Variability of Monthly Mean Sea Level and its Regional Features Around Japan and Korea

Tomizawa, Kazuo; Hanawa, Kimio; Kurasawa, Y.; Toba, Yoshiaki

doi:10.1016/s0422-9894(08)70306-4

Cited by 8 publications

(5 citation statements)

References 1 publication

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“…A comparison of Figures g and b shows that the seasonal variations in sea surface height caused by SA (amplitude of 0.16 m) are smaller than the spurious seasonal variations arising from the use of a 2 day sampling interval (amplitude of 0.65 m). The seasonal variations in sea surface height caused by SA are consistent with those in the East China Sea [ Tomizawa et al ., ], and are generally believed to be caused by thermobaric effects [ Wakata , ]. We considered the impact of SA during tidal simulations, but did not include it during the harmonic analyses of the ADCP data because the removal of SA might erase the normal seasonal variations of the Kuroshio volume transport.…”

Section: Tidal Harmonic Analysismentioning

confidence: 98%

Tidal currents and Kuroshio transport variations in the Tokara Strait estimated from ferryboat ADCP data

et al. 2017

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From 2003 to 2011, current surveys, using an acoustic Doppler current profiler (ADCP) mounted on the Ferry Naminoue, were conducted across the Tokara Strait (TkS). Resulting velocity sections (1234) were used to estimate major tidal current constituents in the TkS. The semidiurnal M2 tidal current (maximum amplitude 27 cm s−1) was dominant among all the tidal constituents, and the diurnal K1 tidal current (maximum amplitude 21 cm s−1) was the largest among all the diurnal tidal constituents. Over the section, the ratios, relative to M2, of averaged amplitudes of M2, S2, N2, K2, K1, O1, P1, and Q1 tidal currents were 1.00:0.44:0.21:0.12:0.56:0.33:0.14:0.10. Tidal currents estimated from the ship‐mounted ADCP data were in good agreement with those from the mooring ADCP data. Their root‐mean‐square difference for the M2 tidal current amplitude was 2.0 cm s−1. After removing the tidal currents, the annual‐mean of the net volume transport (NVT) through the TkS ± its standard derivation was 23.03 ± 3.31 Sv (Sv = 106 m3 s−1). The maximum (minimum) monthly mean NVT occurred in July (November) with 24.60 (21.47) Sv. NVT values from the ship‐mounted ADCP were in good agreement with previous geostrophic volume transports calculated from conductivity temperature depth data, but the former showed much finer temporal structure than those from the geostrophic calculation.

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Section: Tidal Harmonic Analysismentioning

confidence: 98%

Tidal currents and Kuroshio transport variations in the Tokara Strait estimated from ferryboat ADCP data

et al. 2017

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“…The spectrum does not have a well-defined peak in this range which indicates that this is not a periodic component but is dominated by random noise. This finding conflicts with Tomizawa et al [1984] who found, by band-pass filtering, that the signal with periods between about 2-10 mths was made up of a periodic and fairly regular 138 d component plus a random component (the numbers are our conversions: they stated that this band was monthly to annual but their data were monthly means and they had a separate band for the annual variation). They attributed the 138 d component to meteorological events and variability of the Kuroshio, but did not present a supporting argument.…”

Section: The Annual Cycle and Biennial Fluctuationsmentioning

confidence: 60%

“…7) shows some irregular variations of about 2-4 yr period but from these data it is not possible to say anything about their cause. Oscillations of this period have been observed by Minobe et al [2004] and references cited therein and attributed to wind pattern anomalies over the North Pacific, while Tomizawa et al [1984] found no regular inter-annual oscillations in records from a wider spread of stations over 1950-1980.…”

Section: Drift Over the 11 Yearsmentioning

confidence: 73%

Effects of Entrance Constriction and Ocean Forcing on Waterlevels in an Unregulated Tidal Inlet

