1995年在美国俄克拉何马州阿得莫尔市发生的一场陆龙卷，诸如屋顶之类的重物被吹出几十英里之远。大多数碎片落在陆龙卷通道的左侧，按重量不等常常有很明确的降落地带。较轻的碎片可能会飞到300多千米外才落地。
龙卷的袭击突然而猛烈，产生的风是地面上最强的。在美国，龙卷风每年造成的死亡人数仅次于雷电。它对建筑的破坏也相当严重，经常是毁灭性的。
在强烈龙卷风的袭击下，房子屋顶会像滑翔翼般飞起来。一旦屋顶被卷走后，房子的其他部分也会跟着崩解。因此，建筑房屋时，如果能加强房顶的稳固性，将有助于防止龙卷风过境时造成巨大损失
龙卷风的防范措施
(1) 在家时，务必远离门、窗和房屋的外围墙壁，躲到与龙卷风方向相反的墙壁或小房间内抱头蹲下。躲避龙卷风最安全的地方是地下室或半地下室。
(2) 在电杆倒、房屋塌的紧急情况下，应及时切断电源，以防止电击人体或引起火灾。
(3) 在野外遇龙卷风时，应就近寻找低洼地伏于地面，但要远离大树、电杆，以免被砸、被压和触电。
(4) 汽车外出遇到龙卷风时，千万不能开车躲避，也不要在汽车中躲避，因为汽车对龙卷风几乎没有防御能力，应立即离开汽车，到低洼地躲避。
在1999年5月27日，美国得克萨斯州中部，包括首府奥斯汀在内的 4个县遭受特大龙卷风袭击，造成至少32人死亡，数十人受伤。据报道，在离奥斯汀市北部40英里的贾雷尔镇，有50多所房屋倒塌，已有30多人在龙卷风丧生。遭到破坏的地区长达 1英里，宽200码。这是继5月13日迈阿密市遭龙卷风袭击之后，美国又一遭受龙卷风的地区。
一般情况下，龙卷风是一种气旋。它在接触地面时，直径在几米到1公里不等，平均在几百米。龙卷风影响范围从数米到几十上百公里，所到之处万物遭劫。龙卷风漏斗状中心由吸起的尘土和凝聚的水气组成可见的“龙嘴”。在海洋上，尤其是在热带，类似的景象在发生称为海上龙卷风。
大多数龙卷风在北半球是逆时针旋转，在南半球是顺时针，也有例外情况。卷风形成的确切机理仍在研究中，一般认为是与大气的剧烈活动有关。
从19世纪以来，天气预报的准确性大大提高，气象雷达能够监测到龙卷风、飓风等各种灾害风暴。
龙卷风通常是极其快速的，每秒钟100米的风速不足为奇，甚至达到每秒钟175米以上，比12级台风还要大五、六倍。风的范围很小，一般直径只有25~100米，只在极少数的情况下直径才达到一公里以上；从发生到消失只有几分种，最多几个小时。
龙卷风的力气也是很大的。1956年9有24日上海曾发生过一次龙卷风，它轻而易举地把一个22万斤重的大储油桶“举”到15米高的高空，再甩到120米以外的地方。
龙卷风在美国又叫旋风，是常见的自然现象。旋风的破坏力往往超过地震。
1879年5月30日下午4时，在堪萨斯州北方的上空有两块又黑又浓的乌云合并在一起。15分钟后在云层下端产生了旋涡。旋涡迅速增长，变成一根顶天立地的巨大风柱，在三个小时内像一条孽龙似的在整个州内胡作非为，所到之处无一幸免。但是，最奇怪的事是发生在刚开始的时候，龙卷风旋涡横过一条小河，遇上了一座峭壁，显然是无法超过这个障碍物，旋涡便折抽西进，那边恰巧有一座新造的75米长的铁路桥。龙卷风旋涡竟将它从石桥墩上“拔”起，把它扭了几扭然后抛到水中。
龙卷风的探测
龙卷风长期以来一直是个谜，正是因为这个理由，所以有必要去了解它。龙卷风的袭击突然而猛烈，产生的风是地面最强的。由于它的出现和分散都十分突然，所以很难对它进行有效的观测。
龙卷风的风速究竟有多大？没有人真正知道，因为龙卷风发生至消散的时间短，作用面积很小，以至于现有的探测仪器没有足够的灵敏度来对龙卷风进行准确的观测。相对来说，多普勒雷达是比较有效和常用的一种观测仪器。多普勒雷达对准龙卷风发出的微波束，微波信号被龙卷风中的碎屑和雨点反射后重被雷达接收。如果龙卷风远离雷达而去，反射回的微波信号频率将向低频方向移动；反之，如果龙卷风越来越接近雷达，则反射回的信号将向高频方向移动。这种现象被称为多普勒频移。接收到信号后，雷达操作人员就可以通过分析频移数据，计算出龙卷风的速度和移动方向。
1995年在美国俄克拉何马州阿得莫尔市发生的一场陆龙卷，诸如屋顶之类的重物被吹出几十英里之远。大多数碎片落在陆龙卷通道的左侧，按重量不等常常有很明确的降落地带。较轻的碎片可能会飞到300多千米外才落地。
龙卷的袭击突然而猛烈，产生的风是地面上最强的。在美国，龙卷风每年造成的死亡人数仅次于雷电。它对建筑的破坏也相当严重，经常是毁灭性的。
在强烈龙卷风的袭击下，房子屋顶会像滑翔翼般飞起来。一旦屋顶被卷走后，房子的其他部分也会跟着崩解。因此，建筑房屋时，如果能加强房顶的稳固性，将有助于防止龙卷风过境时造成巨大损失。
龙吸水：龙卷风的别名。龙卷风，因为与古代神话里从波涛中窜出、腾云驾雾的东海跤龙很相象而得名，它还有不少的别名，如“龙吸水”、“龙摆尾”、“倒挂龙”等等。
龙卷风的特点
龙卷风是大气中最强烈的涡旋现象，影响范围虽小，但破坏力极大。它往往使成片庄稼、成万株果木瞬间被毁，令交通中断，房屋倒塌，人畜生命遭受损失。龙卷风的水平范围很小，直径从几米到几百米，平均为250米左右，最大为1千米左右。在空中直径可有几千米，最大有10千米。极大风速每小时可达150千米至450千米，龙卷风持续时间，一般仅几分钟，最长不过几十分钟，但造成的灾害很严重。
龙卷风常发生于夏季的雷雨天气时，尤以下午至傍晚最为多见。袭击范围小，龙卷风的直径一般在十几米到数百米之间。龙卷风的生存时间一般只有几分钟，最长也不超过数小时。风力特别大。破坏力极强，龙卷风经过的地方，常会发生拔起大树、掀翻车辆、摧毁建筑物等现象，有时把人吸走，危害十分严重。
