Publications

Guo, JT; Nie, YF; Sun, BA; Lv, XQ (2022). Remote sensing of transparency in the China seas from the ESA-OC-CCI data. ESTUARINE COASTAL AND SHELF SCIENCE, 264, 107693.

Abstract
Water transparency, often measured by Secchi disk, is an intuitive indicator of water quality and plays an important role in aquatic environments. The European Space Agency (ESA) Ocean Colour Climate Change Initiative (OC-CCI) datasets provide daily and monthly remote-sensing reflectance over the period 1997-2019, which can be used to estimate Secchi disk depth (Z(sd)) with an innovative mechanistic model developed by Lee et al. (2015). In this study, the analytically-derived Z(sd) was validated by in situ Z(sd) measurements ranging from 0.1 to 38 m. The in situ Z(sd) measurements were collected in the first large-scale systematic survey on the marine environment in the China's offshore waters. Results indicated a good agreement between the in situ and satellite measurements. Based on the validated OC-CCI Z(sd) products, the spatio-temporal patterns and long-term changes of transparency in the China seas over the period 1997-2019 were studied. Regions with significant increase and decrease in Z(sd) on a long-term scale were also identified. Results of this work demonstrate the importance of both the OC-CCI Z(sd) products and remote sensing techniques in accessing water quality from long-term observations.

DOI:
10.1016/j.ecss.2021.107693

ISSN:
1096-0015