Observed deep circulation in the Ulleung Basin

Records from 16 current meters and 23 pressure gauges moored near the sea floor in the Ulleung Basin of the southwestern Japan/East Sea (JES) characterized the deep circulation between June 1999 and July 2001. Mean currents range from 1 to 4 cm/s and deep pressure anomalies range from 3 to 10 mbar, with horizontal correlation scales of about 40 km, and with integral time scales that range from about 5 to 20 days. Focusing here on the 90-day to interannual variability, synoptic maps of the deep currents and dynamic pressure fields determine that the deep circulation in the Ulleung Basin is cyclonic, with additional multiple cyclonic and anticyclonic cells that occur on sub-basin spatial scales. Over the Korea Plateau a northward deep outflow is observed that suggests an anticyclonic circulation pattern to the north. The annual average deep currents are remarkably similar for the 2 years, only slightly weaker in the second year. No seasonal pattern is discernable, except weakly at one or two sites.