tornado
In early August 1982, two consecutive weeks of torrential rains and typhoons raged, and the ocean was everywhere. Many reservoirs and dams were dangerous, and even the flood storage area along the Huai River also exploded the dams. All the cadres of the organs went down to the front line of flood control. Late that night, 30 miles west of the place where the hail had appeared in the previous year, a small mountain village with only a dozen families was hit by a terrible tornado. It was raining heavily, the wind was blowing, and everyone was sleeping at home, when they were suddenly awakened by the sound of thunder. Immediately after the house collapsed. Less than half an hour before and after. At that time, there were flood control cadres stationed in the village, and immediately led the village cadres to organize all the villagers to move to a high place on the mountain. Then send someone to the township government to report on the situation. After dawn, the relevant leaders and meteorological experts in the districts, townships, and counties rushed to the site of the tornado accident. Specifics: There were no casualties, only one villager in the center of the village had a large hole in the roof of the house, the rest of the houses collapsed, and the entire village was destroyed. No one saw what the tornado looked like at that time. Later, some superstitious legends began. It is said that there is a dragon under the ground where the roof has a hole, because the house built on it presses the dragon, so the dragon is angry and rushes out, so the big hole will appear in his house. Later, when the whole village was rebuilding after the disaster, the family was moved elsewhere. Later, when I took a meteorological class, I realized that the original tornado was a meteorological disaster.
. First, the formation of tornadoes requires four conditions: one is flat ground or water, the second is strong convective weather, the third is strong winds, and the fourth is that the air is relatively humid. In summer, the air temperature near the ground is higher, while the temperature at high altitude is lower. The hot air on the ground will move upwards, while the cold air at high altitude will move downwards. This movement sometimes causes the air to spin and spin faster and faster. This creates a tornado. The specific formation process is as follows:
First, the instability of the atmosphere produces a strong updraft, which is further strengthened due to the influence of the maximum transit airflow in the rapids . Second, due to interaction with winds that are sheared in both velocity and direction vertically, updrafts begin to rotate in the middle of the troposphere, forming mesoscale cyclones.
Third, as the mesoscale cyclone develops and extends upward toward the ground, it itself thins and strengthens. At the same time, a small area of reinforcement, that is, the formation of an initial tornado inside the cyclone, produces the same process of cyclone, forming the core of the tornado.
Fourth, the rotation in the core of the tornado differs from that in a cyclone, and it is strong enough to stretch the tornado all the way to the ground. When the developing vortex reaches the height of the ground, the ground air pressure drops sharply and the ground wind speed rises sharply, forming a tornado.
Second, the tornado is extremely destructive, its life history is short, but its destructive power is amazing. It can uproot large trees, blow down buildings, or roll parts of the ground into the air. Specific grade Estimated wind speed (m/s) Typical tornado damage levels are as follows:
F0 < 33 Mild damage damage to the chimney; Scraping branches; Uproot shallow-rooted trees; Destroy shop signs.
F1 33-50 Moderate damage Lift roof tiles; Scratching or flipping mobile homes; The moving car is scraped off the road.
F2 51-70 More severe damage scraping off the roof; Demolition of mobile homes; Overturning train cars; Uprooting trees; Light objects fly wildly in the air; The car was swept off the ground.
F3 71-92 Severe damage The roof and walls of fortified houses are scraped off; Overturning the train; Most of the trees in the forest are uprooted; Heavy vehicles were swept off the ground and thrown.
F4 93-116 Devastating destruction Solid houses razed to the ground; Buildings with poor foundations are scraped away; Cars were thrown into the air, and large objects flew in the air.
F5 117-142 Extreme destruction Solid house frame scraped away; Car-sized objects fly more than 100 meters in the air; Flying debris hanging from the treetops; Unbelievable phenomena arise.
Third, the most mysterious part of the tornado is the eye of the tornado, which is also the most powerful place. The eye of a tornado is the very center of a tornado.
Wind speeds near the center of the tornado can reach 100m/s to 200m/s, and the maximum is 300m/s, which is several times larger than the maximum wind speed near the center of the typhoon. The central air pressure is very low, generally as low as 400 hPa, as low as 200 hPa. Therefore, the tornado is a rapidly rotating object (such as a stick) moving, due to the action of centrifugal force, it has a great sucking effect, can suck the sea (lake) water away from the sea (lake) surface, forming a water column, and then connected with the clouds, commonly known as "dragon water". So, the roof of the house in the eyes of the tornado was sucked off. It wasn't the dragon that rushed off.
