Published Papers

Ashjian, C., R. Arnone, C. Davis, B. Jones, M. Kahru, C. M. Lee, and B. G. Mitchell, Biological structure and seasonality in the Japan/East Sea, Oceanography, 19(3), 126-137, 2006.

Chang, K.-I., W.J. Teague, S.J. Lyu, H.T. Perkins, D.-K. Lee, D.R. Watts, Y.-B. Kim, D.A. Mitchell, C.M. Lee, and K. Kim, Circulation and currents in the southwestern East/Japan Sea: Overview and Review, Progress in Oceanography, 61, 105-156, 2004.  [ Abstract ]

Fox, D.N., W.J. Teague, C.N. Barron, M.R. Carnes, and C M. Lee, The Modular Ocean Data Assimilation System (MODAS), Journal of Atmospheric and Oceanic Technology, 19(2), 240-252, 2002.  [ Abstract ]

Gordon, A.L., C.F. Giulivi, C.M. Lee, A. Bower, H.H. Furey, and L. Talley, Japan/East Sea intra-thermocline eddies, Journal of Physical Oceanography, 32(6), 1960-1974, 2002.  [ Abstract ]

Lee, C.M., C.E. Dorman, R.W. Gould, and B.H. Jones, Preliminary Cruise Report: Hahnaro 5 — Dynamics, Biology, Optics and Meteorology of the Subpolar Front in the Japan/East Sea, APL-UW Technical Memorandum 3-99, University of Washington, Seattle, July 1999.

Lee, C.M., L.N. Thomas, and Y.Yoshikawa, Intermediate water formation at the Japan/East Sea subpolar front, Oceanography, 19(3), 54-64, 2006.

Thomas, L., and C.M. Lee, Intensification of ocean fronts by down-front winds, Journal of Physical Oceanography, 35(6), 1086-1102, 2005.  [ Abstract ]

Data Reports

Bahr, R., Acoustic Doppler Current Profiling During Sea of Japan/East See SeaSoar Cruise JES2, May, June 1999.

Bahr, R., SeaSoar Data Processing, Sea of Japan/East Sea Cruise, May 19 to June 3, 1999.


Chang et al., 2004
A review is made of circulation and currents in the southwestern East/Japan Sea (the Ulleung Basin), and the Korea/Tsushima Strait which is a unique conduit for surface inflow into the Ulleung Basin. The review particularly concentrates on describing some preliminary results from recent extensive measurements made after 1996. Mean flow patterns are different in the upstream and downstream regions of the Korea/Tsushima Strait. A high velocity core occurs in the mid-section in the upstream region, and splits into two cores hugging the coasts of Korea and Japan, the downstream region, after passing around Tsushima Island located in the middle of the strait. Four-year mean transport into the East/Japan Sea through the Korea/Tsushima Strait based on submarine cable data calibrated by direct observations is 2.4 Sv (1 Sv = 106 m3 s-1). A wide range of variability occurs for the subtidal transport variation from subinertial (2-10 days) to interannual scales. While the subinertial variability is shown to arise from the atmospheric pressure disturbances, the longer period variation has been poorly understood.

Mean upper circulation of the Ulleung Basin is characterized by the northward flowing East Korean Warm Current along the east coast of Korea and its meander eastward after the separation from the coast, the Offshore Branch along the coast of Japan, and the anticyclonic Ulleung Warm Eddy that forms from a meander of the East Korean Warm Current. Continuous acoustic travel-time measurements between June 1999 and June 2001 suggest five quasi-stable upper circulation patterns that persist for about 3-5 months with transitions between successive patterns occurring in a few months or days. Disappearance of the East Korean Warm Current is triggered by merging the Dok Cold Eddy, originating from the pinching-off of the meander trough, with the coastal cold water carried Southward by the North Korean Cold Current. The Ulleung Warm Eddy persisted for about 20 months in the middle of the Ulleung Basin with changes in its position and spatial scale associated with strengthening and weakening of the transport through the Korea/Tsushima Strait. The variability of upper circulation is partly related to the transport variation through the Korea/Tsushima Strait. Movements of the coastal cold water and the instability of the polar front also appear to be important factors affecting the variability.

