Internal Tides in the Southwestern Japan/East Sea

This paper investigates the internal tidal energy distribution in the southwestern Japan/East Sea using vertical round-trip travel time (τ) data from 23 pressure-sensor-equipped inverted echo sounders (PIES). The τ 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 τ 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

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Department of Mathematical SciencesThis thesis is a thorough review of the Ph.D thesis titled "The Zeros of Elliptic Curve $L$-functions" by Simon Spicer. His thesis is devoted to compute the ranks of elliptic curves. Firstly, we provide basic knowledge and facts about elliptic curves and in Section 8, we explain his algorithm. Below is his algorithm to compute the rank of elliptic curves. \bigskip Let $E$ be an elliptic curve with the global minimal Weierstrass equation $E : y^2+a_1xy+a_3y=x^3+a_2x^2+a_4x+a_6$ with the conductor $N_E$. The algorithm goes like : \begin{enumerate} \item Compute the real period $\Omega_E$ of $E$. \item Set $k = \lceil 26+3.86\log_{2}N_E+\log_{2}(\Gamma(1.8+0.25\log{N_E}))-\log_{2}\Omega_E \rceil$. \item Evaluate $L_E(1)$ to $k$ bits precision. \item If $k$-bit binary digits are not zero, then the rank is 0. \item Otherwise, $L_E(1) \equiv 0$ and now evaluate $L_E'(1)$. That is, $m \mapsto m+1$. \item This procedure stops if $L_E^{(m)}(1)$ is not zero to $k$ bits precision, and then output the analytic rank of elliptic curve $r_E = m$. \end{enumerate} \bigskip For elliptic curves with large conductors, we give an upper bound and a lower bound on the rank. \begin{align*} \frac{1}{2} \log{N_E} -4.426 - \beta_E < r_E < 0.5 +0.32 \log{N_E}. \end{align*} In the last section, we collected a list of minor mistakes and typos in his thesis. \vfillope

Fundamental‐mode basin oscillations in the Japan/East Sea

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\u27s 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

Comment on “Current system east of the Ryukyu Islands” by A. Nagano et al.

The fact that human beings have a fundamental right,such as human rights. Of the many human rights attached to these, there is a right to obtain information, where one means to obtain the information coming from the press. The embodiment of popular sovereignty in a democratic state is the guarantee of human rights including freedom of the press, including the Indonesian nation that embraces democracy. Freedom of the press is part of the constitutional rights of citizens of Indonesia as the mandate of Article 28 of the Constitution of the Republic of Indonesia Year 1945. Of the mandate of the Constitution of the Republic  of Indonesia Year 1945, the Government of the Republic of Indonesia implements it in the form of a legislation, namely the Law of the Republic of Indonesia Number 40 of 1999 on the Press in order to provide legal guarantees for the independence and freedom of the press in Indonesia. Efforts to build a democracy with social justice and human rights guarantees necessary to have an atmosphere that is safe, orderly, peaceful, and conducted responsibly and in accordance with prevailing laws and regulations

KINEMATIC FACTORS AFFECTING THE SCORE IN ARCHERY: USING SEM

INTRODUCTION: The shooting movements of Archery are paths of continuous and causal movements. Structural equation modeling (SEM) grows out of and serves purposes similar to multiple regression and may be used as a more powerful alternative to multiple regression, path analysis, factor analysis, time series analysis, and analysis of covariance. Some reachers in marketing have used SEM to analyze data deprived from experiments (e.g.,Mackenzie,Lutz, and Belch,1986; Ryan,1982). The purpose of this study was to investigate the structural equations between kinematic factors affecting score during backtension which was basic and important in archer

A Multi-Index GEM Technique and Its Application to the Southwestern Japan/East Sea

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 (τ) 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 τ 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

Evidence of Bottom-Trapped Currents in the Kuroshio Extension Region

As part of the Kuroshio Extension System Study, observations from five current meter moorings reveal that the abyssal currents are weakly bottom intensified. In the framework of linear quasigeostrophic flow, the best fitted vertical trapping depths range from 8 to 15 km in the absence of steep topography, but one mooring near an isolated seamount exhibited vertical trapping that was more pronounced and energetic with a vertical trapping depth of 5 km. The ratios of current speeds and geostrophic pressure streamfunctions at the sea surface compared to the bottom are 88% in the absence of steep topography, 63% near an isolated seamount, and overall on average 83% of their value at a reference depth of 5300 m. It is hypothesized that weakly depth-dependent eddies impinging upon topographic features introduce to the flow the horizontal length scales of the topography, and these smaller lateral scales are subject to bottom intensification