High and low pressures

Atmosphere layers

Because of the action of the Sun, the closer the air is to the Equator, the warmer it will get. As it gets warm, it expands and rises, so pressure decreases. When the air molecules reach the tropopause, they are forced to head for the poles while lowering temperature in the process. Near Parallel 30º, because of accumulation and temperature, the air comes down again compressing, heating and stacking itself, so generating high pressure.

We will explain this in a little more detail; The Sun heats the earth more at the equator than at the poles for several reasons and the first is that the equator is about 6 thousand km closer to the Sun than the poles, the rays entering the atmosphere only have to pass through a few kilometers of this before touching the ground at the equator but cross a much longer space to touch the poles as seen in the following graph and therefore arrive weaker. Another important reason is the angle with which they affect the Earth, which as we see in the graph is very different, so the rays are reflected in a different way in one point and in another.

The air when heated expands therefore has less density per cubic meter (imagine that each square of the grid in the previous graph is a cubic meter) which makes it float in relation to the more dense air. Each red bubble in the graph represents an air molecule, they all weigh the same but clearly they are of different size, so a bubble is using different number of squares, which means that in a grid column there are more or less bubbles therefore, the weight in each column is different and the larger the bubbles, the lower the weight of the column or, what is the same, the lower atmospheric pressure.

When the bubbles get at the tropopause they are forced to travel towards the poles but in reality they never reach them because they are losing temperature on the way and they start to have a higher density again, in addition to all these red bubbles (which they will now catch a colder color as you will see in the video) do not fit in the airspace of the poles since it is much smaller than the equator and as a result the air comes back down around the 30th parallel generating a high pressure, which is obviously the opposite of a low.

The lowering air is piled on itself compressing and gaining temperature, when descending it makes impossible the formation of clouds and for that reason the nonexistence of rain, for these two reasons here we have the desert areas of the planet.

As a consequence of the Earth rotation, in the Northern Hemisphere the wind will blow clockwise. Due to the accumulation of the air, pressure increases in the center of the anticyclone, so the air particles tend to travel down to low pressures though, they get turning inertia along the isobars.

Watch full video

Deja un comentario

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *