PEM10-01

会場:A01

時間:5 月 27 日 16:15-16:45

赤道ファウンテン
Equatorial Fountain in the Middle and Upper Atmosphere
津田 敏隆 1∗ ; 山本 衛 1 ; 橋口 浩之 1
TSUDA, Toshitaka1∗ ; YAMAMOTO, Mamoru1 ; HASHIGUCHI, Hiroyuki1
1
1

京都大学生存圏研究所
Research Institute for Sustainable Humanosphere (RISH), Kyoto University

We are studying coupling processes in the Sun-Earth system, focusing on the behavior of the atmosphere in response to thesolar energy inputs to the Earth. The solar energy is mainly divided into two parts: the solar radiation involving infra-red, visible,
ultra-violet and X-ray, and the solar wind whose effects are evident in a polar region.
The solar radiation becomes maximum at the equator, then atmospheric disturbances are generated in the troposphere (altitude
up to 10-15 km). In particular, over Indian Ocean to western Pacific, centered by Indonesia, cumulonimbus convection is mostactive in the world. It further excites various atmospheric waves that propagate upward transporting energy and momentum
into the upper atmosphere. Various kinds of materials (atmospheric minor constituents) originating at low- and mid-latitude
regions converge into the equatorial region, and they are blown upward passing through the equatorial tropopause at about 15
km altitude into the middle atmosphere (10-100 km), and spread to the whole globe. In the upper atmosphere above 100 km,
plasma disturbances and equatorial ionization anomaly are generated around the equator. We are trying to capture the energy andmaterial flow that occur in all height ranges of the equatorial atmosphere as Equatorial Fountain.
We constructed the Equatorial Atmosphere Radar (EAR) right over the equator in West Sumatra, Indonesia in 2001 under close
collaboration with Indonesian research institutes and universities; LAPAN, BPPT, LIPI, BIG, BMKG and ITB. On the basis of
successive achievements with EAR, we have been promoting a project to construct a state-of-the-art large atmospheric radar thatis named the Equatorial Middle and Upper Atmosphere Radar (EMU). EMU is 10 times more powerful than EAR, and it will
enable us to study the behavior of the troposphere, middle atmosphere and upper atmosphere. We will also enhance collaboration
with international community, inviting researchers and students to the EMU observatory in order to study together the scientificmystery of the Equatorial Fountain.

キーワード: 赤道大気, 赤道ＭＵレーダー, 大気波動, 対流圏界面, 中層大気, プラズマバブル
Keywords: Equatorial atmosphere, Equatorial MU Radar, Atmospheric Waves, Tropopause, Middle Atmosphere, Plasma Bubble

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PEM10-02

会場:A01

時間:5 月 27 日 16:45-17:00

赤道 MU レーダー計画の現状
Current status of Equatorial MU Radar project
山本 衛 1∗ ; 橋口 浩之 1 ; 津田 敏隆 1
YAMAMOTO, Mamoru1∗ ; HASHIGUCHI, Hiroyuki1 ; TSUDA, Toshitaka1
1
1

京都大学生存圏研究所
RISH, Kyoto University

Research Institute for Sustainable Humanosphere, Kyoto University (RISH) has been studying the atmosphere and ionosphereby using radars. The first big facility was the MU (Middle and Upper atmosphere) radar installed in Shiga, Japan in 1984. Thisis one of the most powerful and multi-functional radar, and is successful of revealing importance of atmospheric waves for the
dynamical vertical coupling processes. The next big radar was the Equatorial Atmosphere Radar (EAR) installed at Kototabang,West Sumatra, Indonesia in 2001. The EAR was operated under close collaboration with LAPAN (Indonesia National Institutefor Aeronautics and Space), and conducted the long-term continuous observations of the equatorial atmosphere/ionosphere. The
EAR, however, had a limited sensitivity to the MU radar as the total output power is just 1/10 to the MU radar. Our new projectis to establish ”Equatorial MU Radar (EMU)” just next to the EAR site in Indonesia. The EMU will have an active phased array
antenna with the 163 m diameter and 1055 cross-element Yagis. Total output power of the EMU will be more than 500 kW.
The EMU is the ”MU radar class” facility, and can detect turbulent echoes from the mesosphere (60-80 km). In the ionosphereincoherent-scatter observations of plasma density, drift, and temperature would be possible. Multi-channel receivers will realizes
radar-imaging observations. The EMU is one of the key element in the project ”Study of coupling processes in the solar-terrestrial
system” that is one of the important project in the Master Plan 2014 of the Science Council of Japan (SCJ). We will report current
status of the EMU project.
キーワード: 大気レーダー, 赤道大気, 低緯度電離圏, インドネシア
Keywords: Atmospheric radar, Equatorial atmosphere, Low-latitude ionosphere, Indonesia

