• Ocean and Polar Research
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• 제30권4호
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• pp.453-466
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• 2008

In order to examine the generation mechanism of long ocean waves along the west coast of Korea and to understand the amplification process of the long ocean waves, sea level, atmospheric pressure and wind data observed every minute from 2007 March 29 to 2007 April 1 were analyzed and onedimensional numerical ocean model experiments were performed. An atmospheric pressure jump propagated southeastward from Backryungdo to Yeonggwang along the west coast of Korea with speed of $13{\sim}27\;m/s$ between 2007 March 30 23:00 and 2007 April 1 1:30. Average magnitude of pressure jump was 4.2 hPa. As a moving atmospheric jump propagated from north to south along the coast, long ocean waves were generated and the sea level abnormally rose or fell at Anheung, Kunsan, Wido and Yeonggwang. Average amplitude of sea level rise (or fall) was about 113.6 cm. In a one-dimensional numerical ocean model, nonlinear shallow water equations were numerically integrated and a moving atmospheric pressure jump with traveling speed of 24 m/s was used as an external force. While the atmospheric pressure jump travels over 60 m depth ocean, a long ocean wave is generated. Because the propagation speed of the atmospheric jump is almost equal to that of the long ocean wave, Proudman resonance occurs and the long ocean wave amplifies. As the atmospheric pressure jump moves into the coastal area shallower than 60 m, the speed of the long ocean wave decreases and Proudman resonance effect decreases. However, the amplitude of the long ocean wave increases and wave length becomes shorter because of shoaling effect. When the long ocean wave hits the land boundary, amplitude of the long ocean wave drastically amplifies due to reflection. Data analysis and numerical experiments suggest that the southeastward propagation of an atmospheric pressure jump over the shallow ocean, which is a necessary condition for Proudaman resonance, generated the long ocean waves along the west coast of Korea on 2007 March 31 and the ocean waves amplified due to shoaling effect in the coastal area and reflection at the shore.

• 한국환경과학회지
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• 제27권1호
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• pp.11-25
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• 2018

Both the propagation velocity and the direction of atmospheric waves are important factors for analyzing and forecasting meteo-tsunami. In this study, a total of 14 events of meteo-tsunami over 11 years (2006-2016) are selected through analyzing sea-level data observed from tidal stations along the west coast of the Korean peninsula. The propagation velocity and direction are calculated by tracing the atmospheric disturbance of each meteo-tsunami event predicted by the WRF model. Then, the Froude number is calculated using the propagation velocity of atmospheric waves and oceanic long waves from bathymetry data. To derive the critical condition for the occurrence of meteo-tsunami, supervised learning using a logistic regression algorithm is conducted. It is concluded that the threshold distance of meteo-tsunami occurrence, from a propagation direction, can be calculated by the amplitude of air-pressure tendency and the resonance factor, which are found using the Froude number. According to the critical condition, the distance increases logarithmically with the ratio of the amplitude of air-pressure tendency and the square of the resonance factor, and meteo-tsunami do not occur when the ratio is less than 5.11 hPa/10 min.

• 한국환경과학회지
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• 제23권12호
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• pp.1999-2014
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• 2014

A meteo-tsunami occurred along the coastline of South Korea on 31 March 2007, with an estimated maximum amplitude of 240 cm in Yeonggwang (YG). In this study, we investigated the synoptic weather systems around the Yellow sea including the Bohai Bay and Shandong Peninsula using a weather research and forecast model and weather charts of the surface pressure level, upper pressure level and auxiliary analysis. We found that 4-lows passed through the Yellow sea from the Shandung Peninsula to Korea during 5 days. Moreover, the passage of the cold front and the locally heavy rain with a sudden pressure change may make the resonance response in the near-shore and ocean with a regular time-lag. The sea-level pressure disturbance and absolute vorticity in 500 hPa projected over the Yellow sea was propagated with a similar velocity to the coastline of South Korea at the time that meteo-tsunami occurred.

• 한국해안해양공학회지
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• 제5권4호
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• pp.318-328
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• 1993

Kuril 열도의 남부에 위치한 Shikotan 섬 지역에 대하여 1990-1992년간에 걸쳐 일련의 장파관측이 수행되었다. 5개 만과 Shikotan 유입부 등의 7개소에 저면 압력 측정장치를 설치하였으며, 해안에 3개의 정밀압력계가 위치하도록 하였다. 관측의 목적은 지진파랑의 관측, 해안지형의 공진특성 평가 및 부진동 생성 메카니즘의 조사에 두었다. 2시간 이상의 주기를 갖는 파동에 있어서는 의력에 의한 장파가, 30-120분 주기에서는 자유장파가 지배적이었으며, 30분 이하의 주기에서는 만의 부진동이 가장 지배적인 장파형태로 나타났다. Krabovaya만의 30분 주기 Helmholtz 모드와 Malokurilskaya만의 18.5분 주기모드가 Shikotan 내역에서 가장 중요한 파동형태이다. 대기 교란경로와 Shikotan섬 연해의 부진동 생성간에 상당한 상관관계가 있으며, 특히 대기압의 급상승은 각각 다른 부진동 주기를 갖는 여러만에 동시에 부진동을 일으킨다. 대기 스펙트럼은 매우 안정적인 것으로 나타났으며, $\omega$$^{-226}$ 지수식으로 나타낼 수 있는 것으로 사료된다.