Option 1: Short wave solar radiation refers to the high-energy radiation emitted by the Sun. This radiation is absorbed by the Earth`s atmosphere but does not directly contribute to heating the atmosphere. Instead, it is responsible for warming the Earth`s surface.

Option 2: Reflected solar radiation refers to the sunlight that is reflected back into space by clouds, aerosols, and the Earth`s surface. This radiation does not directly heat the atmosphere but plays a role in the Earth`s energy balance.

Option 3: Long wave terrestrial radiation, also known as infrared radiation or heat radiation, is emitted by the Earth`s surface and the lower atmosphere. This radiation is absorbed by greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, which leads to the heating of the atmosphere.

Option 4: Scattered solar radiation occurs when sunlight interacts with particles and molecules in the atmosphere, causing the light to scatter in different directions. While this process contributes to the distribution of solar radiation, it is not a primary factor in heating the atmosphere.

The correct answer is option 3, as long wave terrestrial radiation is the main source of heating for the Earth`s atmosphere.