Tracing high-temperature and low-salinity waters in the East China Sea : A novel approach using wave glider and satellite

Abstract

The Changjiang river water in summer disperses toward Jeju Island and then into the East/Japan Sea due to dominant southerly wind. The Changjiang freshwater contributes to the upper ocean variability in the East China Sea (ECS) and Yellow Sea (YS). Recently, the surface water in summer 2016 showed the highest sea surface temperature that increased >2~3 degree C compared to 2015 in the ECS. The Changjiang river also was loaded the wide range of the freshwater to offshore ECS with the highest value from 2000. From the hydrographic cruise around the coast of Jeju Island, surface water temperature is > 32 degree C and low-salinity water (~28 psu) stratifies under 10~15 m depth. To trace offshore high-temperature and low-salinity waters in the ECS, a proxy was developed using the wave glider and satellite date during summer 2016. The wave glider (wave-propelled autonomous vehicle) instrumented with a variety of oceanography (CTD, fluorometer, turbidity, wave height, ADCP, etc) and meteorological sensors (air temperature, air pressure, wind, camera, etc) were launched from the south of Jeju Island in Aug. 19, 2016 and navigated along and across lines (~1000 km) until Sep. 22, 2016. Wave glider navigated the west side and then the east region of Jeju Island along longitudinal and latitudinal lines. A comparison of ocean color and wave glider-measured data revealed the high-temperature and low-salinity waters with west-ea (YS). Recently, the surface water in summer 2016 showed the highest sea surface temperature that increased >2~3 degree C compared to 2015 in the ECS. The Changjiang river also was loaded the wide range of the freshwater to offshore ECS with the highest value from 2000. From the hydrographic cruise around the coast of Jeju Island, surface water temperature is > 32 degree C and low-salinity water (~28 psu) stratifies under 10~15 m depth. To trace offshore high-temperature and low-salinity waters in the ECS, a proxy was developed using the wave glider and satellite date during summer 2016. The wave glider (wave-propelled autonomous vehicle) instrumented with a variety of oceanography (CTD, fluorometer, turbidity, wave height, ADCP, etc) and meteorological sensors (air temperature, air pressure, wind, camera, etc) were launched from the south of Jeju Island in Aug. 19, 2016 and navigated along and across lines (~1000 km) until Sep. 22, 2016. Wave glider navigated the west side and then the east region of Jeju Island along longitudinal and latitudinal lines. A comparison of ocean color and wave glider-measured data revealed the high-temperature and low-salinity waters with west-