Consider the following statements regarding terrestrial radiation :

I. Insolation received by the Earth is in shortwaves.

II. The Earth's energy heats the atmosphere from below.

III. The shortwave radiation from the Earth is absorbed by the greenhouse gases.

Which of the statements given above are correct?

Statement I is correct: Solar radiation (insolation) reaches the Earth's surface primarily as shortwave radiation. Statement II is correct: The atmosphere is largely transparent to incoming shortwave solar radiation but is heated from below by terrestrial radiation emitted by the Earth's surface. This process involves conduction and convection in the lower layers. Statement III is incorrect: The radiation emitted by the Earth is longwave radiation (infrared). Greenhouse gases like carbon dioxide and water vapor are effective absorbers of this outgoing longwave terrestrial radiation, which creates the greenhouse effect. They do not significantly absorb the incoming shortwave radiation from the sun.