Deep circulation in the Ulleung Basin is primarily cyclonic and commonly consists of one or more cyclonic cells, and an anticyclonic cell centered near Ulleung Island. The cyclonic circulation is conjectured to be driven by a net inflow through the Ulleung Interplain Gap, which serves as a conduit for the exchange of deep waters between the Japan Basin in the northern East Sea and the Ulleung Basin. Deep currents are characterized by a short correlation scale and the predominance of mesoscale variability with periods of 20-40 days. Seasonality of deep currents is indistinct, and the coupling of upper and deep circulation has not been clarified yet.

Fox et al., 2002
The Modular Ocean Data Assimilation System (MODAS) is used by the U.S. Navy for depiction of three-dimensional fields of temperature and salinity over the global ocean. MODAS includes both a static climatology and a dynamic climatology. While the static climatology represents the historical averages, the dynamic climatology assimilates near-real-time observations of sea surface height and sea surface temperature and provides improved temperature and salinity fields. The methodology for the construction of the MODAS climatology is described here. MODAS is compared with Levitus and Generalized Digital Environmental Model climatologies and with temperature and salinity profiles measured by SeaSoar in the Japan/East Sea to illustrate MODAS capabilities. MODAS with assimilated remotely sensed data is able to portray time-varying dynamical features that cannot be represented by static climatologies.

Gordon et al., 2002
Intrathermocline eddies (ITE) with diameters of 100 km and of thickness greater than 100 m are observed within each of the three quasi-stationary meanders of the Tsushima Current of the Japan/East Sea. Within the ITE homogenous, anticyclonic flowing core, the temperature is near 10°C with a salinity of 34.12 psu. Because of compensatory baroclinicity of the upper and lower boundaries of the ITE core, the ITE has minor sea level expression. The ITE core displays positive oxygen and negative salinity anomalies in comparison to the surrounding thermocline water, indicative of formation from winter mixed layer water along the southern side of the Japan/East Sea subpolar front. The winter mixing layer is then overridden, or slips below, the regional upper thermocline stratification with its characteristic salinity maximum layer. The winter mixed layer off the coast of Korea closely matches the ITE core characteristics, and is considered as a potential source region. Other sources may be present along the southern boundary of the subpolar front, including a frequently observed warm eddy over the western side of Yamato Rise.

Thomas and Lee, 2005
Many ocean fronts experience strong local atmospheric forcing by down-front winds, that is, winds blowing in the direction of the frontal jet. An analytic theory and nonhydrostatic numerical simulations are used to demonstrate the mechanism by which down-front winds lead to frontogenesis. When a wind blows down a front, cross-front advection of density by Ekman flow results in a destabilizing wind-driven buoyancy flux (WDBF) equal to the product of the Ekman transport with the surface lateral buoyancy gradient. Destabilization of the water column results in convection that is localized to the front and that has a buoyancy flux that is scaled by the WDBF. Mixing of buoyancy by convection, and Ekman pumping/suction resulting from the cross-front contrast in vertical vorticity of the frontal jet, drive frontogenetic ageostrophic secondary circulations (ASCs). For mixed layers with negative potential vorticity, the most frontogenetic ASCs select a preferred cross-front width and do not translate with the Ekman transport, but instead remain stationary in space. Frontal intensification occurs within several inertial periods and is faster the stronger the wind stress. Vertical circulation is characterized by subduction on the dense side of the front and upwelling along the frontal interface and scales with the Ekman pumping and convective mixing of buoyancy. Cross-front sections of density, potential vorticity, and velocity at the subpolar front of the Japan/East Sea suggest that frontogenesis by down-front winds was active during cold-air outbreaks and could result in strong vertical circulation.