Tropical cyclones, hurricanes, typhoons. Hurricanes A hurricane occurring in the tropical Pacific Ocean

The destructive activity of typhoons and hurricanes is carried out due to the combined action of the colossal force of the wind, the enormous amount of precipitation, the storm's rise in sea level and the resulting giant waves.

The Beaufort scale for a unified assessment of the state of the sea from one (calm sea) to 12 points (hurricane - a sea white with foam and waves reaching a height of 15 m) turned out to be unsuitable for characterizing wind speed during typhoons and hurricanes. To these 12 points, 5 more were added; the last 17 points corresponds to a wind speed of 460 km/h.

Modern instruments are not capable of recording wind speeds of more than 300 km/h. The record speed is approximately 400 km/h, which does not mean an instant gust, but a wind blowing for 5 minutes. Individual gusts have a speed of 20 - 30% more.

In tropical cyclones, wind speeds often reach 300 - 400 km/h. Such speeds cannot be measured. They are judged by the destruction that cyclones leave behind. These hurricanes often produce heavy rain and hail. Waterfalls falling from the sky and accompanied by the roar of the wind are terrifying. There are known cases when, in areas of future typhoons, the surfaces of bays were covered dead fish, who died from excess fresh water.

Tropical cyclones along their path cause enormous material damage and claim many human lives.

Residents of the Philippine Islands, Indochina and Japan have known the word “typhoon” since time immemorial. Bay of Bengal typhoons have claimed many victims. They contribute to storm floods that inundate low-lying, densely populated coastlines.

There are cases when one typhoon claimed thousands of lives, for example, Typhoon Vera in September 1959 killed 5,500 people. This number will increase significantly if you take into account the people who died later from hunger and disease.

Damage caused material assets, can be divided into direct and indirect. Direct is damage that manifests itself directly during the storm (destruction of buildings, fires, loss of crops, etc.). Indirect damage is damage that occurs long after typhoons and hurricanes pass over islands and continents. For example, the absence of a harvest for several years in those fields from which the surface layer of soil was carried away, a reduction in production in destroyed plants and factories. The amount of indirect damage caused by a tropical cyclone can be several times greater than the amount of direct damage. Long-term statistics of observation of tropical cyclones have made it possible to identify some patterns linking the amount of damage caused to the physical characteristics of tropical cyclones. This allows you to get a rough idea of ​​the scale of the impending disaster.

Biological significance cyclones lie in their ability to transport seeds of plants, and sometimes quite large animals, over vast distances. Apparently, it was these winds that contributed to the settlement of many volcanic and coral islands that arose in the vastness of the oceans, and the migration of plants and animals. The hurricane of 1865 brought pelicans to Guadeloupe, previously unknown there.

The famous Great Hurricane in October 1780 destroyed the city of Savanna-la-Mar (Georgia, USA). According to an eyewitness, the residents were petrified with amazement when they saw the approach of an unprecedented wave; sweeping away all obstacles in one gigantic squall, it flooded the city and demolished everything and everyone. Seven days later the storm reached its maximum strength. It completely devastated the island of St. Lucia, where 6,000 people died under the ruins, and sank the English fleet anchored off the island. The sea here rose so high that it flooded the fleet and, carrying a ship on the crest of one of its gigantic waves, threw it onto the naval hospital, destroying the building with the weight of the ship. The hurricane then headed towards the island of Martinique, where 40 French transport ships carrying 4,000 soldiers were sunk. The islands of Dominica, St. Eustatius, St. Vincent, and Puerto Rico located to the north were also devastated, and a large number of ships caught in the path of the cyclone were sunk.

On the night of November 13, 1970, an incredible typhoon hit the coastal areas of East Pakistan (since 1971, the People's Republic of Bangladesh). A powerful wave up to 8 m high, raised by the wind, passed over a chain of densely populated islands. It was a colossal wall of water, boiling and seething, a huge shaft of water that was thrown up by the ocean. Sweeping away everything in its path, it hit the coast and, together with hurricane winds, brought catastrophic destruction. For several hours these islands and part of the mainland coast were under water. The consequences of the typhoon are catastrophic: bridges are torn down, highways and railways are destroyed, entire villages are completely destroyed along with their inhabitants. According to newspaper reports, a total of more than 10 million people were affected by the typhoon. The death toll exceeded half a million, and according to some sources, about a million people. One of the most severe natural disasters in the history of mankind occurred.

A hurricane of extraordinary force hit 11 states in North America in 1974. Sowing death and destruction, the hurricane and the accompanying tornadoes in 8 hours left in its path, according to published data, 350 killed, thousands of wounded and missing. In the states of Illinois, Indiana, Ohio, Kentucky, West Virginia, Virginia, Tennessee, North Carolina, Alabama and Georgia, hundreds of homes and stores, schools, hospitals and churches were destroyed. Material damage, according to incomplete data, is estimated at $1 billion. Among the hardest hit by the hurricane is the city of Zinia in Ohio. According to eyewitnesses, the hurricane struck suddenly at about 5 o'clock. evening, rumbled like a passenger train rushing at great speed. In a city with a population of 25 thousand, over 70% of buildings were completely or partially destroyed, including the state university. The city of Brandenberg ceased to exist. In Alabama, the cities of Jasper and Guin were wiped off the map.

On the eve of 1975, tropical cyclone Tracy almost completely destroyed the capital of the northern territory of Australia, Darwin, a city with a population of 44 thousand people. The wind force reached a speed of 260 km/h. The hurricane tore roofs off houses like balls and tossed tourist buses through the streets. Numerous cottages were collapsing under the pressure of the wind, like houses of cards. But administrative buildings and high-rise hotels were hardly more stable. Darwin's downtown has been reduced to mountains of rubble and debris. A large naval base located near the city was destroyed. Several ships sank.

