Tag: process of heat transfer in the atmosphere

Solar radiation is radiant energy emitted by the sun from a nuclear fusion reaction that creates electromagnetic energy. The spectrum of solar radiation is close to that of a black body with a temperature of about 5800 K. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum.

Radiation is the direct heating by the transmission of the heat waves. The upper layer of the atmosphere absorbs some amount of heat of the sun as they pass through the atmosphere. Radiation from the earth is called terrestrial radiation. Terrestrial radiation is long wave radiated by the earth. 

The sun's radiation must make it through multiple barriers before it reaches Earth's surface. The first barrier is the atmosphere. About 26% of the sun's energy is reflected or scattered back into space by clouds and particulates in the atmosphere 34. Another 18% of solar energy is absorbed in the atmosphere.

A part of the solar radiation falling on any surface is reflected back. Thus a certain amount of energy is lost and it does not play any role in heating the atmosphere. The reflectivity of a substance usually expressed as a percentage of the incident radiation reflected is known as it's albedo or reflection coefficient. It differs from place to place as well as from time to time.

The conditions of the atmosphere as well as the seasons affect the actual amount of insolation received at a place on the earth. Following are the factors which are responsible for variation in insolation:-

• The energy from the sun to earth comes in the form of solar radiation while the earth radiates it back to the atmosphere in the form of terrestrial radiations, hence option B is correct.
• Radioactivity is the energy released with the breakdown of matter in the form of gamma rays.
• Insolation is the reduction of energy transfer between objects.

• Incoming solar radiation from the sun is called insolation.
• Terrestrial radiation is the energy radiated back by the earth to the atmosphere.
• Sleet is partly frozen rain
• Drizzle is light rain falling with very small droplets.

As the temperature of the air increases its capacity to hold moisture increases while with the decrease in the temperature of the air, its capacity to hold moisture decreases. Thus the capacity of the atmospheric air to contain water vapor is directly proportional to its temperature. Hence option B is correct.

Isotherms are imaginary lines joining places of equal temperature. For convenience, the temperature are reduced to sea level as if the places actually existed at sea level. The spacing of isotherms indicated the steepness of temperature change. Closely spaced isotherms indicated higher thermal gradient.