Published Papers 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, Progress in Oceanography, 61, 105-156, 2004.  [ Abstract ] Mitchell, D.A., W.J. Teague, M. Wimbush, D.R. Watts, and G.G. Sutyrin, The Dok Cold Eddy, Journal of Physical Oceanography, 35, 273-288, 2005.  [ Abstract ] Mitchell, D.A., D.R. Watts, M. Wimbush, W.J. Teague, K.L. Tracey, J.W. Book, K.-I. Chang, M.-S. Suk, and J.-H. Yoon, Upper circulation patterns in Ulleung Basin, Deep-Sea Research II, 52, 1617-1638, 2005.  [ Abstract ] Mitchell, D.A., M. Wimbush, D.R. Watts, and W.J. Teague, The residual GEM technique and its application to the southwestern Japan/East Sea, Journal of Atmospheric and Oceanic Technology, 21, 1895-1909, 2004.  [ Abstract ] Nam, S.-H., S.-J. Lyu, Y.-H. Kim, K. Kim, J.-H. Park, and D. R. Watts, Correction of TOPEX/Poseidon altimeter data for nonisostatic sea level response to atmospheric pressure in the Japan/East Sea, Geophysical Research Letters, 31, doi:10.1029/2003GL018487, 2004.  [ Abstract ] Park, J.-H. and D.R. Watts, Internal tides in the southwestern Japan/East Sea, Journal of Physical Oceanography, 36, 22-34, 2006.  [ Abstract ] Park, J.-H., and D.R. Watts, Near-inertial oscillations interacting with mesoscale circulation in the southwestern Japan/East Sea, Geophysical Research Letters, 32, doi:10.1029/2005GL022936, 2005.  [ Abstract ] Park, J.-H., and D.R. Watts, Response of the southwestern Japan/East Sea to atmospheric pressure, Deep-Sea Research II, 52, 1671-1683, 2005.  [ Abstract ] Park, J.-H., D.R. Watts, K.L. Tracey, and D.A. Mitchell, A multi-index GEM technique and its application to the southwestern Japan/East Sea, Journal of Atmospheric and Oceanic Technology, 22, 1282-1293, 2005.  [ Abstract ] Park, J.-H., D.R. Watts, M. Wimbush, J.W. Book, K.L. Tracey and Y. Xu, Rapid variability and its links to mesoscale circulation in the Japan/East Sea: basin oscillations, internal tides, and near-inertial oscillations, Oceanography, 19, 76-85, 2006. Teague, W.J., P.A. Hwang, G.A. Jacobs, J.W. Book, and H.T. Perkins, Transport Variability Across the Korea/Tsushima Strait and the Tsushima Island Wake, Deep Sea Research II, 52, 1784-1801, 2005.  [ Abstract ] Teague, W.J., G.A. Jacobs, D.A. Mitchell, M. Wimbush and D.R. Watts, Decadal Current Variations in the Southwestern Japan/East Sea, Journal of Oceanography, 60, 1023-1033, 2004.  [ Abstract ] Teague, W.J., K.S. Ko, G.A. Jacobs, H.T. Perkins, J.W. Book, S.R. Smith, K.I. Chang, M.-S. Suk, K. Kim, S.J. Lyu, and T.Y. Tang, Currents Across the Korea/Tsushima Strait: Review of LINKS Observations, Oceanography, 19, 50-63, 2006. Teague, W.J., K.L. Tracey, D.R. Watts, J.W. Book, K.-I. Chang, P.J. Hogan, D.A. Mitchell, M.-S. Suk, M. Wimbush, and J.-H. Yoon, Observed deep circulation in Ulleung Basin, Deep-Sea Research II, 52, 1802-1826, 2005.  [ Abstract ] Watts, D.R., M. Wimbush, K.L. Tracey, W.J. Teague, J.-H. Park, D.A. Mitchell, J.-H. Yoon, M.-S. Suk, and K.I. Chang, Currents, eddies, and a "fish story" in the southwestern Japan/East Sea, Oceanography, 19, 64-75, 2006. Xu, Y., D.R. Watts, M. Wimbush, and J.-H. Park, Fundamental-mode basin oscillations in the Japan/East Sea, Geophysical Research Letters, 34, 10.1029/2006GL028755, 2007.  [ Abstract ] Technical Reports Xu, Y., K.L. Tracey, D.R. Watts, M. Wimbush, W. Teague, and J. Book, Current Meter Data Report: Ulleung Basin of Japan/East Sea, June 1999 to July 2001, GSO Technical Report 2003-02, University of Rhode Island, 2003. Mitchell, D.A., Y. Xu, K.L. Tracey, D.R. Watts, M. Wimbush, and W. Teague, Inverted Echo Sounder Data Report: Ulleung Basin of Japan/East Sea, June 1999 to July 2001, GSO Technical Report 2004-02, University of Rhode Island, 2004. Dissertations Mitchell, D.A., Upper Current Structure and Variability in the Southwestern Japan/East Sea, PhD Dissertation, Graduate School of Oceanography, University of Rhode Island, 140 pp, 2003.  [ Abstract ] Xu, Y., Analyses of Sea Surface Height, Bottom Pressure and Acoustic Travel Time in the Japan/East Sea, PhD Dissertation, Graduate School of Oceanography, University of Rhode Island, 86 pp, 2006.  [ Abstract ] Conference Presentations Chang, K.-I., K. Kim, H. Perkins, W. Teague, R. Watts, D. Mitchell, M.-S. Suk, S. J. Lyu, D.-K. Lee, and J.