In 1980, during August and September 1980 alone, four cases of tropical cyclone development were noted in the northern hemisphere and one case in the southern hemisphere, of which two were hurricanes in the Caribbean Sea and three were typhoons in the Pacific Ocean.

Hurricane Alley occurred in early August off the coast of Haiti and Jamaica. The wind speed there reached 70 m/s. The second hurricane, Hermine, was observed on the 20th of September off the northern coast of Honduras, as well as off the coast of Mexico and Guatemala. The wind speed there reached 30 m/s.

Typhoon Orchid originated in the western Pacific Ocean and swept over the Japanese Islands and South Korea on September 11-12, causing significant destruction and flooding there. The influence of this typhoon became noticeable a day later in the Khabarovsk and Primorsky territories and on Sakhalin. Observed heavy rains and wind, the wind speed in some places reached hurricane speed (33 m/s). About a month later, in mid-October, another typhoon came to the Japanese islands of Kyushu and Shikoku from the south, temporarily disrupting not only air but also railway communications.

At the beginning of the third ten days of September, Typhoon Kay arose in the southeastern part of the Pacific Ocean, in the center of which the wind speed reached 30-40 m/s.

There were tropical cyclones in subsequent years, both in the northern and southern hemispheres. In particular, tropical cyclones Eilena, which struck the Comoros Islands in the Indian Ocean on January 10, 1983, and Andry, which caused great destruction on the northwestern coast of the island of Madagascar in the Indian Ocean, were very destructive.

1985 was also a good year for tropical cyclones: in the South China Sea during the summer and autumn of this year, seven tropical cyclones - typhoons - occurred, causing catastrophic floods and human casualties in the coastal areas of Vietnam and China.

One of the typhoons, Lee, penetrated far to the north onto the Korean Peninsula and, turning into an ordinary cyclone, brought with it heavy rains to the territory of Soviet Primorye in mid-August.

Another typhoon on September 10-12 destroyed a third of the fruit harvest and caused damage to about 90% of the cultivated area in Japanese island Honshu.

At the end of October, Typhoon Saling killed more than 60 residents of the island of Luzon in the Philippines and caused more than 700 million pesos in damage to the island's farms. Almost simultaneously, in the other hemisphere, in the Gulf of Mexico, another tropical cyclone arose - Hurricane Juan, which severely affected residents of several coastal US states, and a month later - Hurricane Kate, which caused floods and significant destruction in northern Cuba and the United States. Hurricane Kate's intensity and extent of damage caused. Cuba and the coast of the Florida peninsula turned out to be one of the most ferocious in the last 50 years; gusts of wind and ocean waves rushing onto the shore destroyed many thousands of houses, more than a million people had to be evacuated from disaster zones, and there were casualties.

Tropical Cyclone Jeanne (September 2004) - Caribbean Sea, Haiti. The death toll from rain, flooding and landslides in Haiti caused by Hurricane Jeanne could reach 2,000, the Associated Press reported. As of September 23, almost 1,100 victims are already known, and another 1,250 people are listed as missing. The most a large number of victims - in the city of Gonaives in the northern part of the island. According to authorities, 1,013 people died here. Representatives of the Red Cross fear the spread of epidemics through water in which the bodies of drowned people remained for several days. The water level in some places exceeds four meters, and as it recedes, more and more victims are discovered. The President of Haiti called what was happening a humanitarian disaster and asked international community about help. In May 2004, the island already suffered one of the worst terrible floods throughout history, as a result of which about 2.5 thousand people died.

Hurricane Katrina is one of the most destructive hurricanes in US history. As a result of the natural disaster, 1,836 residents died, economic damage amounted to $81.2 billion. Physical characteristics. Before it reached the US coast, it was classified as a level 5 hurricane on the Saffir-Simpson Hurricane Scale. Fortunately, about 12 hours before hitting the coast, the hurricane weakened to Category 4. The wind speed during the hurricane reached up to 280 km/h (according to other reports, 62 m/s (? 223 km/h). On August 27, 2005, it passed over the coast of Florida near Miami and turned towards the Gulf of Mexico. On August 29, 2005 it reached the south east coast of the United States in the region of Louisiana and Mississippi. Due to their location below sea level, many cities of the southeastern coast of the United States were flooded. In New Orleans, this happened to 80% of the city, many buildings collapsed. Economic damage amounted to $ 125 billion. ( estimate, 2007). About 800 thousand people were left without electricity and telephone communications. The officially confirmed number of victims was 1,407 people, according to later data 1,600, of which more than 720 were in New Orleans; in addition, as of December 2005, 47 people were missing missing More than a quarter of the population of New Orleans (150 thousand people) have still not returned to the city (August 2006).

On March 14, 2007, Madagascar was again hit by disaster. Another tropical cyclone, Indlala, reached category 3 in strength. The wind speed in this cyclone reached 115 knots with gusts up to 140 knots. According to news agencies, over the past few days this cyclone has claimed the lives of 36 people, leaving 53 thousand 750 people homeless. Since December 2006, Cyclone Indlala was the fourth to hit Madagascar. On March 19, 2007, he left the island. While the north of the island experiences devastating floods due to powerful cyclones, its South part experiencing drought and famine. The cyclone season in the southern Indian Ocean usually lasts from November to March. But the 2006/07 season. differs from the previous ones by greater activity.

On October 7, 2008, Mexico was literally in the grip of tropical cyclones. Tropical Storm Marco has formed in the Gulf of Mexico. Wind gusts reached 27 m/s. Storm "Marco" came close to the coast. Brought torrential rains. On the other side of Mexico, over the waters Pacific Ocean, another cyclone is Hurricane Norbert.

