Abstract: The calculation of land surface temperature from thermal radiation requires the emissivity value of rock. However,there are lots of rocks in the Earth,and even the rocks of the same type may have obviously different emissivity. Recent methods for measuring the emissivity of rock are relatively complex,and most of them depend excessively on environmental condition. Therefore,when plenty of emissivity data are needed,it is necessary to develop a simple method of measurement. In fact,emissivity is a constant at room temperature,and the radiation of instrument itself and environment can enjoin the inversion as an unknown quantity. Then emissivity can be obtained by least square method through measuring the radiation of rock in a series of temperature and radiation conditions. On the basis of this method,the emissivities of 16 rock samples were measured. The square error of the results keeps in about 0.01,mostly less than 0.01,and the correlation coefficient of all linear fits is larger than 0.99.

Key words: emissivity, rock sample, method of measurement

摘要： 利用地表辐射(亮温)求取地面温度需要通过岩石比辐射率进行换算。地球上的岩石千差万别,即使岩石学上分类一致的岩石,比辐射率也可以显著不同,需要大量的比辐射率时,现有测量方法显得过于复杂或环境要求过高,发展简便的比辐射率测量方法十分必要。实际上,在室温情况下,比辐射率为常数,可以通过测量一系列的温度和相应的辐射值,仪器本身的辐射和环境辐射可直接当作未知量参加反演,最终利用最小二乘法拟合获得比辐射率,大大降低了测量的难度。文中测量了16种岩石标本的比辐射率,方差一般保持在0.01左右,大多数<0.01;线性拟合的相关系数均>0.99。

关键词: 比辐射率, 岩石标本, 测量方法