[A-CG30] Extratropical oceans and atmosphere

[ACG30-P03] Tsushima Warm Current and the Snowfall along the Japan Sea coast of Japan

*Cocoro Yokomatsu¹, Shinichiro Kida² (1.Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 2.Research Institute for Applied Mechanics, Kyushu University)

Keywords:Tsushima Warm Current, Japan Sea, Snowfall

Heavy snowfall occurs often along the Japan Sea coast of Japan. One of the main drivers of this snowfall is the Tsushima Warm Current (TWC), the oceanic current that advects warm water from the East China Sea to the Japan Sea. When the winter monsoonal wind from the continent blows from the northwest, evaporation is enhanced over the warm water of the Japan Sea, which results in heavy snowfall. Hirose and Fukudome (2006) showed that the inter-annual variability of the TWC transport during autumn is strongly correlated with the snowfall along the Japan Sea coast in winter. However, this result was based on observations between 1997 and 2005. We, therefore, examined whether the same relationship holds till recently, between 2006 and 2017. We used Radar-AMeDAS data for precipitation and velocity measurements along the ferry route of the Tsushima Strait for estimating the TWC transport. To our surprise, we found snowfall and the TWC transport uncorrelated in recent years, especially along the Tohoku area. Our analysis suggests that there may be several regimes in the relationship between the TWC and the snowfall along the Japan Sea coast on the inter-annual time scale. We plan to analyze the connection that connects the two processes in more detail, such as that between the TWC transport and the SST in the Japan Sea.