울릉도와 독도에 영향을 미치는 열대저기압 활동의 기후적 특성과 장기 변화

초록

Tropical cyclone (TC) activity on Ulleung-do and Dok-do must be defined and analyzed separately from that on the mainland of Korea (i.e., the Korean Peninsula) because they are located 130 km and 216 km from the eastern coast of the Korean Peninsula, respectively. Furthermore, the recent increase in the frequency and intensity of TCs toward the eastern part of the Korean Peninsula implies a growing impact on the islands. Hence, we investigated the climatological characteristics and long-term change of TC activity on Ulleung-do and Dok-do, as well as the underlying environmental changes, for the period 1945~2022. According to our results, TCs mainly influence the islands from July to September (JAS) in terms of frequency, but with peak intensity in September and October. There was a statistically significant change in 1985 in the number of TCs affecting the Ulleung-do and Dok-do, marking an increase in frequency of 0.45 and a decrease in central pressure of 6.09 hPa. In contrast, no significant change point was observed for TCs affecting the mainland of Korea. The increase in the frequency of TCs affecting the Ulleung-do and Dok-do is attributed to the strengthening of the subtropical high over the east of Japan. Meanwhile, the stronger TCs are driven by increased sea surface temperature (SST) and weakened vertical wind shear along their tracks. Our results suggest that a statistical seasonal forecasting model tailored to Ulleung-do and Dok-do is required.

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