Magdalena Andres 1, Jae-Hun Park 1, Mark Wimbush 1, Kyung Il Chang 2, Hiroshi Ichikawa 3 1 Graduate School of Oceanography, University of Rhode Island 2 School of Earth and Environmental Sciences, Seoul National University 3 Institute of Observational Research for Global Change, JAMSTEC May 24, 2007 The 14 th PAMS/JECSS Workshop

Observational highlights of Kuroshio in the ECS Introduce study area and instruments Velocity  mean cross-section  depth of maximum velocity  near-bottom velocity time series Transport:  mean  time series  spectrum

Study area (Dec – Nov. 2004) East China Sea Near PN-line

Study area East China Sea Near PN-line PIES & CPIES 23 months ADCPs 13 months (K.I. Chang)

Emits 12 kHz sound pulses at sea floor Measure (hourly):   : echo time from surface  P: bottom pressure  V: deep horizontal current Calculate:  geostrophic shear from  (using dynamic height inferred from a lookup table)  deep geostrophic flow from P  reference deep flow with the current, V ABSOLUTE VELOCITY AND TRANSPORT CPIES ( Current- Pressure- sensor-equipped Inverted Echo Sounder)

Recirculation Subsurface velocity core 13-month mean absolute velocity Countercurrent Schematic Plan view: Cross-section:

Depth of maximum velocity 53% 0.4 – 2.0 m/s 47% 0.3 – 1.1 m/s Bimodal distribution

Near-bottom velocity 23-month means: C1 C6

Transport component 24.0 Sv -0.5 Sv -4.9 Sv Positive flow, countercurrent, recirculation

28.9 Sv 3.8 Sv Net transport 18.5 Sv

Absolute Velocity (m/s) Net Transport

Net transport spectrum

11 day  James et al., 1999  Fastest growing instability – spectral model 15 day  Johns et al., 2001  Inflow east of Taiwan 64 day  K.I. Chang, B.-H. Lim, J.-H. Park  Related to winds over ECS

Summary of Observational highlights Mean velocity cross-section  Positive (northeastward flow)  Countercurrent (along slope beneath positive flow)  Recirculation (off-shore of positive flow) Near-bottom velocity  Positive flow extends to bottom km seaward of shelfbreak  Persistent countercurrent along slope  High frequency variability on the upper slope Transport  Mean: Net: 18.5 Sv (mse = 0.8 Sv;  4.0 Sv) Positive: 24.0 Sv (mse = 0.9 Sv;  4.4 Sv) Recirculation: -4.9 Sv (mse = 0.3 Sv;  1.8 Sv)  Range in net transport: 4 – 29 Sv Spectral characteristics  64, 15, 11 day peaks in transport

Many thanks to the following individuals and organizations… Karen Tracey Gerry Chaplin Capt. Sadao Ishida and the crew aboard the R/V Yokosuka of JAMSTEC Capt. Bong-Won Lee and the crew aboard the R/V Onnuri of KORDI Capt. Sunao Masumitsu and the crew aboard the T/V Kagoshima- maru of Kagoshima University Capt. Jeoung Chang Kim and the crew aboard the R/V Tamyang of Pukyong National University CTD data used in the GEM calculations were kindly provided by the Nagasaki Marine Observatory, Japan Meteorological Agency ONR KORDI JAMSTEC NRL URI/GSO PAMS/JECCS Organizing Committee