著者

SATO Kazutoshi KAMEDA Takao SHIRAKAWA Tatsuo

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2022-045, (Released:2022-07-22)

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Iwamizawa on the Sea of Japan side of Hokkaido is one of the cities in Japan that experience frequent heavy snowfall events. Warm surface-layer ocean anomalies over the Sea of Japan can induce heavy snowfall over the Sea of Japan side of Japan; however, the relationship between ocean temperature over the northern Sea of Japan and snowfall events at Iwamizawa remains uncertain. This study used reanalysis data to investigate atmospheric and oceanic circulation anomalies associated with each anomalous heavy snowfall winter month at Iwamizawa. During all anomalous snowfall winter months at Iwamizawa, a cold air anomaly with northwesterly winds existed over the Far East that was associated with a dipole pattern with anticyclone anomalies over the north coast of the Eurasian Continent and cyclonic anomalies extending zonally over the Far East and northern Pacific Ocean. The surface cold air temperature and strong wind speed anomalies are major factor for anomalous upward turbulent heat flux over the northern Sea of Japan during all anomalous snowfall winter months at Iwamizawa. Additionally, during anomalous snowfall January, warm surface-layer ocean anomaly over the northern Sea of Japan, which preceded the heavy snowfall events at Iwamizawa by two months, has an important role in upward turbulent heat flux anomaly. This preceding warm ocean temperature anomaly was associated with a strong Tsushima Warm Current anomaly. Results showed that warm surface-layer ocean anomaly over the northern Sea of Japan that precedes anomalous cold advection from the Eurasian Continent has also large impact on producing heavy snowfall events over western Hokkaido coastal regions near Iwamizawa in January.