Analysis of Sea Surface Temperature Variations off Wando During Summer Using Multiple Linear Regression

Summer sea surface temperatures (SSTs) along the southern coast of Korea have short-term variability with a large amplitude, which significantly affects the coastal marine ecosystem. To identify the factors influencing short-term variability of summer SSTs, multiple linear regression analyses were performed on SST data from summers spanning 2016 to 2021. The regression included independent variables such as alongshore and cross-shore Ekman heat transports in the middle of the Jeju Strait as well as alongshore and cross-shore local heat transports in coastal waters. Analysis revealed that, except for the summer of 2020, the standardized regression coefficients of the cross-shore Ekman heat transport were significant. This suggests that the primary drivers of summer SST fluctuations off Cheongsando (CSD), Korea, are the cross-shore Ekman current and the cross-shore temperature gradient in the Jeju Strait. Particularly, the meridional temperature gradient across the Jeju Strait influences coastal SSTs with a 3–4-day lag, implying that changes in temperature gradients in the Jeju Strait take 3–4 days to propagate spatially to CSD. These findings indicate the significance of wind data in developing a numerical model-based SST prediction system to forecast summer ocean heatwaves along the southern coast of Korea. Additionally, they emphasize the importance of accurately simulating SSTs in the middle of Jeju Strait and coastal currents along the southern coast for the prediction of coastal SSTs.