A Near-Infrared Band-Based Algorithm for Suspended Sediment Estimation for Turbid Waters Using the Experimental Tiangong 2 Moderate Resolution Wide-Wavelength Imager

摘要

Ocean color remote sensing using visible spectral bands with or without the combination of near infrared (NIR) bands for the retrieval of suspended sediment (SS) concentration (SSC) has been proven to be successful in low and medium turbid waters, but the visible bands are prone to be saturated and less sensitive to high-turbid waters. This paper proposes an NIR bands SS index (NISSI) for SSC estimation using an experimental ocean-color sensor, the moderate resolution wide-wavelength imager onboard the Chinese Tiangong 2 Space Lab. The NISSI takes advantage of the reflectance peak height around 820 nm, which is highly related with SSC. Validation using in situ dataset at the Poyang and Taihu Lakes of China and comparison with conventional approaches showed higher accuracy with mean relative error values of 21.9% and 18.6%, respectively. Benefits of NISSI algorithm is proven with higher saturation level of 300 mg/L. Sensitivity of the algorithm is affected by the sensor noise, and SSC variations lower than 12 mg/L would be significantly impeded. The results showed a promising solution for ocean-color remote sensing of extremely turbid waters, with alternative or new NIR bands around 820 nm, or short-wave infrared bands for SSC estimation.