Decreasing trend of kuroshio intrusion and its effect on the chlorophyll-a concentration in the Luzon Strait, South China Sea

Material exchange between oceans and currents is crucial for biogeochemical processes in marginal seas, such as the Kuroshio intrusion Luzon Strait, which contributes to nutrient phytoplankton growth adjacent water. Therefore, it necessary understand changes major current systems their possible effects on marine ecology. In this study, we applied an edge-detection method satellite-derived sea-surface temperature (SST) images identify SST front index of during 1985–2017. Chlorophyll-a (Chl-a) concentrations geostrophic (determined from satellite observations after 1993) were examined by comparing long-term variations related using empirical-mode decomposition analysis. The into Strait gradually decreased 1990s, did Chl-a speed Strait. contrast, Current eastern Philippine tended increase, indicating that northward Philippines became stronger, curtailing westward branch correlated with bifurcation North Equatorial (NEC), upstream starting southeast Philippines. NEC latitude may have shifted more southward, strengthened water mass Kuroshio, resulting motion through Consequently, weakening caused a decreasing trend South China Sea.