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1.
K.-I. Chang W.J. Teague S.J. Lyu H.T. Perkins D.-K. Lee D.R. Watts Y.-B. Kim D.A. Mitchell C.M. Lee K. Kim 《Progress in Oceanography》2004,61(2-4):105
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. 相似文献
2.
Seasonality of materials transport through a coastal freshwater marsh: Riverine versus tidal forcing
Transports of nitrate and suspended solids were measured six times from January 1984 until January 1985 in a small freshwater tidal bayou in south-central Louisiana. The bayou and adjacent marshes are influenced by Atchafalaya River discharges, tides, and coastal weather patterns. Large net ebb-directed water transports occurred in winter, spring, and summer, coincident with high river discharges, indicating riverine dominance. A very small net flood-directed water transport occurred in fall, indicating tidally dominated hydrology. Nitrate and suspended solids transports were net ebb-directed in all seasons, but were two orders of magnitude higher during high river flow. Exports changed as hydrology switched from river dominated to tidally dominated, and as concentrations of materials changed. Comparison of suspended solids and nitrate concentrations in the river and bayou shows that these materials were usually lower in the bayou, indicating retention by the marsh/aquatic system. 相似文献
3.
Fernandez D.M. Meadows L.A. Vesecky J.F. Teague C.C. Paduan J.D. Hansen P. 《Oceanic Engineering, IEEE Journal of》2000,25(4):458-471
HF radar has become an increasingly important tool for mapping surface currents in the coastal ocean. However, the limited range, due to much higher propagation loss and smaller wave heights (relative to the saltwater ocean), has discouraged HF radar use over fresh water, Nevertheless, the potential usefulness of HF radar in measuring circulation patterns in freshwater lakes has stimulated pilot experiments to explore HF radar capabilities over fresh water. The Episodic Events Great Lakes Experiment (EEGLE), which studied the impact of intermittent strong wind events on the resuspension of pollutants from lake-bottom sediments, provided an excellent venue for a pilot experiment. A Multifrequency Coastal HF Radar (MCR) was deployed for 10 days at two sites on the shore of Lake Michigan near St. Joseph, MI. Similarly, a single-frequency CODAR SeaSonde instrument was deployed on the California shore of Lake Tahoe. These two experiments showed that when sufficiently strong surface winds (2 about 7 m/s) exist for an hour or more, a single HE radar can be effective in measuring the radial component of surface currents out to ranges of 10-15 km. We also show the effectiveness of using HF radar in concert with acoustic Doppler current profilers (ADCPs) for measuring a radial component of the current profile to depths as shallow as 50 cm and thus potentially extending the vertical coverage of an ADCP array 相似文献
4.
Monthly Variations of Water Masses in the Yellow and East China Seas, November 6, 1998 总被引：4，自引：0，他引：4
The monthly water mass variations in the Yellow Sea and the East China Sea are investigated using over 40 years of historical
temperature and salinity observations via a cluster analysis that incorporates geographical distance and depth separation
in addition to the temperature and salinity. Results delineate monthly variations in the major water masses and provide some
insight into formation mechanisms and intermixing. The major water masses include the Kuroshio-East China Sea water (KE),
the Yellow Sea surface water (YSS) and bottom cold water (YSB), mixed water (MW), and coastal water (CW). The distribution
of the KE water mass reveals the intrusion pattern into the area west of Cheju. A separate mixed water type appears between
the KE water mass and the Yellow Sea water masses during winter. The formation mechanism of the YSB appears to be the surface
cooling and active mixing in winter. In the East China Sea, during summer, surface water is differentiated from the subsurface
water while there is no differentiation during winter. In the Yellow Sea, a three layer system exists in the summer and fall
(May–November) while a two layer system exists during the rest of the year. A fresh water mass generated by Yangtze River
discharge (YD) is present over the northern East China Sea and the southern Yellow Sea during summer.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Jeffrey?W.?BookEmail author Pavel?Pistek Henry?Perkins Keith?R.?Thompson William?J.?Teague Gregg?A.?Jacobs Moon-Sik?Suk Kyung-Il?Chang Jae-Chul?Lee Byung?Ho?Choi 《Journal of Oceanography》2004,60(6):977-993
