The amount of precipitation that falls in different parts of our planet is not the same, in some places it rains almost every day, while other regions suffer from drought. The article examines the question at what latitudes most precipitation falls.
Blue ball and latitude concept
Before proceeding to the consideration of the question at what latitudes the amount of precipitation falls the greatest, it is necessary to remember what our planet is and what is latitude.
Since our planet is a ball (strictly speaking, it is a geoid), then to determine the position of objects on its surface, angular coordinates are used: longitude and latitude.
Latitude is understood as the angle between the equator line and a certain point on the terrain, while the vertex of the angle in the center of the Earth is located, and the arc drawn along the surface of the planet between the considered point and the equator should pass along the meridian, that is, be perpendicular to the equatorial line. This line divides the globe into two equal parts: the northern hemisphere and the southern hemisphere. The set of coordinates of one latitude on the surface of the planet is called parallel.
According to this definition, the equator line will have 0 o latitude, and the North and South poles +90 o and -90 o latitude, respectively. All parallels lying between 23 o north latitude (Tropic of Cancer) and 23 o south latitude (Tropic of Capricorn) form the so-called tropical climate zone. Parallels located between 23 o and 66 o latitude in each hemisphere belong to the temperate climate zone. Finally, the areas located between 66 o and 90 o are the polar earth zones.
The amount of solar radiation - the main factor determining the level of rainfall
At what latitudes is the highest rainfall? Of course, in places where high humidity is observed. Precipitation, which is the deposition of water on the earth's surface in the form of rain or snow, can exist only when the atmosphere contains a high percentage of water vapor, which, rising up and cooling, condenses into clouds, and then returns to the ground.
To saturate the air with water vapor, huge energy is needed to transfer water from liquid to gaseous state of aggregation. This energy on an earthly scale can only be obtained from sunlight. Therefore, answering the question of where the greatest amount of precipitation falls, we can say with confidence that in the latitudes that receive the greatest amount of solar energy.
Equator and tropical zones of the planet
Since the planet Earth has a spherical shape, the rays from the Sun fall on its various latitudes at different angles. At the equator, they are perpendicular to the surface, so low latitudes receive maximum radiation from our star. With increasing latitude, the angle of incidence of the rays becomes smaller and the amount of solar energy is reduced.
This means that the correct answer to the question in which latitudes of precipitation the greatest amount will be the following: in the tropical zone, that is, between the tropics of Capricorn and Cancer.
Note that within the tropical zone, usually two types of climate are distinguished:
- equatorial, which is characterized by average annual temperatures of 18-27 ° C and a large amount of rain that occurs here almost every day;
- actually tropical, here the temperature regime experiences more severe fluctuations throughout the year (10-30 ° C), and rainfall is uneven (there is a drought season and a rainy season).
Other factors affecting rainfall
In addition to solar radiation, which contributes to the evaporation of water and the formation of clouds, the presence of this water is necessary. The air masses that carry rains with them form over the oceans and seas. This means that the highest rainfall occurs due to rain on island states and countries that are located in the tropical zone near the coastline of the continents. So, if you look at the map, you can see that countries such as Chad or Saudi Arabia (southern part) are located in the tropical zone, but since they are located far from the oceans, rains in most of their territory are rare.
In addition to the distance from the oceans, here are two more factors that can affect the level of precipitation:
- Monsoons. These are winds that blow in the summer from the ocean, and in the winter from the continent, so in summer the amount of precipitation in the zones they reach increases.
- Mountainous terrain. When the sea air mass meets mountains on its way, then it cannot overcome them. Humid air, gradually rising along the mountain slopes, cools, the water vapor in it condenses and falls to the ground in the form of rain. That is why the greatest amount of precipitation falls in the foothills.
Specific areas with a lot of rain
As it was found above, the greatest amount of precipitation falls in the latitudes of tropical and equatorial. Below are examples of places on earth where torrential rains often occur:
- Vaialeale Volcano, Hawaiian Islands. In this mountainous zone, which intercepts all the rain clouds passing through it, the rainfall is estimated at 11,500 mm per year.
- Milford Track, New Zealand. Hundreds of rivers, waterfalls and lakes are the main characteristic of the landscape of this place. The average rainfall is 6000-8000 mm per year.
- Jungle Borneo, Malaysia. This selva is virgin. Annual precipitation here is about 5000 mm.
- Yakushima, Japan. This is an island that is covered with dense forests. From 4,000 to 10,000 mm of precipitation is recorded here, depending on the year.
- Cherapundji, India. For a long time, this Indian territory was considered the rainiest on the planet. About 11430 mm of precipitation per year is recorded here.
As can be seen from the above list, the greatest amount of precipitation occurs in equatorial latitudes on islands with mountainous terrain.
The rainiest place on earth
Choco is a Colombian department located in the north-west of the country on the Pacific coast. The largest amount of precipitation falls here, according to some estimates it is 13,000 mm per year. The reasons why it rains here, according to locals "35 days a month", are not only the proximity of Choko to the equator and the Pacific Ocean, but also because the department is located in a zone of low air pressure, which attracts many marine air masses.