What atmospheric natural phenomena are considered dangerous. Hazardous atmospheric phenomena

Science

The earth's atmosphere is a source of amazing and amazing phenomena. In ancient times, atmospheric phenomena were considered to be manifestations God's will, today someone takes them for aliens. Nowadays, scientists have uncovered many secrets of nature, including optical phenomena.

In this article we will tell you about amazing natural phenomena, some of them are very beautiful, others are deadly, but all of them are an integral part of our planet.

Atmospheric phenomena

A lunar rainbow, also known as a night rainbow, is a phenomenon created by the Moon. Always located on the opposite side of the sky from the Moon. For a lunar rainbow to appear, the sky must be dark and rain must be falling on the opposite side of the moon (except for those rainbows caused by a waterfall). Such a rainbow is best seen when the moon phase is close to the full moon. A lunar rainbow is paler and thinner than a regular solar rainbow. But this phenomenon is also rarer.

Bishop's Ring is a brown-red circle around the Sun that occurs during and after volcanic eruptions. Light is refracted by volcanic gases and dust. The sky inside the ring becomes light with a blue tint. This atmospheric phenomenon was discovered by Edward Bishop in 1883, after the famous eruption of the Krakatoa volcano.

A halo is an optical phenomenon, a ring of light around a light source, usually the Sun and Moon. There are many types of halos and they are caused primarily by ice crystals in cirrus clouds at altitudes of 5-10 km in the upper atmosphere. Sometimes the light through them is refracted so strangely that so-called false suns appear, which in ancient times were considered a bad omen.

The Belt of Venus is an atmospheric optical phenomenon. Appears as a pink to orange band between the dark night sky below and the blue sky above. Appears before sunrise or after sunset and runs parallel to the horizon in the opposite direction from the Sun.

Noctilucent clouds are the highest clouds in the atmosphere and a rare natural phenomenon. They are formed at an altitude of 70-95 km. Noctilucent clouds can only be observed during the summer months. In the northern hemisphere in June-July, in southern hemisphere at the end of December - beginning of January. The time of appearance of such clouds is evening and early evening twilight.

Northern lights, aurora (Aurora Borealis) are the sudden appearance of colored lights in the night sky, usually green. Caused by the interaction of charged particles arriving from space and interacting with atoms and molecules of air in the upper layers earth's atmosphere. The aurora is observed mainly at high latitudes of both hemispheres in oval zones - belts surrounding the Earth's magnetic belts.

The Moon itself does not emit light. What we see is just a reflection sun rays from its surface. Due to changes in the composition of the atmosphere, the Moon changes its usual color to red, orange, green or blue. The rarest color of the Moon is blue. It is usually caused by ash in the atmosphere.

Mammatus clouds are one of the varieties of cumulus clouds that have a cellular structure. They are rare, mainly in tropical latitudes, and are associated with the formation of tropical cyclones. Mammatus are located under the main cluster of powerful cumulus clouds. Their color is usually gray-blue, but due to direct rays of the Sun or the backlight of other clouds, they may appear golden or reddish.

A fire rainbow is one of the types of halo, which is the appearance of a horizontal rainbow against the background of light, high clouds. This rare weather phenomenon occurs when light passing through cirrus clouds is refracted through flat ice crystals. Rays enter through vertical side wall hexagonal crystal emerging from the bottom horizontal side. The rarity of the phenomenon is explained by the fact that the ice crystals in the cloud must be oriented horizontally to refract the sun's rays.

Diamond dust is solid precipitation in the form of tiny ice crystals floating in the air, formed in frosty weather. Diamond dust usually forms under clear or nearly clear skies and resembles fog. However, unlike fog, it does not consist of water droplets, but of ice crystals and in rare cases slightly reduces visibility. Most often this phenomenon can be observed in the Arctic and Antarctic, but can occur anywhere at an air temperature of -10, -15.

Zodiacal light is a faint glow of the sky, visible in the tropics at any time of the year, extending along the ecliptic, i.e. in the area of the Zodiac. This is the result of dispersion sunlight in dust accumulations in the region of the Earth's rotation around the Sun. It can be observed either in the evening over western part horizon, or in the morning above the eastern one. It has the appearance of a cone, narrowing with distance from the horizon, gradually losing brightness and turning into the zodiacal stripe.

Sometimes during sunset or sunrise you can see a vertical stripe of light stretching from the sun. Solar pillars are formed by the reflection of sunlight from flat ice crystals in the Earth's atmosphere. Usually the pillars are formed due to the sun, but the light source can be the Moon and artificial light sources.

Natural hazards

A firespout or tornado is a rare natural phenomenon. For its formation, several large fires are required, as well as strong winds. Next, these several fires combine to form a huge bonfire. The air rotation speed inside the tornado is over 400 km/h, and the temperature reaches 1000 degrees Celsius. The main danger of such a fire is that it will not stop until it burns everything in its path.

