Does anyone have information about meteorology or lightning protection!!! It’s urgent!

People usually call lightning clouds thunderclouds. In fact, there are several types of clouds related to lightning, such as stratocumulus, nimbostratus, cumulus, and cumulonimbus. The most important ones are Cumulonimbus, generally the thundercloud mentioned in professional books refers to cumulonimbus.

The formation process of clouds is a process in which water vapor in the air reaches a saturated or supersaturated state through various reasons and condenses. Saturating the water vapor in the air is a necessary condition for the formation of clouds. The main methods are:

(1) The water vapor content remains unchanged and the air cools down;

(2) The temperature does not change Change, increase the water vapor content;

(3) Not only increase the water vapor content, but also reduce the temperature.

But for the formation of clouds, the cooling process is the most important process. In the cooling process, the cooling effect caused by rising motion is the most common.

Cumulonimbus is a cloud formed during strong vertical convection. Since the ground absorbs much more radiant heat from the sun than the air layer, the ground temperature rises more during the day, and this warming is more obvious in summer. Therefore, the temperature of the atmosphere near the ground also rises due to heat conduction and thermal radiation, and the gas temperature rises. The height will inevitably expand, the density will decrease, and the pressure will also decrease. According to the mechanical principles, it will rise. The density of the air layer above is relatively high, so it will sink. The hot air flow expands and depressurizes as it rises, and at the same time exchanges heat with the low-temperature air at high altitudes. As a result, the water vapor in the rising air mass condenses and fog droplets appear, forming clouds. During strong convection, the fog droplets in the clouds further cool down and turn into supercooled water droplets, ice crystals or snowflakes, which gradually increase with height. At the freezing altitude (-10 degrees Celsius), latent heat is released due to the freezing of a large amount of supercooled water, causing the cloud top to suddenly develop upward, reach near the tropopause and then spread in the horizontal direction to form a cloud anvil, which is a distinctive feature of cumulonimbus clouds.

During the formation of cumulonimbus clouds, under the simultaneous action of the atmospheric electric field, temperature difference charging effect, and fragmentation charging effect, positive and negative charges accumulate in different parts of the cloud. When the charge accumulates to a certain extent, a discharge will occur between clouds and clouds or between clouds and the ground, which is what people usually call lightning.

Thunder and lightning have brought heavy disasters to human society with their huge destructive power. Especially in recent years, lightning disasters have occurred frequently and the harm to the national economy has become increasingly serious. We should strengthen our awareness of lightning protection, actively cooperate with meteorological departments, and do preventive work to minimize lightning damage losses.

When human society enters the electronic information age, the characteristics of thunder disasters are greatly different from those in the past. They can be summarized as follows: (1) The disaster area has greatly expanded, from the two traditional fields of electricity and construction. Expanded to almost all industries, characterized by fields most closely related to high and new technologies, such as aerospace, national defense, postal and telecommunications, computers, electronics industry, petrochemical industry, financial securities, etc.; (2) From two-dimensional space invasion to three-dimensional space Invasion. From direct lightning strikes and overvoltage waves transmitted along the line to space lightning, pulsed electromagnetic fields invade from three-dimensional space to any corner, causing disasters everywhere. Therefore, lightning protection projects have evolved from direct lightning strikes and induction lightning to lightning electromagnetic pulse protection. (LEMP). The former refers to the expansion of the industries affected by lightning, and here refers to the expansion of the spatial scope of lightning disasters. For example, at about 14:40 on July 25, 2000, a lightning strike caused two units near Caobao Road and Guijing Road to be hit by lightning at the same time, instead of the previous lightning that only damaged one building. (3) The economic losses and harm caused by lightning disasters have greatly increased. The direct economic losses to the target itself are sometimes not too great, while the resulting indirect economic losses and impacts are difficult to estimate. For example, at 2 a.m. on August 27, 1999, a paging station was struck by lightning, causing the station to interrupt paging for several hours. The direct loss was limited, but the indirect loss would greatly exceed the direct loss. (4) The fundamental reason for the above characteristics, that is, the key characteristic is that the main targets of lightning disasters have been concentrated on microelectronic devices and equipment. Lightning itself has not changed, but the development of science and technology has changed the production and living conditions of human society. The application of microelectronics technology has penetrated into various fields of production and life. The extreme sensitivity of microelectronic devices is easily affected by the pervasive LEMP, causing the microelectronic equipment to lose control or be damaged.

For this reason, the importance, urgency, and complexity of lightning protection work in today's era have greatly increased. Lightning defense has changed from direct lightning protection to system protection. We must stand at a new height in the historical era. Come to understand and study modern lightning protection technology and improve mankind's comprehensive ability to defend against lightning disasters.

How do lightning strikes cause disasters?

Thunder and lightning is a weather phenomenon that often occurs in summer. Thunder disasters pose a huge threat to natural resources and the material civilization created by mankind. So how does lightning cause disaster?

First, lightning produces scorching high temperatures. When lightning occurs, a strong current passes through the object, generating huge heat in an instant. According to analysis, the temperature of the lightning current channel can reach 6000°C to 10000°C, sometimes even higher, which is enough to melt metal. If the lightning current channel encounters flammable substances, it may cause a fire. For example, from June to August 1989, Jinxi, Qinhuangdao, Huangdao and other oil depots were struck by lightning, causing multiple oil tanks to catch fire and explode, causing heavy losses.

