Faculty Profiles - SHIOKAWA, Kazuo

Papers - SHIOKAWA, Kazuo

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Relationship between propagation direction of gravity waves in OH and OI airglow images and VHF radar echo occurrence during the SEEK-2 campaign Reviewed Open Access

Onoma F, Otsuka Y, Shiokawa K, Ogawa T, Yamamoto M, Fukao S, Saito S

ANNALES GEOPHYSICAE Vol. 23 ( 7 ) page： 2385 - 2390 2005

Geoeffectiveness of shocks in populating the radiation belts Reviewed

JB Blake, PL Slocum, JE Mazur, MD Looper, RS Selesnick, K Shiokawa

Multiscale Coupling of Sun-Earth Processes page： 125 - 133 2005

Language：English Publishing type：Research paper (international conference proceedings) Publisher：ELSEVIER SCIENCE BV

On 24 March 1991, ions and electrons with energies of 10s of MeV were observed by CRRES to be injected into the Earth's magnetosphere. The injection created a stable new radiation belt that persisted for years. Later in the decade, several geomagnetic storms and associated energetic solar particle events led to new radiation belts, but none with comparable stability until two injections occurred in November 2001 that lasted for two years. Using data from SAMPEX, Polar, 1997-068, and the 210 Magnetic Meridian Chain, we examine observations of storms that lead to new long-lasting belts. We find that stable belts arise after a deep injection into the slot region (L similar to 2.5). Associated with these injections is an unusually rapid rise in the magnetic field impulse as seen by ground-based magnetometers.

DOI： 10.1016/B978-044451881-1/50010-1

Web of Science

Scopus

The first coordinated observations of mid-latitude E-region quasi-periodic radar echoes and lower thermospheric 557.7-nm airglow Reviewed Open Access

Ogawa, T, Otsuka, Y, Onoma, F, Shiokawa, K, Yamamoto, M

ANNALES GEOPHYSICAE Vol. 23 ( 7 ) page： 2391 - 2399 2005

Simultaneous ground- and satellite-based airglow observations of geomagnetic conjugate plasma bubbles in the equatorial anomaly Reviewed Open Access

Ogawa T, Sagawa E, Otsuka Y, Shiokawa K, Immel TI, Mende SB, Wilkinson P

EARTH PLANETS AND SPACE Vol. 57 ( 5 ) page： 385 - 392 2005

Spatial relationship of equatorial plasma bubbles and field-aligned irregularities observed with an all-sky airglow imager and the Equatorial Atmosphere Radar Reviewed

Otsuka Y, Shiokawa K, Ogawa T, Yokoyama T, Yamamoto M, Fukao S

GEOPHYSICAL RESEARCH LETTERS Vol. 31 ( 20 ) page： L20802 2004.10

中間圏の大気光画像中に現れた湾曲波面を持つ大気重力波の構造 Reviewed Open Access

鈴木臣, 塩川和夫, 中村健治, 大塚雄一, 小川忠彦, 中村卓司

大会講演予講集 Vol. 86 page： . 2004.10

Cosmic Ray and Riometer Observations in Associated with Thunderstorm at Brazilian Geomagnetic Anomaly Region Reviewed

MAKITA Kazuo, TORII Tatuo, HOSHINO Mituo, NISHINO Masonori, SHIOKAWA Kazuo, SCHUCH Nelson Jorge

Bulletin of science and engineering, Takushoku University Vol. 9 ( 2 ) page： 37 - 42 2004.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Takushoku University

A field mill and a cosmic-ray detector have been newly installed at Brazilian geomagnetic anomaly region. We have compared 38.2 MHz riometer with these data during strong thunderstorm period. Although no clear relationship have been recognized yet between electric field and the fluctuation of cosmic-ray intensity, however a good relationship was found between electric field and 38.2 MHz intensity. This result may suggest that 38.2 MHz radio wave was excited by acceleration of particles under the thunderstorm electric field.

