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.
Purpose: The purpose of this study was to investigate the relationships between regular exercise, cognitive function, and depression in Korean elderly people, and to explore whether age group affects the relationships between these variables. Methods: This study utilized data from the Korean Longitudinal Study of Aging (KLoSA) from waves 1 to 6. The sample in the current study was 4244 participants, aged 65 and older who were in wave 6 (in 2016). Welch’s test were conducted to identify the relationships between regular exercise, cognitive function, and depression. Results: First, participants undertaking exercise had better cognitive function than non-exercising participants. Second, old-old elderly people who had started exercising in the last 2 years after at least 8 years of having an inactive lifestyle had better cognitive function than those who have not exercised for more than 10 years. Third, participants who exercised had lower levels of depression than those who did not exercise. Fourth, old-old elderly people who started exercising in the last 2 years after at least 8 years of a sedentary lifestyle tended to have lower levels of depression than those who had not exercised for more than 10 years. Conclusion: The current study extends knowledge on the importance of regular exercise on cognitive function and depression in elderly people. Furthermore, this study suggests that the positive effects of exercise on cognitive function and depression may be greater for the old-old compared to the young-old age groups.