Case Analysis —— Low-temperature Freezing Disaster in South China at the beginning of the year
(I) Overview of low-temperature freezing disasters in 28
After January 1, 28, the weather situation in China has changed significantly. From sunny, warm and rainy weather since last winter to low temperature and rainy and snowy weather. The continuous low temperature, rain, snow and freezing weather from January 1th to February 2nd caused great disasters to 2 provinces (autonomous regions and municipalities) such as Hunan, Hubei, Anhui, Jiangxi, Guangxi and Guizhou. Cold damage mainly caused large-scale water and power cuts, traffic jams, a large number of passengers stranded on roads, stations and airports, and the long-term saturated logistics and energy systems collapsed in extreme environments, resulting in 129 deaths and direct economic losses of more than 15 billion yuan (Figure 8-1).
Figure 8-1 Low-temperature freezing disaster in China in 28
(according to May 1, 211)
The specific disasters are as follows:
1) Power system: continuous heavy snow and freezing rain broke cables and collapsed tower poles, causing large-scale power outages in some areas of the above provinces (autonomous regions and municipalities). In cold weather, the power consumption has soared, and the power supply is in short supply.
2) Electric coal transportation: The pressure of electric coal transportation on roads, railways, aviation and ports such as Daqin Railway and Beijing-Hangzhou Canal has increased; Due to the traffic disruption in the south of the Yangtze River, it is difficult to transport the northern coal to the south, and the coal supply in the southern region is tight.
3) transportation: the southern section of Beijing-Guangzhou line and some sections of Shanghai-Kunming line were stopped, the trains were delayed many times, and some sections of Beijing-Zhuhai Expressway were closed, resulting in a large number of passengers stranded on the road and at the station.
4) Communication: Several signal communication towers of China Mobile were crushed by the continuous heavy snow and freezing rain, which made it impossible to communicate in some areas for a period of time, and there was no cell phone signal.
5) commodity supply: some agricultural products in the south are frozen, or cannot be transported to the north in time due to traffic reasons, and food supply in many areas in the north and disaster-stricken areas in the south is in short supply or prices are rising continuously.
6) Many electricians and traffic policemen were killed or injured.
(II) Characteristics of low-temperature freezing disasters
1. Wide range
The continuous low-temperature freezing weather affects Guizhou, Hunan, Hubei, Anhui, Jiangxi, Guangxi, Chongqing, Guangdong, Zhejiang, Fujian, Sichuan, Shaanxi, Jiangsu, Yunnan, Gansu, Henan, Qinghai, Tibet, Shanxi and Shanghai.
2. High intensity
Since January 1th, 28, the precipitation in six provinces (regions) of Henan, Sichuan, Shaanxi, Gansu, Qinghai and Ningxia has reached the maximum value in the same period since 1951. The minimum temperature in the middle and lower reaches of the Yangtze River dropped to-6 ~ ℃, and the daily maximum temperature was close to the minimum temperature. The average daily temperature in Wuhan and Changsha is close to or lower than ℃ for more than half a month. The temperature in most of Hubei, Anhui, Jiangxi, Hunan and Guizhou provinces is 2 ~ 4℃ lower than normal, and the temperature in central and eastern Hubei, most of Hunan and eastern Guizhou is more than 4℃ lower. The average temperatures in Henan, Hubei, Hunan, Guangxi, Guizhou, Gansu and Shaanxi are the lowest in the same period in history, and Jiangxi, Chongqing and Ningxia are the second lowest. The maximum temperature drop in Jiangnan, South China and most parts of the northwest reaches 1 ~ 2℃, with the northwest of South China exceeding 2℃. The snowstorm in Zhejiang is the strongest since 1984, and the snow depth in parts of Anhui and Jiangsu is close to 5 years.
3. Long duration
From December 1, 27 to January 31, 28, the longest continuous days in the middle and lower reaches of the Yangtze River (Jiangsu, Anhui, Hubei, Hunan, Jiangxi and Shanghai) and Guizhou where the daily average temperature was less than 1℃ were only less than those in 1954-1955, and the duration was the second largest in the same period in history; The number of rainy and snowy days in the middle and lower reaches of the Yangtze River and Guizhou exceeded 1954-1955, which was the largest in the same period in history. The number of frozen days is close to 1954 ~ 1955, which is the second largest in the same period in history. Among them, the freezing rain and snow weather in Hunan and Hubei has lasted the longest and had the most serious impact since 1954.
4. The disaster has a heavy impact
The continuous low temperature, rain, snow and freezing weather has caused great disasters to 2 provinces (autonomous regions and municipalities) such as Hunan, Hubei, Anhui, Jiangxi, Guangxi and Guizhou, especially to transportation, energy supply, power transmission, communication facilities, agricultural production and people's lives. The affected area and direct economic losses of crops have exceeded the whole year of 27.
(III) Causes of low-temperature freezing disaster
The abnormal atmospheric circulation that caused this low-temperature freezing disaster is mainly manifested in four aspects:
1) Since January 28, the atmospheric circulation in the middle and high latitudes of Europe and Asia has been distributed in the west and low in the east, which is conducive to the continuous invasion of cold air into China from the northwest along the Hexi Corridor.
2) The low pressure trough in the south branch of the southern margin of the Qinghai-Tibet Plateau is active, which makes warm and humid air continuously transported to China along the Yunnan-Guizhou Plateau.
3) The subtropical high in the northwest Pacific is strong to the north, and keeps stable in the southeast of China, so that the main areas where cold and warm air meet are located in the middle and lower reaches of the Yangtze River and its south.
4) In the intersection of cold and warm air, warm and humid air is forced to rise, forming a stable inversion layer in the middle and lower troposphere, and freezing rain occurs in a large area. This stable combination of abnormal forms of atmospheric circulation has been maintained for more than 2 days, resulting in a rare large-scale continuous low-temperature rain, snow and freezing weather in eastern China.
(4) Measures taken by the government to deal with low temperature and freezing disasters
1) Go deep into the front line and command from the front;
2) Strengthen the prediction and early warning, and do a good job of prevention beforehand;
3) Strengthen the emergency on duty and do a good job in information submission;
4) Strengthen information dissemination and do a good job in publicity and guidance;
5) all parties should make concerted efforts to "protect electricity, traffic and people's livelihood";
6) Strengthen overall planning and do a good job in emergency material allocation;
7) do a good job in post-disaster reconstruction.
(V) Thinking about the low-temperature and freezing disasters in South China
The low-temperature and freezing disasters in South China have exposed four weak links in the current disaster reduction work:
1) The existing comprehensive monitoring and detection scope, accuracy and temporal-spatial resolution of meteorological disasters can not meet the requirements of meteorological disaster prevention and reduction.
2) The meteorological department has not sufficiently estimated the persistence and intensity of disastrous weather, and the relevant departments have not sufficiently pre-assessed the risks of lifeline projects such as transportation and electric power.
3) Disaster reduction is the behavior of the whole society, and the cooperation of key departments and the sharing of information need to be strengthened, and the social emergency linkage and departmental coordination need to be strengthened.
4) The channels and means of early warning information release cannot meet the needs of the public, the coverage of early warning information is not wide enough, and leading cadres and the public lack awareness and scientific knowledge of disaster prevention.