Sea surface temperature (SST) in the western North Pacific (WNP) strongly affects the regional marine ecosystem and modulates East　Asian weather. Although the mechanisms of SST variability in the WNP have been extensively examined, it remains unclear how it is influenced by remote forcing from high-latitude regions. Using reanalysis datasets spanning 1979–2024, this study examined the linkage between the summer atmospheric circulation over northeastern Siberia (NES) and autumn SST variability in the WNP and elucidated the underlying influencing processes. Results revealed that anomalous high pressure over NES in August, concurrent with frequent heat waves, is typically followed by colder autumn SST in the WNP. The ocean cooling is modulated by a low-pressure system over the WNP, which reduces insolation through increased cloud cover and enhances evaporation via dry air advection. Together, these processes result in net surface heat loss, thereby contributing to subsequent SST cooling. This cooling, plausibly sustained by ocean thermal inertia, persists until November. This linkage, observed only following August heat waves over NES, is facilitated by the oceanic thermal structure characterized by a shallow mixed layer, which enhances the sensitivity of SST to surface heat loss. These findings suggest that the late-summer atmospheric circulation over NES might be helpful in predicting autumn SST variability in the WNP and provide new insights into the connection be- tween high-latitude heat extremes and midlatitude SST variability.

これまで南極および北極を対象として、海洋–海氷–氷床の相互作用に関する観測 研究に取り組んできた。 とくに、海洋熱塩循環や海水準上昇、ひいては気候変動に密接に関係する「極域 特有の水塊形成・変質プロセス」 および「海洋による氷床末端部（棚氷）の融解プロセス」に焦点を当ててきた。 本セミナーでは、その中でも近年注力している東南極における海洋–氷床相互作 用研究の成果を紹介する。 セミナー後半では、最新の南極観測（JARE67）の概要および初期結果についても 紹介する。