Measuring of thermal radiation multi-reflection information in soil-vegetation system

First of all the paper discussed the action of objects´ thermodynamic characteristics, environmental factors, microclimatological parameters, soil physical parameters, ecological parameters, especially sensible and latent heat exchange on thermal radiation exchange. Particularly, increase or decrease of the objects´ temperature was mentioned when measuring thermal infrared multi-reflection in a non-isothermal system. Reflection radiation and emission radiation should be separated when extracting multi-reflection radiation information from measured signals of the thermal radiometer. And the applicability of Kirchhoff´s law in a nonisothermal system should also be considered. On the base of above, an instrument for measuring thermal infrared multi-reflection was developed and a kind of algorithm was put forward for extracting reflection radiation from mixed thermal radiation information. We did field experiments for measuring thermal infrared multi-reflection in 2004. Experiments and results showed that measurement accuracy of twice-thermal reflection radiation in soil-vegetation system could meet the needs of the most models at present.