Question

(i) What is insolation?
(ii) Write a short note on the three parts of insolation.

Answer 1

Hint: It is basically measured by the amount of solar energy that is received per square centimetre per minute. It also affects the temperature considerably. In general, the more the insolation, the higher the temperature. It is said that the strongest isolation is received at noon.

Complete answer:
(i)The main source of energy and heat is Sun. It provides solar energy or at times fuel for the process of weather as well as climate. The energy that is emitted by the sun is called solar radiation. The incoming solar radiation to the earth termed as insolation. Insolation comprises a bundle of rays of radiant energy of different wavelengths.
(ii) In accordance to the wavelength, insolation can be divided into three parts, which are:
1. Infra-red rays: These types of rays possess long waves and are largely absorbed in the atmosphere.
2. Ultra-violet rays: The shortwave sun rays are referred to as ultraviolet rays. It is said to be the most harmful ray of sun. It is the ozone layer that protects us from these harmful rays of the sun.
3. Visible rays: The visible portion of the spectrum that lies between the invisible ultraviolet as well as infrared rays that most effectively heat the earth is known as the visible rays of the sun. Due to the visible rays, one can see the objects on the surface of the earth.

Note: The amount of insolation that is received on the surface of the Earth and is generally not uniform everywhere. It ranges according to the place as well as time. When the tropical regions receive maximum annual insolation, it gradually decreases towards the poles. Insolation generally takes place more in summers while less in winters. The main factors influencing the amount of insolation received are: Solar constant, The angle of incidence of the sun’s rays, Duration of the day, Earth Distance from Sun and Transparency of the atmosphere.