Describe the distribution of pressure belts on the surface of
the Earth.
Answers
Answer:
On the earth's surface, there are seven pressure belts. They are the Equatorial Low, the two Subtropical highs, the two Subpolar lows, and the two Polar highs. ... Warm air being light, the air at the Equator rises, creating low pressure. At the poles the cold heavy air causes high pressure to be created/formed.
Explanation:
hope it helps
Answer:
On the earth's surface, there are seven pressure belts. They are the Equatorial Low, the two Subtropical highs, the two Subpolar lows, and the two Polar highs. ... Warm air being light, the air at the Equator rises, creating low pressure. At the poles the cold heavy air causes high pressure to be created/formed
Explanation:
Pressure Belts Of The Earth
Pressure –
A column of air exerts weight in terms of pressure on the surface of the earth.
The weight of the column of air at a given place and time is called air pressure or atmospheric pressure.
Atmospheric pressure is measured by an instrument called a barometer.
Atmospheric pressure is measured as force per unit area. The unit used for measuring pressure is called millibar.
One millibar is equal to the force of nearly one gram per square centimeter.
Factors Controlling Pressure Systems –
There are two main causes, thermal and dynamic, for the pressure differences resulting in high and low-pressure systems.
Thermal Factors –
When air is heated, it expands and, hence, its density decreases. This naturally leads to low pressure. On the contrary, cooling results in contraction. This increases the density and thus leads to high pressure.
Formation of equatorial low and polar highs are examples of thermal lows and thermal highs, respectively.
Dynamic Factors
Apart from variations of temperature, the formation of pressure belts may be explained by dynamic controls arising out of pressure gradient forces and rotation of the earth (Coriolis force).
What is Pressure Gradient?
The rate of change of atmospheric pressure between two points on the earth’s surface is called the pressure gradient.
On the weather chart, this is indicated by the spacing of isobars.
Close spacing of isobars indicates a strong pressure gradient, while wide spacing suggests a weak gradient.
Vertical Distribution
The columnar distribution of atmospheric pressure is known as the vertical distribution of pressure.
The mass of air above in the column of air compresses the air under it hence its lower layers are denser than the upper layers; As a result, the lower layers of the atmosphere have higher density, hence, exert more pressure.
Conversely, the higher layers are less compressed and, hence, they have low density and low pressure.
The temperature of the air, the amount of water vapor present in the air, and the gravitational pull of the earth determine the air pressure of a given place and at a given time.
Since these factors are variable with a change in height, there is a variation in the rate of decrease in air pressure with an increase in altitude.
Rising pressure indicates fine, settled weather while falling pressure indicates unstable and cloudy weather.
Horizontal Distribution
The factors responsible for variation in the horizontal distribution of pressure are as follows:
Air temperature – Equator Polar regions
The earth’s rotation – Coriolis force
Presence of water vapor – Inversely related to pressure
Air Temperature
Earth is not heated uniformly because of unequal distribution of insolation, differential heating and cooling of land and water surfaces
Air pressure is low in equatorial regions and it is higher in polar regions.
Low air pressure in equatorial regions is due to the fact that hot air ascends there with a gradual decrease in temperature causing thinness of air on the surface.
In the polar region, cold air is very dense hence it descends, and pressure increases