fnctId=thesis,fnctNo=426
Characteristics of East Asian Cold Surges Associated with the Arctic Warming
- 작성자
- 기후시스템전공
- 저자
- YeongHwa Ko
- 발행사항
- 발행일
- 2026-02
- 저널명
- 국문초록
- 영문초록
- In recent decades, Arctic amplification has been suggested to be closely associated with changes in midlatitude atmospheric circulation and East Asian winter cold extremes. However, the covariability structure of temperature fluctuations between the Arctic and East Asia, as well as the temporal processes through which such covariability contributes to the development of cold surges, remains insufficiently understood. This study examines the phase-dependent formation processes of East Asian cold surges and their associated time-lagged characteristics based on covarying wintertime temperature patterns between the Arctic and East Asia. The results indicate that cold-surge development differs markedly between the Positive Phase and Negative Phase, defined by the leading coupled mode of Arctic?East Asian temperature covariability. During the Positive Phase, a pronounced dipole structure emerges, characterized by warm temperature anomalies over the Barents?Kara Seas and cold anomalies over midlatitude East Asia. Approximately five days prior to cold-surge onset, an upper-tropospheric ridge gradually intensifies near the Ural Mountains, accompanied by the southeastward development and expansion of the Siberian High. Following this upper-level circulation development, the East Asian trough deepens and low-level northerly winds strengthen, resulting in vertically organized cold-air intrusions and the subsequent development of cold surges. These features suggest that changes in the Arctic?Eurasian upper-tropospheric circulation are linked to East Asian cold surges through a distinct time-lagged process. In contrast, during the Negative Phase, wave propagation is comparatively weak, and cold surges are primarily associated with localized intensification of the Siberian High and short-lived circulation variability. As a result, cold-surge development during this phase is dynamically distinct from that observed during the Positive Phase.
Furthermore, change-point detection applied to the Arctic amplification time series reveals a clear difference in cold-surge evolution before and after 2004. After the change point (P2), enhanced Arctic warming is accompanied by the earlier development and sustained expansion of the Siberian High several days prior to cold-surge onset, leading to relatively longer-lasting cold surges through persistent northerly flow. In contrast, before the change point (P1), cold surges tend to be triggered primarily by short-term synoptic-scale circulation variability.
- 일반텍스트
- 첨부파일