Is the cold wave coming?

Strong cold air in the north broke out in the south, and there was severe cooling and windy weather in the path. When the temperature drops to a certain standard, it is called a cold wave. China Meteorological Bureau defines a cold wave as: within 24 hours, the average temperature drops by more than 10℃, and the lowest temperature reaches below 5℃. China has a vast territory and complex terrain, and the climate varies greatly from place to place. Therefore, local meteorological stations can also formulate cold wave standards in their own regions according to local climate characteristics.

The main reason for the cold wave weather is that in the Arctic, due to the weak sunlight, the ground and the atmosphere get less heat, and it snows all the year round. In winter, the direct sunlight passes through the equator and reaches the southern hemisphere. The arctic region is colder and wider, and the temperature is generally below MINUS 40℃-50℃. Large-scale cold air masses gather to a certain extent, and under the action of suitable high-altitude circulation, they will invade southward on a large scale, forming cold wave weather.

Cold wave and strong cold air usually bring strong winds and cool weather, which is the main disastrous weather in winter half a year in China. Cold waves and strong winds are a great threat to coastal areas, such as the cold wave on April 2 1 ~ 25, 1969. Strong winds hit the Bohai Sea, the Yellow Sea and Hebei, Shandong, Henan and other provinces, with land winds of 7 ~ 8 and offshore winds of 8 ~ 10. At this time, the astronomical tide was just right, and the outbreak of cold wave caused the rare storm surge in Bohai Bay and Laizhou Bay for decades. On the northern shore of Shandong Province, the sea water rose by more than 3 meters, washed away the seawall by more than 50 kilometers, and the sea water flowed backwards for 30 ~ 40 kilometers.

The outbreak of cold wave has different characteristics in different geographical environments. In the northwest desert and loess plateau, it is characterized by less wind and snow, which is easy to cause sandstorm weather. In Inner Mongolia grassland, it is windy, snowy and cold. In North China and Huanghuai areas, cold waves are often accompanied by snow and snow. In the northeast, it shows more violent winds and heavy snow, and the snowfall is the highest in the country. Jiangnan is often accompanied by freezing rain.

The freezing rain, snow and ice weather brought by the cold wave is extremely harmful to transportation. For example, 1987 1 1 A cold wave process in the last ten days caused the turnouts of several stations under the jurisdiction of Harbin, Shenyang, Beijing and Urumqi to freeze, the tracks were buried by snow, the communication signals failed, and the train operation was blocked. After the rain and snow, the roads were frozen and skidded, and traffic accidents increased obviously. Cold wave is very harmful to human health. The windy and cool weather can easily lead to colds, tracheitis, coronary heart disease, cor pulmonale, stroke, asthma, myocardial infarction, angina pectoris, migraine and other diseases, and sometimes make patients worse.

Cold wave is a kind of disastrous weather, which brings great harm to society. Once the meteorological station issued a cold wave warning, people should pay attention.