Retrieval of Secchi disk depth in offshore marine areas based on simulated HICO from in-situ hyperspectral data

Abstract

In this study, field data such as secchi depth of th Sishili Bay and its adjacent areas in Yantai’s coastal waters were observed, meanwhile, hyperspectral remote snesing data were measured with Ocean Optics USB4000 spectrometer during two cruises carried out on 22nd and 23rd June 2009. The coastal water-leaving refectance of HICO was simulate from in situ hyperspectral remote sensing spectrum with 0.19 nm spectral resolution. According to the spectral simulation, characteristics bands of HICO were identified for water clarity estimation model. On the basis of correlation analysis between water transparency and simulation spectra, a single band model for estimating Secchi depth was established. Moreover, the relationship between Secchi depth band ratios of HICO were analyzed, and then a linear regression model of water clarity using simulated HICO was developed, with a mean relative error of 5.6% and relative mean square error of 0.29 m. The result indicates that the band ratio model of Rrs(507.18)/Rrs(518.64) of HICO could be used to retrieve Secchi depth in coastal waters.