Hinwood

Aoki

2013

Coastal Engineering Journal

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Long period waterlevel variations, from 14 d to 1 yr, are examined for Hamanako, a tidal inlet on the Pacific coast of Honshu, Japan. Eleven years of records, prior to the regulation of the entrance to the inlet, are analyzed. At all the frequencies examined there were substantial fluctuations, some periodic and some irregular. Dominant features were abrupt changes in mean waterlevel and tidal range, and regular 14 d and 28 d cycles in most years. These cycles have been related to the role of the entrance constriction in generating spring-tidal pumping (STP). The rapid changes in tidal amplitude and mean waterlevel are explained in terms of changes in the hydraulic resistance of the entrance and have been correlated with outflows from the tidal lagoon caused by typhoons and catchment runoff. An annual cycle of amplitude 12.5 cm has been explained in terms of the annual cycle of the Kuroshio. Novel features of this study are the extensions to conventional time series analysis, and showing that the 14 d periodic fluctuations were caused by STP and that this process also contributed to the 28 d fluctuations. STP is invariably present in estuaries with a shallow inlet but is rarely identified; this paper shows methods to evaluate it and other long period components of the waterlevel record.

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“…We used in this study monthly MSL data collected by the Korean Hydrologic Agency, monthly mean atmospheric surface pressure (MBP) data collected by the Korea Meteorological Agency, and hydrographic data collected roughly bimonthly by the National Fishery Research and Development Agency of Korea for the 14 year period 1979 – 1992. The monthly mean adjusted sea level (ASL) is computed as the sum of MSL and cMBP, where the conversion factor c = 1 cm mbar –1 minus any linear trend in the sum over the 14 year period as determined by the method of least squares [ Tomizawa et al , 1984].…”

Section: Methodsmentioning

confidence: 99%

“…Mean seasonal variation η s ( j ) and anomaly η ano ( i , j ) are obtained by the following calculations: where i and j are yearly and monthly indices. Following Tomizawa et al [1984], the anomaly η ano ( i , j ) is further divided into an interannual variation and short‐term fluctuation. The interannual variation η 13 ( i , j ) is calculated using a 13 month moving average, which eliminates variations with periods <1 year.…”

Section: Methodsmentioning

confidence: 99%

Sea level variability at Ulleung Island in the East (Japan) Sea

et al. 2002

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[1] Monthly adjusted sea level (ASL) was analyzed to examine the characteristics of sea level variation at Ulleung Island in the East (Japan) Sea from 1979 to 1992. It is remarkable that the nonseasonal variation is comparable with the mean seasonal variation in amplitude at Ulleung Island, whereas the mean seasonal variation is dominant along the eastern coast of the Korean peninsula. At Ulleung Island the variation in the mean seasonal, interannual, and short-term component variability is 54, 13, and 30% of the total ASL variance, respectively. ASL variability is highly correlated with the upper layer heat content around Ulleung Island. There are two factors that contribute to large nonseasonal variation of the ASL around the island. One is the location of the polar front that divides the northern cold water region and the southern warm water region. The other is the presence of a warm eddy that frequently forms near Ulleung Island. When the northern cold water region extends southward to Ulleung Island, the heat content of the upper layer decreases, and ASL around the island falls. In contrast, when the southern warm water region extends northward to the island, the heat content increases, and ASL rises greatly. The movement of the front with a period of 1 -2 years causes interannual variation of ASL. When a warm eddy approaches Ulleung Island, the heat content increases, and ASL rises. The short-term variation in ASL is caused primarily by the migration of the warm eddy around Ulleung Island.

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Variability of Monthly Mean Sea Level and its Regional Features Around Japan and Korea

Cited by 8 publications

References 1 publication

Tidal currents and Kuroshio transport variations in the Tokara Strait estimated from ferryboat ADCP data

Tidal currents and Kuroshio transport variations in the Tokara Strait estimated from ferryboat ADCP data

Effects of Entrance Constriction and Ocean Forcing on Waterlevels in an Unregulated Tidal Inlet

Sea level variability at Ulleung Island in the East (Japan) Sea

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