Observations of near-inertial internal waves in the east (Japan) sea by synthetic aperture radar

Propagation of near-inertial (18 hours) internal waves were observed on the western part of East (Japan) Sea during May 18 and 19, 2004 from C-band Synthetic Aperture Radar (SAR) image data. Current and temperature measurements carried out during the field experiment from 10 May to 9 June, 2004 (IWXES2004, Internal Wave Experiment in the East Sea), were analyzed to study why near-inertial internal wave can be seen in SAR image and how it evolutes. The spatial distributions of horizontal wavelength and the phase speed estimated from the successively acquired two SAR images, are consistent with those inferred from water temperature and current measurements obtained during the field experiment. Based on these two independent observations (SAR and IWXES2004) we report that the observed wave patterns in the SAR images during IWXES2004 are near-inertial internal waves propagating into the east coast of Korea with phase speed of about 0.3 m/s