Journal of Korean Society of Coastal and Ocean Engineers (한국해안해양공학회지)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
권호 표지

Modeling of Circulation for the East Sea Using Reduced Gravity Models

감쇠중력 모형을 이용한 동해의 순환모델링

  • Choi, Byung-Ho (Department pf Civil Engineering, Sung Kyun Kwan University) ;
  • Wang, Ou (Second Institute of Oceanography)
  • Published : 1997.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

Wind is one of the main forcing contributing the circulation of the East Sea. By using 1.5-layer and 2.5-layer reduced gravity models, circulation in the East Sea is simulated. The bifurcation of the Tsushima Warm Current (TWC), the separation of East Korea Warm Current (EKWC) from the east coast of Korea, the Nearshore Branch of TWC, and the cyclonic gyres stretched from the East Korea Bay to the northern half of the East Sea are compared well with the schematic map. The features of the upper and the lower layer are very similar except for those of the central region. The Polar Front is the separating line of two different features. The main feature of northern part of the East Sea, north of the Polar Front is cyclonic gyres, which are composed of three cyclonic gyres in most seasons. North Korean Cold Current (NKCC) and Liman Cold Current (LCC) are the nearshore part of these cyclonic gyres. In the south of the Polar Front the current systems of both layers are anticyclonic in most seasons, except that those of the upper layer in winter and spring are not anticyclonic. Along the coast of Korea and Russia, the velocity structure is barotropic, while that of the central region is baroclinic. The effects due to the seasonal variations of wind stress and local Ekman suction/pumping are studied by imposing the domain with modified wind stress. which is spatial mean with temporal variations and temporal mean with spatial variations. It is found that the local Ekman suction/pumping due to wind stress curl is important to the formation of the cyclonic gyres in the western and the northwestern region of the East Sea.

바람은 동해의 순환에 기여하는 중요한 외력이다. 1.5층 및 2.5층 감쇠중력 모형을 이용하여 동해의 순환을 시뮬레이션하여 대마난류의 분기, 동해안의 동한난류의 분기, 동한만 및 동해북부에서의 반시계 방향성 순환현상을 기존순환모형도와 비교하였다. 상층과 하층의 양상은 동해의 중앙부를 제외하고는 유사하였는데 극전선이 다음과 같이 서로 다른 두양상을 제시한다. 극전선의 북측의 주양상은 대부분의 계절에 발생하는 3개소의 반시계방향 와동이며 이 와동의 내측연안을 따라서 북한류와 리만한류가 흐른다. 극전선의 남측에서 상하 양층의 해류체계는 겨울과 봄의 상층순환을 제외하고는 시계방향 순환이다. 한국과 러시아 연안을 따라 류속구조는 순압적이나 동해중부는 경압적이다. 바람응력의 계절적 변화와 Ekman 수송(suction/pumping)을 시간변화를 갖는 공간적평균과 공간적변화를 갖는 시간적으로 수정된 바람응력을 부여함으로서 조사하였다. 동해의 서측과 북서측 해역의 반시계방향 와동의 형성에 있어서 바람응력 컬(curl)에 의한 국지적인 Ekman suction/pumping이 중요함을 확인하였다

Keywords

References

  1. J. Phys. Oceanogr. v.10 A numerical study of Loop Current intrusions and eddy shedding Hurlburt, H.E.;Thompson, J.D.
  2. J. Oceanogr. v.52 Modeling of the winddriven circulation in the Japan Sea using a reduced gravity model Kim, C.-H.;Yoo, J.-H.
  3. J. Geophys. Res. v.101 Coupled dynamics of the South China Sea, the Sulu Sea, and the Pacific Ocean Metzger, E.J.;Hurlburt, H.E.
  4. Mar. Sci.(Kaiyo Kagaku) v.9 The oceanographic fluctuations in the Japan Sea Naganuma, K.
  5. J. Oceanol. Soc. Korea v.27 Monthly-mean sea surface winds over the adjacent seas of the Korean Peninsula Na, J.-Y.;Seo, J.-W.;Han, S.-K.
  6. J. Imp. Fish. Exp. Sta. v.5 The results of simultaneous oceanographical investigations in the Japan Sea and its adjacent waters in May and June, 1932 Uda, M.
  7. Problems of Oceanography Study state of the Japan Sea circulation Yarichin, V.G.;V. Pokudov(ed.)
  8. J. Oceanogr. Soc. Japan v.38 Numerical experiment on the circulation in the Japan Sea, PartⅠ. Formation of the East Korean Warm Current Yoon, J.-H.
  9. J. Oceanogr. Soc. Japan v.38 Numerical experiment on the circulation in the Japan Sea, PartⅢ. Mechanism of the nearshore branch of the Tsushima Current Yoon, J.-H.