A mirage is a natural phenomenon that results in imaginary images of various objects appearing. This happens due to the refraction of light flows at the boundary between layers of air that are sharply different in density and temperature. Mirages are divided into upper - visible above the object, lower - visible under the object, and lateral.

A rare complex optical phenomenon consisting of several forms of mirages, in which distant objects are visible repeatedly and with various distortions, is called Fata Morgana. Travelers in the Al-er-Rawi desert often become victims of mirages. In front of people, in the vicinity, oases appear, which are actually 700 km away.

To the dangerous atmospheric processes include: cyclones, tornadoes, heavy rains, snowfalls, etc. Countries located near ocean coasts often suffer from destructive cyclones. In the Western Hemisphere, cyclones are called hurricanes, and in the northwestern sector of the Pacific Ocean - typhoons.

The formation of cyclones is associated with intense heating (above 26-27°) of air above the ocean surface compared to its temperature above the continent. This leads to the formation of spiral-shaped updrafts of air, bringing heavy rain and destruction to the coast.

The most destructive are tropical cyclones, which hit the continental shores with hurricane-force air currents at speeds of more than 350 km/h, rainfall reaching 1000 mm for several days and storm waves up to 8 m high.

The conditions for the formation of tropical cyclones have been studied quite well. Seven areas of their origin have been identified in the World Ocean. All of them are located near the equator. Periodically, in these areas, the water warms up above the critical temperature (26.8°C), which leads to sudden atmospheric disturbances and the formation of a cyclone.

Every year on globe On average, about 80 tropical cyclones occur. The most vulnerable to them are the coasts of the south of the Asian continent and equatorial zone Northern and South America(Caribbean region) (Table 3). Thus, in Bangladesh over the past 30 years, more than 700 thousand people have died from cyclones. The most destructive cyclone took place in November 1970, when more than 300 thousand inhabitants of this country died and 3.6 million people were left homeless. Another cyclone in 1991 killed 140,000 people.

Japan experiences more than 30 cyclones annually. The most powerful cyclone in the history of Japan (Ise-wan, 1953) killed more than 5 thousand, injured 39 thousand people, destroyed about 150 thousand residential buildings, washed away or buried under sediments more than 30 thousand hectares of arable land, damaged 12 thousand damages on roads, about 7 thousand landslides occurred. The total economic damage amounted to about 50 billion dollars.

In September 1991, the mighty Typhoon Mireille swept over Japan, killing 62 people and destroying 700 thousand houses. Total damage amounted to $5.2 billion.

Very often, cyclones bring catastrophic rainfall to the shores of Japan. One of these showers hit the flat part in 1979

Dangerous atmospheric phenomena(signs of approach, damaging factors, preventive measures and protective measures)

Meteorological and agrometeorological hazards

Meteorological and agrometeorological hazards are divided into:

storms (9-11 points):

hurricanes (12-15 points):

tornadoes;

vertical vortices;

large hail;

heavy rain (rain);

heavy snowfall;

heavy ice;

severe frost;

severe snowstorm;

extreme heat;

heavy fog;

frosts.

Fog is the concentration of small drops of water or ice crystals in the surface layer of the atmosphere from air saturated with water vapor as it cools. In fogs, horizontal visibility is reduced to 100 m or less. Depending on the horizontal visibility range, there is heavy fog (visibility up to 50 m), moderate fog (visibility less than 500 m) and light fog (visibility from 500 to 1000 m).

A slight clouding of the air with horizontal visibility of 1 to 10 km is called a veil. The veil can be strong (visibility 1-2 km), moderate (up to 4 km) and weak (up to 10 km). Fogs are distinguished by origin: advective and radiation. Deteriorating visibility complicates the work of transport - flights are interrupted, the schedule and speed of ground transport changes. Drops of fog, settling on the surface or ground objects under the influence of gravity or air flow, moisten them. There have been repeated cases of overlapping of insulators of high-voltage power lines as a result of drops of fog and dew settling on them. Fog drops, like dew drops, are a source of additional moisture for field plants. As the droplets settle on them, they maintain high relative humidity around them. On the other hand, drops of fog, settling on plants, contribute to the development of rotting.

At night, fogs protect vegetation from excessive cooling due to radiation and weaken the harmful effects of frost. During the day, fogs protect vegetation from solar overheating. The settling of fog droplets on the surface of machine parts leads to damage to their coatings and corrosion.

Based on the number of days with fog, Russia can be divided into three parts: mountainous regions, the central elevated part and lowland regions. The frequency of fogs increases from south to north. A slight increase in the number of days with fog is observed in spring. Fogs of all types can be observed at both negative and positive soil surface temperatures (from 0 to 5°C).