Archived article from No. 6 (42) for 2005.

Tropical cyclones are one of the most amazing and, at the same time, formidable and destructive natural phenomena on Earth, raging over the tropical waters of all oceans, with the exception of the South Atlantic and the southeast Pacific Ocean.

On average, about 80 tropical cyclones are observed on our planet per year.

Intense tropical cyclones in each region have their own name. In the Atlantic and Northeast Pacific they are called hurricanes; in the northwest Pacific Ocean - typhoons; in the Arabian Sea and Bay of Bengal - by cyclones; in the southern part of the Indian Ocean - orcans; off the coast of Australia - willy-willy; in Oceania - wheelie-wow; in the Philippines - Baguio.

Tropical cyclones are huge vortices, reaching a diameter of 1000-1500 km and extending throughout the entire thickness of the troposphere. A distinctive feature of tropical cyclones is a significant drop in pressure over short distances, which leads to the formation of hurricane-force winds. The pressure in the center of developed cyclones is about 950-960 hPa (the minimum recorded is 855 hPa).

Tropical cyclones occur over warm climates ocean waters in the tropics of both hemispheres in the latitude zone 5-20°. They are a formidable product of the interaction between the ocean and the atmosphere.

Most tropical cyclones form in the intertropical convergence zone - the zone of convergence of the trade winds of the two hemispheres, or trade winds, and the equatorial westerlies. Such a convergence zone is characterized by the presence of disturbances of varying intensity - some of them reach the stage of tropical depressions, some of which, under favorable conditions, develop into a tropical storm and hurricane. What contributes to the formation and further intensification of a tropical cyclone? First of all, this is the presence of an initial disturbance and a slight horizontal wind shear between the lower and upper troposphere. To create the “twisting” effect, a sufficient value of the Coriolis force is necessary, due to the rotation of the Earth around its axis - tropical cyclones do not form near the equator, where the horizontal component of this force is zero. One of the conditions for the formation of tropical cyclones is the presence of moist, unstable air and the development of convection.

Finally, there is the existence of an energy source - the thermal potential of the ocean. Simply put, tropical cyclones form over the ocean if its surface temperature exceeds 26°C. The ocean supplies much of the heat needed to maintain the low pressure at the center of the cyclone. As water temperature rises, evaporation increases and the flow of so-called latent heat increases, which forms a warm core in the middle troposphere, causing a sharp decrease in pressure in the center of a tropical cyclone. A tropical cyclone can be thought of as a heat engine, the operation of which is connected with the ocean as a source of energy and as a trigger mechanism - the initial vortex is formed over a superheated area of ​​​​the ocean. In addition, the thermal state of the ocean also affects the trajectory of tropical cyclones. But at the same time, the evolution of tropical cyclones is also determined by various atmospheric processes. We are dealing with a complex set of interactions between the ocean and the atmosphere.

Mature tropical cyclone – powerful atmospheric vortex, which is characterized by large pressure gradients (differences) and, consequently, hurricane winds - up to 90 m/s, with the belt of maximum winds located between 20 and 50 km from the center. In tropical cyclones, intense cloudiness develops, and the amount of precipitation can reach 2500 mm per day. In well-developed cyclones, a phenomenal phenomenon is observed - the eye of the storm - an area where the sky clears, the wind weakens, sometimes to the point of calm, and at its border the precipitation suddenly stops. The eye is surrounded by a wall of powerful clouds. Satellite images reveal the existence of "hot towers" - altitude zones rain clouds, which are located above the “walls” of this same “eye”, are much higher than the main part of the hurricane. The "towers" extend all the way to the "ceiling" - upper layers troposphere. Experts believe that “hot towers” ​​play a key role in the process of increasing the power of a hurricane. By the way, such “towers” ​​were also discovered in Hurricane Katrina. The appearance of the eye of the storm is associated with an increase in centrifugal force as it approaches the center of the cyclone. The average diameter of the “eye” is 20-25 km; in destructive hurricanes and typhoons it is 60-70 km. There are also two-eyed tropical cyclones.

The energy of a tropical cyclone is very high; According to experts, the average tropical cyclone produces an amount of energy equal to several thousand atomic bombs.

In three weeks, a hurricane generates energy comparable to what our Bratsk hydroelectric power station would have generated in 26 thousand years. Humanity is not yet able to either use this energy or receive it in such quantities from any other sources.

The resulting tropical cyclone first moves from east to west, gradually deviating to higher latitudes: in the northern hemisphere - to the northwest. But if the cyclone reaches 20-30° latitude above the ocean, it begins to go around the subtropical anticyclone and its direction changes to the northeast. This point on the trajectory is called the turning point. The trajectories of cyclones are mostly curvilinear, sometimes even “loops” appear. average speed The movement of tropical cyclones within the tropics is only 10-20 km/h. Coming onto land or into mid-latitudes, a tropical cyclone fades or turns into an intense cyclone of temperate latitudes. Russian Primorye in the summer-autumn period is often exposed to such cyclones - former typhoons that bring abnormal precipitation and hurricane winds. Thus, in 1973, a typhoon that hit Primorye brought more than half of the annual precipitation to Vladivostok. The author of the article experienced all the “delights” of the raging elements when in August 1979 Typhoon Irving hit the Far East, flooding the Primorsky and Khabarovsk Territories.

In hydrometeorological practice, depending on the wind speed, tropical disturbances are divided into tropical depression, tropical storm, severe tropical storm, tropical cyclone, typhoon, hurricane. In turn, the latter are divided into five categories (“hurricane” Saffir-Simson scale) depending on wind speed. The fifth category includes hurricanes with speeds exceeding 70 m/s.