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PEM10-03

会場:A01

時間:5 月 27 日 17:00-17:15

赤道 MU レーダーの観測角度範囲拡大のためのアンテナ配置に関する研究
Study on Antenna Arrangement of Equatorial MU Radar for Widening Observation Angle
Range
橋口 浩之 1∗ ; 寺田 凜太郎 1 ; 西村 耕司 2 ; 佐藤 亨 3 ; 山本 衛 1
HASHIGUCHI, Hiroyuki1∗ ; TERADA, Rintaro1 ; NISHIMURA, Koji2 ; SATO, Toru3 ; YAMAMOTO, Mamoru1
1

京都大学生存圏研究所, 2 国立極地研究所, 3 京都大学情報学研究科
Research Institute for Sustainable Humanosphere (RISH), Kyoto University, 2 National Institute of Polar Research (NIPR),
3
Graduate School of Informatics, Kyoto University
1

Cumulonimbus convection is active in the equatorial atmosphere. It generates various atmospheric waves that propagate
upward to transport energy and momentum into the upper atmosphere including the ionosphere. The Equatorial Atmosphere
Radar (EAR) has been operated in Kototabang, West Sumatra in Indonesia (0.20S, 100.32E) since 2001. The EAR has a circularantenna array of approximately 110 m in diameter, consisting of 560 three-element Yagis. However its peak power is only 100
kW, which is 1/10 of the MU radar in Shigaraki, Japan. It is proposed to construct the Equatorial MU radar (EMU) which has
the similar function and performance as the MU Radar. The antenna of EMU consists of 55 groups, and each group consists of
19 three-element crossed Yagi antennas. Its peak output power is 500 kW in total.
We investigate the optimum antenna arrangement of EMU. Antenna arrangement of the MU Radar and EAR, triangulararrangement, has a problem of generating a grating lobe when the beam zenith angle is over 40 degrees. We tried to findthe optimum antenna arrangement that has no grating lobe, lower sidelobe level and simple arrangement by using optimization
method of trial and error (antenna potential function method) [Nishimura and Sato, 2009]. We use this method under various
restricting conditions, and get various antenna arrangements that are possible to be the optimum antenna arrangement.
We conclude that the following arrangement is the best for EMU in this method: Each group (having 19 antennas) is hexagonshaped triangular arrangement, and groups are arranged so that each ridge of the hexagon is in parallel with ridge of an adjacenthexagon. In the best arrangement, a grating lobe is reduced by 5 dB. Therefore, it becomes possible to observe low elevation
angle by using adaptive clutter rejection method [Kamio et al., 2004]. However, sidelobe levels of other directions are increased
by 15 dB at most. Further investigation is needed to decide to adopt this arrangement or not to EMU.
キーワード: 赤道ＭＵレーダー, アンテナ配置, グレーティングローブ
Keywords: Equatorial MU Radar, Antenna Arrangement, Grating Lobe

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PEM10-04

会場:A01

時間:5 月 27 日 17:15-17:30

海大陸の気象および気候の理解を目指した国際キャンペーン YMCYears of the Maritime Continent (YMC): To better understand the weather and climate
systems of the Maritime Continent
米山 邦夫 1∗ ; Zhang Chidong2
YONEYAMA, Kunio1∗ ; ZHANG, Chidong2
1
1

海洋研究開発機構, 2 マイアミ大学
JAMSTEC, 2 University of Miami

It is time to challenge to precisely understand complicated weather and climate systems of the Maritime Continent, whichhosts various atmospheric and oceanic phenomena and acts as a heat engine of the global atmospheric circulation. To meet this,a 2-year field campaign Years of the Maritime Continent (YMC) starting from mid-2017 is being proposed. Its overarching goal
is to improve understanding and prediction of local multi-scale variability of the MC weather and climate systems and global
impact. The following five themes are set to be key for success of the campaign; 1) atmospheric convection, 2) ocean and airsea interaction, 3) troposphere-stratosphere interaction, 4) aerosols, and 5) prediction improvement. YMC itself is a framework
which enables of coordination and collaboration to conduct several intensive observations and numerical modeling challenges
among participants. Routine observations by local agencies and long-term deployed measurement systems such as Equatorial
Atmospheric Radar will be bases for observation network.