-H. Yoon, "Currents and circulation in the Ulleung Basin and the Korea/ Tsushima Strait," CREAMS/PICES Symposium Proceedings, Seoul, Korea, August 22-24, 2002. Mitchell, D.A., W.J. Teague, D.R. Watts, and M. Wimbush, "Gravest empirical modes determined from historical hydrographic observations in the southwestern Japan/East Sea," 2000 AGU Fall Meeting, EOS Transactions AGU 81, December 15-19, 2000, San Francisco, CA (Abstract OS12B-04). Mitchell, D.A., M. Wimbush, and D.R. Watts, "Determining gravest empirical modes from hydrographic data in the southwest Japan/East Sea," 2001 CREAMS Symposium Proceedings, February 20-23, 2001, Honolulu, HI. Mitchell, D.A., W.J. Teague, D.R. Watts, M. Wimbush, and K. Tracey, "Daily maps of temperature, salinity, and velocity in the southwestern Japan/East Sea," 2002 Ocean Sciences Meeting, EOS Transactions AGU 83, February 11-15, 2002, Honolulu, HI (Abstract OS21Q-07). Mitchell, D.A., W.J. Teague, M. Wimbush, and D.R. Watts, "The Dok Cold Eddy," 2004 Ocean Sciences Meeting, AGU, EOS Transactions AGU 84, January 26-30, 2004, Portland, OR (Abstract OS41B-08). Park, J.-H., D.A. Mitchell, Karen L Tracey, K.-I. Chang, M.-S. Suk, and D.R. Watts, "Intermediate water circulation in the southwestern Japan/East Sea," IUGG/IAPSO Symposium P02/30A/c25-003 Proceedings, Sapporo, Japan, June 30-July 4, 2003. Park, J.-H., and D.R. Watts,"Internal Tides in the Southwestern Japan/East Sea," 2004 Ocean Sciences Meeting, AGU, EOS Transactions AGU 84, January 26-30, 2004, Portland, OR (Abstract OS41F-04). Park, J.-H., and D.R. Watts "Interaction of internal gravity waves with mesoscale circulation observed in the southwestern Japan/East Sea," IAPSO/SCOR Ocean Mixing Conference, Victoria, BC, October 11-14, 2004. Teague, W.J., G.A. Jacobs, D.A. Mitchell, M. Wimbush, and D.R. Watts, "Decadal Connections of Mesoscale Current Variability in the Ulleung Basin," 2004 Ocean Sciences Meeting, EOS Transactions AGU 84, January 26-30, 2004, Portland, OR (Abstract OS41B-05). Watts, D.R., M. Wimbush, K.L. Tracey, D.A. Mitchell, W.J. Teague, J.W. Book, M.-S. Suk, and J.-H. Yoon, "Shallow and Deep Current Variability in the Southwestern Japan/East Sea," 2002 Ocean Sciences Meeting, EOS Transactions AGU 83, February 11-15, 2002, Honolulu, HI, (Abstract OS21Q-05). Wimbush, M., K.L. Tracey, D.R. Watts, D.A. Mitchell, J.W. Book, and W.J. Teague, "Tides of the Southwest Japan/East Sea Determined From an Array of 23 Bottom Pressure Recorders," 2002 Ocean Sciences Meeting, EOS Transactions AGU 83, February 11-15, 2002, Honolulu, HI, (Abstract OS21Q-06). Abstracts 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. Mitchell, 2003 Continuous acoustic travel-time measurements from a two-dimensional array of pressure-gauge-equipped inverted echo sounders spanning the entire Ulleung Basin of the southwestern Japan/East Sea between June 1999 and July 2001 are used to examine the upper temperature and current patterns. A new method, referred to as the GEM/MODAS technique, combined with optimal interpolation, interprets the travel-time data into a three-dimensional (x,y,p) time-series of daily, synoptically mapped current and temperature fields. During the two-year measurement period, at least five distinctive persistent flow patterns are found. The patterns during the first year coincide with changes in the total volume transport through the Korea/Tsushima Strait, while the patterns of the second year do not. The mean temperature of the basin displays strong interannual variability and is correlated with the total Korea/Tsushima Strait transport, with a higher mean temperature in the first year when total volume transport was higher. In addition, a new framework for describing the flow patterns is presented. A newly described cold-core eddy, referred to as the Dok Cold Eddy, is about 60 km in diameter and typically forms southwest of Dok (Takeshima) Island when the Subpolar Front loops southward between Ulleung and Dok Islands and sheds an eddy. The Dok Cold Eddy is highly variable in space and time, and it tends to propagate westward towards the coast of Korea, where it merges with cold waters from the north. Three such propagation events precede the disappearance of the East Korean Warm Current, which then remains absent between June and November 2000. The so-called Offshore Branch of the Tsushima Current forms by branching