Tropical cyclones that become tropical hurricanes get their own names. This tradition dates back to World War II, when air force meteorologists naval forces The United States monitored typhoons and, to avoid confusion, named typhoons after their wives or girlfriends. After the war, the US National Weather Service compiled alphabetical list female names to facilitate communication and avoid difficulties when several cyclones develop in the region. When, in 1979, the true essence and strong half humanity, the World Meteorological Organization (WMO), together with the US National Weather Service, included male names in the list. Justice has prevailed. (Not all evil is from a woman!) These lists are used constantly and are compiled in advance for each year and each region. However, if a tropical cyclone is particularly destructive, the name assigned to it is removed from the list and replaced by another. So we can say quite definitely that we will never hear about a hurricane called Katrina again.

The destructive effect of tropical cyclones is due to hurricane-force winds, deadly streams of water that hit the coast with the arrival of a hurricane - up to 20 million tons of water per day. For example, in January 1966, tropical cyclone Denis swept over Reunion Island in the Indian Ocean, bringing an incredible amount of rain - 182 centimeters per day. Added to the rainfall is a “storm surge” - a rise in sea level, reaching 10 m in extreme cases. Floods associated with storm surges are the most destructive consequences of hurricanes. In 1970, Cyclone Ada in the Indian Ocean inundated the low-lying coast of Bangladesh with surge waves. More than 300 thousand people died then. Hurricane Hugo in 1989 dumped a wall of water 6 meters high on South Carolina. Such a blow can destroy buildings, roads, and wash away banks.

In the northern hemisphere, the hurricane season lasts, on average, from May to November. The longest period of development of tropical cyclogenesis is observed in the western Pacific Ocean. According to the Hydrometeorological Center of Russia, which has compiled a database of tropical cyclones around the globe, on average 26 tropical cyclones form in the western Pacific Ocean. In the Atlantic, the peak of hurricanes occurs in August-September and there are about 9-10 cyclones per year. Research by scientists has shown that tropical cyclone activity has increased in the Atlantic in recent decades. Thus, from 1970 to 1979 their number was 81, from 1980 to 1989 – 96, from 1990 to 1999 – 105; Moreover, in 1995, 19 tropical cyclones were recorded (the record still remains for 1933, when 21 cyclones formed in the Atlantic). According to the forecasts of American scientists, this trend will continue in the first decades of the 21st century, and the current year 2005 may break all records. This is due, first of all, to an increase in ocean surface temperature. Satellite data showed that in 2005 the water surface temperature in the Atlantic Basin increased by an average of 2-4°C compared to previous years.

Until recently, the record holder among Atlantic cyclones was Hurricane Andrew, which swept over the states of Florida and Louisiana at the end of August 1992 and caused damage in the amount of $25 billion. The minimum pressure in its center dropped to 923 hPa, and the wind speed reached 76 m/s.

However, Katrina, apparently, turned out to be a record holder in its parameters: the minimum pressure in its center was 902 hPa, and the wind speed exceeded 75 m/s (gusts up to 90 m/s). Katrina originated on August 23, 2005, east of Bahamas and, passing through southern Florida and intensifying in the Gulf of Mexico, where water temperatures exceeded 31 ° C, struck New Orleans on August 29, 2005, destroying levees and completely flooding the city. The death toll exceeded a thousand people, and economic damage amounted to tens of billions of dollars. It was the most destructive hurricane to ever hit the North American coast.

Following Katrina, Rita rushed to the US coast, becoming the seventeenth tropical storm of the 2005 hurricane season.

Fortunately, she weakened before causing any colossal harm. Both Katrina and Rita originated north of normal latitudes where Atlantic tropical cyclones swirl. But the most unusual thing for the Atlantic was the twentieth hurricane named Vince. He managed to spin around the Azores Islands, which is significantly north (30-35 parallel) of the usual area of ​​their formation. True, it failed to achieve great intensity and, having reached the first category, “Vince” quickly weakened to a tropical storm.

Tropical cyclones significantly redistribute energy in the atmosphere and therefore, despite their “compact” size, influence atmospheric processes far beyond their “habitat”. For example, climatologists have noticed an interesting fact about the relationship between the frequency of hurricanes in the Atlantic and good weather in Europe. As a rule, with increased activity of tropical cyclogenesis, large, inactive cyclones form over Scandinavia. Along their periphery most Western European winds spread southern directions, which provide sustainable warm weather. Eastern Europe is at the mercy of an anticyclone, causing good weather. So our long “Indian summer” of 2005 is partly due to the “raging” Atlantic.

There is no need to talk about the importance of studying tropical cyclones and forecasting their evolution. Direct measurements in a cyclone are practically impossible, although many useful information was obtained during aircraft sounding and special expeditionary observations. Modern methods for studying and forecasting tropical cyclones are based on numerical modeling and the use of satellite information, laboratory experiments. Methods have been developed to predict the occurrence, evolution and direction of movement of these cyclones based on numerical methods and satellite data. Although it is not yet possible to accurately calculate the origin of a tropical cyclone, it is quite possible to determine the most likely area of ​​its origin. Over the past 30 years, significant advances have been made in predicting cyclone trajectories.

The enormous damage caused by tropical cyclones raises the challenge of not only predicting their development and movement, but also of possible influence on them in order to reduce their intensity and change the trajectory of movement. A wide variety of projects were proposed: dispersing clouds with dry ice or silver iodide, cooling the ocean with icebergs, covering water with a special oil film, irradiating the epicenter of a hurricane with microwaves from space or detonating it with hydrogen bombs. It should be noted that all of them are quite expensive and may turn out to be completely pointless if not accurate forecast place of origin, size and intensity of the cyclone. In addition, it is impossible to calculate the consequences of such impacts, which can be no less destructive than the tropical cyclone itself. So for now we can only hope for improved methods for forecasting tropical cyclones and adequately respond to warnings from specialists. And now, thanks to the improvement of warning systems and methods of saving people, the number of human casualties has begun to gradually decline.

