植生キャノピーの反射モデルを用いた葉面積指数(LAI)の逆推定法の草地における適用性に関する検討

抄録

The accuracy of Leaf Area Index (LAI) estimation from multi-angle optical remotely sensed data depends on the BRF sensitivity to LAI and BRF inversion methods. The objective of this study is to investigate the limitations of the BRF inversion method for LAI estimation. We explored the BRF sensitivity to LAI, leaf reflectance/transmittance, and soil reflectance which strongly influence the BRF changes. Sensitivity analyses using simulated BRF data showed that BRF in the near infrared has high sensitivity to LAI up to 2. However when LAI>4, BRF has no sensitivity to LAI. LAI estimation accuracy using the BRF inversion method also depends on the initial guesses. The BRF inversion experiments using several initial guess patterns suggest that estimated LAI is accurate when LAI initial guesses are lower than true LAI. However estimation accuracy deteriorates in all initial guess patterns when LAI>3. Finally we applied the BRF inversion method for the BRF data acquired by the ground measurement. The results were consistent with those of simulation experiments.