Ice is an atmospheric phenomenon that is formed as a result of the freezing of drops of supercooled rain or fog on the surface of the earth and objects. It is a layer of dense ice, transparent or matte, which grows on the windward side.

The most significant icy conditions are observed during the passage of southern cyclones. When cyclones move from Mediterranean Sea to the east and filling them over the Black Sea, black ice is observed in the south of Russia.

The duration of black ice varies - from parts of an hour to 24 hours or more. The formed ice remains on objects for a long time. As a rule, black ice forms at night at negative air temperatures (from 0° to - 3°C). Black ice together with strong winds cause significant damage to the economy: under the weight of the ice, wires break, telegraph poles fall, trees die, traffic stops, etc.

Frost is an atmospheric phenomenon that is the deposition of ice on thin long objects (tree branches, wires). There are two types of frost: crystalline and granular. The conditions of their formation are different. Crystalline frost is formed during fog as a result of sublimation (the formation of ice crystals directly from water vapor without its transition to liquid state or upon rapid cooling below 0°C) water vapor, consists of ice crystals. Their growth occurs on the windward side of objects in light winds and temperatures below - 15°C. The length of the crystals, as a rule, does not exceed 1 cm, but can reach several centimeters. Granular frost is snow-like loose ice that grows on objects in foggy, mostly windy weather.

It has sufficient strength. The thickness of this frost can reach many centimeters. Most often, crystalline frost occurs in the central part of the anticyclone with high relative humidity air below the inversion layer. According to the conditions of formation, granular frost is close to glaze. Frost is observed throughout Russia, but is distributed unevenly, since its formation is influenced by local conditions - terrain height, relief shape, slope exposure, protection from the prevailing moisture-carrying flow, etc.

Due to the low density of frost (volume density from 0.01 to 0.4), the latter only causes increased vibration and sagging of power and communication wires, but can also cause their breaks. Frost poses the greatest danger to communication lines during strong winds, since the wind creates additional load on the wires, which sag under the weight of deposits, and the risk of their breakage increases.

A blizzard is an atmospheric phenomenon that is the wind transporting snow over the surface of the earth with deteriorating visibility. There are such snowstorms as drifting snow, when most snowflakes rise a few centimeters above the snow cover; a blowing snow, if the snowflakes rise to 2 m or higher. These two types of snowstorms occur without snow falling from the clouds. And, in the end, a general, or upper, snowstorm - snowfall with strong winds. Snowstorms reduce visibility on the roads and interfere with transport.

A thunderstorm is a complex atmospheric phenomenon in which electrical discharges (lightning) occur in large rain clouds and between the clouds and the ground, which are accompanied by a sound phenomenon - thunder, winds and rainfall, often hail. Lightning strikes damage ground objects, power lines and communications. Squalls and downpours, floods and hail accompanying thunderstorms cause damage agriculture and some areas of industry. There are intramass thunderstorms and thunderstorms that occur in areas of atmospheric fronts. Intramass thunderstorms are usually short-lived and occupy a smaller area than frontal thunderstorms. They arise due to strong heating of the underlying surface. Thunderstorms in the zone of an atmospheric front are distinguished by the fact that they often appear in the form of chains of thunderstorm cells that move parallel to each other, covering a large area.

They occur on cold fronts, occlusion fronts, and also on warm fronts in warm, humid, typically tropical air. The zone of frontal thunderstorms is tens of kilometers wide with a front length of hundreds of kilometers. Approximately 74% of thunderstorms are observed in the frontal zone, other thunderstorms are intramass.

During a thunderstorm you should:

in the forest, take refuge among low trees with dense crowns;

in the mountains and in open areas, hide in a hole, ditch or ravine;

place all large metal objects 15-20 m away from you;

having taken refuge from the thunderstorm, sit down with your legs tucked under you and your head down on your legs bent at the knees, with your feet together;

put under yourself, plastic bag, branches or spruce branches, stones, clothes, etc. isolating itself from the soil;

on the way, the group should disperse, walk one at a time, slowly;

in the shelter, change into dry clothes, or, as a last resort, thoroughly wring out the wet ones.

During a thunderstorm you cannot:

take shelter near solitary trees or trees that protrude above others;

lean against or touch rocks and steep walls;

stop at the edges of the forest, large clearings;

walk or stop near bodies of water and in places where water flows;

hide under rock overhangs;

run, fuss, move in a dense group;

wear wet clothes and shoes;

stay on high ground;

be near watercourses, in crevices and cracks.

Blizzard

A snow storm is one of the types of hurricane, characterized by significant wind speeds, which contributes to the movement of huge masses of snow through the air, and has a relatively narrow range of action (up to several tens of kilometers). During a storm, visibility deteriorates sharply, and transport links, both intracity and intercity, may be interrupted. The duration of the storm varies from several hours to several days.

