Magdalena Andres1, Jae-Hun Park1, Mark Wimbush1,

Kyung Il Chang2, Hiroshi Ichikawa3

1 Graduate School of Oceanography, University of Rhode Island2 School of Earth and Environmental Sciences, Seoul National University3 Institute of Observational Research for Global Change, JAMSTEC

May 24, 2007 The 14th 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. 2002 – Nov. 2004)

East China Sea

Near PN-line

Study area

East China Sea

Near PN-line

PIES & CPIES 23 months

ADCPs13 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)

VVV

V

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-monthmeans:

C1C6

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

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 50-100 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