キーワード: 海大陸
Keywords: Years of the Maritime Continent, YMC, Field campaign

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PEM10-05

会場:A01

時間:5 月 27 日 17:30-17:45

Study of the Equatorial Atmospheric Kelvin Waves during El Nino events
Study of the Equatorial Atmospheric Kelvin Waves during El Nino events
DAS, Uma1 ; PAN, Chen-jeih1∗
DAS, Uma1 ; PAN, Chen-jeih1∗11Institute of Space Science, National Central University, Jhongli-32001, Taiwan
Institute of Space Science, National Central University, Jhongli-32001, Taiwan

The effect of El Nino Southern Oscillation (ENSO) on equatorial stratospheric Kelvin waves is investigated using temperature
data retrieved from Global Positioning System Radio Occultation (GPS RO) observations of FORMOSAT-3/COSMIC during
the period from August 2006 to December 2013. Enhanced Kelvin wave activity is observed during the El Nino event of 20092010. The easterly winds above the tropopause during this period favored the vertically upward propagation of these waves thatinduced a fast descending westerly regime by the end of 2010. The zero-wind line is observed to take only 5 months to descendfrom 10 to 50 hPa. Meanwhile, the Westerly Wind Events (WWEs) are noticed in the western Pacific Ocean that might haveparticipated in the occurrence of El Nino which also pushed the low OLR region into the central Pacific region. This study
shows using observational data the effect of El Nino on equatorial Kelvin waves and consequently on the stratospheric quasibiennial oscillation (QBO) through wave-mean flow interactions. Earlier El Nino events of 1987 and 1998 are also investigated,
qualitatively, to understand the effects of ENSO on QBO. It is found that although El Nino events can result in enhanced equatorial
wave activity, an effect is observed on QBO only when the ambient zonal winds in the lower stratosphere favor their upward
propagation and consequently interact with the mean flow.
キーワード: Equatorial Atmospheric Kelvin Waves, El Nino Southern Oscillation (ENSO)
Keywords: Equatorial Atmospheric Kelvin Waves, El Nino Southern Oscillation (ENSO)

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PEM10-06

会場:A01

時間:5 月 28 日 09:00-09:30

Strateole 2: a long-duration balloon campaign at the Equator
Strateole 2: a long-duration balloon campaign at the Equator
HERTZOG, Albert1∗ ; PLOUGONVEN, Riwal1 ; COCQUEREZ, Philippe2 ; VENEL, Stephanie2
HERTZOG, Albert1∗ ; PLOUGONVEN, Riwal1 ; COCQUEREZ, Philippe2 ; VENEL, Stephanie2
1
1

Laboratoire de meteorologie dynamique, CNRS, France, 2 Centre National d’Etudes Spatiales, CNES, France
Laboratoire de meteorologie dynamique, CNRS, France, 2 Centre National d’Etudes Spatiales, CNES, France

The atmospheric region located between 14 and 20 km altitude in the tropics, called the Tropical Tropopause Layer (TTL), hasintermediate properties between those of the tropical troposphere and stratosphere. Air parcels that have been rapidly lofted bydeep convection to the bottom of the TTL are radiatively heated in the TTL and ascends to the stratosphere within a few weeks ormonths. During this timeframe, the air-parcel water vapor mixing ratio decreases to stratospheric values under the influence of anumber of dynamical (e.g., planetary and gravity waves) and microphysical (e.g., nucleation) processes that cover a wide rangeof scales. Despite recent improvements of spaceborne sensors, an accurate global picture of these processes and their interactions
is still missing.
Strateole 2 is a superpressure balloon campaign design to improve our knowledge of small and mesoscale processes in the
TTL. Superpressure balloons, which have been sucessfully used in previous campaigns in Antarctica (Vorcore 2005, Concordiasi2010), can fly for several months in the lower stratosphere (18-20 km). They move with the winds on constant-density surfaces,
and thus behave as quasi-Lagrangian tracers of air-parcel motions. During Strateole 2, many in-situ and remote-sensing instruments aimed at characterizing the TTL dynamics and composition will be hosted on the balloon and perform high-resolution
measurements along the flights.
Strateole 2 observations will be used to document the occurrence of subvisible cirrus clouds in the TTL, as well as the mechanisms responsible for their formation. They will also serve to quantify the momentum flux associated with gravity waves
generated by deep convection, and their contribution in the driving of the stratospheric quasi-biennial oscillation. Strateole 2
observations will also be assimilated by operational numerical weather prediction system to improve their representation of theupper-tropospheric lower-stratospheric circulation.
The presentation will provide a description of Strateole 2 scientific objectives and schedule. It will also show results regarding
gravity-wave activity obtained during the previous long-duration balloon campaigns.