in the Korea/Tsushima Strait and is present during much of our two-year observation period. When the East Korean Warm Current separates from the coast of Korea on a northerly path, the Subpolar Front is well described by thin-jet theory. The East Korean Warm Current separated on such a northerly path from March 13 until June 15, 2001, during which time the Subpolar Front developed a large meander between Ulleung and Dok Islands that oscillated with a period of 60-90 days. The oscillation period and meander wavelength and amplitude are consistent with a "breather" solution of the modified Korteweg-DeVries equation in this thin-jet theory. Mitchell et al., Journal of Physical Oceanography, 2005 Current and temperature patterns in the Ulleung Basin of the Japan/East Sea are examined using acoustic travel-time measurements from an array of pressure-gauge-equipped inverted echo sounders moored between June 1999 and July 2001. The focus here is the formation and behavior of a persistent cold eddy observed south of Dok Island, referred to as the Dok Cold Eddy (DCE), and meandering of the Subpolar Front. The DCE is typically about 60 km in diameter and originates from the pinching off of a Subpolar Front meander between Ulleung and Dok Islands. After formation, the DCE dwells southwest of Dok Island for 1-6 months before propagating westward toward Korea, where it deflects the path of the East Korean Warm Current (EKWC). Four such DCE propagation events between January and June 2000 each deflected the EKWC, and after the fourth deflection the EKWC changed paths and flowed westward along the Japanese shelf as the "Offshore Branch" from June through November 2000. Beginning in March 2001, a deep, persistent meander of the Subpolar Front developed and oscillated with a period near 60 days, resulting in the deformation and northwestward displacement of the Ulleung Eddy. Satellite-altimeter data suggest that the Ulleung Eddy may have entered the northern Japan/East Sea. The evolution of this meander is compared with thin-jet nonlinear dynamics described by the modified Korteweg-deVries equation. Mitchell et al., Deep-Sea Research II, 2005 Continuous acoustic travel-time measurements from a two-dimensional array of pressure-gauge-equipped inverted echo sounders spanning the entire Ulleung Basin of the southwestern Japan/East Sea between June 1999 and July 2001 are used to examine the upper temperature and current patterns. A new method, referred to as the Residual GEM Technique, interprets the travel-time data into a three-dimensional (x,y,p) time-series of daily, synoptically mapped current and temperature fields. During the two-year measurement period, at least five non-repeating persistent flow patterns are found. The patterns during the first year coincide with changes in the total volume transport through the Korea/Tsushima Strait, while the patterns of the second year do not. The mean temperature of the basin displays strong interannual variability and is correlated with the total Korea/Tsushima Strait transport, with a higher mean temperature in the first year when total volume transport was higher. In addition, a new framework for describing the flow patterns is presented. A newly described cold-core eddy, referred to as the Dok Cold Eddy, is about 60 km in diameter and typically forms southwest of Dok Island when the Subpolar Front loops southward between Ulleung and Dok (Takeshima) Islands and sheds an eddy. The Dok Cold Eddy is highly variable in space and time, and it tends to propagate westward towards the coast of Korea, where it merges with cold waters from the north. Three such propagation events precede the disappearance of the East Korean Warm Current, which then remains absent between June and November 2000. The Offshore Branch forms by branching in the Korea/Tsushima Strait and is present during much of our two-year observation period. Mitchell et al., 2004 The standard gravest empirical mode (GEM) technique for utilizing hydrography in concert with integral ocean measurements performs poorly in the southwestern Japan/East Sea (JES) because of a spatially variable seasonal signal and a shallow thermocline. This paper presents a new method that combines the U.S. Navy's Modular Ocean Data Assimilation System (MODAS) static climatology (which implicitly