NUMERICAL ANALYSIS ON THE DEPENDENCY OF UPPER WINDS OF VOLCANIC METEOTSUNAMIS

Abstract

 A huge volcanic eruption occurred at Hunga-Tonga Hunga-Ha’api in Tonga on 15 January, 2022. The volcanic meteotsunami was observed globally according to the propagation of atmospheric shockwaves such as Lamb waves. The present study attempted the numerical analysis using the Princeton Ocean Model to investigate the effect of the upper wind to the so-called Proudman resonance caused by the coupling of atmospheric pressure waves and ocean long waves. Under the no wind condition, the computed wave height was as small as 50-60% of the wave height of the in situ observation by NOAA DART bouy systems. However the computed waves under the jet stream conditions was higher by 1.3-1.5 times of the no wind conditions at Shikoku-Oki and by 2.5-3.0 times at Tohoku-Oki. Power spectrum of the sea level elevation showed that waves with the period around 10 minutes were much more enhanced with the against winds, rather than the Lamb wave.