Origins of Atmospheric Disturbance Resulted in Meteotsunamis propagated over the East China Sea in Winter and Spring Season

Abstract

Abiki is a kind of meteotsunami (a large amplified seiche) reached to west Kyushu coastal area. This study is aimed to clarify the characteristics of the atmospheric disturbance forcing the tsunami-like ocean long wave. The sea-level pressure disturbance observed and modeled over the East China Sea had its source over the southeastern China mountains and was then propagated by a jet stream toward western Japan with a help of both wave-duct and wave-CISK (conditional instability of the second kind) mechanisms. The backward trajectory analysis also showed that the atmospheric gravity wave propagated with its phase speed of aroung 30 ms^-1, and it took 8-12 hours from atmospheric wave source to Kyushu coastal area. Hence, the forecast of the midtroposhere instability can be useful for the meteotsunami prediction.