Cyclones, anticyclones, typhoons, hurricanes, tornadoes, tornadoes - these phenomena are caused by vortex movements in the atmosphere, accompanied by precipitation (larger or smaller). Consider the characteristics and conditions of this element.
The movement of air masses in the atmosphere
In the atmosphere of our planet there is a constant circulation of air masses with the transfer of energy and material components. Movement occurs:
- from north to south and in the opposite direction (meridional);
- from west to east and in the opposite direction (latitudinal).
In the troposphere, in addition to meridional and latitudinal transport of air masses, there are vortex movements of the atmosphere, accompanied by precipitation - cyclones and anticyclones.
These phenomena cause a change in climatic conditions in all regions of the planet.
In the lower layers of the troposphere, in the tropical zone, the air masses are heated quite strongly. At the same time, air masses are filled with moisture (especially over the oceans). Heated air rises up to a height of 1000-1200 meters, where it begins to cool, followed by cloud formation. In place of the raised warm masses come the cold northern ones (in the northern hemisphere). Warm air masses are captured by the Coriolis force caused by the rotation of the Earth. They begin to move not only upward, but also horizontally, deviating from the straight line direction - in the northern hemisphere to the northeast. Cold masses go southwest (in the southern hemisphere, air masses move in exactly the opposite direction). So the trade winds are formed.
The water surface of the ocean, warmed by the end of summer and the beginning of autumn, provides the possibility of the formation of other air masses filled with moisture - monsoons. Their direction is strictly opposite to the trade winds.
The thermal balance of the planet is maintained due to global inter-latitudinal transport: heat from tropical latitudes to high, cold from subpolar (high) latitudes to the tropics.
The cyclonic activity of the atmosphere is based on the connection of tropical circulation with the vortex activity of air masses in temperate latitudes.
Cyclogenesis
This term refers to the formation, development, or folding of the vortex motion of the atmosphere, accompanied by precipitation. That is just any cyclone - a vortex with low pressure inside. "In the bowels" of cyclones of the northern hemisphere winds blow counterclockwise. The lower region of the cyclone is characterized by a deviation of the wind towards its center.
Modern meteorology divides cyclonic eddies into two types: according to their place of origin and subsequent activity, tropical and extratropical (cyclones of temperate latitudes).
The former are formed in the tropic zone, with development they reach a size of up to a thousand kilometers (very rarely more). The second is the vortex motion of the atmosphere in the zone of temperate and subpolar latitudes. Non-tropical cyclones reach enormous (up to several thousand kilometers) sizes.
The speed of vortex air movement in tropical cyclones is huge, can reach storm values. These vortices can become extratropical when moving.
Conditions necessary for the formation of a tropical whirlwind
In order for a tropical vortex to form, it is necessary that the surrounding air is saturated with moisture (this gives an instability factor). The water in the ocean warms to a depth of fifty meters, to a temperature of more than twenty-six degrees Celsius. Upon vapor condensation in the lower layers of the troposphere, the air must cool very quickly (this is the main source of cyclone energy).
Typhoons and hurricanes - tropical cyclones
In the Far East and in Southeast Asia, tropical swirling movements of the atmosphere accompanied by precipitation are called typhoons. In the countries of the Americas - by hurricanes (among the Mayan Indians, the god of the wind is Huracan). If the speed of a storm during a storm exceeds one hundred seventeen kilometers per hour, then this is a hurricane.
Tropical cyclones bring rain showers. At sea, during a typhoon and a hurricane, huge waves arise. But they weaken, getting under the influence of winds on land. Rainfall caused by tropical cyclones spills inland at distances up to forty kilometers. This is very important to mitigate the dry climate of the continents.
The cyclones themselves transfer the energy reserve from one place on the planet to another, from the tropics to temperate zones. This is important for global cyclonic processes in the atmosphere, because it leads to the convergence of temperatures on the planet, smoothing the climate and making it milder.
Extratropical cyclones and anticyclones
Enormous in size (several thousand kilometers) vortex movements of the atmosphere, accompanied by precipitation and occurring in the temperate and circumpolar zones, are called extratropical cyclones and anticyclones. The air vortices in the northern cyclones rotate in the same direction as the northern typhoons.
With the arrival of such a hurricane, inclement weather sets in, but the anticyclone brings a clear and sunny day.
The emergence of temperate cyclones
To represent the mechanism of occurrence of these formations, it is necessary to operate with the concept of the atmospheric front. In a first approximation, this is simply a border separating two different air masses.
In fact, this is a zone of several tens of kilometers, tilted at an angle of one degree. In the case of a warm front, its slope lies in the direction of movement (it seems to cover the cold mass from above). When cold - on the contrary, in the opposite side of the movement. The equation of atmospheric motion is expressed through the formula of Max Margules (Australian meteorologist).
The interaction of warm and cold fronts leads to the formation of a cyclonic vortex. With this connection, part of the warm front is introduced into the cold mass in the form of an elongated “tongue”. In this case, warm air rises up, as lighter.
During this interaction, two processes occur, leading to a cyclonic vortex. The molecules of steam (water), rising, begin to rotate: they are affected by the Earth's magnetic field. They draw all the surrounding air into this rotational movement. As a result, a huge whirlpool is formed from it and water molecules.
Upstairs, the air masses cool. In this case, condensation of water vapor occurs, which turns into clouds (this is subsequent rain, hail, snow). Such weather with bad weather can be delayed for several days, or even weeks. This will depend on the “longevity” of the cyclone: the greater the intake of warm air, the longer the cyclone exists.
The emergence of anticyclones
The occurrence of this vortex is due to the lowering of the atmospheric masses when they are heated with the surrounding masses, without the exchange of heat. In this process, the humidity inside drops, and this entails the evaporation of existing clouds. Under the influence of the Earth's magnetic field, water molecules begin to rotate - in the northern anticyclones - clockwise. Stable weather during this process can last up to three weeks.