1995 in the United States Oklahoma State in the Afghan city of Mohr a LU Long volumes, such as heavy objects like the roof was Chuichu dozens of miles away. Most debris landed LU Long Volume channel to the left, by weight often have very clear from the landing zone. Lighter debris may reach over 300 kilometers, before landing.
Tornado sudden and violent attacks, the wind is the strongest on the ground. In the United States, tornadoes a year after the number of deaths caused by lightning. It also damaged the building very serious, often devastating.
Strong tornadoes in the attacks, the roof of the house, like hang gliding as fly. Once the roof was swept away, other parts of the house will follow the collapse. Therefore, housing construction, if we can strengthen the roofs of stability, will help prevent the transit when the tornado caused huge losses
Tornado preventive measures
(1) at home, be sure to stay away from doors, windows and external walls of the housing, and the tornado躲到the opposite direction of the wall or small room in Baotou squat. Tornado avoid the safest place is the basement or semi-basement.
(2) in pole down, the collapse of an emergency situation should be promptly cut off power to prevent electric shock or fire the human body.
(3) opposition tornado extramarital affairs, they should find the nearest low-lying and V on the ground, but to stay away from trees, poles, so as not to Piza, the pressure and electric shock.
(4) vehicle encountered on tornadoes, should not avoid driving, do not avoid the car, because almost no cars on the Tornado defense capability, should immediately left the car, the low-lying places to avoid.
In the May 27, 1999, the United States in Central Texas, in Austin, including the four counties suffered major tornado attacks, killing at least 32 people were killed and dozens were injured. According to reports, from the Austin, 40 miles north of the town of Jarrell, more than 50 houses collapsed and more than 30 people have been killed in the tornado. The damaged areas up to 1 miles, 200 yards wide. This is the May 13 Miami by tornadoes after the attacks, the United States suffered another tornado areas.
Under normal circumstances, the tornado is a cyclone. In contact with the ground, the diameter ranging from a few meters to one kilometer, on average several hundred meters. Tornado from the affected area a few metres to tens of hundreds of kilometers, everything went looting. Tornadoes, funnel-shaped center by suction from the dust and condensation of water vapor that formed the "dragon mouth." In the ocean, particularly in the tropics, a similar scene in the event of sea known as tornadoes.
