Estimation of Chlorophyll content of Phragmites australis based on PROSPECT and DART models in the saltmarsh of Yangtze Estuary

摘要

Phragmites australis is a native dominant species in the Yangtze Estuary, which plays a key role in the structure and function of the wetland ecosystem. One key question is how to estimate chlorophyll content (Cab) quickly and effectively at large scales, which could be used to reflect the growth condition and calculate the vegetation productivity. The aim of this work was to estimate Cab of P. australis based on the PROSPECT and DART (Discrete Anisotropic Radiative Transfer) models. Six widely used vegetation indices (VIs) [i.e., Normalized Difference Vegetation Index (NDVI), Structure Insensitive Pigment Index (SIPI), Colouration Index (COI), Simple Ratio Index (SR), Cater Index (CAI), and Red-edge Position Linear Interpolation (REP_(Li))] were calculated to explore their relationships with Cab. The results showed that COI and SIPI were sensitive to the leaf scale chlorophyll content. Meanwhile, no obvious saturation phenomenon was observed for these two indices compared to other indices.