Tracing the sea surface warming effects on low-salinity water in the East China Sea using satellite and wave glider

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. Large amount of freshwater can create a pronounced salinity-induced mixed layer (ML) above the top of the thermocline. The layer between the base of the ML and the top of the thermocline is called a barrier layer (BL), because it acts as a barrier that isolates the warm surface water from cold deep water. Increasing Changjiang river discharge maintains a high sea surface temperature water through BL that links to enhance wave column stratification in summer. 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) was launched from the south of Jeju Island in Aug. 19, 2016 and navigated along and across lines (~1000 km) until Sep. 22, 2016. A comparison of ocean color and wave glider-measured data revealed the high-temperature and low-salinity waters with west-east 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. Large amount of freshwater can create a pronounced salinity-induced mixed layer (ML) above the top of the thermocline. The layer between the base of the ML and the top of the thermocline is called a barrier layer (BL), because it acts as a barrier that isolates the warm surface water from cold deep water. Increasing Changjiang river discharge maintains a high sea surface temperature water through BL that links to enhance wave column stratification in summer. 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) was launched from the south of Jeju Island in Aug. 19, 2016 and navigated along and across lines (~1000 km) until Sep. 22, 2016. A comparison of ocean color and wave glider-measured data revealed the high-temperature and low-salinity waters with west-east