Most tornadoes in the northern hemisphere is counter-clockwise rotation, is clockwise in the Southern Hemisphere, there are exceptions. Volume winds formed the exact mechanism is still in the research, and the atmosphere is generally believed that the intense activities.
From the 19th century, GREatly enhance the accuracy of weather forecasts, weather radar capable of monitoring to cyclones, hurricanes and other disasters turmoil.
Tornado is usually extremely fast, with winds of 100 meters per second is not surprising, even to more than 175 meters per second, compared to 12 typhoons a five, six times. The scope of small wind, the general diameter of only 25 to 100 meters, only a very small number of cases to reach one kilometer in diameter or more from a loss only to a fraction of up to several hours.
Tornado strength is also GREat. 1956 September 24, Shanghai had been a tornado, it easy to bring a heavy burden of the 220,000 large reservoir oil drums "give" to a height of 15 meters high, then Shuaidao 120 meters outside the local.
Tornadoes in the United States known as cyclones, is a common natural phenomenon. Cyclones often more than the destructive earthquake.
At 16:00 on May 30, 1879, in Kansas over the North Youhei You have two thick clouds combined. After 15 minutes in the bottom of the clouds produced a vortex. Vortex of rapid growth and become an indomitable spirit, in the GREat wind, in three hours as a Nielong similar abuses throughout the state, went Wuyixingmian. However, the most surprising thing happened in the beginning when the tornado vortex of a river crossing, an event of a cliff, is clearly not over this barrier, then pack vortex pumped into the West, there happen to have a new 75 Metre-long railway bridge. Jingjiang tornado vortex from the stone pier on it, "Stubbs", it twisted and then thrown a few twisting water.
Tornado detection
Tornado has long been a mystery precisely because of this reason, it is necessary to understand it. Tornado sudden and violent attacks, the wind is the strongest ground. Because of its dispersed and there are very suddenly, it is difficult it was effective observation.
Tornado winds Just how » No one really knows, because tornadoes in the short time to disperse, the role of small size, so the existing detection equipment do not have enough sensitivity to the tornado accurate observation. Relatively speaking, Doppler radar is more effective and a common observation equipment. Doppler radar at the tornado's microwave beam, microwave signal was in the tornado and debris rained reflection after being re-radar receivers. If the tornado hit away from the radar, reflecting back to the low-frequency microwave signal frequency will be moving the contrary, if the tornado increasingly close to the radar, reflecting back to the high frequency signal to move. This phenomenon is known as the Doppler frequency shift. After receiving the signal, the radar operators can shift through the analysis of data, calculated the speed of tornadoes and direction of movement.
1995 in the United States Oklahoma State in the Afghan city of Mohr a LU Long volumes, such as heavy objects like the roof was Chuichu dozens of miles away. Most debris landed LU Long Volume channel to the left, by weight often have very clear from the landing zone. Lighter debris may reach over 300 kilometers, before landing.
Tornado sudden and violent attacks, the wind is the strongest on the ground. In the United States, tornadoes a year after the number of deaths caused by lightning. It also damaged the building very serious, often devastating.
Strong tornadoes in the attacks, the roof of the house, like hang gliding as fly. Once the roof was swept away, other parts of the house will follow the collapse. Therefore, housing construction, if we can strengthen the roofs of stability, will help prevent the transit when the tornado caused huge losses.
Long-absorbent: Tornado alias. Tornadoes, as with ancient mythology, from the waves of Cuanchu, mood-elevating the East China Sea Jiao Long was named Xiang Xiang, there are many aliases, such as "water dragon", "Long pendulum tail", "Long inversion" And so on.
The characteristics of tornado
Tornadoes in the atmosphere is the strongest vortex phenomenon, the affected area is small, but GREat destructive power. It often makes a film crops, as the destruction of 10,000 Ceriops tagal moment, traffic disruption, homes, life for people and livestock losses. Tornado levels of the small diameter from a few meters to several hundred meters, with an average of about 250 meters, the largest of about 1 km. In the air can have Jiqian Mi diameter, the largest of 10 km. Great winds up to 150 kilometers per hour to 450 km, tornadoes duration, generally only a few minutes, the longest But dozens of minutes, but the disaster is very serious.
Tornadoes often occur in the summer lightning storm, especially in the afternoon to the evening most common. The scope of small attacks, tornadoes in the general diameter of 10 meters to 100 meters between. The tornado survival time normally only a few minutes, the longest more than a few hours. Wind particularly large. Extremely destructive, after the tornado, uprooted trees often happens, overturned vehicles, destroyed buildings, and other phenomena, sometimes people take suction, very serious harm.
