Extracting winter wheat chlorophyll concentration vertical distribution based on bidirectional canopy reflected spectrum

The objective of this study was to discuss the method of extracting dynamic growth information for foliage vertical layers by canopy spectral reflectance for improving the accuracy of quantitative remote sensing canopy chlorophyll concentration models, so as to provide a theoretic basis for monitoring the growth and development of winter wheat. The ratio of transformed chlorophyll absorption reflectance index(TCARI) to optimized soil-adjusted vegetation index(OSAVI) was named as canopy chlorophyll inversion index(CCII), the values of CCII at nadir, ±20°, ±30° view angles were selected and assembled named as bottom layer chlorophyll concentration inversion index(LBCI) for the inversion of chlorophyll concentration at vertical bottom layer; the values of CCII at nadir, ±30°, ±40° view angles were selected and assembled named as middle layer chlorophyll concentration inversion index(MBCI) for the inversion of chlorophyll concentration at vertical middle layer; the values of CCII at ±50°, ±60° view angles were selected and assembled named as upper layer chlorophyll concentration inversion index(UBCI) for the inversion of chlorophyll concentration at vertical upper layer. The vertical chlorophyll concentration inversion can be used for monitoring the crop growth status and the management of fertilizer and irrigation.