Abstract
Explosively developing cyclones are becoming one of the important factors affecting winter climate. In recent instances in December 2014, high waves induced by two successive explosive cyclones developed over the Japan Sea hit the wide area along Japanese coasts. In this study, both frequency and duration of explosive winter cyclones as well as wave height during the winter storms are shown to be on an increasing trend for this few years around Japan based on reanalysis and observed data. High waves accompanied by the explosive cyclones in 2014 are found to have completely different features in the wave direction and growth rate from high waves induced by a typical winter monsoon.