Text: Olga Razorenova (senior researcher, Institute of Oceanology RAS)
Photo: Levan Mtchedlishvili

First hit full strength. The house is falling apart. I looked at the barometer, which showed 674.5 mm, dropped it into the water, and was blown out into the sea by the wind.

I came to in a tree and saw that I was stuck in the branches of a palm tree 20 feet above the ground.

“You can easily imagine my surprise, chagrin... when I saw the terrible situation of the island of Barbados and the destructive power of the hurricane. The strongest buildings and entire blocks of houses, most of which were made of stone and were distinguished by their solidity, succumbed to the fury of the wind and were torn down to the ground. Entire forts on the fortress were destroyed, and many of the heavy guns were carried more than 100 feet from them. If I hadn't seen it myself, nothing would have made me believe it. More than six thousand people died, and all homes were completely destroyed." To this testimony of Admiral Rodney, who was at that time the commander of the English fleet and an eyewitness of the “Great Hurricane” in the West Indies in 1780, one can only add that the total number of human casualties then amounted to more than twenty thousand. thousand Dozens of ships with their entire crew sank, the islands of Barbados, St. Lucia, Dominica, St. Vincent, and Puerto Rico were completely devastated.

In some tropical regions of the globe, residents of islands and coastal areas sometimes suffer terrible disasters caused by small-diameter cyclones, in which wind speeds in some cases exceed 120 meters per second, and the amount of precipitation falling per day reaches 1000 - 12000 millimeters.

All cyclones originating in the tropics can be divided into four groups:

– tropical disturbance – area of ​​weak cyclonic circulation;

– tropical depression – a weak tropical cyclone with a pronounced surface circulation; the highest steady wind speed does not exceed 12.5 meters per second;

– tropical storm – a cyclone, the highest sustained wind speed of which reaches 33 meters per second;

– a tropical hurricane is a cyclone in which the wind speed exceeds 33 meters per second.

In Japan, tropical hurricanes are called “typhoons”, in the Philippines – “bagwiz”, in Australia – “willy-willy”. All these names translated into Russian mean “big wind” or “ strong wind».

There are several theories about the origin of tropical hurricanes.

According to the convective theory, hurricanes arise due to the development of intense convective vertical air currents over the hottest parts of the ocean, distant from the equator at such a distance at which the deflecting force of the Earth's rotation is capable of imparting vortex motion to air masses. The unstable thermal stratification of the atmosphere that often occurs in these areas contributes to the intense rise of air supersaturated with water vapor. At the moment of steam condensation, a huge amount of latent heat of vaporization is released, which turns into the kinetic energy of the cyclone.

In the central part of the cyclone, under the influence of centrifugal ejection of air with a small influx of air in the surface layer, the pressure quickly drops. Initially mild depression atmospheric pressure deepens, and after just a few days a powerful cyclone begins to move westward, increasingly increasing its depth and speed of movement. The strength of the wind in it also increases. The cyclone develops into a tropical hurricane.

And finally, the eastern wave theory explains the formation of hurricanes by the passage of a long (up to 2000 kilometers long) wave of atmospheric pressure. This wave, moving from east to west, loses its stability and turns into a whirlwind.

The average duration of a tropical hurricane ranges from 6 to 9 days. The longest-lived hurricanes are those that originate near the coast of Africa and in the area of ​​the Cape Verde Islands, crossing twice Atlantic Ocean and going far to the north. Their duration is 3 or 4 weeks. Sometimes tropical hurricanes turn into ordinary cyclones, and then the duration of their existence is enormous.

Thus, the hurricane of 1900, which killed 6,000 people in Galveston (USA) on September 8, began on August 27 in the mid-Atlantic, crossed the Caribbean Sea, the Gulf of Mexico and went deep into the continent. In the Great Lakes region, it transformed into a regular hurricane, but, maintaining strength, crossed North America, Atlantic Ocean, Europe and went far to Siberia. The duration of this hurricane was 27 days.

At the surface of the earth, a hurricane usually represents an almost circular area of ​​storm and hurricane winds with a diameter of up to 500, and in some cases up to 1000 kilometers. The highest wind speeds, sometimes exceeding 80 meters per second, occur in the ring at a distance of 30 kilometers from the center of low pressure. However, in some cases, destructive winds affect a wider area. For the Pacific Ocean, the average size of the destruction zones accompanying a typhoon reaches 40 - 80 kilometers at general sizes hurricane up to 1500 kilometers.

An amazing feature of tropical vortices is a high funnel (up to 10 - 14 kilometers) with steep sides, rotating at enormous speed.

Here is how an observer from an airplane crossing a hurricane picturesquely talks about the central part of the typhoon: “We are in the wall of the typhoon, in the zone of maximum winds, in the zone of convergence - the convergence of air flows, where crumpled, oblique, compressed winds are madly rushing towards a giant funnel of depression and cannot overcome the mysterious border of the wall.

And suddenly, when it seems that the Boeing is captured by the last explosion of elemental madness, there is a sudden silence.

This is the eye

This is the area of ​​the lowest pressure and the highest temperature...

This is an abyss, an abyss in the atmosphere, where, as if at the call of a prophet, fantastic hordes of millions of cubic meters of air rush, consumed by impatience and dizziness, aggravated by the heat, howling and whirling, raising the ocean in waves and foam, like road dust, thrown back, colliding with others crowds seized by the same mystical madness of matter...

