What are the meteorological disasters, what are their characteristics and early warning signals?

Rainstorm is a short-term or continuous heavy precipitation process. In low-lying and blocked areas, rainwater cannot be discharged quickly, resulting in water accumulation in farmland and supersaturation of soil moisture, which brings disasters to agriculture. Heavy rain may even cause flash floods, river flooding and dam break, causing huge economic losses to the people and the country. According to the regulations of China Meteorological Department, the rain with a precipitation of more than 50 mm in 24 hours is called "rainstorm". The Yangtze River basin is a frequent area of rainstorm and flood disasters, especially in the two lakes basin and the Yangtze River Delta. 1983, 1988, 199 1, 1998, 1999.

Tropical cyclone (typhoon), tropical cyclone is the general name of strong vortex with high center temperature and low pressure formed in tropical marine atmosphere. It is a very destructive weather phenomenon, which will lead to severe weather such as strong winds, heavy rains, huge waves and storm surges. The average annual loss is more than10 billion yuan. For example, Yunna, who landed in Zhejiang in 2004, created10 billion at a time.

Wind hail, wind hail disaster refers to the disaster caused by the condensation of ice in cumulonimbus clouds falling from the air under the control of convective weather. Hail often destroys large areas of crops and orchards, damages buildings and threatens human safety. It is a serious natural disaster, which usually occurs in summer and autumn. According to statistics, the area affected by agricultural wind and hail reached more than 99 million mu in severe disaster year (1993) and 56 million mu in light disaster year (1994).

Low-temperature freezing, low-temperature freezing disaster is mainly an agrometeorological disaster caused by the invasion of cold air and cold wave, which leads to crop damage and yield reduction. In the years of severe freezing injury, such as 1968, 1975, 1982, the area of seedlings killed by freezing injury reached more than 20%. 1977 65438+1From October 25 to 29, a strong cold wave made the snow in Inner Mongolia and Xinjiang as deep as 0.5 meters, the grasslands were buried, and a large number of livestock died.

Blizzard, a natural phenomenon of large-scale snowstorm caused by long-term heavy snowfall. Hazards include: seriously affecting or even destroying lifeline projects such as transportation, communication and transmission lines, which have a great impact on people's production and life. On June 5438+February, 2005, Weihai and Yantai in Shandong suffered the biggest snowstorm in 40 years, with direct economic loss of 37 1.43 billion yuan.

2. What are the characteristics of meteorological disasters?

(1) There are many kinds of meteorological disasters. Other disasters mainly include rainstorm, flood, drought, tropical cyclone, frost and low temperature, wind and hail, continuous rain and fog, sandstorm and so on. If subdivided, it can reach dozens or even hundreds.

(2) Meteorological disasters are widespread. Meteorological disasters can occur all year round; Whether in mountainous areas, plains, plateaus, islands, rivers, lakes, oceans and air, meteorological disasters are everywhere.

(3) The frequency of meteorological disasters is high. During the 38 years from 1950- 1988, China experienced various disasters every year, with an average of 7. Five droughts, 5.8 floods and 6.9 tropical cyclones landed in China.

(4) Meteorological disasters last for a long time.

For example, 195 1- 1980, and the drought year in North China is 14.

5] The mass is outstanding.

Some disasters often occur in many areas at the same time. Thunderstorms, hail, strong winds, tornadoes and other strong convective weather often appear in groups from March to May every year. On April 22nd, 1972, 15-22, 16, more than 350 counties and cities in Liaoning to Guangdong * * successively experienced hail, and some areas experienced meteorological disasters such as gale and tornado above 10.

[6] The chain reaction of meteorological disasters is remarkable.

Weather and climatic conditions often trigger or aggravate natural disasters such as floods, mudslides, pests and diseases, resulting in continuous response.

Once the meteorological disaster is serious. According to 1947- 1980 published by the United Nations, the number of deaths caused by natural disasters in the world reaches 12 13000, of which 6 1% is caused by meteorological disasters.

3, meteorological disaster warning signal

Looking back at the severe meteorological disasters in the history of China, it is found that drought, rainstorm, flood and typhoon caused by tropical cyclones are the most common and serious disasters in China. Among meteorological disasters, drought is also the biggest and most serious disaster in China. Drought is characterized by a wide range, a long time and a far-reaching impact. Therefore, drought is also one of the most serious meteorological disasters in China. In China, rainstorm and flood disasters are the meteorological disasters second only to drought. In addition, lightning, sandstorm, frost, hail, fog and other disasters are also frequent and harmful meteorological disasters in China.

In 2008, a huge snowstorm happened in China. In this snowstorm, China exposed several weak links in meteorological disaster prevention:

First, the detection range, accuracy and spatial-temporal resolution of the existing comprehensive monitoring of meteorological disasters can not meet the requirements of meteorological disaster prevention and mitigation; Secondly, although the meteorological department has made a more accurate forecast of every disaster process of low temperature, rain, snow and freezing weather since June 5438+ 10/0, it has not predicted the persistence and intensity of disastrous weather, nor has it pre-evaluated the impact of transportation, electricity and other industries. Third, the prevention of meteorological disasters needs to strengthen departmental cooperation and information sharing, especially after the release of early warning information, social linkage, departmental coordination and effective response are not enough; Fourth, the channels and means of early warning information release can not meet the needs of the public, the coverage of early warning information is not wide enough, and the public lacks disaster prevention awareness and scientific knowledge.