Blizzards, blizzards, and blizzards are accompanied by sudden changes in temperature and snowfall with strong gusts of wind. Temperature changes, snow and rain at low temperatures and strong winds create conditions for icing. Power lines, communication lines, building roofs, various kinds supports and structures, roads and bridges are covered with ice or wet snow, which often causes their destruction. Ice formations on the roads make it difficult, and sometimes even completely prevent the operation of road transport. Pedestrian movement will be difficult.

Snow drifts occur as a result of heavy snowfalls and blizzards, which can last from several hours to several days. They cause disruption of transport communications, damage to communication and power lines, and negatively affect economic activity. Snow drifts are especially dangerous when snow avalanches from the mountains

The main damaging factor of such natural disasters is the effect of low temperatures on the human body, causing frostbite and sometimes freezing.

In the event of an immediate threat, the population is notified, the necessary forces and means, road and utility services are put on alert.

A blizzard, snowstorm or blizzard can last for several days, so it is recommended to create a supply of food, water, fuel in the house in advance, and prepare emergency lighting. You can only leave the premises when exceptional cases and not alone. Restrict movement, especially in rural areas.

You should only travel by car on main roads. In the event of a sharp increase in wind, it is advisable to wait out the bad weather in or near a populated area. If the machine breaks down, do not move out of sight from it. If further movement is impossible, you should mark a parking lot, stop (with the engine facing upwind), and cover the engine on the radiator side. In case of heavy snowfall, make sure that the car is not covered with snow, i.e. Rake snow as needed. The car engine must be periodically warmed up to avoid it from “defrosting”, while preventing exhaust gases from entering the cabin (body, interior), for this purpose, make sure that the exhaust pipe is not blocked with snow. If there are several cars, it is best to use one car as a shelter, and drain the water from the engines of the remaining cars.

Under no circumstances should you leave your shelter (car); in heavy snowfall, landmarks may be lost after several tens of meters.

You can wait out a blizzard, blizzard or blizzard in a shelter equipped with snow. It is recommended to build a shelter only in open areas, where snow drifts are excluded. Before taking cover, you need to find landmarks on the ground in the direction of the nearest housing and remember their location.

Periodically it is necessary to control the thickness of the snow cover by piercing the ceiling of the shelter, and clear the entrance and ventilation hole.

You can find an elevated, steadily standing object in an open and snowless area, hide behind it, and constantly throw away and trample down the growing snow mass with your feet.

In critical situations, it is permissible to completely bury yourself in dry snow, for which you should put on all your warm clothes, sit with your back to the wind, cover yourself with plastic wrap or a sleeping bag, pick up a long stick and let the snow cover you. Constantly clear the ventilation hole with a stick and expand the volume of the resulting snow capsule in order to be able to get out of the snow drift. A guide arrow should be placed inside the resulting shelter.

Remember that a blizzard, due to multi-meter snow drifts and drifts, can significantly change appearance terrain.

The main types of work during snow drifts, blizzards, blizzards or blizzards are:

searching for missing people and providing them with first aid, if necessary;

clearing roads and areas around buildings;

providing technical assistance to stranded drivers;

elimination of accidents on utility and energy networks.

Hail is an atmospheric phenomenon associated with the passage of cold fronts. Occurs during strong rising air currents during warm seasons. Droplets of water, falling to great heights with air currents, freeze, and ice crystals begin to grow on them in layers. The drops become heavier and begin to fall down. When falling, they increase in size from merging with droplets of supercooled water. Sometimes hail can reach the size of a chicken egg. Typically, hail falls from large rain clouds during a thunderstorm or rainstorm. It can cover the ground with a layer of up to 20-30 cm. The number of days with hail increases in mountainous areas, on hills, and in areas with very rough terrain. Hail falls mainly in the afternoon in relatively small areas of several kilometers. Hail usually lasts from a few minutes to a quarter of an hour. Hail causes significant property damage. It destroys crops, vineyards, knocks flowers and fruits off plants. If hailstones are large in size, they can cause destruction of buildings and loss of life. IN given time Methods for identifying hail clouds have been developed, and a hail control service has been created. Dangerous clouds are “shot” with special chemicals.

Dry wind is a hot and dry wind with a speed of 3 m/s or more, with high air temperatures up to 25°C and low relative humidity up to 30%. Dry winds are observed in partly cloudy weather. Most often they occur in the steppes on the periphery of anticyclones that form above Northern Caucasus and Kazakhstan.

The highest dry wind speeds were observed during the day, and the lowest at night. Dry winds cause great damage to agriculture: they increase the water balance of plants, especially when there is a lack of moisture in the soil, since intensive evaporation cannot be compensated by the supply of moisture through the root system. With prolonged exposure to dry winds, the above-ground parts of plants turn yellow, the foliage curls, and they wilt and even die of field crops.

