A bio-optical inversion model to retrieve absorption contributions and phytoplankton size structure from total minus water spectral absorption using genetic algorithm

• Published in: Chinese journal of oceanology and limnology 2013-09, Vol.31 (5), p.970-978
• Main Author: 林俊芳 曹文熙 周雯 胡水波 王桂芬 孙兆华 许占堂 宋庆君
• Format: Article
• Language: English
• Subjects: Absorption; Absorption spectra; Algorithms; Biogeochemistry; Biology; Chlorophyll; Chlorophylls; Colour; data collection; Datasets; Earth and Environmental Science; Earth Sciences; Genetic algorithms; Inversion; Marine; model validation; Oceanography; Phytoplankton; Plankton; Root-mean-square errors; Seawater; Spectra; Water absorption; 反演模型; 吸收光谱; 大小结构; 检索; 水下; 浮游植物; 生物光学; 遗传算法
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-013-2330-9

We propose a bio-optical inversion model that retrieves the absorption contributions of phytoplankton and colored detrital matter （CDM）, as well as the phytoplankton size classes （PSCs）, from total minus water absorption spectra. The model is based on three-component separation of phytoplankton size structure and a genetic algorithm. The model performance was tested on two independent datasets （the NASA bio-Optical Marine Algorithm Dataset （NOMAD） and the northern South China Sea （NSCS） dataset）. The relationships between the estimated and measured values were strongly linear, especially for aCDM（412）, and the Root Mean Square Error （RMSE） of the CDM exponential slope （ScDM） was relatively low. Next, the inversion model was directly applied to in-situ total minus water absorption spectra determined by an underwater meter during a cruise in September 2008, to retrieve the phytoplankton size structure in the seawater. By comparing the measured and retrieved chlorophyll a concentrations, we demonstrated that total and size-specific chlorophyll a concentrations could be retrieved by the model with relatively high accuracy. Finally, we applied the bio-optical inversion model to investigate changes in phytoplankton size structure induced by an anti-cyclonic eddy in the NSCS.