Hybrid Method for Full-wave Simulations of Vegetation

Password: Goblue

Knowledge of the global soil moisture distribution is crucial for water resource management and the climate change prediction, etc. The microwave satellites including the ESA’s SMOS and NASA’s SMAP have been launched to monitor the soil moisture for decades. To improve accuracy of the soil moisture retrieval, a two-step hybrid method combing both the analytical and the numerical solutions is developed for full-wave simulations of vegetation in this dissertation.

A realistic vegetation field setup is introduced to consider the plant structures and gap spacing within the vegetation canopy. In the first step, the numerical solver is employed to perform full-wave simulations of one single plant, from which the corresponding T-matrix is extracted to characterize the multiple scattering caused by the plant structure. In the second step, the T-matrix is combined with Foldy-Lax multiple scattering equations to consider the interactions among different plants. Full-wave Monte Carlo simulations of wheat and forest are performed using the hybrid method to investigate the vegetation effects on the microwave.  The microwave transmissivity predicted by the hybrid method is significantly higher than those obtained from the classical radiative transfer model. This indicates that (1) it is potential to use the L-band signal to retrieve soil moisture over forested area or area with large vegetation water content, and (2) the higher frequency channel such as the S- and C-band can also be utilized to retrieve the Earth information.

Chair: Professor Leung Tsang