Construction of CTD hydrographic observation systemby fishermen in northwest Kyushu, Japan

Abstract

For better understanding of hydrographic conditions and improving the accuracy of coastal ocean prediction models, we need to construct high-resolution observation system. In this study, we developed a new CTD sensor that is affordable, robust, and handy for coastal fishermen. We then set up a hydrographic observation system supported by the fishermen and conducted demonstration experiments in the real fishing grounds. This observation system allowed us to collect numerous CTD data at unprecedented spatiotemporal scales in the coastal waters northwest of Kyushu Island. The fluctuation of salinity at 10–20 days’ cycle is found in the Iki Channel from July to September 2019. Involving fishermen has been shown to be very effective for the coastal observation system since the number of fishermen observation data is an order of higher than the existing observation system. The CTD data from the fishing vessels have been assimilated into a coastal ocean model since January 2019, contributing to the accurate prediction of coastal fishing environment.