キーワード: Troposphere-Stratosphere coupling, Equatorial atmosphere, Long-duration balloon, Gravity waves
Keywords: Troposphere-Stratosphere coupling, Equatorial atmosphere, Long-duration balloon, Gravity waves

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PEM10-07

会場:A01

時間:5 月 28 日 09:30-09:45

Comparison of Raindrop Size Distributions in Equatorial Indonesia during Convectively
Inactive and Active MJO
Comparison of Raindrop Size Distributions in Equatorial Indonesia during Convectively
Inactive and Active MJOMARZUKI, Marzuki1∗ ; HASHIGUCHI, Hiroyuki2 ; SHIMOMAI, Toyoshi3 ; KOZU, Toshiaki3 ;TAKAHASHI, Yukihiro4
MARZUKI, Marzuki1∗ ; HASHIGUCHI, Hiroyuki2 ; SHIMOMAI, Toyoshi3 ; KOZU, Toshiaki3 ;TAKAHASHI, Yukihiro4
1

Department of Physics Andalas University, Padang, Indonesia, 2 RISH, Kyoto University, Japan, 3 Shimane University, Japan,
Hokkaido University
1
Department of Physics Andalas University, Padang, Indonesia, 2 RISH, Kyoto University, Japan, 3 Shimane University, Japan,
4
Hokkaido University
4

The variability of rainfall and drop size distributions (DSDs) as a function of MJO phases and storm characteristics is investigated using measurements from the Equatorial Atmosphere Radar (EAR) facility at Koto Tabang, Indonesia. Observations
are obtained from a 2D-Video Disdrometer (2DVD) with a near continuous record of operation over eight consecutive years(2003?2010). Vertical profile of DSD is investigated using a Micro Rain Radar (MRR) measurement. Bulk rainfall characteristics are partitioned according to convective and stratiform precipitation classifications, and MJO phase. Notably, on average,
the DSD during the inactive phases tends to have the higher concentration of medium and large-size drops (D >3 mm) than
the active counterpart. But, the DSD during the active phase has more small raindrops with D <2 mm. The evidence of intraseasonal variation of DSD becomes more obvious during heavy rain. Differences in the DSD for the two MJO phases may
indicate the difference in characteristics of microphysical process accompanying the formation and evolution of DSD during eachphase. The microphysical processes are investigated using vertical profile of precipitation from 1.3 GHz wind profiler, brightness
temperature from satellite, lightning from the World Wide Lightning Location Network (WWLLN), cloud properties from daily
MODerate resolution Imaging Spectroradiometer (MODIS), and vertical air motion from EAR measurement.
キーワード: Raindrop size distribution, Equatorial, MJO
Keywords: Raindrop size distribution, Equatorial, MJO

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PEM10-08

会場:A01

時間:5 月 28 日 09:45-10:00

インドネシア海大陸域の対流活動による大気上下結合
Vertical coupling by convections over the Indonesian maritime continent
山中 大学 1∗ ; 荻野 慎也 1 ; 橋口 浩之 2
YAMANAKA, Manabu D.1∗ ; OGINO, Shin-ya1 ; HASHIGUCHI, Hiroyuki2
1
1

海洋研究開発機構大気海洋相互作用研究分野／神戸大学大学院理学研究科, 2 京都大学生存圏研究所
DCOP, JAMSTEC / DP-GSS, Kobe U, 2 RISH, Kyoto U

海大陸およ周辺海洋上の観測から，(i) 地表日射強度、雲頂高度、成層圏重力波活動度が海大陸を中心とした赤道域で極大、(ii) 雲頂高度周波数スペクトル強度地理的分布における日・年周期成分の陸域卓越、 (iii) 雲頂高度・圏界面重力波に共通する周波数約-2 乗則、(iv) 雲頂高度・圏界面重力波に共通する水平波数-5/3 および-3 乗則（水平波長約 400 km
より高周波・低周波側）が示される。
地球の自転・公転に伴う日・年周期日射加熱の大気への強制には、昼夜・夏冬半球間連続変化（潮汐、天文学的モン
スーン・潮汐）、および海岸線周辺の「不連続」変化（海陸風、地理学的モンスーン）の 2 種がある。それらの全て（さらに地球の球面効果のよる日射の緯度変化による Hadley 循環も）が海大陸域では交錯し相互作用する。例えば、陸面の午前晴間により日射加熱の年周期が海風循環に強弱に反映され、また陸面の雲活動極大が日没に重なることから日傘効
果は実質的に抑制される。また、海陸風循環を構成する上伝・下伝重力波重畳のうちの上伝波が成層圏に浸透し、循環の上昇流部分（条件付不安定域）に集中する背の高い対流雲も成層圏（強い安定域）を叩いて重力波を生成する。