contains the mean seasonal signal) with historical hydrography to construct a "residual GEM" from which profiles of such parameters as temperature (T) and specific volume anomaly (δ) can be estimated from measurements of an integral quantity such as geopotential height or acoustic echo time (τ). This is called the residual GEM technique. In a further refinement, sea surface temperature (SST) measurements are included in the profile determinations. In the southwestern JES, profiles determined by the standard GEM technique capture 70% of the T variance and 64% of the δ variance, while the residual GEM technique using SST captures 89% of the T variance and 84% of the δ variance. The residual GEM technique was applied to optimally interpolated τ measurements from a two-dimensional array of pressure-gauge-equipped inverted echo sounders moored from June 1999 to July 2001 in the southwestern JES, resulting in daily 3D estimated fields of T and δ throughout the region. These estimates are compared with those from direct measurements and good agreement is found between them. Nam et al., 2004 High frequency (2-20 days) sea level fluctuations, driven by atmospheric pressure changes, must be eliminated from TOPEX/POSEIDON altimeter data, else these data sampled at 10-day interval will suffer aliasing when interpreted as lower frequency variability of the subsurface pressure and circulation. A simple analytic Helmholtz-like model [Lyu et al., 2002 ], which explains successfully the nonisostatic sea level response in the Japan/East Sea (JES), is applied to correct the high-frequency sea level fluctuation effects on the T/P data. The model removes these pressure-driven fluctuations better than the standard inverse barometer (IB) method, leaving residuals smaller by about 10% in the corrected mean sea level (MSL) data used in this study. Because the maximum difference between the model correction and the IB correction can reach 10 cm, the impact of the correction choice is substantial. Moreover, uncorrected or IB corrected T/P along-track data contain substantial high frequency variability which can lead to "trackiness" errors between crossing and neighboring tracks, contaminating their use for synoptic mapping. The model correction reduced the trackiness significantly better than the usual IB correction. Park and Watts, 2006 This paper investigates the internal tidal energy distribution in the southwestern Japan/East Sea using vertical round-trip travel time (t) data from 23 pressure-sensor-equipped inverted echo sounders (PIES). The t records are analyzed by bandpass filtering to separate time-dependent variability of the semidiurnal and diurnal bands. The semidiurnal internal tides exhibit a horizontal beam pattern of high energy, propagating into the open basin. They originate from a restricted portion of the shelf break where the Korea Strait enters the Ulleung Basin. The generation appears to occur at ~200-m water depth near 35.5°-35.7°N and 130°-131°E, where the slope of bottom topography matches that of the wave characteristics, coinciding with the location where the semidiurnal barotropic cross-slope tidal currents are strongest. Maximum vertical displacement of the thermocline interpreted as a long-wave first baroclinic mode from the measured t is about 25 m near the generation region. Annual and monthly variations of the propagation patterns and generation energy levels are observed, and these are closely associated with changes in the mesoscale circulation and stratification. Eastward (westward) refraction is observed when a warm (cold) eddy crosses the path of internal tide propagation. Moreover, when the generation region is invaded by cold eddies that spoil the match between shelf break and thermocline depth, the internal tidal energy level decreases by a factor of about 2. A simple geometric optics model is proposed to explain the observed horizontal refraction of the beam of semidiurnal internal tides in which stratification and current shear play essential roles. In contrast, diurnal internal tides are observed to be trapped along the continental slope region around 36°N. Park and Watts, Geophysical Research Letters, 2005 The near-inertial internal wave energy distribution is investigated in the southwestern Japan/East Sea using vertical round-trip