During the winter of 2017/2018, significantly low water temperatures were detected around the western and southern coasts of Korea (WSCK). In this period, sea surface temperature (SST) in the Korea Waters was about 2℃ lower than mean temperature. Using the real-time observation system, we analyzed the temporal variation of SST during this period around the western and southern coasts. Low water temperature usually manifested over a period of about 10 ~ 20 days. The daily Arctic oscillation index was also similarly detectable with the variation of SST. From the cross-correlation function, we compared two periodic variations, which were SST around the WSCK and the Arctic oscillation index. The cross correlation coefficients between both variations were approximately 0.3 ~ 0.4. The time lag of the two time series was about 6 to 7 days. Therefore, significanlyt low water temperatures during winter in the Korean coastal areas usually became detectable 6 to 7 days after the negative peak of Arctic oscillation.

Abstract
 1. Introduction
 2. Data and Methods
 3. Results
  3.1 Feature of water temperatures during the winter of2017/2018 around the Korean peninsula
  3.2 Temporal variation of SST and Arctic oscillation
  3.3 Relationship between SST and Arctic oscillation
 4. Summary and Discussion
 References

• In-Seong Han(Ocean Climate and Ecology Research Division, National Institute of Fisheries Science) Corresponding Author
• Joon-Soo Lee(Ocean Climate and Ecology Research Division, National Institute of Fisheries Science)
• Ju-Yeon Kim(Ocean Climate and Ecology Research Division, National Institute of Fisheries Science)
• Ji-Yeon Hong(Ocean Climate and Ecology Research Division, National Institute of Fisheries Science)