Rapid Estimation of the Ecological State of Coastal Water Areas Based on Shipboard Passive Remote Optical Sensing of the Water Surface

Abstract

The study of the ecological state of coastal areas often requires rapid acquisition of detailed data. In this work, sea radiance coefficient spectra are analyzed, which were measured with a new three-channel passive optical complex for ecological monitoring of marine aquatoria (EMMA), developed by us, which operates semiautomatically on board a moving ship. The measurements were carried out near the Brazilian coast at the Rio Grande river mouth. The spectra are processed using an original technique which is based on intrinsic properties of the pure sea water absorption spectrum (WASM – water absorption step method) and has been modified for eutrophic Case II waters. This enables us to estimate the absorption indices of the suspended matter and colored organic matter. The comparison of these remote estimates with the estimates made from water samples taken at special stations shows their high correlation. The distributions of the suspended matter and colored organic matter are retrieved from remote measurement data and compared to the satellite imagery for the water area under study.