Dust, or black, storms - transference large quantity dust or sand by strong winds. They occur during dry weather due to the movement of sprayed soil over vast distances. The occurrence, frequency and intensity of dust storms are greatly influenced by orography, the nature of the soil, forest cover and other features of the area.

Most often, dust storms occur from March to September. The most intense and dangerous spring dust storms occur during a long absence of rain, when the soil dries out and the plants are still poorly developed and do not form a continuous cover. At this time, storms blow away soil over vast areas. Horizontal visibility is reduced. S.G. Popruzhenko researched dust storm in 1892 in the south of Ukraine. This is how he described it: "Dry, strong east wind for several days it tore up the earth and drove away masses of sand and dust. The crops, which were turning yellow from the dry air, were cut at the roots, like with a sickle, but the roots could not survive. The earth was demolished to a depth of 17 cm. The channels are filled up to 1.5 m.

Hurricane

A hurricane is a wind of destructive force and considerable duration. A hurricane occurs suddenly in areas with a sharp change in atmospheric pressure. Hurricane speed reaches 30 m/s or more. In terms of its harmful effects, a hurricane can be compared to an earthquake. This is explained by the fact that hurricanes carry colossal energy; the amount of energy released by an average hurricane in one hour can be compared with the energy of a nuclear explosion.

A hurricane can cover an area up to several hundred kilometers in diameter and can travel thousands of kilometers. At the same time hurricane wind destroys durable and demolishes light buildings, devastates sown fields, breaks wires and knocks down power and communication line poles, damages highways and bridges, breaks and uproots trees, damages and sinks ships, and causes accidents on utility and energy networks. There were cases when hurricane winds threw trains off the rails and knocked down factory chimneys. Hurricanes are often accompanied by heavy rainfall, which causes flooding.

A storm is a type of hurricane. The wind speed during a storm is not much less than the speed of a hurricane (up to 25-30 m/s). Losses and destruction from storms are significantly less than from hurricanes. Sometimes a strong storm is called a storm.

A tornado is a strong small-scale atmospheric vortex with a diameter of up to 1000 m, in which the air rotates at a speed of up to 100 m/s, which has great destructive power (in the USA it is called a tornado).

On the territory of Russia, tornadoes are observed in Central region, Volga region, Urals, Siberia, Transbaikalia, Caucasian coast.

A tornado is an upward vortex consisting of extremely rapidly rotating air mixed with particles and moisture, sand, dust and other suspended matter. On the ground, it moves in the form of a dark column of rotating air with a diameter of several tens to several hundred meters.

In the internal cavity of a tornado, the pressure is always low, so any objects that are in its path are sucked into it. The average speed of a tornado is 50-60 km/h, and as it approaches, a deafening roar is heard.

Strong tornadoes travel tens of kilometers and tear off roofs, uproot trees, lift cars into the air, scatter telegraph poles, and destroy houses. Notification of a threat is carried out by issuing the “Attention to all” signal with a siren and subsequent voice information.

Actions upon receiving information about an impending hurricane, storm or tornado - you should carefully listen to the instructions of the management body for civil emergency situations, which will indicate the expected time, strength of the hurricane and recommendations on rules of conduct.

Upon receipt of a storm warning, it is necessary to immediately begin carrying out preventive work:

strengthen insufficiently strong structures, close doors, dormer openings and attic spaces, cover the windows with boards or cover them with shields, and cover the glass with strips of paper or fabric, or, if possible, remove it;

in order to balance the external and internal pressure in the building, it is advisable to open doors and windows on the leeward side and secure them in this position;

It is necessary to remove things from roofs, balconies, loggias and window sills that could cause injury to people if they fall. Items located in courtyards must be secured or brought indoors;

It is also advisable to take care of emergency lamps - electric lights, kerosene lamps, candles. It is also recommended to create supplies of water, food and medicine, especially dressings;

extinguish the fire in the stoves, check the condition of electrical switches, gas and water taps;

take pre-prepared places in buildings and shelters (in the case of tornadoes - only in basements and underground structures). Indoors, you need to choose the safest place - in the middle part of the house, in the corridors, on the ground floor. To protect against injury from glass fragments, it is recommended to use built-in cabinets, durable furniture and mattresses.

The safest place during a storm, hurricane or tornado is shelters, basements and cellars.

If a hurricane or tornado finds you in an open area, it is best to find any natural depression in the ground (ditch, hole, ravine or any notch), lie down at the bottom of the depression and press tightly to the ground. Leave the vehicle (no matter what you are in) and take refuge in the nearest basement, shelter or recess. Take measures to protect against heavy rainfall and large hail, as... hurricanes are often accompanied by them.

be on bridges, as well as in close proximity to facilities that use toxic, potent and flammable substances in their production;

take shelter under separately standing trees, poles, come close to power line supports;

be near buildings from which tiles, slates and other objects are blown away by gusts of wind;

After receiving a message that the situation has stabilized, you should leave the house carefully; you need to look around to see if there are any overhanging objects or parts of structures, or broken electrical wires. It is possible that they are energized.

