K. Sato

Silver-sheathed BiPbSrCaCuO wires were fabricated using the powder-in-tube method. Critical current densities at 77.3 K were 4.7*10/sup 4/ A/cm/sup 2/ in a zero magnetic field, 3.1*10/sup 4/ A/cm at 0.1 T, and 1.1*10/sup 4/ A/cm/sup 2/ at 1 T. In liquid He, these wires can carry 1.03*10/sup 5/ A/cm/sup 2/ at 23 T. J/sub c/ and J/sub c/-B enhancements are due to grain-boundary improvements. Detailed investigation of J/sub c/-B characteristics in magnetic fields, especially increasing and decreasi

Using hourly data from a three‐year simulation based on a gravity‐wave resolving general circulation model, we have first inferred a global view of gravity wave sources and propagation affecting significantly the momentum balance in the mesosphere. The meridional cross section of momentum fluxes suggests that there are a few dominant propagation paths originating from the subtropics in summer and the middle to high latitudes in winter. These gravity waves are focused into the mesospheric jets in

Abstract Gravity wave characteristics in the middle- to high-latitude Southern Hemisphere are analyzed using simulation data over 3 yr from a high-resolution middle-atmosphere general circulation model without using any gravity wave parameterizations. Gravity waves have large amplitudes in winter and are mainly distributed in the region surrounding the polar vortex in the middle and upper stratosphere, while the gravity wave energy is generally weak in summer. The wave energy distribution in win

A new indirect method is proposed to estimate momentum flux based on the theory of slowly varying gravity waves and equatorial waves in vertical shear by Dunkerton [this issue] which explains the discovery by Sato et al. [1994] that the cospectra of temperature and zonal wind fluctuations at Singapore (1.4°N, 104.0°E) are synchronized with the quasi‐biennial oscillation (QBO) of mean zonal wind in the stratosphere. The indirect estimates obtained from cospectra correspond to the summation of abs

Abstract Intensive radiosonde observations were performed at Syowa Station (69.0°S, 39.6°E) over about 10 days in each of March, June, October, and December 2002 to examine inertia–gravity wave characteristics in the Antarctic lower stratosphere. Based on the 3-hourly observation data, two-dimensional (i.e., vertical wavenumber versus frequency) spectra of wind fluctuations were examined, utilizing a double Fourier transform method. Clear signals of gravity waves whose phases propagate upward, s

This paper describes small-scale wind disturbances associated with Typhoon Kelly (October 1987) that were observed by the MU radar, one of the MST (mesosphere, stratosphere, and troposphere) radars, continuously for about 60 hours with fine time and height resolution. First, in order to elucidate the background of small-scale disturbances, synoptic-scale variation in atmospheric stability related to the typhoon structure during the observation is examined. When the typhoon passed near the MU rad

Critical currents of superconducting silver-sheathed tapes of Bi1.8Pb0.4Sr2Ca2.2Cu3Ox have been measured in the magnetic flux density range 0–19.75 T at 4.2, 15, and 20 K. One tape achieved a critical current of 60.6 A at 19.75 T and 20 K; the corresponding critical current density is 551 A/mm2. In the same field, the tape has critical currents of 72.3 A (657 A/mm2) at 15 K and 94.2 A (856 A/mm2) at 4.2 K. At 77 K and in zero field, the tape carries 32.9 A (299 A/mm2). These results indicate tha

The filter paper disk method was used to determine the map of the 4 tastes (sweet, salty, sour and bitter) on the tongue and soft palate in 69 healthy individuals. The equipment used for testing included filter paper disks 8 mm in diameter and taste solutions, which were sequentially diluted (in 13 stages from 80% sucrose, 12 stages from 20% NaCl, 12 stages from 8% tartaric acid and 14 stages from 4% quinine hydrochloride). The threshold at which each taste was recognized in three locations (cen

Global characteristics of gravity waves in the lower stratosphere are examined using a GCM with high resolution in both the horizontal (T106, corresponding to about 120 km) and the vertical (∼600 m). The bottom boundary condition of the model is that of an aquaplanet with perpetual February sea surface temperature. The simulated gravity waves are in good agreement with mesosphere–stratosphere–troposphere (MST) radar observations at a middle latitude on the gravity wave structure and on the frequ

An analysis is made of vertical wind disturbances (VWDs) observed by the MU radar (Shigaraki, Shiga, Japan) in terms of the wave structures, sources, and vertical momentum flux. First, it is shown through spectral and lag-correlation analyses that there are several common features in three observation periods when the VWDs appeared: large power in the vertical wind fluctuations exists below a height of ∼20 km and is distributed largely at lower frequencies. The decrease in power near 20 km is sh

Vertical wind disturbances are frequently observed during midsummer afternoons in association with cumulus convection. To examine the relation of these wind disturbances to atmospheric stability and turbulence intensity, we carried out intensive observations of wind, temperature and humidity over a large vertical region extending from the boundary layer to the lower stratosphere using UHF/VHF radars and radiosondes at Shiga, Japan (35°N, 136°E). The wind disturbances propagate quickly into the u

It is well known that the vertical wavenumber ( m ) spectra of temperature and horizontal wind fluctuations have a steep slope (almost proportional to m −3 ) in the middle atmosphere. These spectra are considered to be due to saturated gravity waves. However, since power spectral analysis assumes sinusoidal waves with constant amplitudes in the height region for which the spectra are calculated, the information on the height position, where the disturbance having each wavenumber is dominant, is