A new method for tracking internal waves using Geostationary Ocean Color Imager (GOCI)

Abstract

The internal wave (IW) occurs in stratified two-layered density structure. They propagate within collections of solitons (called packets) preserving bow-like curvature (on a plane view) and significant amplitudes which are maximum at the interface between fluids (vertical view). The IW has found in the East/Japan Sea, a large marginal sea with in-situ measurements (e.g. CTD, Acoustic Doppler Current Profiler (ADCP) and thermistor chain) and satellite measurements (e.g. Synthetic Aperture Imager). However, there is a limitation of narrow view in field observation (stationary) and discontinuity of satellite measurements (about 1 day). To solve these problems, we used two high spatial/temporal resolution satellite imagery, which is Landsat-8 Operational Land Imager (OLI) and Geostationary Ocean Color Imager (GOCI), respectively. From the Landsat-8 OLI imagery with sun-glint, we identified three packets of IWs in the East/Japan Sea in time. Also, propagation and vertical mixing by IWs directly bring bottom waters up (or upper waters down) which allows detecting IW by elevation (or depression) of chlorophyll maximum depth. For the first time, hourly GOCI chlorophyll-a concentration measurements were approached to trace IWs that propagated from the Korea Strait to Ulleung Basin in East/Japan Sea up to 7 continued-hours. Two to three packets of IWs were detected by one shot of GOCI with the broader field of view of the sateterface between fluids (vertical view). The IW has found in the East/Japan Sea, a large marginal sea with in-situ measurements (e.g. CTD, Acoustic Doppler Current Profiler (ADCP) and thermistor chain) and satellite measurements (e.g. Synthetic Aperture Imager). However, there is a limitation of narrow view in field observation (stationary) and discontinuity of satellite measurements (about 1 day). To solve these problems, we used two high spatial/temporal resolution satellite imagery, which is Landsat-8 Operational Land Imager (OLI) and Geostationary Ocean Color Imager (GOCI), respectively. From the Landsat-8 OLI imagery with sun-glint, we identified three packets of IWs in the East/Japan Sea in time. Also, propagation and vertical mixing by IWs directly bring bottom waters up (or upper waters down) which allows detecting IW by elevation (or depression) of chlorophyll maximum depth. For the first time, hourly GOCI chlorophyll-a concentration measurements were approached to trace IWs that propagated from the Korea Strait to Ulleung Basin in East/Japan Sea up to 7 continued-hours. Two to three packets of IWs were detected by one shot of GOCI with the broader field of view of the sate