Unless absolutely necessary, do not enter damaged buildings, but if such a need arises, then this must be done carefully, making sure that there is no significant damage to stairs, ceilings and walls, fires, breaks in electrical wires, and you should not use elevators.

The fire should not be lit until it is certain that there is no gas leak. When outdoors, stay away from buildings, poles, high fences, etc.

The main thing in these conditions is not to give in to panic, to act competently, confidently and wisely, to prevent yourself and to restrain others from unreasonable actions, and to provide assistance to the victims.

The main types of injury to people during hurricanes, storms and tornadoes are closed injuries to various areas of the body, bruises, fractures, concussions, and wounds accompanied by bleeding.

Federal Agency for Education Russian Federation

Far Eastern State technical university

(FEPI named after V.V. Kuibyshev)

Institute of Economics and Management

discipline: BJD

on the topic: Atmospheric hazards

Completed:

Student of group U-2612

Vladivostok 2005

1. Phenomena occurring in the atmosphere

The gaseous environment around the Earth, rotating with it, is called the atmosphere.

Its composition at the surface of the Earth: 78.1% nitrogen, 21% oxygen, 0.9% argon, in small fractions of a percent carbon dioxide, hydrogen, helium, neon and other gases. The lower 20 km contains water vapor (3% in the tropics, 2 x 10-5% in Antarctica). At an altitude of 20-25 km there is a layer of ozone, which protects living organisms on Earth from harmful short-wave radiation. Above 100 km, gas molecules decompose into atoms and ions, forming the ionosphere.

Depending on the temperature distribution, the atmosphere is divided into the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Uneven heating contributes to general circulation atmosphere, which influences the Earth's weather and climate. Wind power earth's surface assessed using the Beaufort scale.

Atmospheric pressure is distributed unevenly, which leads to the movement of air relative to the Earth from high pressure to low. This movement is called wind. An area of low pressure in the atmosphere with a minimum in the center is called a cyclone.

The cyclone reaches several thousand kilometers across. In the Northern Hemisphere, the winds in a cyclone blow counterclockwise, and in the Southern Hemisphere they blow clockwise. The weather during a cyclone is predominantly cloudy with strong winds.

An anticyclone is an area high blood pressure in an atmosphere with a maximum in the center. The diameter of the anticyclone is several thousand kilometers. An anticyclone is characterized by a system of winds blowing clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere, partly cloudy and dry weather and weak winds.

The following electrical phenomena take place in the atmosphere: air ionization, atmospheric electric field, electrical charges of clouds, currents and discharges.

As a result of natural processes occurring in the atmosphere, phenomena are observed on Earth that pose an immediate danger or impede the functioning of human systems. Such atmospheric hazards include fog, ice, lightning, hurricanes, storms, tornadoes, hail, blizzards, tornadoes, downpours, etc.

Ice is a layer of dense ice that forms on the surface of the earth and on objects (wires, structures) when supercooled drops of fog or rain freeze on them.

Ice usually occurs at air temperatures from 0 to -3°C, but sometimes even lower. The crust of frozen ice can reach a thickness of several centimeters. Under the influence of the weight of ice, structures can collapse and branches break off. Ice increases the danger to traffic and people.

Fog is an accumulation of small water drops or ice crystals, or both, in the ground layer of the atmosphere (sometimes up to a height of several hundred meters), reducing horizontal visibility to 1 km or less.

In very dense fogs, visibility can be reduced to several meters. Fogs are formed as a result of condensation or sublimation of water vapor on aerosol (liquid or solid) particles contained in the air (so-called condensation nuclei). Most fog droplets have a radius of 5-15 microns at positive air temperatures and 2-5 microns at negative temperatures. The number of drops per 1 cm3 of air ranges from 50-100 in light fogs and up to 500-600 in dense fogs. Fogs, according to their physical genesis, are divided into cooling fogs and evaporation fogs.

According to the synoptic conditions of formation, intramass fogs are distinguished, forming in homogeneous air masses, and frontal fogs, the appearance of which is associated with atmospheric fronts. Intramass fogs predominate.

In most cases, these are cooling fogs, and they are divided into radiation and advection. Radiation fogs form over land when the temperature drops due to radiation cooling of the earth's surface, and from it the air. They most often form in anticyclones. Advection fogs are formed due to the cooling of warm humid air when it moves over a colder surface of land or water. Advective fogs develop both over land and sea, most often in the warm sectors of cyclones. Advection fogs are more stable than radiation fogs.

Frontal fogs form near atmospheric fronts and move with them. Fogs prevent the normal operation of all types of transport. Fog forecast is important for safety.

