Cyclones are tropical storms formed in centers of low pressure, areas associated with cloud formation, moisture and to storms. THE instability in these areas causes an intense air movement converging at its center, concentrating moisture and heat.
According to the United States Oceanic and Atmospheric Administration, a cyclone is a phenomenon that represents a rotating system of clouds and storms graduated in tropical waters or subtropical.
Features
The cyclones, or low pressure area systems, according to the National Institute of Meteorology, are an area that has lower atmospheric pressure than neighboring areas and have a closed circulation center, whose winds blow inwards, around this center. The circulation of cyclones differs in the two hemispheres: in the HemisphereNorth, rotate towards counter-clockwise, and in the South hemisphere, in the sense schedule.
According to the Center for Weather Forecasting and Climate Studies (Cptec), cyclones usually arise in the oceans, may last several days and walk through a long way, with a lot intensity.
Also know: Why is the United States so hit by hurricanes?
Causes
Cyclones are caused by air movement in a low atmospheric pressure zone: o hot air It's humid rises to the upper layers of the atmosphere, while the cold air, drier and denser, descends to the surface, causing a reduction in atmospheric pressure.
Thus, there is a great deal of heat release caused by condensation—when warm, moist air rises and condenses—thereby heating the air mass. What causes the convection process and creates an area of instability, thus initiating the cyclone phenomenon.
Cyclone x hurricane
Hurricane Michael hit Florida, United States, in 2018, causing extensive damage.*
The term cyclone is a generic definition for meteorologists. thus, tornadoes, typhoons and hurricanes are examples of cyclones, therefore, all these phenomena tropical storms. The different names vary depending on the place of origin and the intensity.
Cyclones that have speeds above 119 km/h are considered hurricanes, and this denomination is used for the storms that occur in the eastern portion of the Pacific Ocean or not Atlantic Ocean.
Tropical storms that occur in the portion west pacific are called typhoon. These are known as tornadoes when they form on land and have speeds above 400 km/h.
Read too: The difference between tornado, hurricane and cyclone
Types
Cyclones are classified according to their origin, intensity and also by their characteristics, such as shape and mode of air circulation.
Cyclones can be classified into:
→ Tropical
Low pressure system that features closed circulation of winds, high humidity and high temperature, associated with intense storms and high-speed winds. It does not have an associated cold front and is characterized by presenting itself in the form of a rounded cloud mass.
This type of cyclone can vary your size and it is measured from the limit distance from the center, known as the “maximum wind radius”. It is usually formed in the latitude between 20º to the south and 20º to the north, that is, around the tropics.
→ Subtropical
Low pressure system, like tropical cyclones, does not have a cold front associated with its formation and also presents itself as a rounded cloud mass. The center of this type of cyclone has a higher temperature than the surrounding atmosphere. It has smaller horizontal size than extratropical cyclones and causes large volume of rain and higher intensity winds. Forms among the tropics.
→ Extratropical
Low pressure system characterized by being graduated at mid and high latitudes, that is, out of the tropics. It differs from the tropical and subtropical cyclone in being associated with cold fronts. Your shape refers to a spiral, and yours center has low temperature in relation to the surrounding atmosphere. This system favors the formation of moderate rains and strong winds.
Read more:Tropics of Earth
Cyclone and Anticyclone
While cyclones represent areas of low atmospheric pressure, that is, a wind convergence zone, anticyclones represent areas of high atmospheric pressure, or a wind dispersal zone.
This is because air masses tend to move from a high pressure zone to a low pressure zone. Thus, the low pressure system, or cyclones, represents regions of instability, characterized by heavy rains and strong winds. The high pressure system, or anticyclones, represents stable weather regions, normally dry and without in the presence of clouds.
THE wind movement for the two systems is different. In cyclones, winds circulate clockwise in the Southern Hemisphere and counterclockwise in the Northern Hemisphere. In anticyclones, the winds move clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
Also know:Movement of the waters of the seas and oceans
Cyclones in Brazil
A survey conducted by the Faculty of Oceanography, University of Rio de Janeiro, points out that between 2004 and 2016, in Brazil, two tropical cyclones and five subtropical cyclones, noting that most of these storms occur in the south coast of the country. Only one of these tropical storms hit the Brazilian coast. In 2004, the extratropical cyclone Catarina reached the coast of the state of Santa Catarina, causing 11 deaths and leaving more than 27 thousand homeless people. This storm initially formed as an extratropical cyclone and changed categories to become a tropical cyclone, or hurricane.
Two subtropical cyclones, And falls (2016) and cari (2015), also caused damage to the Brazilian coast. Despite not having reached the mainland, both provoked strong winds and rains, wreaking havoc in some cities in Santa Catarina, at the Rio Grande do Sul and also in parts of the state of Rio de Janeiro.
*Image credit: terry kelly / Shutterstock
by Rafaela Sousa
Graduated in Geography