CiNii Research

Statistical characteristics of gravity waves observed by an all-sky imager at Darwin, Australia Reviewed Open Access

Shin Suzuki, K. Shiokawa, Y. Otsuka, T. Ogawa, P. Wilkinson

Journal of Geophysical Research D: Atmospheres Vol. 109 ( D20 ) page： D20 - S07 2004.8

Language：English Publishing type：Research paper (scientific journal)

An all-sky airglow imager with a cooled charge-coupled device camera in place at Darwin (12.4°S, 131.0°E), Australia, since October 2001 has been used to obtain two-dimensional gravity wave images in the mesopause region. Using airglow images of the OI (557.7 nm, emission altitude ∼96 km) and OH band (720-910 nm, ∼86 km) emissions obtained for October 2001 to August 2002, we investigated the wavelengths, phase velocities, and propagation directions of gravity waves. Wave occurrence in OH images (60-90%) is higher than in OI images (30-70%) for all seasons. The waves have wavelengths of less than 90 km (peak: 30-50 km) and phase velocities ofless than 90 m/s (peak: 30-60 m /s). Most of the waves propagate in the meridional direction, and the directionality strongly depends on the season. In winter, waves propagate both poleward and equatorward, while in summer almost all waves propagate poleward. An examination of airglow-imaging statistics at Adelaide (35°S, 138°E), Australia, obtained by Walterscheid et al. [1999], leads us to conclude that this clear directionality is caused by the location of the wave sources and by the wave ducting processes
that is, poleward waves in summer come from an equatorial convective source through a thermal duct structure. The effect of wind filtering on the waves is also discussed for zonal wave propagation. Copyright 2004 by the American Geophysical Union.

DOI： 10.1029/2003JD004336

Open Access

Web of Science

Scopus

Geomagnetic conjugate observations of medium-scale traveling ionospheric disturbances at midlatitude using all-sky airglow imagers Reviewed

Y Otsuka, K Shiokawa, T Ogawa, P Wilkinson

GEOPHYSICAL RESEARCH LETTERS Vol. 31 ( 15 ) 2004.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

We report for the first time simultaneous observations of medium-scale traveling ionospheric disturbances (MSTIDs) at geomagnetic conjugate points in both hemispheres, using two all-sky airglow imagers at midlatitudes. A 630-nm all-sky CCD imager at Sata, Japan, detected MSTIDs with a wavefront elongated from NW to SE on the night of August 9, 2002. During this event, MSTIDs with a wavefront elongated from SW to NE were observed at the geomagnetic conjugate point, Darwin, Australia. To investigate geomagnetic conjugacy of the MSTID structures, the Darwin images were mapped The MSTID structures mapped from Darwin to its magnetic conjugate points along the geomagnetic field lines ( B) coincide closely with those in the Sata images. This result suggests that polarization electric field (E-p) plays an important role in the generation of MSTIDs. E-p maps along B and moves the F region plasma upward or downward by E x B drifts, causing plasma density perturbations with structures mirrored in the northern and southern hemispheres.

DOI： 10.1029/2004GL020262

Web of Science

Scopus

内部磁気圏ミッションの提案

塩川和夫, 関加奈子, 三好由純, 小原隆博, 小野高幸

第4回宇宙科学シンポジウム proceeding page： 349 - 352 2004.8

Comparison of OH rotational temperatures measured by the spectral airglow temperature imager (SATI) and by a tilting-filter photometer Reviewed

Shiokawa, K, Otsuka, Y, Ogawa, T, Takahashi, H, Nakamura, T, Shimomai, T

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS Vol. 66 ( 11 ) page： 891 - 897 2004.7

大気光画像データを用いた中間圏重力波の運動量フラックスの導出 Reviewed Open Access

鈴木臣, 塩川和夫, 大塚雄一, 小川忠彦, 中村卓司, FRITTS D. C.

大会講演予講集 Vol. 85 page： . 2004.5

Simultaneous mesosphere/lower thermosphere and thermospheric F region observations during geomagnetic storms Reviewed Open Access

Balan, N, Kawamura, S, Nakamura, T, Yamamoto, M, Fukao, S, Igarashi, K, Maruyama, T, Shiokawa, K, Otsuka, Y, Ogawa, T, Alleyne, H, Watanabe, S, Murayama, Y

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 109 ( A4 ) 2004.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Blackwell Publishing Ltd

