【摘要】 遥感传感器所获取的植物遥感数据是随时间而变化的。这主要取决于物候现象及太阳高度角的变化。植被分类遥感研究的最佳时相,是植物种间光谱反射率差异最大的季节。本研究认为,在湖北省及北亚热带地区,植被分类研究的遥感影象最佳时相应选在4月、5月及11月。更多还原

【Abstract】 Vegetation remote sensing data from sensor change with phenology and the sun altitude angles. Therefore, the optimum temporal images must be selected from different periods for vegetation studies. The season of the greatest vegetation reflection difference in the visible and near-infrared regions is the optimum temporal for the vegetation classifying studies. The results indicate that the absolute difference and relative difference of plant species in reflectance are the greatest in spring and early summer. Then the greatest number of crop types can be identified in the images. The autumn images are most sui- table for identifying deciduous leaf vegetation, for the leaf pigments of all kinds ap- pear at that time. Vegetation reflectances in MSS₅ and MSS₇ decrease with the decre- ase of the altitude angles of the sun. Therefore, appropriate images of the sun altitu- de angles must be selected for the study of vegetation. The author concludes that the optimum temporal images of remote sensing for ve- getation studies in Hubei Province or north tropics are those taken in April, May and November.更多还原