Evaluation the Contribution of Scattering Effect to the Directional Canopy Emissivity and Brightness Temperature Simulation Based on CE-P Model

A new directional canopy emissivity model (CE-P) based on spectral invariants can separate the multiple scattering effect and single scattering in vegetation canopy. So we can further evaluate the contribution of scattering effect to the canopy emissivity and brightness temperature based on CE-P model. Numerical analysis shows that the contribution of more than three times scattering can be ignored when the leaf (soil) emissivity is no less than 0.90. Then, we optimize CE-P model and obtain the expressions containing the first twice collisions $(\varepsilon_{2})$ and first three times collisions $(\varepsilon_{3})$ . The result shows that $\varepsilon_{3}$ can simulate the emissivity in any case with an error less than 0.001. Furthermore, we simulate the brightness temperature distribution using the optimized model and compare it with DART model. The difference between them is less than 0.3K and the R 2 of them is over 0.96 in all of the selected samples.