Chlorophyll-a concentration estimation using three difference bio-optical algorithms, including a correction for the low-concentration range: the case of the Yiam reservoir, Korea

ABSTRACT

Bio-optical algorithms have been applied to monitor water quality in surface water systems. Empirical algorithms have been applied to estimate the chlorophyll-a (chl-a) concentrations. However, the performance of each algorithm severely degrades at concentrations notably lower than 10 mg m⁻³. This could be attributed to the chl-a specific absorption coefficient that became less consistent at low chl-a concentrations. Nonetheless, no effort has been made in previous studies to correct existing algorithms. In this study, we propose a correction approach to improve their performance for chl-a estimation in Yiam reservoir, Korea. Estimated chl-a concentrations of the algorithms improved after applying the correction process proposed in this study; Nash–Sutcliffe efficiency values increased from 53% to 65% and root mean square error decreased from 39% to 43%, respectively. Further research is needed to verify the correction approaches for different years or study sites.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [grant number NRF-2014R1A1A2059680] and in part by the Environmental Research and Technology Development Fund of the National Institute of Environmental Research, Republic of Korea [grant number 1900-1946-342-210].