During 1999–2000, 13 bottom mounted acoustic Doppler current profilers (ADCPs) and 12 wave/tide gauges were deployed along two lines across the Korea/Tsushima Strait, providing long-term measurements of currents and bottom pressure. Tidally analyzed velocity and pressure data from the moorings are used in conjunction with other moored ADCPs, coastal tide gauge measurements, and altimeter measurements in a linear barotropic data assimilation model. The model fits the vertically averaged data to the linear shallow water equations in a least-squares sense by only adjusting the incoming gravity waves along the boundaries. Model predictions are made for the O1, P1, K1, μ2, N2, M2, S2, and K2 tides. An extensive analysis of the accuracy of the M2 surface-height predictions suggests that for broad regions near the mooring lines and in the Jeju Strait the amplitude prediction errors are less than 0.5 cm. Elsewhere, the analysis suggests that errors range from 1 to 4 cm with the exception of small regions where the tides are not well determined by the dataset. The errors in the model predictions are primarily caused by bias error in the model’s physics, numerics, and/or parameterization as opposed to random errors in the observational data. In the model predictions, the highest ranges in sea level height occur for tidal constituents M2, S2, K1, O1, and N2, with the highest magnitudes of tidal velocities occurring for M2, K1, S2, and O1. The tides exhibit a complex structure in which diurnal constituents have higher currents relative to their sea level height ranges than semi-diurnal constituents. 相似文献
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Seok Lee Heung-Jae Lie Cheol-Ho Cho Sok Kuh Kang William J. Teague Kyung-Il Chang Kyu-Min Song Kyung-Hee Oh 《Ocean Science Journal》2011,46(2):73-84
The vertical structure of the M2 tidal current in the Yellow Sea is analyzed from data acquired using an acoustic Doppler current profiler. The observed vertical
profiles of the M2 tidal current are decomposed into two rotating components of counter-clockwise and clockwise, and restructured using a simple
one-point model with a constant vertical eddy viscosity. The analyzed results show that the internal fictional effect dominates
the vertical structure of the tidal current in the bottom boundary layer. In the Yellow Sea, the effect of the bottom friction
reduces the current speed by about 20–40% and induces the bottom phase advance by about 15–50 minutes. In the shallower coastal
regions, the effects of bottom topography are more prominent on the vertical structure of tidal currents. The vertical profile
of the tidal current in summer, when the water column is strongly stratified, is disturbed near the pycnocline layer. The
stratification significantly influences the vertical shear and distinct seasonal variation of the tidal current. 相似文献
9.
Daniel M. Fernandez John F. Vesecky Calvin Teague 《Oceanic Engineering, IEEE Journal of》2006,31(4):919-921
This paper is an extension of other work that addresses the use of radar echoes from ships of opportunity to determine the proper phase corrections for small-loop phased-array antennas used within high-frequency (HF) ground-wave radar systems. This technique also yields estimates for unknown ship bearings that (for cases where there is adequate signal-to-noise ratio of 20 dB or more) are consistent to within 2deg-3deg among measurements from independent radar frequencies. Within this paper, phase corrections gathered from actual ships of opportunity are compared to phase corrections gathered during a calibrated transponder run, in which the ship bearing is known. The phase corrections derived from the ship of opportunity presented in this paper were consistent with the known phase corrections to within 13.2deg (for the worst case). Furthermore, the estimates of the ship bearings collected from the two usable radar frequencies were consistent to within 1deg of each other 相似文献
10.
Near-inertial currents in the DeSoto Canyon region are described using current and wind observations taken between April 1997 and March 1998 for the “DeSoto Canyon Eddy Intrusion Study”. Distinct energy peaks are present at near-inertial frequencies for the clockwise spectrum and there is little energy at the same frequencies for the counterclockwise current spectrum. In this region, amplitudes of the near-inertial currents can be as high as 40 cm s−1. These currents are surface-intensified and display an increase in amplitude from the shelf break to offshore. Between November 1997 and March 1998, they were effectively generated by shifting winds accompanying passages of cold fronts. For this time period, near-inertial currents are reasonably well-simulated by a mixed-layer model forced by observed winds. During summer 1997, however, enhanced near-inertial motions often resulted from resonance between winds and existing currents. 相似文献