Simultaneous mesosphere/lower thermosphere (MLT) and thermospheric F region observations made during geomagnetic storms are presented using the MU radar (35°N, 136°E) in alternate meteor and incoherent scatter (IS) modes, MF radar (45°N, 136°E), optical mesosphere thermosphere imagers (OMTI) (35°N, 136°E) and over 1000 GPS receivers in Japan. The observations were made during one of the MTEC-S (mesospherethermosphere experiments for coupling studies) campaigns conducted during 23 March to 2 April 2001 when a major storm with Dst reaching -358 nT and a moderate storm with Dst reaching -112 nT occurred and solar activity varied from high to very high (F10.7 = 220 to 270). The campaign has provided zonal and meridional wind velocities at MLT altitudes (80-95 km) over the MU and MF radars
meridional wind velocity in the upper thermosphere (220-450 km) and ionospheric electron density (150-600 km), peak height and plasma drift velocity over the MU radar
all-sky airglow intensities at 557.7 nm, 630.0 nm, and 777.4 nm wavelengths over the MU radar location
and vertical GPS-TEC all over Japan. Study of the data indicates that following the major storm, the meridional wind in the upper thermosphere over the MU radar (35°N) becomes weak (less poleward) during daytime and its diurnal amplitude reduces. The winds and tides at MLT altitudes show changes during both nonstorm times and storm times, but this study is not able to confirm any statistically significant changes related to the storms. In the ionosphere, following the onset of the major morning storm, the electron density increases at altitudes near and above the ionospheric peak, which after about 5 hours is followed by large increase in density at all altitudes above about 200 km. On the following night, though the density is generally low, there is a large increase in density in the bottomside for about 3 hours centered at 0230 LT. During this time, a rare intense optical activity has occurred at all wavelengths (557.7 nm, 630 nm, and 777.4 nm) over the low midlatitude location (35°N), and an associated large-scale traveling ionospheric disturbance (LSTID) has propagated from north to south at F region altitudes. Copyright 2004 by the American Geophysical Union.

DOI： 10.1029/2003JA009982

Open Access

Web of Science

Scopus

VHF海外放送電波の伝搬とプラズマバブルとの関連 Reviewed

長嶋郁生, 中田裕之, 大塚雄一, 鷹野敏明, 坂井来人, 塩川和夫, 小川忠彦

大気電気研究 Vol. 64 page： 82 - 83 2004.3

Optical Observation at Okinawa Reviewed

MAKITA Kazuo, HOSHINO Mituo, MASUDA Yoshihisa, SHIOKAWA Kazuo

Bulletin of science and engineering, Takushoku University Vol. 9 ( 1 ) page： 19 - 26 2004.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Takushoku University

CCD imager and Photometer were installed at CRL Oogimi ionospheric station at Okinawa (26.7 N, 128 E) in order to compare optical data obtained at INPE Southern Space Observatory, Brazil (29.6 S, 306 E). These two observatories are nearly opposite side of earth. From Okinawa optical data, 630nm enhancement was observed at pre-morning sector (03-05 LT). The peak luminosity of 630nm was about 300-400 R and no clear enhancement in 557.7nm. These phenomena are very similar to the optical data obtained at Brazilian observatory. It suggests that the pre-morning enhancement of 630nm observed here must be general phenomena in low latitude region. We are now examining the relationship between ionospheric electron density and those 600nm enhancement.

CiNii Research

Comparison of winds measured by MU radar and Fabry-Perot interferometer and effect of OI5577 airglow height variations Reviewed

J Fujii, T Nakamura, T Tsuda, K Shiokawa

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS Vol. 66 ( 6-9 ) page： 573 - 583 2004

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

We have compared wind velocities around mesopause height measured by the middle and upper atmosphere (MU) radar (meteor mode) and O1 (5577) airglow observation by an Fabry-Perot Interferometer (FPI), at Shigaraki (34.8degreesN, 136.1degreesE), Japan, on November 13/14, 1999. When we assume the airglow height is constant throughout the night, it was difficult to find a single height exhibiting small r.m.s. differences between the two methods for both eastward and northward wind velocities. However, in the case we introduce a time variation of the airglow height due to a large-scale gravity wave activity, we have found very small r.m.s. wind difference: The assumptions are of the airglow height variation with an amplitude of 1.5 km, a period of 5.7 h and a linear trend of -0.19 km/h having the average height of 92.8 km. Further analysis of time and height variations of the winds and diffusion coefficients measured by the MU radar indicated that a gravity wave with a very similar structure predicted in the above comparison between the FPI and meteor winds has been detected as a dominant wave component. Thus, we conclude that the existence of a gravity wave which can change the airglow height will lead to differences in wind velocities observed with FPI and radar techniques. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jastp.2004.01.010

Web of Science

Scopus

Time evolution of high-altitude plasma bubbles imaged at geomagnetic conjugate points Reviewed Open Access