There is a wall stretching around, a fortress, which seems to have been erected to make us captives of this country full of magical charm...”

And here is an excerpt from P. A. Molan’s book “Typhoon Hunters” (1967):

“You should not think that the typhoon is clearly demarcated, that it looks like a millstone spinning and grinding the earth into powder, or like a rotating column. It has no distinct boundaries - it is a vaguely outlined mass twice as tall as Everest, with a crater in the center that anyone who has seen it at least once can never forget. This is a world of violent forces, a world of inevitable destruction, a world with energy equal to that of three atomic bombs per second.”

Indeed, the energy of tropical hurricanes is enormous.

What is a cyclone? Almost every person is interested in the weather - they look at forecasts and reports. At the same time, he often hears about cyclones and anticyclones. Most people know that these atmospheric phenomena are directly related to the weather outside the window. In this article we will try to figure out what they are.

A cyclone is an area of ​​low pressure covered by a system of circular winds. Simply put, it is a huge flat atmospheric vortex. Moreover, the air in it moves in a spiral around the epicenter, gradually approaching it. The reason for this phenomenon is considered to be low pressure in the central part. Therefore, warm, moist ones rush upward, rotating around the center of the cyclone (the eye). This causes the accumulation of high-density clouds. Strong winds are raging in this zone, the speed of which can reach 270 km/h. The rotation of the air is counterclockwise with some vortex towards the center. In anticyclones, on the contrary, the air swirls clockwise. Tropical cyclone in Southern Hemisphere works almost the same. However, the directions are reversed. Cyclones can reach different sizes. Their diameter can be very large - up to several thousand kilometers. For example, a large cyclone can cover the entire European continent. As a rule, these atmospheric phenomena are formed in certain geographical points. For example, a southern cyclone comes to Europe from the Balkans; areas of the Mediterranean, Black and Caspian Seas.

Mechanism of cyclone formation - first phase

What is a cyclone and how does it form? At fronts, that is, in zones of contact between warm and cold air masses, cyclones arise and develop. This natural phenomenon is formed when a mass of cold polar air meets a mass of warm, humid air. At the same time, the warm ones burst into the array of cold ones, forming something like a tongue in them. This is the beginning of the formation of a cyclone. Sliding relative to each other, these flows with different temperatures create a wave on the frontal surface, and therefore on the front line itself. The result is a formation resembling an arc, concavely facing towards warm air masses. Its segment, located in the front eastern part of the cyclone, is a warm front. The western part, which is located from the rear atmospheric phenomenon, is a cold front. In between, zones of good weather often occur in a cyclone, which usually lasts only a few hours. This deflection of the front line is accompanied by a decrease in pressure at the top of the wave.

Cyclone evolution: second phase

The atmospheric cyclone continues to evolve further. The formed wave, moving, as a rule, to the east, northeast or southeast, gradually deforms. Language warm air penetrates further north, forming a well-defined warm sector of the cyclone. In its front part, warm air masses float onto colder and denser ones. As you rise, steam condenses and thick cumulonimbus clouds form, leading to precipitation (rain or snow) that lasts a long time. The width of the zone of such frontal precipitation is about 300 km in summer, and 400 km in winter. At a distance of several hundred kilometers before the warm front, the air near the earth's surface reaches a height of 10 km or more, at which moisture condenses to form ice crystals. White ones are formed from them. Therefore, it is from them that one can predict the approach warm front cyclone

The third phase of the formation of an atmospheric phenomenon

Further characteristics of the cyclone. Moist warm air of the warm sector, passing over the colder surface of the Earth, forms low stratus clouds, fog, and drizzle. After the passage of a warm front, a warm period begins cloudy weather with southerly winds. Signs of this are often the appearance of haze and light fog. Then a cold front approaches. Cold air, passing along it, floats under the warm air and displaces it upward. This leads to the formation of cumulonimbus clouds. They cause showers and thunderstorms, which are accompanied by strong winds. The width of the cold front's precipitation zone is about 70 km. Over time, the rear part of the cyclone comes to replace it. It brings strong winds, cumulus clouds and cool weather. Over time, cold air pushes warm air east. After this, clear weather sets in.

How cyclones form: fourth phase

As a tongue of warm air penetrates into a mass of cool air, it becomes increasingly surrounded by cold air masses, and itself is forced upward. This creates a zone of low pressure in the center of the cyclone, into which the surrounding air masses rush. In the Northern Hemisphere, under the influence of the Earth's rotation, they turn counterclockwise. As mentioned above, southern cyclones have opposite directions of rotation of air masses. It is precisely due to the fact that the Earth turns around its axis that the winds are not directed towards the center of the atmospheric phenomenon, but go tangentially to the circle around it. As the cyclone develops, they intensify.

The fifth phase of cyclone evolution

Cool air in the atmosphere moves at a higher speed than warm air. Therefore, the cold front of the cyclone gradually merges with the warm one, forming the so-called occlusion front. The surface of the Earth is no longer warm zone. Only cold air masses remain there.

Warm air rises, where it gradually cools and is freed from moisture reserves that fall to the ground in the form of rain or snow. The difference between the temperature of cold and warm air is gradually leveled out. At the same time, the cyclone begins to fade. However, there is no complete homogeneity in these air masses. Following a given cyclone near the front on the ridge new wave a second one arises. These atmospheric phenomena always occur in series, with each successive one slightly further south than the previous one. The height of the cyclone vortex often reaches the stratosphere, that is, it rises to a height of 9-12 km. Especially large ones can be found at altitudes of 20-25 km.