The second is a violent shock wave: lightning causes the air near the lightning current channel to expand violently and spread around at the speed of ultrasonic waves. The relatively cold air on the periphery is strongly compressed, and the expansion and contraction of the air produces violent vibrations. This is the shock wave. Affected by the shock wave, the lightning current channel and the surrounding environment are similar to a bomb explosion, which is very destructive.

In addition, there is lightning induction. Lightning induction includes electrostatic induction and electromagnetic induction, which will produce induced high voltage. For buildings, if they are struck by lightning, their internal structures and poorly grounded metal devices are prone to sparks, which is very dangerous for warehouses storing flammable materials and can cause explosions. Finally, there is indirect lightning strike, which refers to a physical process in which high voltage and strong current exist between thunderstorm clouds and the earth. During lightning, an instantaneous strong current is introduced indoors through transmission cables, communication lines, telephone lines and metal pipes, or electromagnetic induction causes lightning strikes in computer networks, communication equipment and industrial control systems. Analysis of lightning strike data in recent years shows that the incidence rate of such accidents is high and the consequences are very serious. Therefore, wherever there are low-voltage electrical appliances and microelectronic equipment, precautions must be taken against indirect lightning strikes.

Lightning strikes caused by lightning are a common natural phenomenon in summer. The harm caused by lightning to humans is generally divided into three types: direct lightning strike, lightning wave intrusion and induced lightning strike. Direct lightning strike means that lightning directly hits buildings, trees, ground, lightning protection devices or human bodies. The direct lightning strike is accompanied by sound and light, which is aggressive and is known to people of all ages. Thunder wave intrusion refers to the effect of lightning on overhead lines and metal pipelines. Thunder waves may Invading the house along these pipelines, endangering personal safety or damaging equipment; induction lightning strikes occur quietly, are difficult to detect, and have serious consequences. Direct lightning strikes and induced lightning strikes damage different objects. Direct lightning strikes mainly damage buildings and transmission lines on the discharge path. , killing and injuring people and animals, etc. Induction mines mainly destroy electronic equipment. Recently, nearly a hundred computer Internet users and TV sets have been struck by lightning in our oil field, which was caused by induced lightning strikes and lightning wave intrusion. Experts remind that induced lightning strikes are on the rise, and 80% of lightning accidents are caused by them. However, people currently have a poor understanding of this hidden lightning disaster. Many people do not realize the need for protection and how to protect it. . In particular, many residential areas are basically blind spots in lightning protection work. The traditional concept of lightning protection that believed that lightning strikes can be avoided as long as lightning rods are installed on buildings needs to be changed. The focus of urban lightning protection should be on preventing "induced lightning strikes."

Induced lightning strikes are due to the electrostatic induction of thunderclouds or electromagnetic induction during discharge, which causes metal objects on buildings, such as pipes, steel bars, wires, reaction devices, etc., to induce charges opposite to those of the thunderclouds. , caused by discharge.

There are three main channels for an electronic equipment to attract induced lightning strikes: 1. Introduction of antennas and feeders; 2. Introduction of power lines; 3. Introduction of signal lines.

For the electronic equipment group in the building, there are six main channels for introducing induction mines: 1. The antennas, feeders, power lines, signal lines, and grounding wires of all electronic equipment in the building are Lightning entry channels of buildings; 2. Various power lines entering and exiting the building and "long" distance signal lines inside the building; 3. All metal pipes in buildings with public grounding, when direct lightning current flows When passing over it, the magnetic field eddy current generated around it induces a lightning shock wave on the metal surface; 4. When lightning discharges, the lightning shock wave is induced on the metal surface; 5. The high-level lightning impact of a building directly struck by lightning; 6. Lightning recoil current from buildings directly struck by lightning. This kind of current can enter its electronic equipment through the ground circuit of adjacent buildings, causing a discharge phenomenon between the casing and movement of the electronic equipment and causing damage.

Lu Ge specially reminded residents that when thunder strikes, turn off computers, TVs and other household appliances as much as possible, and unplug power plugs, signal lines, computer network cables, etc. to prevent lightning from power lines, signal lines, etc. Line intrusion can damage electrical appliances, cause fires or cause death by electrocution; try not to make phone calls during thunderstorms to reduce induced lightning current along the telephone lines and cause harm to people; do not use the outdoor antenna of the TV set. If lightning hits the TV antenna, it will It will be transmitted indoors along the TV antenna, threatening electrical appliances and personal safety. When thunder strikes, people should not stand under electric lights; do not open windows during thunderstorms to prevent spherical lightning from entering the house; sticking your head out of the window or touching the metal frame of the window with your hands may be struck by lightning; use it to dry clothes, bedding, etc. Do not pull the iron wire to windows, doorways, or lightning protection down wires to prevent the iron wire from drawing lightning into the room. If lightning protection measures are taken properly, the damage caused by lightning strikes will be greatly reduced.

Answer: Ah Chan - Juren Level 4 3-17 13:47

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