Theory of Forced Shelf Waves over a Double Shelf

방익찬,김태희 제주대학교 해양과환경연구소 1992 해양과환경연구소 연구논문집 Vol.16 No.-

황해와 동중국해에서 해수면의 장주기 변화와 대륙붕파

방익찬 濟州大學校海洋硏究所 1995 해양과환경연구소 연구논문집 Vol.19 No.-

해수면 관측자료로부터 해수면의 장주기변하를 분석해 본 결과 황해, 동중국해, 동해 해역에서 기사으이 효과는 전반적으로 해수면변화의 반 정도를 설명해 주며 나머지 반은 해수운동에 의한 것으로 보인다. 해수운동에 의하여 발생하는 해수면변화는 대마해류역에서 가장 크며 대마해류의 영향을 적게 받는 곳일수록 작아져 해수면변화가 대마해류와 관계있음을 보여준다. 장주기 해수면변화를 정성적으로 분석해 보기 위해 황해와 동중국해의 해저지형에 의해 형성되는 대륙붕파의 이론을 전개하여 분산관계를 구하였으며, 대한해협에서 강제파가 반사에 의해 자유파를형성시키는 해를 구하였다. 전개된 대륙붕파 이론을 해수면변화에 적용시켜 본 결과 쿠로시오해류의 변화에 의해 동중국해에 가해진 파동은 강제파로 대한해협으로 전파되며 대한해협에 이르러 일본연안의 파동은 동해로 계속 전파되는 반면, 우리나라 연안의 파동은 해저지형에 의해 반사하게 된다. 반사된 파동은 자유파로 동중국해 대륙붕을 따라 남서방향으로 진행하며 북동방햐응로 진행하는 강제파와 더불어 동중국해의 해수면변화를 결정하게 된다. The analysis of long-period sea level variations with tidal record data in the Yellow Sea, the East China Sea, and the East Sea shows that about half of the variations is due to atmospheric causes and the rest half seems to be due to the water movements. The sea level variation by water movements is the largest in the coasts along the Tsushima Current. To analyze sea level variations qualitatively, the theory of continental shelf waves is developed over the bottom topography of the Yellow Sea and the East China Sea. The dispersion relation is derived and the reflected free waves is solved for incident forced waves in the Korea Strait. The application of the theory to the sea level variations shows that the long period Kuroshio variation propaggate to the Korea Strait as forced waves. The wave continuously propagates to the East Sea through the eastern channel, but reflects in the western channel due to bottom topography. The reflected waves propagate southwestward along the East China Sea as free waves and determine the sea levels with forced waves.

제주도 북서해역의 해수분포와 해수순환

방익찬,노홍길,김태희 제주대학교 해양연구소 1994 해양자원연구소연구보고 Vol.18 No.-

Theory of Forced Shelf Waves over a Double Shelf

방익찬,김태희 제주대학교 해양연구소 1992 해양자원연구소연구보고 Vol.16 No.-

The first order wave equation over a double shelf has wind stresses on both coastal boundaries and wind stress curl forcing across the shelf. In the Yellow Sea, the effect of wind stress curl can be neglected as a forcing of shelf waves. The decay distance of Kelvin waves are much greater than that of continental shelf waves so that Kelvin waves are transmitted nearly intact through the northern embayment. The numerical method of characteristics has been modified to accomodate wave propagation of opposite directions. The Kelvin wave makes a substantial contribution to sea level fluctuations. However, it contributes almost nothing to alongshore velocity. Velocity is due mainly to the presence of continental shelf waves, among which the 1st modes contribute the most.

제주도 서부 연안역의 용승

방익찬,김태희 제주대학교 해양연구소 1993 해양자원연구소연구보고 Vol.17 No.-

The characteristics of the vertical temperature and salinity distributions in the western sea of Cheju Island is a upper-upwelling and lowerdownwelling feature. Although it is not clear in winter and summer seasons, it seem to be continued through the year. The feature is likely to be weaker, as waters flow north. The upwelling feature was very strong in November, when northerly winds had been blowing for 10 days before the observation, so that it reached to the bottom and the lower-downwelling feature disappeared then. The year-lasting upwelling feature can not be explained by only winds, but, the effect of winds seems to be the strongest. There are a couple of problems in the explanation of upwelling by negative vorticity due to clockwise flows. First, it can not explain the lower-downwelling feature. Second, it is hard to explain why the feature is weaken, as waters flow north. Third, its estimated effect is so small compared to the observations. The upper-upwelling and lower-downwelling feature may be caused by negative vorticity in the upper layer and positive vorticity in the lower layer. Such a vorticity variation can be driven when waters flow along the isobaths of which widths are widening. It will be followed by horizontal divergence in the upper layer and horizontal convergence in the lower layer.