Cyclone speed

Cyclones are almost always on the move. The speed of their movement can be very different. However, it decreases as the atmospheric phenomenon ages. Most often they move at a speed of about 30-40 km/h, covering a distance of 1000-1500 km or more in 24 hours. Sometimes they move at a speed of 70-80 km per hour or even more, covering 1800-2000 km per day. At this rate, the cyclone, which was raging in the area of ​​England today, in 24 hours may already be in the area of ​​Leningrad or Belarus, provoking sudden change weather. As the center of the atmospheric phenomenon approaches, the pressure drops. There are different names for cyclones and hurricanes. One of the most famous is Katrina, which caused serious damage to the United States.

Atmospheric fronts

We have already figured out what cyclones are. Next we will talk about their structural components - atmospheric fronts. What makes huge masses of moist air rise high in a cyclone? To get an answer to this question, we first need to understand what the so-called atmospheric fronts. We have already said that warm tropical air moves from the equator to the poles and on its way encounters cold air masses of temperate latitudes. Since the properties of warm and cool air differ sharply, it is natural that their masses cannot immediately mix. At the meeting point of air masses different temperatures a clearly defined strip appears - a transition zone between air fronts with different physical properties, which in meteorology is called the frontal surface. The zone separating the air masses of temperate and tropical latitudes is called the polar front. And the frontal surface between temperate and arctic latitudes is called arctic. Since the density of warm air masses is less than that of cold ones, the front represents inclined plane, which always leans towards the cold mass at an extremely small angle to the surface. Cool air, being denser, when meeting warm air, lifts the latter upward. When imagining a front between air masses, you must always keep in mind that this is an imaginary surface inclined above the ground. The line that is formed when this surface intersects with the earth's is marked on weather maps.

Typhoon

I wonder if there is anything in nature more beautiful than such a phenomenon as a typhoon? A clear, calm sky above a well of walls created by a crazy whirlwind, pierced by zigzag lightning, two Everest-high walls? However, big troubles threaten anyone who finds themselves at the bottom of this well...

Originating in equatorial latitudes, typhoons head west and then (in the Northern Hemisphere) turn northwest, north, or northeast. Although each does not exactly follow the path of the other, most of them move along a curve that is shaped like a parabola. The speed of typhoons increases as they move northward. If near the equator and towards the west they move at a speed of only 17-20 km/h, then after turning to the northeast their speed can reach 100 km/h. However, there are times when, unexpectedly deceiving all forecasts and calculations, typhoons either stop completely or rush madly forward.

eye of the hurricane

The eye is a bowl with convex walls of clouds, in which there is a relatively weak wind or complete calm. The sky is clear or partially covered with clouds. The pressure is 0.9 of the normal value. The eye of a typhoon can range in size from 5 to 200 km in diameter, depending on the stage of its development. In a young hurricane, the size of the eye is 35-55 km, while in a developed one it decreases to 18-30 km. As the typhoon subsides, the eye grows again. The more clearly defined it is, the more powerful the typhoon. In such hurricanes, the winds are stronger near the center. Closing all the currents around the eye, the winds swirl at speeds of up to 425 km/h, gradually slowing down as they move away from the center.

Tropical cyclones, hurricanes, typhoons

Especially dangerous phenomenon nature are deep cyclones of various origins, which are associated with strong winds, heavy precipitation, surges and high wind waves at sea. The depth of the cyclone is determined by the air pressure at its center.

The size and power of deep cyclones depends on many factors and, first of all, on the place of their origin. Cyclones that originate in the tropical latitudes are characterized by the greatest power. They are called tropical in contrast to extratropical cyclones(extratropical cyclones), among which are cyclones of temperate latitudes and Arctic cyclones. The higher the geographic latitude of the cyclone's origin, the lower its maximum power.

Tropical cyclones carry enormous reserves of energy and have great destructive power. The kinetic energy of a medium-sized tropical cyclone is comparable to the explosion energy of several powerful ones. hydrogen bombs and accounts for about 10% of the total kinetic energy of the northern hemisphere.

Most often (in 87% of cases) tropical cyclones occur between latitudes 5° and 20°. At higher latitudes they occur in only 13% of cases. The occurrence of tropical cyclones north of 35° N has never been observed. w. and south of 22° S. w.

Tropical cyclones can occur at any time of year in the tropical parts of all oceans except the southeastern Pacific and South Atlantic. Most often they form in the northern part tropical zone Pacific Ocean: on average, about 30 cyclones are tracked here per year. The main season for the development of tropical cyclones is August-September; in winter and spring their frequency is very insignificant.

Tropical cyclones usually originate over the oceans, and then move over their waters and reach the coasts of continents and islands, hitting them with strong winds, torrents of rain, causing surge waves up to 8 m high, as well as waves in the open sea over 10 m high.

Tropical cyclones that have reached significant intensity have their own name in each region. In the eastern part of the Pacific Ocean and in the Atlantic they are called hurricanes (from the Spanish word “huracan” or English “haricane”), in the countries of the Hindustan Peninsula - cyclones or storms, in Far East- typhoons (from the Chinese word “tai”, which means strong wind). There are also less common local names: “willy-willy” in Australia, “willy-wow” in Oceania and “baguio” in the Philippines.

To describe the intensity of tropical cyclones, the Saffir-Simpson scale is used, shown in table. 3.3.1.1. It shows that as the cyclone deepens, the wind speed and surge height increase, and the cyclone itself is classified as either a storm or a hurricane from the first to fifth categories.

This scale is used by almost all hurricane and typhoon monitoring centers. IN Lately The Saffir-Simpson scale began to be used to classify deep extratropical cyclones that reached the strength of a storm or hurricane. From this table it follows that hurricanes and typhoons have five categories (from the first category hurricane or typhoon H1 to the fifth category hurricane or typhoon H5). Tropical depressions and tropical storms are not divided into categories.

