588 / 2024-09-18 15:18:01

Different meso-scale upwelling processes in the East Sea

meso-scale upwelling, physical-biological interaction, deep convection,

Session 46 - Oceanic Mesoscale and Submesoscale Processes: Characteristics, Dynamics & Parameterizations

The significant coastal upwelling is influenced by the duration and intensity of sea surface wind stress and geophysical components such as bottom topography, the entrainment of water masses, and vertical stratification. Furthermore, strong alongshore currents can drive upwelling along the coasts. Accordingly, this presentation introduces how wind stress and ocean currents contribute relatively to changing coastal upwelling along the southwest coast of the East Sea (Japan Sea), which has not yet been reported quantitatively. This study aims to estimate each geophysical factor affecting upwelling processes using the upwelling age index. The index assesses the major contributors to the upwelling process using the relationship between physical forcing and upwelling water fraction estimated from shipboard hydrographic data from January 1993 to October 2018. While these findings reveal that wind-driven upwelling was dominant off the northern coast, current-driven upwelling prevailed off the southern coast. These results suggest that persistent alongshore currents through the Korea Strait make the southern region a prolific upwelling area. Accordingly, this can provide a good basis for inferring the mechanisms of coastal upwelling processes, which is crucial for understanding the influence of physical forces on ocean ecosystems.