it is understood by Atmospheric Circulation the movement of air masses. This movement takes place in the Troposphere, the layer of atmosphere closest to Earth.
Atmospheric circulation occurs due to the imbalance of radiation received by the Earth along its length. The regions that are located closer to the Equator line receive more solar radiation and, consequently, become warmer. While in the polar regions, the radiation index is lower and so is the heating. Thus, in order to achieve greater balance, there are many exchanges of air masses between the hottest and coldest regions.
The movement of air masses is only possible thanks to pressure differences. Cold air is heavier and, therefore, tends to go down and cause greater pressure, while warm air tends to rise and decrease the pressure of the atmosphere. As the decision of cold air and the rise of hot air happen simultaneously, there is a movement constant and circular of these masses, which is responsible for the occurrence of winds and variations climate.
The atmosphere's circulation pattern takes place through three movement cells (see diagram below), which are direct consequences of the rotation and translation movements.
Diagram of the Earth's air masses; note the direction of movement of each cell
The first movement cell is the tropical cell. It occurs in low-latitude regions (closer to the Equator). It is characterized by poleward movement occurring in the upper atmosphere.
The second movement cell is the ferrel cell or midlatitude cell. As the name implies, it occurs at intermediate latitudes (between the Equator and the poles). It is characterized by the direction of movement towards the poles occurring in the lower portion of the atmosphere
The third movement cell is the polar cell. The air coming from the other two cells, upon reaching the poles, descends and forms a strong polar pressure. Then, the surface displaces this air to zones of lower pressure and to tropical zones.
By Rodolfo f. Alves Feather
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/geografia/circulacao-atmosferica.htm
