Rice Brdf Models Integrated And Applied Research

Rice is the main crop of china, and its product is the first in the world. So rice growing monitoring and yield estimating have been arising people抯 attention. Since remote sensing technique can get agricultural information rapidly and wide applicability, it has great advantages in crop growing monitoring and yielding estimation. But rice yield estimating by satellite is very difficult and has become the world wide question. The Zhejiang province rice satellite yield estimating system has been studied by the institute of agricultural remote sensing and information application of Zhejiang university for 18 years, but the estimating accuracy is still uneven. The principle reason is that there are short of deeply studying on mechanic of remote sensing information. We hope we can know more about the rice canopy reflectance character by studying on rice canopy bi-directional reflectance, so that can enhance the accuracy of remote sensing yield estimating, improve the application of remote sensing in agriculture. ? The development of bi-directional reflectance There are intensive relations by plant bi-directional reflectance, view azimuth and zenith angle, canopy structures (such as canopy depth, canopy angle distribution, 123 leaf relative size and spatial distribution), the spectrum character of canopy components and the spectrum character of under plant. The bi-directional reflectance studying is to know the changing of canopy reflectance by view angles and sun angles. To study the hi-directional reflectance model we will modeling the photon transition in plant canopy. So we can know more about the relation between the bi-directional and the canopy depth, canopy angle distribution, leaf relative size and spatial distribution and the spectrum character of under plant. By inversing we can get abundant information about canopy structures. So we can monitoring plant growth and forecasting the yield. The studying of hi-directional reflectance began in 7O~, and became to the most popular region of remote sensing in 80th Now the development is steady, the studying is concentrating in ground measurment and application but not in new theory development. The main characters are: (1) Great development in theory is not very possible. The studying concentrats in theory mending, detailing and consummating. The simple theory arose more attention because it抯 easy to be inversed. (2) The application of inclination remote sensor (such as POLDER,VEGETATION, MQDIS, MJSR, MERIS, ADEQS, AVNIR ASAS, et al ) will push forward its development and application, and some hi-directional reflectance models have been used in these remote sensor. (3) Fewer ground measuring has been done, so we lack of abundant datum to validate the models, its no good at the development of bi-directional reflectance. Now the hi-directional model can be classified into three kinds: transitive 124 model, geometry model and compute model. ? Experiment designing (1) Experiment in field: the experiments were done in 1999 and 2000. The same dealt rice canopy was measured in 1999, then five different kind of n...