## Feb 16, 2009

Electromagnetic radiation is transmitted through a kind of energy. As gravity or a magnet in a vacuum can pendulum swing, the same electromagnetic wave energy having to go through any medium can be in a vacuum delivery. X-ray, ultraviolet, visible light, microwaves, radio waves are a kind of electromagnetic wave. The biggest impact of climate mostly between the ultraviolet to the infrared band, is the strongest band of solar radiation .

A blackbody radiation characteristics of the material, if the higher temperature, emitted energy concentrated in the shorter wavelength band; In contrast, low temperature, energy concentrated in the longer wavelength band. This is the external causes of displacement law, which is a maximum energy of electromagnetic waves is inversely proportional to wavelength and temperature. Such as the Sun as a blackbody, the biggest part of the radiation concentrated in the visible light (wavelength of 0.4 ~ 0.7μm). Temperature of the Earth's radiation balance is well below the temperature of the sun, so the energy concentrated in the longer-wavelength infrared band (wavelength around the near 10μm).

From Figure 3-2, we can clearly see the sun and earth radiation energy concentrated band, a great difference between each other, overlapping part of small and very small in the energy band. We, therefore, can easily distinguish between the Sun and the Earth's radiation. Solar radiation due to a shorter wavelength, commonly known as short-wave radiation; earth radiation, relatively speaking, a longer wavelength, known as long-wave radiation.