Hourly Observed Internal Waves by Geostationary Ocean Color Imagery in the East/Japan Sea

Abstract

As internal waves (IWs) are generated via internal tidal energy near the bottom shelf break of the Korea Strait, continuous evolutions of IWs are extremely difficult to observe using satellite observations. However, the Geostationary Ocean Color Imager (GOCI) has enabled the detection of IWs in the East/Japan Sea (EJS) on an hourly basis to investigate their propagation behavior. For an extended IW analysis, a total of seven packets were identified using GOCI chlorophyll-a concentration (Chl-a) measurements around the Ulleung Basin and Dok Island in the EJS. The results demonstrate that the IW locations had lower Chl-a values than non-IW-affected regions on 10, 11, 13, and 14 August 2013. The lower Chl-a values are due to the significant wave heights of the IWs, which cause surface water masses to be dispersed. In addition, from the continuous trajectories of the waves in the hourly GOCI Chl-a imagery, quantitative physical parameters of the IWs, such as their pathway (northeasterly), phase speed (1.46-1.61 m s (1)), amplitude (20.62-26.76 m), and period (12.29 h), could be obtained. Therefore, the advantage of using GOCI is the ability to detect and analyze the physical characteristics of IWs on an hourly time scale.