Our Sun is a storehouse of heat that continuously radiates heat. The temperature at the center of the Sun is estimated to be 280 million degrees Celsius. The huge bundle of heat waves coming out from the Sun is called insolation, which travels at a tremendous speed of more than 1.5 crore kilometers per minute and reaches the Earth’s surface in 9 minutes. The amount of heat is constant everywhere, and this is why it is called Saurthic temperature.
Factors Affecting Insolation
- Amount of insolation – The Sun is 1,488 lakh kilometers away from the Earth, and its surface temperature is 6,700°C. According to scientist Kimball, 5 percent of the insolation is lost on the way, in which 42 percent of the heat is returned to the upper-level gases. 15 percent of the heat is intercepted by water vapor, dust particles, and other lower gases. Only 42 percent of the heat reaches the Earth’s surface, and this is called level.
- Height of the land – The upper parts of the mountains receive less temperature, and the lower parts receive more. The temperature remains constant because the surface of the Earth also provides heat along with the Sun.
- Sun’s rays – The Sun’s rays do not fall equally on the ground. Somewhere the rays fall vertically, and somewhere obliquely. The rays of the Sun fall vertically in the parts of the equator and obliquely towards the poles.
- Distribution of land and water – The land gets heated up quickly and cools down quickly compared to the water. The reason for this is the rough bottom of the land and the smooth bottom of the water. To heat the water, five times the heat is required as compared to the land. The cover of water vapor and clouds over the water part proves to be an obstacle in the heat radiation from the Sun and the Earth.
- Nature of the Earth – The nature and color of the Earth also affect the insolation. Soil color also has an effect. Black soil absorbs more sunlight, and rocky areas get heated quickly compared to icy parts. More insolation enters the dry land of the region without vegetation.
- Thickness and transparency of the atmosphere – Where the thickness of the atmosphere is more, the insolation is less at that place. If there are more dust particles and clouds in the sky, then the radiation of insolation is less.
- Number of sunspots – When the number of sunspots on the Sun is high, insolation occurs on the Earth’s surface. Due to the release of more solar power, more vapor is formed, and more clouds are formed in which less insolation reaches the Earth’s surface.
- Distance of the Sun from the Earth – The distance of the Earth from the Sun does not always remain the same. The distance is more in the subsolar region, and less in other regions.
Insolation and latitude – The distribution of insolation is related to the latitudes. From the equator to the poles, the insolation gradually decreases and becomes zero at the poles. Radiation is the main reason for this, followed by reflection.