Surface currents observed by the HF radar Northeast of Taiwan

The reliability of two-and-a-half-year surface velocity data collected from the two High-Frequency radar systems (CODAR) operated at Suao and Han-Ben northeast of Taiwan is evaluated via comparison with real-time drifter trajectory. The result suggests apparent seasonal dissimilarity which might due to strongly stratified water characteristic at observing area, and the localized large differences of speed measurements between 15-meter-deep drifter and surface radar system could be the result of actually comparing two separate layers of water whose flow pattern is weakly related to each other.