travel time of sound τ data from 23 pressure-sensor-equipped inverted echo sounders (PIESs) and data from Aanderaa recording current meters (CMs). Currents associated with low-mode near-inertial internal waves are slightly inclined and displace the thermocline vertically, which can be detected in τ. The band-pass filtered τ records exhibit high near-inertial energy distributions that vary interannually with changes observed in mesoscale circulation. An explanation for this is offered as trapping of near-inertial energy in anticyclonic regions, which is supported by scatterplots of monthly-rms band-pass filtered τ at inertial frequency bands vs. monthly-mean relative vorticity. The spectra from all but one deep CM exhibit a blue shift, consistent with the equatorward propagation of near-inertial waves. The exception has the highest near-inertial wave energy, and is located near the center of a warm anticyclonic eddy. Park and Watts, Deep-Sea Research II, 2005 The response of the southwestern Japan/East Sea (JES) to atmospheric pressure (Patm) and wind-stress forcing is investigated by analyzing 2-year bottom pressure (Pbot) data and coastal tide-gauge records. Coherence analyses between Pbot data reveal that the response of the southwestern JES is nearly uniform at frequencies lower than 0.6 cycles per day (cpd). The Ulleung Basin (UB) average Pbot departs significantly from inverted-barometer (IB) response to the basin average Patm at frequency bands from 0.2 to 0.7 cpd. The coherence between average Patm and average Pbot has maximum value at 0.2 cpd. Multiple coherence analysis, applied with average Patm and UB average wind stress as inputs and average Pbot as output, reveals that the average Patm is the most significant forcing, with a peak at frequencies between 0.2 and 0.3 cpd. A simple model [Garrett, 1983. Variable sea level and strait flows in the Mediterranean: a theoretical study of the response to meteorological forcing. Oceanologica Acta 6, 79-87; Lyu et al., 2002. Atmospheric pressure-forced subinertial variations in the transport through the Korea Strait. Geophysical Research Letters 29, 10.1029/2001GL014366] is used to investigate the limiting role of the three straits on the JES response to Patm. Coastal sea-level (η) data inside the JES as well as outside the straits demonstrate that the JES responds with a damped Helmholtz-like resonance. The resonance frequency predicted by this simple model is near the frequency of maximum coherence between average Patm and average sea-level ηd, estimated from the average Pbot by the hydrostatic approximation. Phase relations and response function gain between these variables confirm the applicability of this simple model to the JES for low-frequency bands below the Helmholtz-like resonance frequency. At higher frequencies, the response relaxes back toward IB, which suggests the mass field adjusts internally within the JES. Park et al., 2005 This paper demonstrates a new gravest empirical mode (GEM) technique that constructs multi-index lookup tables of temperature (T) and specific volume anomalies (δ) using historical hydrocasts as a function of three indices: round-trip travel time (t) from sea floor to the surface, sea surface temperature, and pressure. Moreover, the historical hydrocasts are separated into non-mixed-layer (NML) and mixed-layer (ML) groups, and a single GEM field is constructed for each group. This is called the MI-GEM technique. The appropriate dates for MI-GEM fields are determined by the monthly distribution of the number of NML and ML profiles in the historical hydrocasts, which are also well correlated with the strength of the winds during the 2 yr of observations. The T and δ profiles that are determined by this MI-GEM technique capture 92% and 88% of the T and δ variances in the depth range of 0-200 db. These values reduce by about one-third of the unexplained error variance of the residual GEM, which was recently developed and applied to the optimal interpolated t data in the southwestern Japan/East Sea (JES) by Mitchell et al. Comparisons with the in situ CTD casts demonstrate that the MI-GEM technique almost always produces improved full water column profiles of T and δ. Whereas the residual GEM estimates had exhibited qualitatively erroneous features like T inversions in