Journal Article Snowfall variations in Japan and its linkage with tropical forcing

Ueda, Hiroaki  ,  Kibe, Ayumi  ,  Saitoh, Mika  ,  Inoue, Tomoshige

35 ( 6 )  , pp.991 - 998 , 2015-05 , Wiley
In this study, the causes of inter-annual variability of wintertime snowfall in the coastal plain facing the Sea of Japan over the past 33 years (1980–2012) are investigated. The observational evidence showed that intensified cold air intrusion from the Eurasian continent towards Japan in combination with anomalous cyclonic circulation favours in situ heavy snowfall. The composite analysis of the tropical convection during the heavy snow winters indicates that enhancement of convection in the vicinity of the Philippines, including the eastern Indian Ocean, is responsible for the emergence of anti-cyclonic circulation over the Asian continent and subsequent anomalous cyclonic circulation around Japan. Idealized experiments by use of the linear baroclinic model (LBM) were conducted to elucidate the origin of the teleconnection. We put idealized diabatic heating in the LBM under the wintertime atmospheric circulation and examined the heat-induced response. The experimental results clearly indicated that the intensified convection over the maritime continents and the neighbouring oceans is primarily responsible for the pair of the anti-cyclonic and cyclonic circulation. Thus, a study of the predictability of the tropical forcing may shed light on the predictable dynamics of snowy winters in Japan.

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