Hail - view atmospheric precipitation, consisting of spherical particles or pieces of ice (hailstones) ranging in size from 5 to 55 mm, there are hailstones measuring 130 mm and weighing about 1 kg. The density of hailstones is 0.5-0.9 g/cm3. In 1 minute, 500-1000 hailstones fall per 1 m2. The duration of hail is usually 5-10 minutes, very rarely up to 1 hour.

Radiological methods for determining the hail content and hail hazard of clouds have been developed and operational services for combating hail have been created. The fight against hail is based on the principle of introduction using rockets or. projectiles into a cloud of reagent (usually lead iodide or silver iodide) that promotes freezing of supercooled droplets. As a result, a huge number of artificial crystallization centers appear. Therefore, hailstones are smaller in size and they have time to melt before falling to the ground.

2. Lightning

Lightning is a giant electrical spark discharge in the atmosphere, usually manifested by a bright flash of light and accompanying thunder.

Thunder is the sound in the atmosphere that accompanies a lightning strike. Caused by air vibrations under the influence of an instantaneous increase in pressure along the path of lightning.

Lightning most often occurs in cumulonimbus clouds. The American physicist B. Franklin (1706-1790), Russian scientists M.V. Lomonosov (1711-1765) and G. Richman (1711-1753), who died from a lightning strike while researching atmospheric electricity, contributed to the discovery of the nature of lightning.

Lightning is divided into intracloud, i.e., passing in the thunderclouds themselves, and ground, i.e., striking the ground. The development process of ground lightning consists of several stages.

At the first stage, in the zone where the electric field reaches a critical value, impact ionization begins, initially created by free electrons, always present in small quantities in the air, which, under the influence of electric field acquire significant speeds towards the ground and, colliding with air atoms, ionize them. In this way, electron avalanches arise, turning into threads of electrical discharges - streamers, which are well-conducting channels, which, when connected, give rise to a bright thermally ionized channel with high conductivity - a stepped leader. The movement of the leader towards the earth's surface occurs in steps of several tens of meters at a speed of 5 x 107 m/s, after which its movement stops for several tens of microseconds, and the glow greatly weakens. In the next stage, the leader again advances several tens of meters, while a bright glow covers all the passed steps. Then the glow stops and weakens again. These processes are repeated when the leader moves to the surface of the earth at an average speed of 2 x 105 m/sec. As the leader moves toward the ground, the field intensity at its end increases and, under its action, a response streamer is ejected from objects protruding on the surface of the earth, connecting to the leader. The creation of a lightning rod is based on this phenomenon. In the final stage, a reverse or main lightning discharge follows along the ionized leader channel, characterized by currents from tens to hundreds of thousands of amperes, strong brightness and high speed of movement of 1O7..1O8 m/s. The temperature of the channel during the main discharge can exceed 25,000°C, the length of the lightning channel is 1-10 km, and the diameter is several centimeters. Such lightning is called prolonged lightning. They are the most common cause of fires. Typically, lightning consists of several repeated discharges, the total duration of which can exceed 1 s. Intracloud lightning includes only leader stages; their length ranges from 1 to 150 km. The probability of a ground object being struck by lightning increases as its height increases and the electrical conductivity of the soil increases. These circumstances are taken into account when installing a lightning rod. Unlike dangerous lightning, called linear lightning, there are ball lightning, which often form after a linear lightning strike. Lightning, both line and ball, can cause serious injury and death. Lightning strikes can be accompanied by destruction caused by its thermal and electrodynamic effects. The greatest destruction is caused by lightning strikes on ground objects in the absence of good conductive paths between the strike site and the ground. From an electrical breakdown, narrow channels are formed in the material, in which a very high temperature is created, and part of the material evaporates with an explosion and subsequent ignition. Along with this, large potential differences may occur between individual objects inside the building, which can cause injury to people electric shock. Direct lightning strikes into overhead communication lines with wooden supports are very dangerous, as this can cause discharges from wires and equipment (telephones, switches) to the ground and other objects, which can lead to fires and electric shock to people. Direct lightning strikes on high-voltage power lines can cause short circuits. Lightning strikes on airplanes are dangerous. When lightning strikes a tree, people nearby can be struck.

3. Lightning protection

Discharges of atmospheric electricity can cause explosions, fires and destruction of buildings and structures, which led to the need to develop a special lightning protection system.

Hazardous phenomena winter period

The Earth's atmosphere has a great influence on the life and activities of people. Those phenomena that occur in it and are observed on the planet represent either a danger or complicate the functioning of human systems. Such dangerous phenomena can be considered fogs, lightning, hurricanes, storms, tornadoes, hail, etc. Dangerous atmospheric phenomena can arise unexpectedly, manifest themselves as spontaneous events, and therefore cause significant damage. Hazardous phenomena associated with features atmospheric circulation, and sometimes with the terrain. The winter period is characterized by such dangerous phenomena as snowfalls, blizzards, frosts, ice, etc.

