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  • Author or Editor: W. J. Teague x
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W. J. Teague
,
Z. R. Hallock
, and
G. A. Jacobs

Abstract

An estimate of the geoid across the Kuroshio Extension at its separation point from Japan is calculated through an analysis of coincident sea surface measurements from inverted echo sounders (IESs) and Topex/Poseidon (T/P). The IESs were positioned along a T/P descending ground track in the vicinity of 35°N, 143°E. This geoid section can be used in conjunction with altimeter data to estimate total sea surface height. Thus, Kuroshio position, surface geostrophic velocity, and transport along the section can be continuously monitored.

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W. J. Teague
,
P. Pistek
,
G. A. Jacobs
, and
H. T. Perkins

Abstract

TOPEX/Poseidon (T/P) can provide accurate tide data in the Yellow and Bohai Seas. The accuracy of T/P as a measurement tool for tides in the coastal seas can be evaluated through comparison to data from in situ pressure gauges and coastal tide stations. The effort here is concentrated on the broad continental shelf region of the Yellow and Bohai Seas. Tide coefficients are derived from five years of T/P data for M2, S2, K1, and O1 constituents. These constituents are responsible for about 80% of the tidal variability in the Yellow Sea. The T/P data are compared with two moored pressure gauges deployed along ground tracks and eight coastal tide gauges near the ground tracks. In addition, for internal consistency, the T/P data are compared at seven crossover points. Comparisons with tidal stations are quite good in the Yellow Sea, but not as good in the Bohai Sea. Comparisons of moored pressure gauges with T/P are better than coastal tide station comparisons in terms of tidal amplitude and phase. Crossover point comparisons are best in the Yellow Sea. The T/P data dropouts degrade the coefficient determination within 20 to 35 km of the coast.

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D. N. Fox
,
W. J. Teague
,
C. N. Barron
,
M. R. Carnes
, and
C. M. Lee

Abstract

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.

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D. A. Mitchell
,
M. Wimbush
,
D. R. Watts
, and
W. J. Teague

Abstract

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.

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Kuh Kim
,
Sang Jin Lyu
,
Young-Gyu Kim
,
Byung Ho Choi
,
Keisuke Taira
,
Henry T. Perkins
,
William J. Teague
, and
Jeffrey W. Book

Abstract

Voltage induced by the Tsushima Current on an abandoned submarine telephone cable between Pusan, Korea, and Hamada, Japan, has been measured since March 1998 in order to monitor the volume transport through the Korea Strait. Voltage has a good linear relationship with the transport measured by bottom-mounted acoustic Doppler current profilers (ADCPs) along a section spanning the Korea Strait. The linear conversion factor is estimated to be Λ0 = (8.06 ± 0.63) × 106 m3 s−1 V−1 with the reference voltage of V 0 = 0.48 ± 0.07 V. The voltage-derived transport reveals various temporal variations that have not been known previously. Measurement of the cable voltage provides a reliable means for continuous monitoring of the volume transport of the Tsushima Current, which determines the major surface circulation and hydrography in the East Sea.

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