Abstract: Carotenoid (Car), the main pigment of green leaves, plays an important role in diagnosing the physiological state of vegetation. The leaves of Kandelia candel were sampled from the Minjiang River estuary in April and July, 2013. In the laboratory, spectral reflectance of leaves (both front and back), and the Car contents (two dimensions: μg·cm^-2 and mg·g^-1) were determined. The common parameters and the best simple ratio spectral index (SR) were used to build the estimation models. The results showed that the spectral reflectance of leaf back was higher than that of leaf front in 350-2350 nm. The relationship between SR calculated from spectral reflectance of leaf back and Car content (μg·cm^-2) was better than other combinations. SR calculated by bands in two zones, including the 520-540 nm and 1000-1100 nm, 700-720 nm and 800-1100 nm had higher correlation coefficient compared with that in other zones. Additionally, most of the parameters calculated by leaf back reflectance had higher correlation coefficients with Car content (μg·cm^-2) than that of leaf front. Consequently, parameters calculated by leaf back reflectance and the Car content in per unit area were selected to establish the estimation and validation models. The model parameters further indicated that the models built by LCI, DD, NDVI_(770,713), NDVI_(773,562), SR_(723,770) and SR_{(1000,700)} could achieve the estimation of Car contents (R²>0.65, RMSE<1.52). The best estimation parameter was SR_(1000,700):R² values of its estimation and validation models were 0.77 and 0.87, and RMSE values were 1.08 and 1.11, respectively. The results impied that hyperspectral remote sensing data could be used to estimate Car contents of K. candel.

Key words: Ross-Li model, clumping index, MODIS BRDF