Everything we call meteorology and the different types of climate occur in the troposphere. That is, in just one of the layers of the atmosphere . The troposphere is the zone of the atmosphere where we live, and it ends between 10 and 16 km in altitude. Above this zone lies the stratosphere . The boundary between these two layers is the tropopause . This is the topic of this article.
The tropopause has distinct characteristics between the layers it separates and is what causes the weather to end at the top. In this post, we tell you everything about the tropopause.
Key features
This is a discontinuous zone between the troposphere and the stratosphere. As we know, the troposphere is the zone where different types of clouds develop and precipitation occurs. Above this layer, the characteristics, gas composition, and other factors of the atmosphere change completely. For example, the stratosphere contains the well-known ozone layer that protects us from the sun's harmful rays.
The tropopause marks the upper limit of water vapor in the air. Above this altitude, the air is completely dry. One of the characteristics of this boundary is that it creates a temperature inversion. That is, the temperature increases with altitude in the stratosphere instead of decreasing. This causes all vertical air movements to stop, in addition to the force of the horizontal winds in the stratosphere.
The temperature gradient of the thermal inversion is 0,2 degrees Celsius per 100 meters . Contrary to popular belief, it is not a continuous layer. Quite the opposite. As we move into mid-latitudes and tropical zones, we can see some breaks in both hemispheres. Interestingly, these breaks coincide with the paths of the jet stream.
The openings in the tropopause allow ozone present in the stratosphere and other dry air to enter the troposphere. The altitude of the tropopause decreases in the regions from the equator to the poles. However, the temperature increases with altitude.
Types of tropopause according to altitude and latitude
Depending on the meteorological and weather variables at each moment, the height of the tropopause varies. For example, it is higher when there are anticyclones in the lower layers and it is lower when there is a depression or a storm. The temperature changes depending on the latitude where you are. There are areas where it is at -85 ° C and in other areas at -45 ° C.
In this way, three different conditions or three types of tropopause can be identified, depending on the area where it is as well as the latitude and altitude.
- Type 1 or normal It is one that has predominantly stationary situations. There is no warm or cold advection in the troposphere.
- Type 2 or H It is also called the high tropopause. It indicates when there is a type of warm advection in the highest and middle zone of the troposphere. This usually occurs in the presence of warm anticyclones.
- Type 3 or S. Also known as sunken. It corresponds to when a cold advection has originated in the upper layers of the troposphere and the rest is formed when there are areas of low pressure in the lower layers.
Importance
Although it may not seem like it, this line separating the two layers of the atmosphere is of great importance to life on Earth. First, thanks to the stability it provides at high altitudes, the famous cirrus clouds can form.
It serves as a water reservoir , as it can store large amounts of water vapor at its lower boundary, originating from tropical zones. Many of the compounds present at this boundary help us to understand more precisely the effects of climate change and how it will affect the planet. This understanding allows us to design other plans to mitigate some of the most dangerous damage caused by this phenomenon.
Clouds that reach the tropopause via convection currents stop rising, as if they've hit a glass wall. The tropopause prevents them from continuing to float upward because it has the same density as the surrounding air. The opposite occurs below the tropopause, where the air has buoyancy that allows it to move up and down. The most powerful storms in the troposphere can push some clouds over the tropopause.
Phenomena caused by the tropopause
There are some phenomena that take place thanks to the existence of this limit. We are going to analyze them one by one.
The first is that, as CO2 concentrations increase, so do the number of collisions between its molecules and those of other gases, such as nitrogen. During these collisions, kinetic energy is absorbed, producing what is known as infrared radiation. This type of radiation belongs to the electromagnetic spectrum and has a long wavelength. This contributes to the increase in heat.
When this occurs, there is a fairly easy transfer of heat in the troposphere, causing the temperature to rise. If this phenomenon takes place in the stratosphere, the infrared radiation produced can escape into space because of the low air density. This lower air density allows it to cool the upper layers of the atmosphere.
The second phenomenon caused by the tropopause occurs when CO2 concentrations increase. In this case, it absorbs heat from the ground, causing a temperature increase in the lower atmosphere. This allows radiation to reach the upper layers.
