This video is about the Intertropical Convergence Zone (ITCZ), abbreviated as ETC, and about how it forms and how it shifts throughout the year. The ITCZ is a low-pressure zone that spans the globe in the equator region and is also called the equatorial trough. The term also reveals two further characteristics: firstly, air masses from north and south converge, meaning the flows in the equator region merge; secondly, despite the seasonal shift towards north and south, which we will look at later, its influence is largely limited to the tropics. It largely determines both the climate of the consistently humid tropics (shown in green) and the strong change from humid tropics (shown in orange). The formation of the ITCZ is due to solar radiation, which is particularly intense at the equator, primarily because the rays strike the equator more or less vertically from above. The sun's rays hit a very small area at the zenith, and these, unlike at the poles which they reach at a shallower angle, are set at a much lower angle. To illustrate this simply, let 's rotate the image 90 degrees. Now, the North Pole is shown on the left and the South Pole on the right. The air layers near the ground heat up considerably as a result of the intense solar radiation. Air that is heated loses density, expands, and rises. A low-pressure area forms at ground level. As it rises, the air cools. Cold air can hold less water vapor than warm air, which means that after a certain cooling, the air is saturated with water vapor. It condenses and forms clouds, which then pile up. We can also observe these clouds in our own country during the summer when there are thunderstorms at an altitude of about 16 to 18 kilometers, where the troposphere, the weather-determining layer, changes and the group begins to pause. These clouds then become a kind of boundary layer for rising air masses. As the air is deflected southward, it can become denser, heavier, and finally sink again towards the ground in the area of ​​the Tropic of Cancer and the Tropic of Capricorn. As the air sinks, it becomes denser. As it rises again to the ground, spatially and temporally stable high-pressure areas form. These so-called subtropical high pressures are found in these hot, arid regions of the Earth. The Sahara, for example, is the largest of these. As compensatory movements between air pressure differences, wind is created that travels from the area of ​​higher air pressure to the area of lower air pressure, i.e., from the subtropical high to the low at the equator. This is called the trade wind. The cycle is completed by the low air pressure at ground level in the area of ​​the ITC. Due to the rising air, the ground is essentially under pressure, acting like a suction effect and literally sucking in the surrounding air masses. This circulation pattern is also called the trade wind circulation. However, the trade wind circulation is not stationary; it does not remain the same. To understand the cause of this, it's helpful to consider the Earth's orbit around the sun. As you know, it takes the Earth almost exactly one year to complete its orbit around the sun. Let's assume the Earth's axis is n't tilted, and therefore the Earth isn't tilted sideways. No matter what point in the Earth's orbit, the same picture would always emerge. At the equator, the sun would be at its zenith. The sun's heat radiation would therefore be directly above, intensely heating the Earth's surface. As a result, the Intertropical Convergence Zone (ITCZ) would form in this area. If the Earth's axis weren't tilted, the ITCZ ​​wouldn't shift throughout the year. Even in winter, it would remain at the equator because the sun is at its zenith there. Incidentally, this is why we wouldn't have seasons, as the sun would heat the Earth's surface with the same intensity all year round. The fact that... The Intertropical Convergence Zone (ITCZ) shifts throughout the year, and the existence of seasons is also due to the obliquity of the ecliptic, i.e., the tilt of the Earth's axis by approximately 23.5°. This tilt of the Earth's axis causes the intensity of solar radiation at a given location to change over the course of the year. While the sun is at its zenith in the regions of the equator ( marked by the black line), for example, on March 21st, in summer, when the Northern Hemisphere is tilted towards the sun, the area of ​​the Tropic of Cancer experiences the strongest radiation perpendicular to the sky. This means that the ITCZ moves northward along with the sun's zenith position. While the same pattern applies to autumn as to spring, with the sun reaching its zenith for the second time in the equatorial regions, it moves further south towards winter. On December 21st, it is at the Tropic of Capricorn, which also causes the ITCZ ​​to shift further south. Shifting southwards, this topic may not seem so simple at first glance, but once understood, it allows you to explain the temperature and precipitation patterns of the entire tropics. The ever- wet zones, with their year-round high rainfall, exhibit particularly high total rainfall in both spring and autumn, which can be clearly seen in a climate diagram like this one. This doubly pronounced rainy season is a direct effect of the Intertropical Convergence Zone (ITCZ), which at this time is located at the equator and thus in the climate zone of the ever- wet zones, causing the ten- year rains with their high rainfall amounts. North and south of the ever-wet zone, the seasonally wet zones meet. Here, too, you can use a climate diagram to explain the occurrence of the simple rainy season in summer, caused by the shifting of the ITCZ ​​due to the moving zenith position and thus also the intense rainfall amounts. This perpetual cycle immediately has a normal influence on the wildlife of Africa, triggering the greatest Animal migrations exist on Earth, with millions of animals alone following the water. The shift of the ITC and the associated northward shift of the high rainfall totals caused by the ITC during the summer can be clearly seen in this animation, where high rainfall totals are highlighted in blue. With the shift of the Inner Tropical Convergence Zone, the associated trade wind circulation and thus the subtropical high pressure also inevitably shift. This allows us to see that in the summer months, southern Europe comes under the influence of the subtropical high pressure belt, recognizable by its white color, which indicates virtually no rainfall. In autumn and winter, this shift finally continues southward. If you want to see the ITC live, you only need to look at current satellite images of the Earth online. Near the equator, Tier 1 clouds will run from west to east, encountering the cloud band of the ITC, and in the area of ​​the tropics, there will be virtually no or very little. (See images.)