研究者詳細 - 塩川　和夫

論文 - 塩川　和夫

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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 85 巻頁： . 2004年5月

Simultaneous mesosphere/lower thermosphere and thermospheric <i>F</i> region observations during geomagnetic storms -: art. no. A04308 査読有り

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 109 巻 ( A4 ) 2004年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Space Physics

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

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VHF海外放送電波の伝搬とプラズマバブルとの関連査読有り

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 64 巻頁： 82 - 83 2004年3月

沖縄の光学観測査読有り

巻田和男, 星野光男, 増田悦久, 塩川和夫

拓殖大学理工学研究報告 9 巻 ( 1 ) 頁： 19 - 26 2004年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：拓殖大学

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.

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

Fujii J, Nakamura T, Tsuda T, Shiokawa K

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS 66 巻 ( 6-9 ) 頁： 573 - 583 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Atmospheric and Solar-Terrestrial Physics

We have compared wind velocities around mesopause height measured by the middle and upper atmosphere (MU) radar (meteor mode) and OI (5577) airglow observation by an Fabry-Perot Interferometer (FPI), at Shigaraki (34.8°N, 136.1°E), 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. © 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jastp.2004.01.010

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Time evolution of high-altitude plasma bubbles imaged at geomagnetic conjugate points 査読有り

Shiokawa K, Otsuka Y, Ogawa T, Wilkinson P

ANNALES GEOPHYSICAE 22 巻 ( 9 ) 頁： 3137 - 3143 2004年

Atmospheric density and pressure inferred from the meteor diffusion coefficient and airglow O<sub>2</sub>b temperature in the MLT region 査読有り

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

EARTH PLANETS AND SPACE 56 巻 ( 2 ) 頁： 249 - 258 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Earth, Planets and Space

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 O2b rotational temperatures. For the present study simultaneous observation data from the meteor radar and SATI imaging spectrometer taken at Shigaraki MU radar observatory (34.9°N, 136.1°E) were used. From the 18 winter nights of data, it is observed that in most of the cases nocturnal variation of the O2 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 O2 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 O2 temperature. © 2004, The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan, The Geodetic Society of Japan, The Japanese Society for Planetary Sciences. All rights reserved.

DOI： 10.1186/BF03353407

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CiNii Research

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

Nakazawa Y., Okada T., Shiokawa K.

Ｅａｒｔｈ，　Ｐｌａｎｅｔｓ　ａｎｄ　Ｓｐａｃｅ 56 巻 ( 12 ) 頁： e41 - e44 2004年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：地球電磁気・地球惑星圏学会、公益社団法人日本地震学会、特定非営利活動法人日本火山学会、日本測地学会、日本惑星科学会

“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. © 2004, The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan, The Geodetic Society of Japan, The Japanese Society for Planetary Sciences. All rights reserved.

DOI： 10.1186/bf03353323

Thermospheric wind during a storm-time large-scale traveling ionospheric disturbance 査読有り Open Access

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

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 108 巻 ( A12 ) 2003年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Space Physics

A prominent large-scale traveling ionospheric disturbance (LSTID) was observed in Japan during the major magnetic storm (Dst ∼ -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 ∼600 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 ∼2 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. Copyright 2003 by the American Geophysical Union.

DOI： 10.1029/2003JA010001

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Statistical study of short-period gravity waves on OH and OI nightglow images at two separated sites 査読有り Open Access

Ejiri M., Shiokawa K., Ogawa T., Igarashi K., Nakamura T., Tsuda T.