キーワード: インドネシア海大陸, 雲対流, 重力波, 日周期
Keywords: Indonesian maritime continent, cloud convection, gravity waves, diurnal cycle

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PEM10-09

会場:A01

時間:5 月 28 日 10:00-10:15

THE STUDY OF CLOUD AND RAINFALL FORMATIONS AT KOTOTABANG IN
SOME RANDOM CASESTHE STUDY OF CLOUD AND RAINFALL FORMATIONS AT KOTOTABANG IN
SOME RANDOM CASESJUAENI, Ina1∗ ; BAMBANG, Siswanto1 ; IIS, Sofiati1 ; DIDI, Satiadi1 ; YAMAMOTO, Mamoru2 ;HALIMURRAHMAN, Mukri1
JUAENI, Ina1∗ ; BAMBANG, Siswanto1 ; IIS, Sofiati1 ; DIDI, Satiadi1 ; YAMAMOTO, Mamoru2 ;HALIMURRAHMAN, Mukri1
11

National Institute of Aeronautics and Space (LAPAN), 2 RISH, Kyoto University
National Institute of Aeronautics and Space (LAPAN), 2 RISH, Kyoto University

Existing of complete equipment at Kototabang space observatory stations is possible to use to study in atmospheric process.
Equatorial Atmosphere Radar (EAR) gave three-dimensional wind speed data in horizontal wind (east-west and north-south
directions) and vertical wind (updraft and downdraft). Development of convective cells vertically or horizontally can be detailed
study with the availability of precipitation echo data from the X-band meteorological radar. EAR data with high resolution, about
8 minutes in time and 150 meters level resolution will contribute to study of the cloud formation and rainfall process. Rainfall
events at January 2008, May 2011 and November 2011 that was recorded by Optical Rain Gauge (ORG) which was not initialed
by vertical convection, or was not triggered by updraft previously is presumed that rainfall was from cloud that exist in mesoscale
area. The rainfall from these process will have high intensity and will happen longer compare to rainfall from clouds that formed
vertically above Kototabang. Rainfall from cloud under 2 km in high will create high intensity flow but in short duration.

キーワード: vertical wind, precipitation echo, rainfall, local scale, mesoscale
Keywords: vertical wind, precipitation echo, rainfall, local scale, mesoscale

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PEM10-10

会場:A01

時間:5 月 28 日 10:15-10:30

Solar Activity’s Role in El Nino Southern Oscillation (ENSO) and Indian Oceanic Dipole(IOD)
Solar Activity’s Role in El Nino Southern Oscillation (ENSO) and Indian Oceanic Dipole(IOD)
Mumtahana Farahhati1∗ ; Sulistiani Santi1 ; 山本 衛 2 ; Kesumaningrum Rasdewita1
MUMTAHANA, Farahhati1∗ ; SULISTIANI, Santi1 ; YAMAMOTO, Mamoru2 ; KESUMANINGRUM, Rasdewita1
1
1

Indonesian National Institute of Aeronautics and Space (LAPAN), 2 RISH, Kyoto University
Indonesian National Institute of Aeronautics and Space (LAPAN), 2 RISH, Kyoto University

ENSO (El Nino Southern Oscillation) and Indian Oceanic Dipole (IOD) are oceanic anomaly and atmospheric phenomenonin equatorial pacific and indian ocean causing global climate system variation. ENSO which is indicated by Southern Oscillation
Index (SOI) describes the air pressure between Darwin (Australia) and Tahiti (Southern Pacific Ocean). Meanwhile, Indian
Oceanic Dipole (IOD), shown by Dipole Mode Index (DMI), desribes the sea surface temperature difference between East region(on the West side of Sumatera) and West region (East side of Africa). Considering these events occur periodically at irregularinterval, it might be triggered by the 11-years of solar cycle as an energy source. In this case, the solar activity is represented by
the variability of the periodical Sunspot number (R). Changes in the rate of heating and the amount of solar energy package ispresumed to be the cause of the ENSO and IOD phenomenon. In this work, we use the data of Sunspot number (R), SOI, andDMI from 1870 to 2013. Derived from those data, spectral analysis of the output energy package has been conducted in order tostudy its correlation with periodicity of ENSO and IOD, and also the connection between those events.
キーワード: ENSO, IOD, DMI, Sunspot number, Solar energy
Keywords: ENSO, IOD, DMI, Sunspot number, Solar energy

