한국해 해양열파 특성과 기작: 지역과 계절 차이

Abstract

Marine heatwaves (MHWs) are phenomena in which the sea surface temperature (SST) anomalous increases over thousands of kilometers for up to several months. As the intensity and frequency of MHWs increase in the future, marine ecosystems are expected to change. To project the effects of MHWs in Korean waters, it is important to understand the difference in seasonal characteristics and mechanisms. However, most previous studies have focused only on summer when MHWs are the most frequent, and few studies on the regional difference. In this study, we aim to investigate the characteristics of MHWs in Korean waters according to season and region, and the effects of the atmosphere and the ocean on the mechanism using OISST (Optimum Interpolation Sea Surface Temperature) data for the recent 37 years (1982 ~ 2018). In the East Sea, the MHWs tend to be longer, stronger, and less frequent while, in the Yellow East China Sea, the MHWs tend to be shorter, weaker, and frequent. Seasonally, in spring and summer, MHWs were strong throughout the Korean waters, but in fall and winter, distributions of strong MHWs in-tensity were relatively concentrated on the polar front in the East Sea. These characteristics are considered to be due to differences in the mechanism. The MHWs in summer were caused by atmospheric influences such as reduced total cloud cover and increased shortwave radiation, whereas the MHWs in the East Sea in winter were affected by the northward shift of the polar front. Our findings suggest that MHWs over Korean waters are different depending on the season and region, and in regional, ocean variability could have a larger contribution than the atmosphere to generating MHWs.