Shiokawa K, Otsuka Y, Ogawa T, Wilkinson P

ANNALES GEOPHYSICAE Vol. 22 ( 9 ) page： 3137 - 3143 2004

Atmospheric density and pressure inferred from the meteor diffusion coefficient and airglow O(2)b temperature in the MLT region Reviewed Open Access

H Takahashi, T Nakamura, K Shiokawa, T Tsuda, LM Lima, D Gobbi

EARTH PLANETS AND SPACE Vol. 56 ( 2 ) page： 249 - 258 2004

Language：English Publishing type：Research paper (scientific journal) Publisher：TERRA SCIENTIFIC PUBL CO

Atmospheric density and pressure in the upper mesosphere-lower thermosphere (MLT) region, around 90 km, are inferred from the meteor trail ambipolar diffusion coefficients, D, and simultaneously observed airglow O(2)b rotational temperatures. For the present study simultaneous observation data from the meteor radar and SATI imaging spectrometer taken at Shigaraki MU radar observatory (34.9degreesN, 136.1degreesE) were used. From the 18 winter nights of data, it is observed that in most of the cases nocturnal variation of the O-2 temperature has a good correlation with D at 90 to 92 km. The inferred densities at 90 km showed a negative correlation with temperature variation, suggesting a constant pressure process. The O-2 emission intensity shows a good correlation with the temperature, and negative correlation with the density variation. The OH rotational temperature and D at 87 km also showed similar results to the case of the O-2 temperature.

DOI： 10.1186/BF03353407

Understanding the “SEKKI” phenomena in Japanese historical literatures based on the modern science of low-latitude aurora Open Access

Nakazawa Yoh, Okada Toshimi, Shiokawa Kazuo

Earth, Planets and Space Vol. 56 ( 12 ) page： e41 - e44 2004

Language：English Publishing type：Research paper (scientific journal) Publisher：Society of Geomagnetism and Earth, Planetary and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan , The Geodetic Society of Japan , The Japanese Society for Planetary Sciences

“SEKKI” phenomena often appear in the Japanese historical literatures as distinct red emission in the nocturnal sky. The Japanese word “SEKKI” means the red atmosphere. We compile 16 events of SEKKI for 12-19th centuries in the literatures. In order to understand the SEKKI phenomena, we compared 2 events of SEKKI on February 21, 1204, and September 17, 1770, with the characteristics of low-latitude auroras studied recently by modern scientific methods. We conclude that these historical SEKKI phenomena are probably giant low-latitude auroras.

DOI： 10.1186/bf03353323

Thermospheric wind during a storm-time large-scale traveling ionospheric disturbance Reviewed Open Access

K Shiokawa, Y Otsuka, T Ogawa, S Kawamura, M Yamamoto, S Fukao, T Nakamura, T Tsuda, N Balan, K Igarashi, G Lu, A Saito, K Yumoto

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS Vol. 108 ( A12 ) 2003.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

[1] A prominent large-scale traveling ionospheric disturbance (LSTID) was observed in Japan during the major magnetic storm (Dst similar to -358 nT) of 31 March 2001. It was detected as enhancements of the 630-nm airglow and foF2, GPS-TEC variations, and a decrease in F-layer virtual height at 1700 - 1900 UT (0200 - 0400 LT). It moved equatorward with a speed of similar to600 m/s. The decrease in the F-layer height was also detected by the MU radar at Shigaraki. Thermospheric wind variations were observed by the MU radar through ion drift measurement and by a Fabry-Perot interferometer (FPI) through a Doppler shift of the 630-nm airglow line at Shigaraki. The wind data show a turn of the meridional wind from -94 m/s (equatorward) to + 44 m/s (poleward) during the LSTID, indicating that an intense poleward wind in the thermosphere passed over Shigaraki as an atmospheric gravity wave and caused the observed ionospheric features of the LSTID. Intense poleward wind was also detected at mesospheric altitudes (95 - 100 km) by the MU radar ( through meteor echoes) and by the FPI ( through the 558-nm airglow) with a delay of similar to2 hours from the thermospheric wind, indicating downward phase progression of the wave. Generation of the observed poleward wind in the auroral zone was investigated using magnetic field data and auroral energy input estimated by the assimilative mapping of ionospheric electrodynamics (AMIE) technique. We suggest that simple atmospheric heating and/or the Lorentz force in the auroral zone do not explain the observed poleward wind enhancement.

DOI： 10.1029/2003JA010001

Open Access

Web of Science

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Papers - SHIOKAWA, Kazuo