the near-surface layer and too thin or thick intermediate water layers in some regions, the MI-GEM estimates avoid those problems, which were inherent to the residual GEM technique in the southwestern JES. Teague et al., Deep Sea Research II, 52, 1784-1801, 2005 Transport variations are calculated across the Korea/Tsushima Strait using continuous current measurements made between May 1999 and March 2000. Twelve bottom-mounted acoustic Doppler current profilers provide velocity profiles along two sections: one section (south line) at the strait entrance southwest (upstream) of Tsushima Island and the other section (north line) at the strait exit northeast (downstream) of Tsushima Island. Transport variations across the strait are large, particularly in the lee of Tsushima Island where a countercurrent commonly exists. The Tsushima Current transport, averaging 2.65 Sverdrups (Sv) (1 Sv =106 m3 s-1), is split into two cores by Tsushima Island, which divides the strait into eastern and western channels. Transport in the western channel is 23% higher than in the eastern channel over the measurement period. Some seasonality in transport variability is observed for both the western and eastern channels. Transports are largest in fall and smallest during winter. The single-velocity core, observed upstream of Tsushima Island, is estimated to split directly behind Tsushima Island over an aperture of about 31 km along the south line. A wake zone that averages 40 km in width is observed downstream of Tsushima Island and appears to follow island-wake-zone dynamics. Reynolds numbers can range from 22 to 90 in the wake zone, and eddy shedding can occur throughout the year. Teague et al., 2004 Absolute geostrophic velocities were calculated along TOPEX/Poseidon (T/P) groundtracks located in the Ulleung Basin of the southwestern Japan/East Sea (JES) from a combined analysis of nearly a decade of T/P data and two years of pressure-gauge-equipped inverted echo sounder (PIES) data obtained during the United States Office of Naval Research's JES Program. Geostrophic velocities have been calculated daily for the Ulleung Basin from June 1999 to July 2001 from a three-dimensional mapping of temperature and salinity produced by PIES data interpreted via the Gravest Empirical Mode (GEM) technique combined with the Navy's Modular Ocean Data Assimilation System (MODAS). These velocities were then used to convert T/P velocity anomalies to absolute velocities for the T/P time period of 1993 to 2002. Current intensities and variabilities associated with the East Korean Warm Current, Ulleung Warm Eddy, and Offshore Branch are examined. Spatial and temporal variations of the sea surface circulation are strong. Intensification of the currents generally occurred during the fall season. The flow pattern in individual years differed greatly from year to year and differed from climatology in important qualitative ways. Teague et al., Deep-Sea Research II, 52, 1802-1826, 2005 Records from 16 current meters and 23 pressure gauges moored near the sea floor in the Ulleung Basin of the southwestern Japan/East Sea (JES) characterized the deep circulation between June 1999 and July 2001. Mean currents range from 1 to 4 cm/s and deep pressure anomalies range from 3 to 10 mbar, with horizontal correlation scales of about 40 km, and with integral time scales that range from about 5 to 20 days. Focusing here on the 90-day to interannual variability, synoptic maps of the deep currents and dynamic pressure fields determine that the deep circulation in the Ulleung Basin is cyclonic, with additional multiple cyclonic and anticyclonic cells that occur on sub-basin spatial scales. Over the Korea Plateau a northward deep outflow is observed that suggests an anticyclonic circulation pattern to the north. The annual average deep currents are remarkably similar for the 2 years, only slightly weaker in the second year. No seasonal pattern is discernable, except weakly at one or two sites. Xu, 2006 The observed water motions in the Japan/East Sea (JES) and the associated sea surface height and bottom pressure fields are heavily influenced by the semi-enclosed nature and the specific configuration of this marginal sea. As part of the United States Office of Naval Research JES program, a two-dimensional array of