ICSE-IX-Geography
13: Insolation
- #6Explain the importance of insolation.Ans : Sun is the most important source of atmospheric heat. Sun’s diameter is more than 100 times the Earth’s diameter and has a surface temperature of more than 10,000 °F. The heat waves radiate from the sun in all directions at a speed 186,000 miles per second of 3 lakh km per second. The solar radiation received by the earth is 1/2000 millionth part of solar output. Yet, this small amount is vital for our existence on the earth. It is estimated that, on the average the earth receives about 1.9 g calories per minute per sq. cm. This is known as ‘solar constant’. All the physical phenomena depend upon insolation. Winds and ocean currents originate due to insolation. The earth is habitable only due to insolation.