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PEM10-11

会場:A01

時間:5 月 28 日 10:30-10:45

Climatology of Equatorial plasma bubbles observed from Equatorial Atmosphere Radar(EAR) - New Aspects
Climatology of Equatorial plasma bubbles observed from Equatorial Atmosphere Radar(EAR) - New Aspects
SUDARSANAM, Tulasiram1∗ ; AJITH, K k1 ; YAMAMOTO, Mamoru2 ; OTSUKA, Yuichi3 ; YOKOYAMA, Tatsuhiro4 ;TSUGAWA, Takuya4
SUDARSANAM, Tulasiram1∗ ; AJITH, K k1 ; YAMAMOTO, Mamoru2 ; OTSUKA, Yuichi3 ; YOKOYAMA, Tatsuhiro4 ;TSUGAWA, Takuya4
1
1

Indian Institute of Geomagnetism, 2 RISH, Kyoto University, Japan, 3 STEL, Nagoya University, Japan, 4 NICT, Tokyo, Japan
Indian Institute of Geomagnetism, 2 RISH, Kyoto University, Japan, 3 STEL, Nagoya University, Japan, 4 NICT, Tokyo, Japan

Using the fan sector backscatter maps of 47 MHz Equatorial Atmosphere Radar (EAR) at Kototabang, Indonesia, the spatial
and temporal evolution of equatorial plasma bubbles (EPBs) were examined to classify the evolutionary-type EPBs from thosewhich formed elsewhere and drifted into the field of view of radar. A total of 535 EPBs were observed during the low to moderate
solar activity years 2010?2012, out of which about 210 (˜39%) are of evolving type and the remaining 325 (˜61%) are drifting-in
EPBs. In general, both the evolving-type and drifting-in EPBs exhibit predominance during the post-sunset hours of equinoxes
and December solstice. Interestingly, a large number of EPBs were found to develop even a few minutes prior to the apex sunset
during equinoxes. Further, the occurrence of evolving?type EPBs exhibits a clear secondary peak around midnight (2300?0100
LT), primarily, due to higher rate of occurrence during the post-midnight hours of June solstices. A significant number (˜33%)
of post-midnight EPBs generated during June solstices did not exhibit any clear zonal drift, while about 14% of EPBs drifted
westward. Also, the westward drifting EPBs are confined only to June solstices. Further, to understand the rise velocity andgrowth rate of EPBs, the generation and subsequent development of plasma bubbles were consistently observed and its seasonaland diurnal variation will be presented.
キーワード: Equatorial Plasma Bubbles, Equatorial Atmosphere Radar, Electric Fields, Thermospheric Neutral Winds
Keywords: Equatorial Plasma Bubbles, Equatorial Atmosphere Radar, Electric Fields, Thermospheric Neutral Winds

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PEM10-12

会場:A01

時間:5 月 28 日 11:00-11:15

Spectral parameters estimation in precipitation using VHF atmospheric radars
Spectral parameters estimation in precipitation using VHF atmospheric radars
GAN, Tong1∗ ; YAMAMOTO, Masayuki2 ; OKAMOTO, Hajime3 ; HASHIGUCHI, Hiroyuki1 ; YAMAMOTO, Mamoru1
GAN, Tong1∗ ; YAMAMOTO, Masayuki2 ; OKAMOTO, Hajime3 ; HASHIGUCHI, Hiroyuki1 ; YAMAMOTO, Mamoru1
1

Research Institute for Sustainable Humanosphere (RISH), Kyoto University, 2 National Institute of Information and Communications Technology (NICT), 3 Research Institute for Applied Mechanics (RIAM), Kyushu University
1
Research Institute for Sustainable Humanosphere (RISH), Kyoto University, 2 National Institute of Information and Communications Technology (NICT), 3 Research Institute for Applied Mechanics (RIAM), Kyushu University

