Atmospheric Pressure - Education and Transformation

It is the force or pressure that gases in the atmosphere exert on a given surface. THE atmospheric pressure can change according to altitude, the lower the altitude the higher the atmospheric pressure.

This happens because places with lower altitudes, such as sea level, have a "column" of atmospheric air higher on its surface, while places with high altitude have a smaller air column over its surface.

See too:

• wind energy
• air properties

Atmospheric pressure is directly related to the dynamics of winds on the planet, so it is necessary to study the general circulation of the atmosphere.

General circulation of the atmosphere.

First, we must be aware of the following characteristics of the atmosphere:

• Places with high atmospheric pressure have a high concentration of gas molecules, so these gases are expelled to places with pressure low atmospheric pressure, the movement of gases from the place of high atmospheric pressure to places with low atmospheric pressure from the origin to the wind. Consequently, places with high atmospheric pressure expel wind and places with low atmospheric pressure receive wind.
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• We call a part of the atmosphere that has low atmospheric pressure and receives winds as a cyclone. We call an anticyclone part of the atmosphere that has high atmospheric pressure and expels winds.
• High atmospheric pressure places are cold and low pressure places are hot.
• All heated air tends to ascend (up) and all cold air tends to descend.
• Areas close to the Equator (0°) are hot and have low atmospheric pressure.
• The farther away from the Equator, the colder the location and high atmospheric pressure.
• Starting from this principle, we can understand how the atmosphere behaves around the globe.
• The hot region, close to the equator (0°), is a region of low atmospheric pressure, that is, a region that receives winds, the region with latitude around 30° tends to be colder, with high pressure atmospheric. The 30° region expels excess gas molecules, it is the moving air, what we call wind, this wind will always be cold, as it approaches the Equator (0°) it will be heated, and as it warms up, it will move upwards, that is, the air will move up. Upon reaching high altitude the air will be cooled again (because the higher the colder) and returns to its place of origin (the 30° latitude region).
• The wind that expels from 30° towards 0° is called the trade winds. The wind that leaves 0° and goes to 30° is called Counter-Trade winds. This cycle of air heating, rising, cooling and descending in regions between 0° and 30° latitude is called hadley cell.

Below is a diagram that illustrates the Hadley cell.

I: Trade winds (wet).
II: Counter-trade winds (dry).
III: The region of Ecuador which, because it receives wind, is also called ZCIT (Intertropical Convergence Zone).

Consider the line that lies horizontally as the Greenwich Meridian, and the small lines that cross this line as latitude, the inversion of latitude and longitude positions occurred in this explanation and representation (in this and the next diagrams that will appear throughout the text) for purposes didactic.

We must keep in mind that there are two Hadley cells on the planet, one in the southern hemisphere and the other in the northern hemisphere.

It is important to emphasize that this dynamics of the atmosphere is one of the factors responsible for the high rainfall in the region of Ecuador, because the trade winds bring moisture to Ecuador, when it is heated and ascends, they form clouds and then precipitation occurs. (rain). With the 30° latitude region, the opposite occurs, there will be a low rate of rain, as they expel winds with humidity, which is why the great deserts on the planet are close to 30° latitude.

There are two more atmospheric cells on the planet, the Ferrel cell and the Polar cell. The Ferrel cell occurs between 30° (high pressure region that blows out wind) and 60° (low pressure region that receives wind) of latitude, of the same the way in which the 30° region expels the trade winds to the equator, it also expels wind (called West winds) to the region with latitude of 60°.

At this point we need to go back to a basic rule, the closer to the Equator (0°) the warmer the region will be, as we move away from 0° the temperature will reduce proportionally. Therefore, regions of 0° will be warm, regions with 30° less hot, regions with 60° cooler, as it is approaching the poles.

As the winds approach 60°, the temperature goes down, when the wind from the West approaches the polar air mass it ascends and returns to the 30° region.

I: West winds (out from the 30° high pressure region to the 60° low pressure region).

The expulsion of the winds from the West to the region of 60°, their ascent and then back to their place of origin (30°), forms the Ferrel cell. There are two Ferrel cells, one in the Northern Hemisphere and the other in the Southern Hemisphere.

Finally, we will study the polar cell, which occurs between the 60° (low pressure) and 90° (high pressure) regions of latitude. In the 90° region, winds are expelled to the 60° region, when the cold wind approaches 60° the air will warming up and rising, when rising and reaching a lower temperature, it cools again and returns to its place of origin (90°).

There is a polar cell in the southern hemisphere and one in the northern hemisphere.

Other articles:

• Southeast region
• South region