China News Agency, Beijing, May 15 (Reporter Chen Su) Recently, strong convective weather has occurred in many parts of China, and tornadoes have appeared in some areas, causing casualties.
On the 15th, the Central Meteorological Observatory upgraded and issued a yellow warning of strong convection.
Why do strong convective weather occur frequently recently?
Why is there a tornado?
Why is it difficult to predict a tornado?
Meteorological experts gave an authoritative interpretation of this.
From May 10th to 12th, a large-scale severe convective weather affected parts of the middle and lower reaches of the Yangtze River in China, and "heavy rains were like notes" in many places.
Later, from the 14th to the 16th, another round of severe convective weather struck. This time the impact was wider. Some areas suffered extreme disasters such as tornadoes and hail. On the evening of the 14th, a tornado occurred in Hubei and Jiangsu, causing many casualties.
Why is there a high incidence of strong convective weather?
Zhang Tao, chief forecaster of the Central Meteorological Observatory, said in an interview with reporters that China has entered a period of high incidence of strong convection, and the types are complex and mixed, including wind and rain, thunder and lightning, extreme winds, extreme precipitation, tornadoes, etc. After mid-April, severe convective weather has increased significantly , And its position moved northward relative to before mid-April, mainly in the middle and lower reaches of the Yangtze River.
Why is it difficult to achieve early warning and early detection of tornadoes?
Zhang Tao said that a tornado is a rare local, small-scale, and sudden severe convective weather. It is a strong, small-scale air vortex caused by air convection under extremely unstable weather conditions. Spin.
In addition to the conditions for strong convection, the occurrence of tornadoes also requires strong low-level jets, which greatly increases the probability of tornadoes.
"Because the scale of tornadoes is very small, this means that the probability of tornadoes being caught by meteorological observatories is small. From the perspective of monitoring and forecasting, it is very difficult to monitor tornadoes both at home and abroad. Forecast and early warning of tornadoes It is a worldwide problem."
Statistics show that spring and summer are the frequent seasons of tornadoes in China. The plain areas are relatively high-incidence areas. The middle and lower reaches of the Yangtze River Plain, the Pearl River Delta, the Northeast Plain, and the North China Plain are all areas where tornadoes occur frequently.
Zhang Tao said that the characteristics of tornadoes determine the difficulty of forecasting and warning.
At present, the possibility of tornadoes is capable of early forecasting. However, some relatively accurate forecasts and warnings of when and where to occur can reach the minute level, and some are completely impossible to forecast. This depends on the strength of the tornado itself. And the relative distance to the radar station network.
The stronger the strength and the closer the distance to the radar station network, the greater the chance of making forecasts and warnings.
On the morning of the 15th, the Central Meteorological Observatory upgraded and issued a yellow warning of strong convection.
Zhang Tao said that tornadoes generally occur in plain areas, and plain areas are densely populated areas. Special attention should be paid to prevent and respond.
He said that in the long time before the tornado, the weather forecast will have a more reliable prediction of the strong convective weather that is the background of the tornado. The follow-up nowcast warning should be paid more attention to, and when the attention is issued a few minutes to a few hours ago When nearby forecasting and early warning, you should reduce your going out and avoid strong convective weather and possible tornadoes in a safe place; when you are already facing the threat of a tornado, if you are outdoors, you should observe the tornado dynamics and avoid its path in time. If you are indoors, Keep away from doors, windows and the outer walls of houses, hide in a relatively strong, permanent reinforced concrete structure building and squat down. The safest place is the basement or semi-basement; in emergencies such as the collapse of electric poles and the collapse of houses Under the circumstances, the power should be cut off in time to prevent electric shock to the human body or cause fire; when you are going out in a car and encounter a tornado, don't hide in the car, you should leave the car immediately and take shelter in low-lying areas.
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