改进的热惯量模式及遥感土壤水分

IMPROVED THERMAL INERTIA MODEL AND REMOTE SENSING OF SOIL MOISTURE

本文提出一个考虑地表显热通量及潜热通量的热惯量模式。模式利用了地面定标的方法并充分利用了热象图的空间分布信息,因而较大幅度地提高了估算土壤水分含量的精度。

Thermal inertia is a useful tool for estimating soil moisture. Remote sensing of thermal inertia lias developed quickly in recent years. Based on our work for several years, using information of distribution in a thermal infrared image and calibration at a field point, parameterization of the sensible heat flux and latent heat flux were done, in which information of soil water content was taken and the thermal inertia model was improved.In the farm field of plain, we calculated the differences of sensible heat flux of each pixels in a thermal infrared image using the maximum temperature point to be as a basic calibrated point and using information of soil temperature between pixels. In the same thermal infrared image, the latent heat flux of the wettest point was also as a basic calibrated point. Based on the linear function between evaporation and evaporativity and soil moisture, we fed back the soil moisture to the thermal inertia model and took the information of thermal inertia and soil moisture.The thermal inertio model which use two approximate hypotheses was tested and verified by measured data in our remote sensing experimental site. When the soil moisture is more than 15 % and the change of the horizontal wind speed is not too big, the calculated precision of soil moisture will be high. The mean error is less than 10 %.