The Kuroshio around Taiwan:  The Kuroshio is the most important current in the northwestern Pacific Ocean.  Mean state, intraseasonal-to-multidecadal variability and dynamics of the Kuroshio in the vicinity of Taiwan were investigated in combined use of satellite remote-sensed images, in-situ hydrographic measurements, Argo-drifter observations, ocean reanalysis products, and numerical modelling. Further, Coral δ18O recorded for 1953-2006 at Nanwan in the southern Taiwan reflects the temperature change on interannual to decadal timescales and is proved to be controlled by the Kuroshio transport.  The impacts of Kuroshio on the paleo circulation of South China Sea and East China Sea were explored by an ocean circulation model designed for paleo oceanic environment.

Pacific equatorial surface current and its impact:  The equatorial current system plays a very important role in regulating the climate system in the ocean and atmosphere.  Its influence can be spread to the global scale via the atmospheric and oceanic circulations.  The seasonality of surface North Equatorial Countercurrent (NECC) across the entire Pacific Ocean was re-explored in detailed, and its dynamics were further clarified by a first-mode baroclinic Rossby wave model. Interannualy, the impacts of Eastern-Pacific and Central-Pacific El Nino on the NECC were compared.  Centennial tendencies of the North Equatorial Current (NEC), NECC, and the northern branch of South Equatorial Current were estimated for the past hundred years based on an ensemble of multiple ocean reanalysis products. Because of the continuous meridional shift of NEC and NECC system in the western Pacific, large warming in the subsurface ocean is evidenced.

Biogeochemistry modelling: By off-line or on-line trajectory simulation with an ocean circulation model, specific biogeochemistry problems are able to be addressed, such as tracking waters originated from given sources, sediment transportation, connectivity between/among multiple ecosystems, and ocean litter simulation.