Many of the changes and movements that occur in the atmosphere of our planet are determined by the movements of the Earth and the irregular characteristics of the Earth’s surface. The Earth’s atmosphere is in constant motion, and this is due to the fluctuation of warm air that flows from the tropics to the poles, and returns cold from the poles to the equator. The layer of the atmosphere closest to the earth’s surface is called the troposphere, and it is the one that contains the air we breathe and where the meteorological phenomena that determine the Earth’s climate occur.. The atmospheric current, that is, the air that fluctuates through seas and oceans around the world, can undergo physical changes throughout its trajectory and the environmental factors that surround it. These changes can be, for example, in its temperature or its humidity, and depending on the characteristics of the air, it will be more or less light and will remain more or less time in the same region.
This AgroCorrn article will explain what cyclones and anticyclones are , meteorological phenomena that occur when there are variations in the pressure of the atmosphere.
Movement of the Earth and the wind: the Coriolis effect
The rotation of the Earth causes the air flowing through the troposphere to bend, that is, the air masses are subjected to a force that deflects their trajectory. This force, commonly known as the Coriolis effect , implies that the rising columns of air in the Northern Hemisphere will deflate in a clockwise direction (clockwise) and those in the Southern Hemisphere will deflect in the opposite direction (anti-clockwise).
This effect produces very important movements not only in the air, but also in bodies of water. This effect is enhanced as it is closer to the equator, since the surface of the Earth in that area is greater and it also turns out to be the area furthest from the center of the Earth.
What is a cyclone and its types
Cyclones are a very common phenomenon, normally considered as strong winds accompanied by storms . These strong winds are formed in areas where the pressure is low (less than 1013 Pa), and these low pressures generate winds that attract other atmospheric air masses with higher pressure. This phenomenon, also called squall or cyclonic flow, It originates when the surface of the sea is at high temperatures, since, in these conditions, the warm air rises loaded with humidity until it condenses into storm clouds. All these clouds are moving in large circles that revolve around themselves, forming extremely strong winds and leaving a space in the center that is known as the eye of the hurricane. These cyclonic flows are especially particular due to the great energy they possess, which comes from the heat given off by the water vapor that is released when condensing.
It can reach up to 200 km in diameter, and the winds of a cyclone can reach speeds between 50 and 250 km / h (depending on the type of cyclone in question, losing force as they approach land or when they arrive to oceanic areas with colder temperatures.
This type of phenomenon produces huge waves and large displacements of water masses. In tropical areas, cyclones often cause major flooding , and are capable of transporting really heavy objects over long distances.
Categories or types of cyclones
Of this classification, the most important is the tropical cyclone, which is subdivided into five categories based on the speed and aggressiveness of the winds. This type of cyclone, depending on its strength, can be called a tropical depression, tropical storm or hurricane. Obviously, the one with the highest speed and aggressiveness is the hurricane, which causes very strong winds and great damage.
Although tropical cyclones can cause great damage, such as the destruction of homes and natural habitats, they can also bring very positive aspects, such as ending periods of drought or regenerating vegetation cover (since the older or weaker trees).
In reference to extratropical cyclones, we can say that they are associated with a low pressure system located between the tropics and the poles and that they depend on the contrast between warm and cold air masses. If there is a very marked drop in atmospheric pressure, this type of cyclone is called explosive cyclogenesis, and causes great damage, such as floods or landslides.
Regarding subtropical cyclones, they have a fusion of characteristics of the two previous cyclones, and their characteristics will depend on their place of origin. In reference to the polar cyclone, we must mention that it is also called an arctic cyclone, and it turns out to be a low pressure system with a fairly large diameter that causes strong winds. Even so, it has a shorter life than that of tropical cyclones, since in 24 hours it can reach its peak.
Finally, the mesocyclone is an air vortex that forms during a convective storm, and is usually associated with electrical storms. This phenomenon is formed in conditions of high instability and when there are strong winds at high altitudes, but it is usually very rare to see.
What are anticyclones and their types
An anticyclone is a zone of high pressure (higher than 1013 Pa), in which the atmospheric pressure is higher than that of the surrounding air and increases from the periphery to the center. Usually it could be associated with the typical stable weather, with clear skies and sunshine.
The air column of an anticyclone is more stable than the air around it. In turn, the air that is descending downwards produces a phenomenon known as subsidence, which means that it prevents the formation of precipitation. Of course, it must be taken into account that the way in which the air will descend will vary depending on the hemisphere in which it is located.
These anticyclonic flows develop more easily in summer, further aggravating the dry season . They tend to be irregular phenomena, both in shape and behavior, unlike cyclones, which are more easily predictable. In general, anticyclones can be classified into four groups or types.
Types or groups of anticyclones
- Subtropical Atlas
- Continental Polar Atlases
- Atlas between series of cyclones
- Atltas produced by the invasion of polar air
The first are the subtropical atlases, which turn out to be large and elongated anticyclonic flows, located in the subtropics and usually stationary or with very slow movements. In this group, the Azores anticyclone should be highlighted, which turns out to be a very important, dynamic anticyclone that conditions the climate of the area and the storms that will come in colder times.
Second are the anticyclones called continental polar atlases, which form in winter on the continents closest to the north and move until they reach warmer waters and are absorbed by the subtropical anticyclone.
The third group of anticyclones are the atlases between the series of cyclones, which are small in size and, as their name indicates, appear between cyclones.
The last anticyclonic group is that of the atltas produced by the invasion of polar air, which, as its name indicates, cold air adsorbs the heat of the warmer waters and after a few days it transforms into a subtropical anticyclone.
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