From the Surface Velocity Program (SVP) drifter current data, a detailed and complete track of strong ocean currents in the north-western Pacific is provided using the bin average method. The focus of this study is on the Kuroshio, the strong western boundary current of the North Pacific flowing northward along the east coast of Taiwan and then turning eastward off southern Japan. With its average flow speed of about 2 knots, the Kuroshio can significantly increase the ship's speed for a “super-slow-steaming” container ship travelling at speeds of 12 knots between the ports of Southeast Asia and Japan. By properly utilizing knowledge of strong ocean currents to follow the Kuroshio on the northbound runs and avoid it on the return trip, considerable fuel can be saved and the transit time can be reduced. In the future, the detailed Kuroshio saving-energy route could be built into electronic chart systems for all navigators and shipping routers.

D'Asaro, in previous work using nearly neutrally buoyant Lagrangian floats in a wind forced mixed layer, found 〈w2〉 = Au2∗, where 〈w2〉 is the mean square vertical velocity and u∗ is the friction velocity estimated from shipboard meteorological measurements using bulk formulas. Depth profiles of A(z) = 〈w2〉(z)/u2∗ within the mixed layer showed a maximum value of A(z) of about 2, which is 1.75–2 times that measured in solid-wall turbulent boundary layers driven by a wall stress alone. This result implied that the ocean mixed layer was more energetic than shear-driven turbulent boundary layers driven by the same stress. Here these results are verified using observations of vertical velocity in the mixed layer from 72 float days of data from two Lagrangian floats in the North Pacific Ocean in the autumn of 2000. These floats were more neutrally buoyant than those used previously by D'Asaro, thus reducing possible biases. Wind stress was estimated from Quick Scatterometer satellite measurements and is... Abstract D'Asaro, in previous work using nearly neutrally buoyant Lagrangian floats in a wind forced mixed layer, found 〈w2〉 = Au2∗, where 〈w2〉 is the mean square vertical velocity and u∗ is the friction velocity estimated from shipboard meteorological measurements using bulk formulas. Depth profiles of A(z) = 〈w2〉(z)/u2∗ within the mixed layer showed a maximum value of A(z) of about 2, which is 1.75–2 times that measured in solid-wall turbulent boundary layers driven by a wall stress alone. This result implied that the ocean mixed layer was more energetic than shear-driven turbulent boundary layers driven by the same stress. Here these results are verified using observations of vertical velocity in the mixed layer from 72 float days of data from two Lagrangian floats in the North Pacific Ocean in the autumn of 2000. These floats were more neutrally buoyant than those used previously by D'Asaro, thus reducing possible biases. Wind stress was estimated from Quick Scatterometer satellite measurements and is...

Ocean currents in the southern East China Sea (ECS) are complex and have long lacked systematic observational data. Observations from coastal radars in northern Taiwan, along with several drifters and satellite data, reveal a detailed ECS surface flow structure and thermal front. Drifter trajectories followed the seasonal flow field and were oscillatory and trapped due to strong tidal currents. Three drifters crossed the oceanic front off the northern coast of Taiwan following the tidal motion with a rapid change in the sea surface temperature by 2.5°C, which was recorded within a small distance of 500 m. A significant seasonal water mass exchange cycle occurred in the southern ECS. Starting in October, the Kuroshio Current intrudes onto the ECS shelf, causing the formation of a southwestward Northern Taiwan Coastal Current that mixes with the China Coastal Current to form a southward flow in the northern Taiwan Strait. Beginning in March, the ocean current off northwestern Taiwan shifts northward and then gradually flows eastward into the Kuroshio region. With satellite‐derived and model‐simulated surface currents contradicting each other over long periods of time, hourly coastal radar data have not only successfully explained the spatiotemporal variations in the sea surface temperature, salinity, and chlorophyll concentration observed by satellites but have also resolved the long‐standing disputes over the surface currents in the southern ECS.

To enhance the immediacy and accuracy of search and rescue missions conducted by Taiwan Coast Guard Administration (TCGA), this study examines the characteristics of ocean currents and estimates the drifting trajectory of objects for two cases of marine incidents. Two methods are used to predict object’s drift tracks: the first one is simply calculating the advection driven by currents and the second method adopts a Monte Carlo based software, SARMAP. Ocean currents data from a high-frequency radar system comprised of 18 radar units surrounding Taiwan supplemented by bottom-mounted Acoustic Doppler Current Profilers (ADCP) data and wind data are used as the primary oceanic environment data. The estimated ending points of drifting for both cases of missing persons in water by using both methods are consistent with the actual recovery locations. Our analyses demonstrate that ocean currents data, if properly used, can be very useful for rapid response in marine search and rescue.