pressure-gauge-equipped inverted echo sounders (PIESs) was deployed in the southwestern JES for two years, from June 1999 to July 2001. The PIESs recorded hourly vertical acoustic travel time and pressure, which are respectively good proxies of baroclinic and barotropic sea level variability. Three topics are investigated based on the PIES data sets: (1) implications of the in-situ measurements for improving interpretation of satellite altimetric data in the JES; (2) basin-mode oscillations in the JES; (3) vertical coupling between upper circulation and abyssal eddy fields in the JES. All the pressure records exhibit a strong remarkably similar signal (common mode). The common mode is driven by sea level changes outside the JES, atmospheric pressure, and along-strait wind stress in the straits connecting the JES to the outside ocean. The common mode has a barotropic wavelength much larger than the size of the JES, so it is in phase throughout the basin. The rms of the common mode is about 5 cm, and is energetic at time scales of 2-70 days, which are shorter than the ERS-2 satellite altimetry Nyquist period of 70 days. Our results show the common mode produces a substantial alias when sampled by satellite altimeter; furthermore, the combined aliasing effects on multi-tracks can mimic mesoscale eddies and may qualitatively alter the synoptic mapping. The alias can be suppressed by removing the common mode from satellite SSH. For time periods other than 1999-2001, 78% of the common mode variance can still be removed in the Japan/East Sea by using coastal tide gauge data to infer the common mode. High frequency oscillations with period around 7 hours are shown to be organized in a fundamental basin mode in the JES. The semi-enclosed nature of the JES not only accounts for the existence of the common mode signal but also limits energy propagation away from the basin and constrains its free oscillations to discrete modes. The fundamental oscillation in the JES is determined by its boundaries and topography. Influenced by the rotation of the earth, the oscillation consists of a single amphidromic point around which the high water propagates counter-clockwise. It has a period of 7 hours with along-coast wavelength equal to the circumference of the basin. The basin oscillations have largest amplitude at the narrow northeast region of the JES. The time series of basin oscillations is modulated in packets with time scales of 2-16 days, and they also exhibit a seasonal modulation. Wind in the direction 60°/240° T is optimal to generate basin oscillations in the Japan/East Sea. Vertical-coupled patterns between upper sea surface height and abyssal pressure field are investigated. The coupled mode analysis confirms that bottom topography has a significant influence on the vertical coupling in the Japan/East Sea. In the first coupled mode, the deep response flows are largely expressed on closed potential vorticity regions created by the Ulleung Basin depression or the Korea Plateau; the upper layer exhibits a migration of the Ulleung Warm Eddy and downstream shift of a meander trough of the Subpolar Front. In the second mode, the upper and deep layer have similar spatial patterns peaked at a site near the southwestern corner of the Korea plateau. The second mode appears to arise from time-varying strength of a mean deep anticyclone, which had been revealed by intermediate float data, flowing around the contours of the Korea Plateau. Xu et al., 2007 We present observational evidence from coastal tide station and bottom pressure data that basin-mode oscillations are frequently excited in the Japan/East Sea (JES). The fundamental basin-mode is a Kelvin-wave-like oscillation consisting of a single amphidromic system around which the high water propagates counter-clockwise. Its period is about 6.7 hours and its coastal wavelength is equivalent to the circumference of the JES. The relative amplitudes of the observed oscillations agree with Rikiishi's [1986] model results except for stations near the Korea Strait where the closed boundary in the model produces unrealistically high amplitudes. The basin oscillation amplitude varies on synoptic time scales (2-17 days) and exhibits seasonal variations. The optimal wind direction to generate basin-mode oscillations is along 60°/240° T.