Application of unstructured grid finite-volume coastal ocean model (FVCOM) to the Yangtze River hypoxic zone

Abstract

Purpose To observe the relations between three important factors resulting in estuarial Hypoxia phenomena of Yangtze River – wind, river flow, and stratification. The purpose of the paper is to analyze the possible reasons why hypoxia occurs in late spring and disappears in October. Design/methodology/approach To overcome the difficulty in examining the role of physical and biological factors affecting hypoxia based on measurement alone, finite-volume community ocean model (FVCOM) was introduced into the investigation. Observed freshwater flux data from Yangtze River, monthly averaged wind speed data, and other observed data were input into the model; the accuracy of which was validated with various kinds of data. The authors used the trajectories of Lagrangian particles from Yangtze River to study the regions of strong riverine influence under different wind forcing conditions and compared the simulation results with former observations. Findings Trade wind is a significant factor to influence the forming and receding of hypoxia across the Yangtze River. Originality/value Using FVCOM to investigate estuary hypoxia is more economical and effective.