제주도 북서해역의 해수분포의 계절변화와 여름철의 황해난류

방익찬,노홍길,이재학 제주대학교 해양연구소 1995 해양자원연구소연구보고 Vol.19 No.-

우리나라 근해의 장기적인 해수면변화

방익찬,오임상 ( Ig Chan Pang,Im Sang Oh ) 한국수산과학회 1994 한국수산과학회지 Vol.27 No.6

Monthly mean sea levels from 103 tidal stations in Korea, Japan, and Russia are analyzed to study long-period sea level variations. Barometric adjustment are done for all the sea level data, using monthly air pressures at sea levels from meteorological stations near tidal stations. Seasonal variation is dominant in most of study area. It is the largest in the coasts along the Tsushima Current, and the smallest in the Russian coasts. The cross-correlations of seasonal variations are very high between the coasts along the Tsushima Current. In these marginal seas, seasonal variations seem to be related with the Tsushima Current. The phase of seasonal variations is generally getting late from south to north, and also from west to east. On the other hand, longer-period variations(longer than seasonal variation) have the largest amplitudes and the earliest phases in the coasts along the Pacific Ocean, which shows that they propagate from the Pacific Ocean. Shorter-period variations (shorter than seasonal variation) have generally lower cross correlations. Their values do not show any dictinct difference between areas, and show a common tendency that they are inversely proportional to distance. It implies that the shorter period waves are generated all over the study areas, and propagate in all the directions with faster dissipations. The trends of sea levels in the study area are generally negative in the coasts along the Pacific Ocean and positive in the other areas during the period of 1965 to 1985. By the trends, the mean volume transport between Cheju and Sasebo can be reduced by about 1 Sv during the period. The seasonal variation of volume transport obtained by sea level difference is about 2 Sv in the Korea Strait. The values are comparable to previous reports.

Coastally Trapped Waves over a Double Shelf Topography(III) : Forced Waves and Circulations Driven by Winds in the Yellow Sea

방익찬,PANG Ig-Chan The Korean Society of Fisheries and Aquatic Scienc 1992 한국수산과학회지 Vol.25 No.6

The first order wave equation over a double shelf has wind stresses on both coastal boundaries and wind stress curl forcing across the shelf. In the Yellow Sea, the effect of wind stress curl can be neglected as a forcing of shelf waves. The decay distance of Kelvin waves is much greater than that of continental shelf waves so that Kelvin waves are transmitted nearly intact through the northern embayment. The numerical method of characteristics has been modified to accomodate wave propagation of opposite directions. Using a little more realistic coastline, the wave model hindcast has been improved for current velocity, but hardly for sea level. It means that Kelvin waves, which mainly determine sea levels, are affected little by the change of bottom slope. For a better hindcast of sea level, input energy of Kelvin waves transmitted from the East China Sea is needed. The basic structure of downwind flows along the coasts and upwind flows along the trough supports the seasonal circulations driven by monsoon winds in the Yellow Sea. 양향성 대륙붕에서 1차 파동방정식은 양 해안경계에서의 바람응력과, 대륙붕폭에 걸친 바람응력의 회전효과를 갖는다. 황해에서 바람응력 회전효과는 대륙붕파를 발생시키는 힘으로서 무시될 수 있다. 켈빈파는 대륙붕파보다 약화될 때까지의 거리가 매우 크기 때문에 황해 북쪽만(별)을 거의 약화되지 않고 통과할 수 있다. 파동특성을 따라 적분하는 수치방법은 반대방향으로 전파되는 파동을 수용하기 위해 조절되었다. 보다 실제와 가까운 해안선을 사용한 결과, 모델재생이 해류에서는 개선되었으나 해수면에서는 거의 개선되지 않았다. 이것은 해수면을 주로 결정하는 켈빈파가 해저지형의 변화에 영향을 극히 적게 받음을 의미한다 보다 개선된 해수면 재생을 위해서는 동지나 해에서 황해로 전파되는 켈빈파의 에너지를 알 필요가 있다. 해안을 따른 순풍류와 골을 따른 역풍류의 기본구조는 계절풍에 의해 발생하는 황해의 계절순환을 뒷받침한다.

황해와 동중국해에서 해수면의 장주기 변화와 대륙붕파

방익찬 제주대학교 해양연구소 1995 해양자원연구소연구보고 Vol.19 No.-

Seasonal Variations of Water Mass Distributions and Their Causes in the Yellow S

방익찬 釜山水産大學校 海洋産業開發硏究所 1993 硏究業績集 Vol.1992 No.-