How Many Pressure Belt are There

Introduction

There are seven pressure belts on the earth's surface. They're the Equatorial Low, the 2 semi-tropical highs, the 2 Subpolar lows, and also the 2 Polar highs. except for the Equatorial low, the others type matching pairs in the Northern and Southern Hemispheres. Over the world, there's a pattern of alternate high and low-pressure belts.
This is often due to the spherical form of the world—different components of the earth are heated unevenly. The Equatorial region receives a good quantity of heat throughout the year. Creating low pressure, warm air being light-weight, the air at the Equator rises. At the poles the cold significant air causes high pressure to be created/formed.

It's additionally because of the rotation of the earth. in the Subpolar region around latitudes 60° to 65° North and South of the Equator, the rotation of the earth pushes up the bulk of the air towards the Equator, making a low-pressure belt in this region.

Pressure Belts

Equatorial Low-Pressure Belts

This low-pressure belt extends from zero to 5° North and South of the Equator. There's intense heating due to the vertical rays of the sun here. The air, therefore, expands and rises as convection current inflicts low pressure to develop here. This low-pressure belt is additionally called the doldrums because it's a zone of total calm with no breeze.

Subtropical High-Pressure Belts

At about 30°North and South of the Equator lies the world where the ascending equatorial air currents descend. This area is thus a region of high pressure. It's conjointly called the parallel of latitude. Winds continually blow from high pressure to low pressure. That the wind blows towards Sub-Polar low-pressure as Westerlies and the other from the subtropical region blow towards the Equator as Trade winds.

Circum-Polar Low-Pressure Belts

These belts settled between 60° and 70° in every hemisphere are referred to as Circum-Polar low-pressure Belts. in the subtropical region, the descendant air gets divided into 2 components. One half blows towards the Equatorial low-pressure Belt. the opposite half blows towards the CircumPolar low-pressure Belt. This zone is marked by the ascent of warm semi-tropical air over cold polar air blowing from the poles. Due to the earth’s rotation, the winds encompassing the Polar region blow towards the Equator. Centrifugal forces operating during this region produce the low-pressure belt suitably referred to as the Circumpolar low-pressure Belt. This region is denoted by violent storms in winter.

Polar High-Pressure Areas

The temperatures are continually very low, at the North and South Poles, between 70° to 90° North and South. The cold descendant air provides rise to high pressures over the Poles. These regions of Polar high pressure are known as the Polar Highs. These regions are characterised by permanent ice caps.

Shifting Of Pressure Belts

If the earth had not been inclined towards the sun, the pressure belts, as represented on top of them, would have been as they're. but it's not so, as a result, the world is inclined 23 1/2° towards the sun. On account of this inclination, variations in the heating of the continents, oceans, and pressure conditions in Jan and Gregorian calendar months vary greatly.

Jan represents the winter season and July, the summer season within the northern hemisphere. Opposite conditions prevail in the southern hemisphere.
Once the sun is overhead on the Tropic of Cancer (21 June) the pressure belts shift 5° northward and once it shines vertically overhead on the Tropic of Capricorn (22 Dec.), they shift 5° southward from their actual position. The shifting of the pressure belts causes seasonal changes in the climate, particularly between latitudes 30° and 40° in each hemisphere.

During this region, the Mediterranean type of climate is seasoned because of the shifting of permanent belts southward and in the north with the overhead position of the sun. During winters Westerlies prevail and cause rain. throughout summers dry Trade Winds blow offshore and are unable to provide rainfall in these regions. Once the sun shines vertically over the Equator on the 21st of March and 23rd Sept (the Equinoxes), the pressure belts stay balanced in each hemisphere.