Brief introduction of snow and ice disasters in southern China
Serious meteorological disasters have affected normal production and life.
The whole country of China mobilized urgently to fight against the disaster.
The characteristics of this disaster are mainly in the following aspects: First, it has a large intensity, a wide range and a long duration.
Second, the loss history is rare.
Third, the task of transferring resettlement and ensuring the lives of people affected by collapsed damaged houses is very great.
Fourth, the task of emergency rescue for passengers stranded on roads and railways is very arduous.
Fifth, the power and communication networks have been severely damaged.
About the reason
Since1.65438+1October 10, a large-scale persistent extreme weather disaster of low temperature, rain, snow and freezing has occurred in China once in 50 years.
Since 65438+1October 10, the weather situation in China has changed obviously.
From sunny, warm and rainy weather since last winter to low temperature and rainy weather.
This rare low-temperature rain, snow and freezing disaster was mainly caused by four weather processes, which occurred in 65438+ 10/0/6, 18-22 and 25-29, 3 1 2 February.
Low temperature, rain, snow and freezing weather lasts for a long time, and the number of rain and snow days in the middle and lower reaches of the Yangtze River and Guizhou is the highest since 1954/55. The number of frozen days is the second highest in the same period in history.
Among them, the freezing rain and snow weather in Hunan and Hubei provinces has the longest duration and the most serious impact since 1954, and the freezing rain and snow weather duration in 43 counties (cities) in Guizhou has exceeded the historical record.
There is 30-50 cm of snow in Jianghuai and other places, and the diameter of wire icing in Guizhou and Hunan is 30-60 mm.
Generally speaking, this meteorological disaster has the characteristics of wide range, high intensity, long duration and heavy disaster impact. Many areas return once every 50 years, and some areas return once every 100 years, which is rare in history.
Wide range.
The continuous freezing rain and snow has affected 20 provinces (autonomous regions and municipalities) such as Guizhou, Hunan, Hubei, Anhui, Jiangxi, Guangxi, Chongqing, Guangdong, Zhejiang, Fujian, Sichuan, Shaanxi, Jiangsu, Yunnan, Gansu, Henan, Qinghai, * * *, Shanxi and Shanghai.
High strength.
Since 65438+1October 10, the precipitation in six provinces of Henan, Sichuan, Shaanxi, Gansu, Qinghai and Ningxia has reached the maximum value in the same period since 195 1.
The minimum temperature in the middle and lower reaches of the Yangtze River dropped to -6-0℃, and the daily maximum temperature was close to the minimum temperature.
The average daily temperature in Wuhan and Changsha has been close to or below 0℃ for more than half a month. The temperature in most parts of Hubei, Anhui, Jiangxi, Hunan and Guizhou is 2-4℃ lower than normal, and the temperature in central and eastern Hubei, most parts 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 cooling range in the south of the Yangtze River, south China and northwest China is 10-20℃, with the temperature in the northwest of south China exceeding 20℃.
The snowstorm in Zhejiang is the strongest since 1984, and the snow depth in parts of Anhui and Jiangsu has reached the extreme value in recent 50 years.
The duration is long.
From 65438+February 2007 1 to 65438+20081October 3 1, the longest continuous days in the middle and lower reaches of the Yangtze River (Jiangsu, Anhui, Hubei, Hunan, Jiangxi, Shanghai) and Guizhou are less than 1℃. The number of rainy and snowy days in the middle and lower reaches of the Yangtze River and Guizhou exceeded 1.954/55 years, the highest in the same period in history. The number of frozen days is close to 1954/55 years, which is the second largest in the same period in history.
Among them, the freezing rain and snow weather in Hunan and Hubei provinces has the longest duration and the most serious impact since 1954.
This disaster has a great impact.
The continuous low temperature, rain, snow and freezing weather has caused great disasters to 20 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 population reached more than 654.38 billion people, and the direct economic loss reached more than 40 billion yuan. The affected area of crops and direct economic losses,
Second, there have been similar meteorological disasters in the world recently.
It is an indisputable fact that the global climate continues to warm. In this context, the world is in a period of frequent extreme weather and climate events, including frequent attacks of extreme snow disasters and freezing disasters.
From 29 June to 3 1 year129 October, 65438, an extremely rare strong snowstorm hit the countries in the eastern Mediterranean, which are famous for their warm climate. The thickness of snow on the border between Syria and Lebanon exceeds 1 m, and strong winds set off huge waves as high as 10 m in the Mediterranean Sea. Bad weather caused domestic flights in Israel to be grounded, and dozens of people froze to death on the streets.