Journal of Geophysical Research D: Atmospheres 108 巻 ( 21 ) 2003年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research D: Atmospheres

Using airglow images of the near-infrared OH band (720-910 nm) and OI (557.7 nm) line, we investigated seasonal, latitudinal, and localt ime variations of short-period gravity waves. The images were obtained at two locations in Japan that are ∼1200 km apart, Rikubetsu (43.5°N, 143.8°E) and Shigaraki (34.9°N, 136.1°E), between October 1998 and October 1999. Our analysis has focused on small-scale gravity waves with wavelengths less than 40 km and dominant phase speeds of ∼20-50 m/s. Wave occurrences for both OH and OI at Rikubetsu and Shigaraki are significantly higher than 60%, with a slightly larger value in summer. The occurrences increase from evening to midnight. There are no obvious local time dependencies in horizontal wavelength, propagation direction, and phase speed. The propagation directions in summer are either northward or northeastward at both locations. However, in winter the propagation directions at Rikubetsu are generally westward (NW, W, and SW), whereas those at Shigaraki are only southwestward. From simultaneous wind observation by the MF radars at Wakkanai (45.4°N, 141.7°E) and Yamagawa (31.2°N, 130.6°E), we discuss possible influences of Doppler and thermal ducting, wind filtering, and source distribution of gravity waves propagating from the lower atmosphere to the airglow heights in the mesopause region. Copyright 2003 by the American Geophysical Union.

DOI： 10.1029/2002JD002795

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Statistical study of short-period gravity waves in OH and OI nightglow images at two separated sites 査読有り

Ejiri MK, Shiokawa K, Ogawa T, Igarashi K, Nakamura T, Tsuda T

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 108 巻 ( D21 ) 2003年11月

Bi-directional electrons in the near-Earth plasma sheet 査読有り

Shiokawa K, Baumjohann W, Paschmann G

ANNALES GEOPHYSICAE 21 巻 ( 7 ) 頁： 1497 - 1507 2003年7月

Optical and radio measurements of a 630-nm airglow enhancement over Japan on 9 September 1999 査読有り

Otsuka, Y; Kadota, T; Shiokawa, K; Ogawa, T; Kawamura, S; Fukao, S; Zhang, SR

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 108 巻 ( A6 ) 2003年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Space Physics

Using a comprehensive data set from optical and radio instruments, we investigate a midnight brightness wave that appeared in 630-nm airglow images over Japan on the night of 9 September 1999. This may be the first such observation of the brightness wave with an all-sky imager in the East-Asian longitudinal sector. The imager at Shigaraki (35.6°N, 136.1°E) tracked a north-northeastward propagation of the wave with an apparent velocity of 500 m s-1 after midnight. Ionosonde observations at five stations in Japan showed that rapid descent of the F2 layer propagated northward beyond 35°N with decreasing amplitude. Incoherent scatter observations with the MU radar at Shigaraki also revealed that the F2 peak altitude decreased from 360 to 280 km during the event. During the F2 layer descent the altitude profile of the electron density became sharp, enhancing the F 2 peak electron density. After the F2 layer altitude reached 280 km, electron density in the F2 layer rapidly decreased because of increased neutral density at low altitude. A Fabry-Perot interferometer (FPI) at Shigaraki observed northward neutral winds of 10-70 m s-1 during the event. A model calculation demonstrates that the meridional winds estimated from the MU radar electron density profiles are fairly consistent with those observed with the FPI. From these results we conclude that the observed northward wind enhancements, probably caused by the midnight temperature maximum, pushed down the plasma in the F2 layer to lower altitudes along the geomagnetic field to cause the 630-nm airglow intensity enhancement. Copyright 2003 by the American Geophysical Union.

DOI： 10.1029/2002JA009594

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P345 オーストラリア・ダーウィンで観測された大気光画像中の重力波の統計解析査読有り

鈴木臣, 塩川和夫, 大塚雄一, 小川忠彦

大会講演予講集 83 巻頁： 416 2003年5月

夜間に観測される海外VHF帯局電波と plasma bubble の相関について査読有り

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 62 巻頁： 91 - 92 2003年4月

Ground and satellite observations of nighttime medium-scale traveling ionospheric disturbance at midlatitude 査読有り

