Albedo is a measure of how much sunlight that hits a surface is reflected without being absorbed. Something that appears white reflects most of the light that hits it and has a high albedo, while something that looks dark absorbs most of the light that hits it, indicating a low albedo.

Conduction, in general, is the process of transmission of energy from one particle of the medium to the other but here each particle of the medium stays at its own position. In conduction of heat, the heat energy is usually transferred from molecule to another molecule as they are in direct contact with each other. However, there is no change in the position of the molecules. Conduction can occur in solids, liquids, and gases.

The transfer of heat energy through liquids and gases by the movement of molecules. When molecules of the liquid or gas come in contact with a source of heat, they move apart and away from the source of heat, and cooler molecules take their place. Eventually, as the cooler molecules are heated, they move as well, and a convection current forms, transferring the heat.

The transfer of energy of the atmosphere, such as heat, cold, or humidity, by the horizontal movement of an air is called Advection.

On the earth’s surface, there are seven pressure belts. They are one Equatorial Low, two Subtropical highs, two Subpolar lows, and two Polar highs.The Equatorial region receives a great amount of heat throughout the year. 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. It is also due to 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, creating a low-pressure belt in this region.
Pressure Belts of Earth

(i) Equatorial Low-Pressure Belts:

This low-pressure belt extends from 0 to 10° North and South of Equator. The vertical rays of the sun here causes intense heating and hence low pressure of air develops here. This low-pressure belt is also called as doldrums.

(ii) Subtropical High-Pressure Belts:

At about 30°- 35°North and South of Equator lies the area where the ascending equatorial air currents descend. This area is thus an area of high pressure. It is also called as the Horse latitude. Winds always blow from high pressure to low pressure. So the winds from subtropical region blow towards the Equator.

(iii) Sub-Polar Low Pressure Belts:

These belts located between 60° and 70° in each hemisphere are known as Sub Polar Low-Pressure Belts. In the Subtropical region, the descending air gets divided into two parts. One part blows towards the Equatorial Low-Pressure Belt. The other part blows towards the Sub Polar Low-Pressure Belt. This zone is marked by the ascent of warm Subtropical air over cold polar air blowing from poles. Due to the earth’s rotation, the winds surrounding the Polar region blow towards the Equator and thus this region create the low-pressure belt appropriately called the Sub polar Low-Pressure Belt.

(iv) Polar High-Pressure Areas:

At the North and South Poles, between 70° to 90° North and South, the temperatures are always extremely low. The cold descending air gives rise to high pressures over the Poles.

1. Planetary Winds:

The winds blowing through­out the year from one latitude to another in response to latitudinal differences in air pressure are called “planetary or prevailing winds”. They involve large areas of the globe.

2. Trade Winds:

These are extremely steady winds blowing from sub-tropical high pressure areas (30°North and South) towards the equatorial low pressure belt. These winds should have blown from the north to south in Northern Hemisphere and south to north in Southern Hemisphere, but, they get deflected to the right in Northern Hemisphere and to the left in Southern Hemisphere due to Coriolis effect and Ferrel’s law. Thus, they blow as north eastern trades in Northern Hemisphere and south eastern trades in Southern Hemisphere.

They are also known as tropical easterlies, and they blow steadily in the same direction. They are noted for consistency in both force and direction.

3. The Westerlies:

These winds blow from sub tropical high pressure belts towards sub-polar low pressure belts. The westerlies of Southern Hemi­sphere are more stronger and constant in direction than Northern Hemisphere. These winds develop be­tween 40° and 65°S latitudes and these latitudes are known as Roaring Forties, Furious Fifties and Shriek­ing Sixties.

4. Periodic Winds:

Periodic winds change their direction periodically with the change in season, e.g., Monsoons, Land and Sea Breezes, Mountain and Valley Breezes.

a. Monsoon Winds:

These winds are seasonal winds and refer to wind systems that have a pronounced, seasonal reversal of direction. According to ‘Flohn’, monsoon is a seasonal modification of general Planetary Wind System.

Summer monsoon is called South Westerly Wind and is characterized by highly variable weather with frequent spells of drought and heavy rains. The winter monsoon is a gentle drift of air in which winds blow from the north-east and is known as North Easterly Wind.

b. Land Breeze:

At night, land masses cool quicker than sea due to rapid radiation which results in high pressure over land and low pressure over sea. And in calm, cloudless weather, air blows from land to sea. This breeze carries no moisture and is little warm and dry.

c. Sea Breeze:

In day time, the land being hotter than the sea develops low air pressure and the sea being cool develops high pressure. The air over land rises and is replaced by a cool breeze known as Sea Breeze from the sea, carrying some moisture.

d. Mountain and Valley Breezes:

A diurnal wind occurs in mountainous regions which are similar to Land and Sea Breezes. During the day the slopes of mountains are hot and air from valley flows up the slopes. This is known as “Valley Breeze”. After sunset the pattern is reversed and cold air slides from mountain to valley and is called “mountain breeze”.

5. Local Winds:

The local difference in tempera­ture and pressure causes local winds. It is of four types: hot, cold, convectional and slope.

It is similar to Chinook. It affects the snow, makes weather pleasant. It ripes grapes and Switzerland get a lot of benefit by Foehn.