangxuan Baizhi District, Guangdong Province, Fujian Province, Hainan Province, Hong Kong Special Administrative Region, Macao Special Administrative Region, Taiwan Province-riKaeerkca
GB/ 21984
GB/28592-
—2012
GB/57 35221-
GB/35228
GB/35229—2017
References
Short-term weather forecast
Precipitation level
Specification for surface meteorological observation
Specification for surface meteorological observation
Specification for surface meteorological observation
Snow depth and snow indication
Editorial Committee of Atmospheric Science Dictionary. Dictionary of Atmospheric Sciences M1. Beijing: Meteorological Press, 1991 Zhu Binghai, Shang Pengfei, Huang Jiaxin. Meteorological Dictionary_M. Shanghai: Shanghai Dictionary Publishing House, 1985-rrKaeerkca-
GB/T 40239—2021
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