Question

Equatorial region ( ) solar radiation
polar region ( )warm
the source of heat and light( )the sun energy emitted by the sun ( ) cold​

Answer 1

Answer:

D

o you feel air around you? Do you

know that we live at the bottom of a

huge pile of air? We inhale and exhale

but we feel the air when it is in motion. It means

air in motion is wind. You have already learnt

about the fact that earth is surrounded by air

all around. This envelop of air is atmosphere

which is composed of numerous gases. These

gases support life over the earth’s surface.

The earth receives almost all of its energy

from the sun. The earth in turn radiates back

to space the energy received from the sun. As

a result, the earth neither warms up nor does

it get cooled over a period of time. Thus, the

amount of heat received by different parts of

the earth is not the same. This variation causes

pressure differences in the atmosphere. This

leads to transfer of heat from one region to the

other by winds. This chapter explains the

process of heating and cooling of the

atmosphere and the resultant temperature

distribution over the earth’s surface.

SOLAR RADIATION

The earth’s surface receives most of its energy

in short wavelengths. The energy received by

the earth is known as incoming solar radiation

which in short is termed as insolation.

As the earth is a geoid resembling a sphere,

the sun’s rays fall obliquely at the top of the

atmosphere and the earth intercepts a very

small portion of the sun’s energy. On an

average the earth receives 1.94 calories per sq.

cm per minute at the top of its atmosphere.

The solar output received at the top of the

atmosphere varies slightly in a year due to the

variations in the distance between the earth and

the sun. During its revolution around the sun,

the earth is farthest from the sun (152 million

km) on 4th July. This position of the earth is

called aphelion. On 3rd January, the earth is

the nearest to the sun (147 million km). This

position is called perihelion. Therefore, the

annual insolation received by the earth on 3rd

January is slightly more than the amount

received on 4th July. However, the effect of this

variation in the solar output is masked by

other factors like the distribution of land and

sea and the atmospheric circulation. Hence, this

variation in the solar output does not have

great effect on daily weather changes on the

surface of the earth.