Definition 1

Snowfall– intense snowfall, leading to reduced visibility and obstruction of traffic.

Such emergency, like snowfall, ranks $4$-$5$ globally in terms of damage caused, but sometimes moves to $3$-$4$ place. Under the influence of snow loads, the roofs of houses can break, trees fall, plantations die, etc. Average snow loads out of the maximum can exceed $250$ kg/cubic m. Major cities as a result of snowfalls they can be paralyzed in a matter of hours. For example, in $1967$ Chicago$58$ cm of snow fell. Residents of the city remembered him as "Blizzard of '67". The severity of this snowfall was across the US Midwest and covered an area from Michigan to Indiana. This snowstorm claimed the lives of $76$ people.

In $1971, heavy snowfall began in Canada, in the provinces of Ontario and Quebec, where short period$61$ cm of snow fell. The storm was named " "Eastern Canadian Blizzard of '71" and was accompanied by strong winds. Visibility on the roads was zero. The very low temperature caused the death of $20 people, and for local residents it was a real disaster.

Tibet$2008 $ Due to the high altitude, it is cool here and there is little snow, but $2008 became an exception for local residents. The heavy snowfall lasted $36$ hours and covered some areas with snow $180$ cm thick. Its average thickness was $150$ cm. Buildings could not stand it, roads did not function.

American city holds record for snowfall Buffalo in $1977$ Compared to surrounding areas, there are more high temperatures and less winter snowfall. The snowfall in 1977 was quite moderate, but with very strong winds, the speed of which was $70 km per hour. At this point, there was already a layer of snow in the city. Not the strongest snow storm caused a terrible frost, zero visibility and a blizzard. After the end of the snowfall in the city, the layer of snow that fell was $5$ meters - it was absolute record season.

Summer hazards

For summer period there are their own dangerous natural phenomena associated with the atmosphere are heat, hot winds, droughts. These also include natural fires, floods, tornadoes, tornadoes, whirlwinds, etc.

Definition 2

Tornado is an ascending vortex of rapidly rotating air with particles of sand, dust, moisture

Over the sea such a whirlwind is called like a tornado, and over land - blood clots. IN North America blood clots are called tornado. This is an air funnel hanging from a cloud in the form of a trunk and falling to the ground. Tornadoes form in different areas of the planet and can be accompanied by thunderstorms and heavy downpours. They can occur both over land and over water.

The birth of a tornado is associated with low cumulonimbus clouds, in the form of a dark funnel descending to the ground, but they can also appear in clear weather. A tornado cloud is $5$-$10$ km across, sometimes even $15$ km. Its height is $4$-$5$ km, sometimes it can be $15$ km. There is usually a short distance between the surface of the earth and the base of the cloud. At the base of the mother cloud there is a collar cloud, the upper surface of which is located at an altitude of up to $1500$ m. The tornado itself hangs from the lower surface of the wall cloud, which lies under the collar cloud. Like a pump, a tornado sucks various objects into the cloud, which, falling into the vortex ring, are held in it and transported tens of kilometers.

The main part of a tornado is funnel, which is a spiral vortex. The movement of air in the walls of a tornado occurs in a spiral at a speed of about $200 m/s. Various objects, even people and animals caught in a tornado, rise up in the walls, and not through the empty internal cavity. Dense tornadoes have small wall thickness compared to the width of the cavity. The air in the funnel can reach high speed from $600$-$1000$ km/h. Such vortices exist for minutes, less often they happen for tens of minutes. One cloud can form entire groups of tornadoes. Tornadoes can travel from hundreds of meters to hundreds of kilometers. Their average speed is $50$-$60$ km/h. For them, seas, lakes, forests, hills are not an obstacle. Having passed along the ground, a tornado can rise into the air without touching it and then descend again. Destructive force a large tornado breaks power and communication lines, disables equipment, destroys residential and industrial buildings, and leads to casualties.

Within Russia, tornadoes most often form in the central regions, the Volga region, the Urals and Siberia. Tornadoes often form on the seas and, when they reach the coast, they increase their strength. The time and place of a tornado's appearance is almost impossible to predict; they usually appear suddenly. Statistics speak of tornadoes near Arzamas, Murom, Kursk, Vyatka, Yaroslavl.

In Europe, these dangerous phenomena are rare, and they can be observed in hot weather. summer weather. In the north, they were recorded in southern Norway, Sweden, the Solovetsky Islands, and in Siberia - up to the lower reaches of the Ob. Losses from these atmospheric phenomena amount to millions of dollars and, most importantly, human lives.

Rules of behavior for different atmospheric phenomena

Certain atmospheric phenomena cause damage not only to the economy, but also to the death of people. From this point of view, people should know the rules - how to behave in an unusual situation so as not to die.

Rules of conduct during snow drifts: