%0 Journal Article
%A HAN  Zhen
%A CHEN  Shuai-kang
%A LI  Pi-xue
%A CHEN  Hao-cheng
%T Inversion of Chlorophyll-a Concentration in Shanghai Offshore Waters Based on BRDF Correction
%D 2024
%R 10.11988/ckyyb.20230373
%J Journal of Yangtze River Scientific Research Institute
%P 169-177
%V 41
%N 9
%X <p id="p00010">To investigate the ecological status of Shanghai’s offshore waters, we applied the water color remote sensing technology to estimate chlorophyll-a concentration. Considering the impact of BRDF (Bidirectional Reflectance Distribution Function) on inversion accuracy, we utilized LandSat-8 remote sensing data and measured water quality data in association with Lee’s model and QAA (Quasi-analytical algorithm) for BRDF correction. Results indicate that suspended sediment concentration is a major factor affecting BRDF. The angle of sunlight has minimal impact on BRDF when the sun is not vertically incident. After BRDF correction, the mean value of <i>R</i><sup>2</sup> increased by 22.2% to 0.9, whereas mean RMSE decreased to 0.74. Before the correction, chlorophyll-a concentrations in Shanghai’s offshore waters were overestimated by an average of 2 mg/m<sup>3</sup>. BRDF correction notably enhances chlorophyll-a inversion accuracy, presenting innovative insights for offshore water color inversion.</p>
%U http://ckyyb.crsri.cn/EN/10.11988/ckyyb.20230373