Table 3.3.1.1. Tropical Cyclone Scale

The life cycle of a tropical cyclone can be divided into four stages:

1. Formation stage. It begins with the appearance of the first closed isobar. The pressure in the center of the cyclone drops to 990 mb. Only about 10% of tropical depressions develop further.

2. Stage of a young cyclone, or stage of development. The cyclone begins to quickly deepen, i.e. there is an intense drop in pressure. Hurricane-force winds form a ring with a radius of 40-50 km around the center.

3. Maturity stage. The drop in pressure in the center of the cyclone and the increase in wind speed gradually stop. The area of ​​stormy winds and intense rainfall increases in size. The diameter of tropical cyclones in the development and mature stages can range from 60-70 to 1000 km.

4. Attenuation stage. The beginning of the cyclone filling (increasing pressure in its center). Attenuation occurs when a tropical cyclone moves into an area of ​​greater low temperatures surface of the water or when moving onto land. This is due to a decrease in the influx of energy (heat and moisture) from the ocean surface, and when reaching land also with an increase in friction with the underlying surface.

After leaving the tropics, a tropical cyclone may lose its specific properties and turn into an ordinary cyclone of extratropical latitudes. It also happens that tropical cyclones, remaining in the tropics, reach the mainland. Here they quickly fill up, but at the same time manage to cause a lot of destruction.

Since ancient times, there has been a practice of assigning proper names to destructive hurricanes and typhoons. At different times, the principles of naming have changed. For hundreds of years, Caribbean hurricanes were named after saints on the church calendar on whose day a devastating hurricane struck a major population center.

Under these names, hurricanes were included in chronicles and legends. An example is Hurricane Santa Anna, which struck Puerto Rico on July 26, 1825 with exceptional force. At the end of the 19th century. Australian meteorologist Clement Wragg began calling tropical storms by female names. Since 1953, the US National Hurricane Center began publishing preliminary lists from which Atlantic tropical storms were named.

Until 1979, only female names were used. Since 1979, both female and male names have been used. The practice of compiling preliminary lists of hurricanes and typhoons has spread to all regions. Now there are 11 such regions in the World Ocean. These preliminary lists for all regions are created and updated by a special international committee of the World Meteorological Organization (WMO).

Damaging factors of hurricanes and typhoons:

Wind kinetic energy;

Intense precipitation;

Surge wave;

Storm waves of considerable height.

Associated SNFs: strong winds, strong waves, intense rains, heavy hail, floods, floods, collapses, landslides, erosion and coastal reworking.

Hurricanes cause colossal damage to the coasts of Northern and South America, islands along the path of their distribution. They strike these coasts with a frequency of once every few years, sometimes forming series within one year. One of the most destructive hurricanes, Mitch in October 1998, killed 10,000 people in Honduras and Nicaragua and left 2 million people homeless.

The hurricane caused the worst floods in these countries in the last two hundred years. The total economic damage from the hurricane exceeded $5 billion. The world's greatest economic damage was caused by Hurricane Andrew, which swept over the United States from August 23 to August 27, 1992. Insurers paid out $17 billion, which covered about 57% of losses from the hurricane.

Underdeveloped countries in the Caribbean suffer severe damage from hurricanes, the consequences of which they take years to recover from. Hurricanes in mid-latitudes are rare: once every 8-10 years. In January 1923, a hurricane captured the entire European part USSR, the center of the hurricane passed through Vologda. In September 1942, a hurricane swept over central regions European part of our country.

The pressure difference was very large, and therefore hurricane-speed winds were formed in places. The usual speed of cyclones is 30-40 km/h; but there are speeds of more than 80 km/h. The September 1942 cyclone covered 2,400 km in one day (i.e. its speed was 100 km/h). On November 18, 2004, the hurricane hit Germany, then moved to Poland and Kaliningrad.

In Germany, the wind speed reached 160 km/h, in Poland 130 km/h, in Kaliningrad - 120 km/h. 11 people died in these countries, 7 of them in Poland. Everywhere the hurricane caused floods, downed power lines, damaged roofs, and toppled trees.

Annual losses from typhoons cause significant damage to the economies of several Asian countries. Most economically underdeveloped countries have great difficulty in repairing the damage caused by typhoons. Of the 25-30 typhoons that appear over each year western part Pacific Ocean, the Sea of ​​Japan and Primorsky Krai, i.e. From one to four typhoons enter the territory of Russia in different years, bringing a sharp deterioration in weather and causing significant economic damage.

They all appear over the ocean northeast of the Philippines. The average duration of a typhoon is 11 days, and the maximum is 18 days. The minimum pressure observed in such tropical cyclones varies widely: from 885 to 980 hPa, but when typhoons enter our territory, the pressure in their centers rises to 960-1005 hPa.

The maximum daily precipitation reaches 400 mm, and the wind speed is 20-35 m/s. In 2000, four typhoons hit the territory of Primorye, one of which - BOLAVEN - turned out to be the most destructive: 116 settlements were flooded, 196 bridges and about 2000 km were damaged. highways. A total of 32,000 people were affected and one person died. Economic damage amounted to more than 800 million rubles.

Forecasting hurricanes and typhoons, detecting their origin, tracking their trajectories is the most important task of meteorological services in many countries, primarily the USA, Japan, China, and Russia. To solve these problems we use space methods monitoring, modeling atmospheric processes, synoptic forecasts.

To reduce damage from hurricanes and typhoons, primarily in terms of human casualties, methods of warning, evacuation, adaptation of industrial processes, and engineering protection of coastlines, buildings, and structures are used.