The left Fig. produced by the Earth Radiation Budget Experiment (ERBE) program of the National Oceanic and Atmospheric Administration (NOAA) (Harrison et al, 1988), shows a map of outgoing longwave radiation, in Wm-2, for the month of April 1985 under clear-sky conditions.
Regions colored in red and purple define regions of high amount of infrared radiation leaving the earth, and green and blue colors denote low IR values. From the Stefan-Boltzmann equation, we can also say that the radiating regions colored red and purple are warmer than those colored green and blue. As expected, the tropical and subtropical regions have the highest outgoing radiation (and temperature) and polar regions have lowest values.
沙砾 0.91
雪 0.995
海水 0.96
地面的平均温度约为300K,对 流层大气的平均温度约为250K, 在这样的温度下,它们的热辐 射, 95%以上的能量集中在 3~120μm的波长范围内。都 是属于肉眼不能直接看见的红 外辐射。其辐射能最大所对应 的波长在10~15 μm范围内。 地面和大气的辐射称为长波辐 射。