Quantitative measurement of spectral parameters (e.g., echo power, Doppler velocity and spectrum width) of the clear air echo
is indispensable for clarifying interactions between dynamical and microphysical processes of cloud and precipitation. Atmospheric radars using VHF band have the ability to detect clear air echoes and hydrometeor echoes simultaneously. In order tominimize the interference of the hydrometeor echoes on calculating the spectral parameters of the clear air echo, we proposed
two methods (top method and two-echo method).
The top method is used when raindrops or solid hydrometeors with small echo intensity exist. The top method sets an echo cut
level (ECL) from the peak level of the clear air echo. The ECL is used for separating the clear air echoes from the hydrometeor
echoes. The two-echo method is used when solid hydrometeors with large echo intensity exist. The two-echo method sets the
ECL from the minimum echo level between the peak level of the clear air echo and that of the hydrometeor echo. Because parts of
the Doppler spectrum points were not used for calculating the spectral parameters, we also proposed functions for correcting theunderestimation of echo power and spectrum width. Numerical simulations were carried out for evaluating the performance of
these two methods. From the simulation results, the optimum value of ECL is determined. Also, the simulation results indicatedthat the two methods can calculate the spectral parameters of the clear air echo with improved accuracy.
A case of simultaneous measurement by a 46.5-MHz atmospheric radar (MU radar) and a 1.3-GHz radar during a precipitation
event on 26 October 2009 is shown. The 1.3-GHz radar can measure reflectivity-weighted Doppler velocity relative to the ground(V air+Z ) and radar reflectivity factor (Z e ) of hydrometeors. By subtracting the Doppler velocity of the clear air echo (W ) measured by the MU radar from V air+Z , reflectivity-weighted Doppler velocity relative to the air (V Z ) was retrieved. Correlation
coefficient of Z e and V air+Z is 0.41. After removing the effect of W , correlation coefficient of Z e and V Z improves to 0.56.
The result indicates that W estimated using our method has sufficient accuracy. The result also indicates that the accurate W
measurement is useful for measuring hydrometer fall velocity.

キーワード: Atmospheric radar, Spectral parameters
Keywords: Atmospheric radar, Spectral parameters

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PEM10-13

会場:A01

時間:5 月 28 日 11:15-11:30

流星レーダーによる運動量フラックス測定および EMU によるビームペア法の期待
Measurement the momentum flux by using meteor radar and expecting beampair methodby EMU
新堀 淳樹 1∗ ; 津田 敏隆 1
SHINBORI, Atsuki1∗ ; TSUDA, Toshitaka1
1
1

松本直樹
Naoki Matsumoto
赤道域では、対流圏で励起された大気波動が上方伝搬する過程で、成層圏下部における準 2 年周期振動（Stratospheric Quasi-Biennial Oscillation：SQBO、平均周期は 26-28 ヶ月）、成層圏上部の半年周期振動（Semi-Annual Oscillation:SAO）および MLT 領域では成層圏と逆相の半年周期振動（MSAO）を駆動しているとされている。
本研究では、インドネシアで長期間運用している流星レーダー等のデータを用いて、赤道域の中間圏・下部
熱圏（Mesosphere-Lower Thermosphere: MLT）の高度 70-110 km における風速の周期振動ならびにそれら
不規則変動を研究する。特に MSAO の西向き風が 2-4 月（北半球の春分季）に 2 年乃至 3 年の不定期間隔で非常に大きくなる特異現象（Mesospheric Quasi-Biennial Enhancement:MQBO）に着目する。
M-QBE は秋分季（9-10 月）に発生せず、2-4 月頃に限定的に発生する。よって 1 年周期を律するプロセスが重畳することで、M-QBE が 2-4 月のみに発生すると考えられるが、そのメカニズムは未解明である。
本研究では 2 つのメカニズムを検討した。
（１）
南北風との相関赤道 MLT 域では南北風が夏半球から冬半球に風が吹くことから、１年周期（AO: Annual Oscillation）を示す。南北風と東西風とが結合する何らかのプロセスがあるならば、東西風に 1 年の周期性を生み出しうる。
実際の観測により東西風と南北風の長期変動を調べると、南北風 AO と東西風 SAO の長期変動の間に同様の変化傾向が見られた。これにより、南北風と東西風とが結合する何らかのプロセスが存在する可能性が示唆された。
（２）
大気重力波による M-QBE の駆動
M-QBE の西向き風増大と MLT 高度での大気重力波強度の増加が明らかに同期していたことが先行研究で報告されている（N.V. Rao et al., 2012）。したがって、大気重力波が M-QBE を駆動している可能性がある。
しかし、大気重力波と M-QBE の関係を明らかにするには、重力波の強度（風速分散）だけでは不十分で、波動にともなう運動量フラックスを測定する必要がある。
運動量フラックスは水平風と鉛直風の摂動分の分散（u w ）だが、2 次の微小量であることから観測は容易ではない。大型大気レーダーについて、beam pair 法を用いて u w を測定する画期的な方法が開発された（Vincent and Reid, 1983）。しかし、MU レーダー級の高性能大型レーダーは世界に数ヶ所しかないため、大気波動の効果の全球分布を知るには新たな計測手法の開発が求められた。
MU レーダーより小型簡便な流星レーダーを用いて beam pair 法を模擬し、u w を推定する手法が提案された（Hocking, 2005）。しかし、その測定精度に疑義が提示されている。
我々はインドネシアで同一仕様の 2 台の流星レーダーを同じ緯度（赤道上）で水平に約 4,000 km 離れた観測点で運用している。これら 2 台の流星レーダーによる u w の測定結果を統計的に比較し、観測手法の妥当性を検討した。
まず、約 4,000 km 離れた東西端のパプア（Biak）と西スマトラ（Koto Tabang）で 2011 年以降に断続的に行われた同時観測のデータを用い、Hocking 法で u w を解析し結果を比較する。運動量フラックスのよく一致している期間は、Koto Tabang および Biak の両者においてデータ利用率が高い期間に含まれている. このことから,Koto Tabang および Biak における観測によって, ノイズではない, 運動量フラックスの類似した変動を観測することができたといえる.
また、Koto Tabang では 10 年以上観測が継続されていることから、季節変動および年々変動、さらに高度層による差違を検討したところ、2 月と 8 月に運動量フラックスが大きな正の値を取り,6 月と 11 月に小さな値あるいは負の値をとる傾向が見受けられた。
M-SQO が大気波動の影響を受けているならば、u w にも半年周期が現れると期待されるが、本研究により、その予想と矛盾しない観測結果を得た。今後、大気重力波が MQBE を駆動している具体的なメカニズムを解明していくことが重要である。

