The Kuroshio east of Taiwan: Modes of variability and relationship to interior ocean mesoscale eddies

Observations from the World Ocean Circulation Experiment PCM-1 moored curre nt meter array in the East Taiwan Channel are analyzed and combined with TO PEX/Poseidon altimetry data and the Parallel Ocean Climate Model simulation to study Kuroshio variability and relationships to westward propagating se a surface height anomalies in the Philippine Sea. Approximately 60% of the total subinertial velocity and temperature varianc e in the Kuroshio east of Taiwan is associated with so-called "transport'' and "meandering'' modes revealed from empirical orthogonal function analysi s. The transport mode is dominated by a 100-day peak, while the most cohere nt energetic meandering signals are found in three limited frequency bands centered near periods of 100 days, 40 days, and 18 days. The detailed struc ture of the meanders is studied by frequency domain EOF analysis, which als o reveals a higher frequency meander centered near 10 days confined to the western side of the channel. On the 100-day timescale, the Kuroshio transport entering the East China Se a is strongly related to meandering of the Kuroshio, which in turn is cause d by westward propagating anticyclonic eddies from the interior ocean. Duri ng low transport events, the Kuroshio meanders offshore and partly bypasses the East Taiwan Channel to flow northward along the eastern side of the Ry ukyu islands. The interior eddy features that lead to the meandering can be identified as far east as 134 degreesE, propagating westward to the coast of Taiwan at about 10 km day(-1). The 100-day variability that is so domina nt in the Kuroshio is virtually absent in the Florida Current but is strong ly present east of Bahamas in the Antilles Current and deep western boundar y current, presumably being blocked from entering the Straits of Florida by the Bahamas Island chain.