Coastal Warm Water Events Observed Using a Vertical Profiler

Since August 2016 a vertical profiling system installed at a coastal research station located southern coast of Korea has been collecting hydrographic data with high temporal resolution. Although the station is close to the coast, comparison of the profiler data with hydrographic data taken offshore sites reveals that the profiling system captures open water properties well. With this system, we were able to observe rapidly changing environment such as the warming or freshening of surface water that could result in large damage to fish farms. Warm water events occurring every summer are associated with low salinity water due to the fresh water discharge from the Yangtze River. Individual warm water events last for serval days or more than 10 days without any regularity. This suggests that at least near the coast warm water is in patches. Within each events, semi-diurnal tide is the main modulator.