The difference between insolation and Terrestrial radiation are as follows:
Sun provides us with solar power or fuel for weather and climate process.This energy that is emitted by our sun is called solar radiation. The incoming solar radiation to the earth is called insolation.
On the other hand, the upper layer of the atmosphere absorbs some amount of heat from the rays of the sun as they pass through the atmosphere. The radiation from the earth is called terrestrial radiation.
Final answer:
The incoming solar radiation to the earth is known as insolation and the radiation from the earth is called terrestrial radiation.