654381October 8, Iran was affected by the biggest snowfall in more than ten years. At least 2 1 person was killed and 88 people were injured when the snow was 55 cm thick in the northern and central areas.
65438+1In mid-October, Afghanistan suffered a rare nationwide continuous snowfall, which triggered a snowstorm. In some areas, the snow was as deep as 2 meters, and more than 60 people died in mountain avalanches and traffic accidents.
In addition, on June 5438+1October 1 1 day, the first snow fell in Iraq since June 5438+000.
165438+ From the end of last year 10 to the beginning of 65438+February, the ridge of high pressure along the northwest coast of North America developed abnormally, causing the cold air in the Arctic to erupt southward and meet with the air flow in the warm and humid zone on the south side of the subtropical high, leading to snowstorms hitting the midwest and northeast of the United States and eastern Canada. As a result, some airports in the United States were closed, flights were delayed or cancelled, and road traffic was paralyzed. The thickness of snow in northern Maine reaches 5 1 cm.
On June 5438+1mid-October, 2007, the western, central and northeastern parts of the United States were affected by snowstorms and severe cooling, and 680,000 households or shops lost power and 65 people were killed in bad weather.
At the same time, on June 5438+1October17-June 5438+08, a strong storm "Cyril" swept across northern Europe, which seriously affected Britain, France, Belgium, Germany, the Netherlands, Poland, the Czech Republic, Hungary and other countries, causing at least 47 deaths and causing large-scale disasters.
The intensity and scope of this disaster and its casualties are rare in northern Europe in recent years.
3. Abnormal atmospheric circulation and La Nina events are the main causes of meteorological disasters.
The abnormal atmospheric circulation in recent 20 days is the fundamental cause of this large-scale low-temperature rain, snow and freezing disaster.
The recent atmospheric circulation anomalies are mainly manifested in four aspects: First, since June 65438+ 10 this year, the atmospheric circulation in the middle and high latitudes in Europe and Asia has been high in the west and low in the east. This abnormal circulation pattern has lasted for 19 days, which is more than three times of the climatic conditions for many years, and it is also the longest duration since June 195 1, which is conducive to the cold air in the northwest going down the southwest along the river.
Secondly, the subtropical high in the northwest Pacific is stronger to the north, and the position of the strong subtropical high is stably maintained over the ocean on the southeast side of China, and it extends to the west many times, so that the main area where cold and warm air meet is located in the middle and lower reaches of the Yangtze River and its south.
Thirdly, the low-pressure trough in the southern branch of the southern margin of the Qinghai-Tibet Plateau is active, which is rare in recent ten years, prompting warm and humid air to be continuously transported to China along the Yunnan-Guizhou Plateau.
Fourthly, at the junction of cold and warm air, warm and humid air is located in the upper part, forming a stable inversion layer in the middle and lower troposphere, which is the main reason for the occurrence of large-scale freezing rain.
The above stable abnormal situation combination of atmospheric circulation has been maintained for more than 20 days since mid-June 65438+1early October, resulting in a rare large-scale continuous low-temperature rain, snow and freezing weather in eastern China.
La Nina incident contributed to the occurrence and development of this disaster.
Since entering La Nina state in August 2007, the SST in the equatorial Middle East Pacific has developed rapidly, and by June 2008, the SST has been lower than 0.5℃ for six consecutive months.
The analysis shows that this La Nina event has the fastest development since 195 1 year and the strongest cumulative intensity in the first six months.
Since the beginning of winter, the abnormal distribution characteristics of precipitation in China are very similar to the winter climate characteristics after the strong La Nina event in history.
This situation shows that this round of La Nina event is one of the important reasons that affect the large-scale continuous low-temperature rain, snow and freezing disaster in eastern China.
Fourth, the weather in the disaster area has improved in stages in the later period, but it is still necessary to prevent low temperature rain, snow and freezing disasters.
According to the latest forecast results of the Central Meteorological Observatory, there will be a weak precipitation process in the southern region on February 4-5 this year. On June 6-9, most precipitation in the south will stop in stages, mainly sunny and hot weather, but the temperature is still low, and snow and freezing are still difficult to melt.
Therefore, we should continue to guard against the freezing disaster of low temperature rain and snow, and be alert to the influence of foggy weather after rain and snow.
Good weather in the north is conducive to transporting goods to the south.
Disaster areas should take advantage of the favorable opportunity of better weather to do a good job in coal, electricity and oil transportation, disaster relief and post-disaster recovery.
According to the deployment of the CPC Central Committee and the State Council, the meteorological department will further strengthen monitoring, forecasting, early warning and disaster impact assessment, actively and timely provide meteorological services to all levels, departments and the public, and make contributions to winning the final victory in disaster relief.