Shiokawa, K; Otsuka, Y; Ihara, C; Ogawa, T; Rich, FJ

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 108 巻 ( A4 ) 2003年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Space Physics

We have investigated a nighttime medium-scale traveling ionospheric disturbance (MSTID) observed by an airglow imager at Shigaraki (34.9°N, 25.4°MLAT), Japan, on 17 May 2001. The structure was identified in the airglow images of 01 (630.0 nm and 777.4 nm) as NW-SE band structures (horizontal wavelength: 230 km) moving southwestward with a velocity of 50 m/s. Neutral wind velocity was measured simultaneously from the Doppler shift of the 630.0-nm emission by a Fabry-Perot interferometer at Shigaraki. From these parameters, we performed model calculations of MSTIDs generated by gravity waves and by an oscillating electric field. We found that for the case of gravity waves, the estimated vertical wavelength was too small to explain the observed amplitudes of airglow intensity. For the case of the electric field, we found that an electric field oscillation of ∼ 1.2 mV/m was sufficient to reproduce the observed airglow amplitudes. This modeled electric field was comparable to that observed by the DMSP F15 satellite as it passed over Shigaraki during our observing period on 17 May 2001. The DMSP ion drift data show that the oscillation of the polarization electric field correlated with the MSTID structure in the airglow image, suggesting that the polarization electric field plays an important role in the generation of MSTlDs. Copyright 2003 by the American Geophysical Union.

DOI： 10.1029/2002JA009639

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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3回宇宙科学シンポジウム proceeding 頁： 435 - 443 2003年4月

Statistical study of nighttime medium-scale traveling ionospheric disturbances using midlatitude airglow images 査読有り Open Access

Shiokawa, K; Ihara, C; Otsuka, Y; Ogawa, T

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 108 巻 ( A1 ) 2003年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Space Physics

We have investigated statistical characteristics of the nighttime medium-scale Traveling ionospheric disturbances (MSTIDs) observed in 630-nm airglow images at two stations, Rikubetsu (43.5°N, 34.8°MLAT) and Shigaraki (34.9°N, 25.4°MLAT), in Japan for 1998-2000 near the solar maximum period. Most of the observed MSTIDs propagate southwestward in the images. The typical wavelength, velocity, period, and amplitude are 100-300 km, 50-100 m/s, 0.5-1.5 h, and 5-15%, respectively. Seasonal variations in these parameters are not clear. The occurrence rate has a major peak (50-60%) in summer that appears ∼2 months earlier at lower latitudes and a minor peak in winter. Similar occurrence.characteristics are obtained from midlatitude spread-F signatures using multipoint ionosonde data in Japan, though the coincidence of the spread-F and the MSTIDs in airglow images is only 10-15%. Copyright 2003 by the American Geophysical Union.

DOI： 10.1029/2002JA009491

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A localized structure in OH airglow images near the mesopause region 査読有り

Shiokawa K, Ejiri MK, Ogawa T, Yamada Y, Fukunishi H, Igarashi K, Nakamura T

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 108 巻 ( D2 ) 2003年1月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Geophysical Research: Atmospheres

An intense localized airglow-depletion structure was observed in OH airglow images (emission altitude ∼86 km) at Shigaraki (34.9°, 136.1°) on 19 December 1998. The structure was a single-band airglow depletion with a small horizontal width (∼15 km) but a large amplitude (∼34% from the average intensity). Airglow rotational temperature indicated a large temperature lapse rate at this time as a result of strong semidiurnal variation. We suggest that nonlinear wave-wave interaction is the most likely cause of this localized structure.

DOI： 10.1029/2002JD002462

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A two-channel Fabry-Perot interferometer with thermoelectric-cooled CCD detectors for neutral wind measurement in the upper atmosphere 査読有り

Shiokawa K, Kadota T, Otsuka Y, Ogawa T, Nakamura T, Fukao S

EARTH PLANETS AND SPACE 55 巻 ( 5 ) 頁： 271-275 2003年

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