研究了植被冠层的热辐射方向性并建立了有关模型.从辐射传输机理出发, 建立了3D冠层场景, 并将场景以微分体元方式进行离散, 根据给定的观测几何参数进行逐个体元内部与体元之间的多次散射及发射辐射传输计算, 最终通过积分运算得到所有微分体在半球空间上对给定观测方向上的热辐射, 得出整个冠层的热辐射方向性.利用两个时相的地面观测数据对3D辐射传输模型及模拟结果进行了验证和分析, 相关系数分别为0.91和0.79, RMSE分别为0.4K和0.6K, 证明建立的模型是有效的, 能改进热红外温度反演精度和实现组分温度反演.

Directional thermal radiation of canopy was studied and the related model was set up. According to the mechanism of radiative transfer, 3D canopy scenes were established and the scenes were discretized by differential cells. According to the observed geometric parameters, the radiative transfer of scatter and emission for every internal cell and among cells was calculated. Finally, the directional thermal radiation of canopy could be retrieved from the integral calculation of all differential bodies in the hemisphere. The existing in-situ data were used to test the 3D radiative transfer model and the simulating results. The correlation coefficients are 0.91 and 0.79, the RMSE are 0.4K and 0.6K, respetively. The results show that the model is effective and it can improve the precision of temperature inversion and realize component temperature inversion.