Continuous monitoring of the solar irradiance have been carried out since the early 80s by instrument in space . this is essential because several portions of the solar radiation spectrum such as ultraviolet and far infrared are blocked by earth s atmosphere 自八十年代初,科学家已使用太空仪器不断监察太阳的辐射度要在太空作观测,是由于部分太阳光谱如紫外线和远红外线等并不能穿过地球大气。