울산신항 연안해역에서 수온과 염분의 계절변동

Abstract

In this study, the seasonal variations of water temperature and salinity were investigated in the coastal waters around Ulsan New Port using quarterly observations at 11 stations from 2020 to 2023. Meteorological and river discharge data showed that precipitation-driven freshwater inflow strongly influenced salinity variations. Low temperature and high salinity occurred in winter due to decreased air temperature and reduced river inflow, whereas high temperature and low salinity were observed in summer with increased rainfall and river discharge. An anomalous low-temperature (<16°C) and high-salinity (>33.4 psu) water mass appeared in the bottom layer during summer 2021, which was attributed to coastal upwelling that restricted the intrusion of East Korea Warm Current (EKWC) surface water. TS diagram analysis showed that the water masses were mainly composed of EKWC surface and middle waters, with the latter dominating during the upwelling period. Strong stratification and low-salinity layers near the coast in summer reflected the influence of freshwater input. These results suggest that the hydrographic conditions in the coastal waters of Ulsan New Port are controlled by the combined effects of freshwater inflow, the EKWC, and coastal upwelling.