A new drifting device to measure internal waves in the upper ocean by Luca Centurioni and Peter Niiler Scripps Institution of Oceanography, La Jolla, CA,USA DBCP Scientific and Technical Workshop, 10/17/2005 In collaboration with Vitalii Sheremet (GSO-URI), Ruo-Shan Tseng (National Sun Yat-sen University) and Jian-Hwa Hu (National Taiwan Ocean University)

Outline Instruments; Experiment design; Summary of observations; Non-linearity; Summary (and future plans).

INSTRUMENTS FOR NLIW EXPERIMENT: 4 drifters with thermistor and pressure chain (20 sensors), ADCPs, GPS and ARGOS

Summary of observations First deployment, leg1,05/02/2005 Second deployment, leg 2, 05/07/2005 xx xx South China Sea Luzon Taiwan

Summary of observations: trajectories of SVP drifters and absolute sea level

Summary of observations: trajectories of SVP drifters (blue) and T-chains (red).

Summary of observations T chain record, legs 1 & 2

Summary of observations: wave packet and lift of chain 38 kHz Echo Sounder att. and T contour (T-Chain)

u v w Nonlinearity. Acoustic current meters profiles: buoy 56415, leg2

u v w

Summary Maps of absolute sea-level are helpful in planning the experiment; Acceleration: vertical advection terms in horizontal momentum equations are of same order of the linear terms; Future plans. Next experiment should try to address the following issues: a) modification of waves along their path; b) measure of horizontal advective terms (closely spaced array);