Hyperspectral characteristics of seawater intrusion in Pearl River Delta, China based on laboratory experiments

In recent years, the Pearl River Delta (PRD) of China experienced serious saline water intrusion in the dry season, leading to water supply crisis. A challenging issue in water supply management is that there is not enough saline water intrusion information for decision making due to limited site-monitoring. Therefore, the objectives of this study is to investigate the spectral characteristics of seawater with different chlorosity, the most fundamental step in remote sensing application. Experiments in laboratory were performed to obtain spectral characteristics of saline water by spectroradiometer. The primary results show that, (1) reflectance of seawater was small between 400 and 850 nm, ranging from 0.01 to 0.14; (2) reflectance spectra of seawater was unique because spectral curves changed slightly in the ranges of 400-700 nm and 850-930 nm, but fluctuated observably in 700-850 nm, i.e., suddenly declined from 700 to 750 nm and then formed a narrow peak (750-770 nm) and a wide peak (770-850 nm); and (3) spectral reflectance increased with the increasing of chlorosity.