Changes in Ocean Current Characteristics Due to Freshwater Discharge from Fjord Regions

To investigate how meltwater runoff affects current patterns in the fjord, a high-resolution numerical model was developed for the Kongsfjorden region in 2007 using Finite Volume Community Ocean Model (FVCOM). Compared to previous studies, the model adopted a higher-resolution grid, resulting in improved simulation performance. The results showed strong agreement with observations, effectively capturing the temporal variations in water temperature and salinity driven by tidal fluctuations and seasonal changes. The model successfully reproduced the characteristic high water temperatures associated with the West Spitsbergen Current (WSC) and captured the intensification of bottom currents following runoff events. The impact of meltwater was quantitatively assessed by comparing simulations with and without the runoff. The results revealed that during the summer (July~August), increased glacier meltwater runoff induces a strong upstream current near the seabed in Kongsfjorden. A rotational circulation forms near the fjord mouth, and the seawater-meltwater mixing at the surface enhances vertical stratification in this area. In contrast, in the absence of meltwater, the rotational current still develops, albeit more weakly, with minimal enhancement of the bottom-layer flow.