Tropic

The intertropical zone, here marked in red, is defined by the Tropic of Cancer to the north and the Tropic of Capricorn to the south and the tropical climate predominates.

Trópico comes from the Latin tropĭcus, and this from the Greek τροπικός [tropikós], which means &# 39;'turn'. The horizontal plane in which the translational movement of the Earth around the Sun occurs is known as the ecliptic plane. Since the axis of rotation of the Earth is not perpendicular to the plane of the elliptic, the intersection of this plane with the sphere does not coincide with the terrestrial equatorial plane. Within the tropical region it is true that at least one day a year the Sun is at the highest point in the sky (the height of the Sun at its zenith is 90º with what are subsolar points). The maximum latitude at which the ecliptic cuts the terrestrial sphere is 23° 26′ 14″ N and 23° 26′ 14″ S (in 2015); Therefore, the parallels that pass through these latitudes have a special relevance and are known as:

• Tropics of Cancerin the northern hemisphere
• Tropic of Capricornin the southern hemisphere

Intertropical Zone

The region between the two tropics is known as the intertropical, torrid or tropical zone, although the first denomination tends to replace the last two for the sake of accuracy; biogeographically, the tropics may extend beyond the parallels of Cancer and Capricorn, v. gr., the Florida peninsula in the United States lies in the subtropics (latitude greater than 23° 26′ N), but is home to many species characteristic of the New World tropics, in part due to the tempering effect of climate provided by the Gulf Stream. Likewise, the middle and lower valleys of the Paraná River are subtropical, but they are part of the neotropical biogeographic region that includes Patagonia and other southern regions of the continent. In the same way, and in reverse, the dry climates of the subtropics (immediately north of the Tropic of Cancer or south of the Tropic of Capricorn) can also extend into the intertropical zone on the western coasts of the continents. These observations are justified by the fact that the lines of the tropics constitute a mathematical concept (geometric, more properly), while the concepts of climate or biogeography are purely geographical and latitude is only one of the five factors that modify these concepts is located between the Tropic of Cancer in the Northern Hemisphere and the Tropic of Capricorn in the Southern Hemisphere.

Locutions

• Tropical year
• Tropic of Cancer
• Tropic of Capricorn

The Polar Circles

They are the parallels that are located at 66°33' to the South or to the North with respect to the Equator, where the sun's rays arrive obliquely, causing 24 continuous hours of darkness or light to occur at this latitude once a year, increasing to the maximum of 3 months of light or darkness followed at the Poles (90° North and 90° South). The latitudes 66º 33' 46" N and 66º 33' 46" S correspond respectively to the arctic and antarctic circles.

General characteristics

The humid intertropical zone is a world with a lot of rain, which is good for agriculture. All this tropical zone occupies 20% of the emerged land, representing 40% of the land useful for human beings, and is home to just over 40% of the world population, although with an unequal distribution in the territory.