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PEM10-13

会場:A01

時間:5 月 28 日 11:15-11:30

キーワード: 中間圏・下部熱圏, 運動量フラックス, 流星レーダー, 赤道 MU レーダー
Keywords: Mesosphere and Lower Thermosphere, momentum flux, meteor radar, Equatorial MU radar

2/2

PEM10-14

会場:A01

時間:5 月 28 日 11:30-12:00

An investigation of meteorological characteristics of ULF waves by ULTIMA global magnetometer observations
An investigation of meteorological characteristics of ULF waves by ULTIMA global magnetometer observations
CHI, Peter1∗ ; ULTIMA, Team1
CHI, Peter1∗ ; ULTIMA, Team1
1
1

Department of Earth Planetary and Space Sciences, UCLA
Department of Earth Planetary and Space Sciences, UCLA

The ultra-low-frequency (ULF) waves in the magnetosphere are phenomena resulting from the coupling between the solar
wind and the magnetosphere as well as processes internal to the magnetosphere, such as magnetic storms and substorms, whoseenergy comes ultimately from the Sun and the solar wind. The known characteristics of ULF waves are mostly obtained throughclimatological studies that can be made by using observations from a handful of ground-based magnetometers. These long-term
characteristics, however, can greatly deviate from the short-term variations of ULF waves. Behaving differently from one magnetic storm to another, the ULF waves are known to contribute to the acceleration, transport, and loss of electrons in the outerradiation belt.
This study examines the short-term variability of ULF waves observed by magnetometer arrays affiliated with the Ultra Large
Terrestrial International Magnetometer Array (ULTIMA) consortium. The global coverage of ULTIMA arrays allows us to examine the meteorological features of storm-time ULF waves in different corners of the magnetosphere. We find that the Pc 5
power can vary by more than 5 orders of magnitude between quiet times and storm times. The Pc 5 wave power at the timeof Dst maximum tends to peak at highest latitudes. In contrast, the Pc 5 wave power at Dst minimum is strongest at auroraland subauroral latitudes. Global magnetometer observations confirm that the enhancement in wave power can be highly variablein the inner magnetosphere, demonstrating the need for future geospace models to address the meteorological characteristics of
ULF waves.

キーワード: ground-based magnetometers, ULTIMA, ULF waves, magnetosphere, magnetic storms
Keywords: ground-based magnetometers, ULTIMA, ULF waves, magnetosphere, magnetic storms

1/1

PEM10-15

会場:A01

時間:5 月 28 日 12:00-12:15

Ground-based network observations of wind and temperature of the thermosphere using
five Fabry-Perot interferometers
Ground-based network observations of wind and temperature of the thermosphere using
five Fabry-Perot interferometers
塩川 和夫 1∗ ; 中村 義弘 1 ; 大山 伸一郎 1 ; 大塚 雄一 1
SHIOKAWA, Kazuo1∗ ; NAKAMURA, Yoshihiro1 ; OYAMA, Shin-ichiro1 ; OTSUKA, Yuichi1
11名古屋大学太陽地球環境研究所
Solar-Terrestrial Environment Laboratory, Nagoya University

It is well known that dynamic variation of Earth’s ionosphere affects human activities in space through interference on the
ground-satellite radio communications and degradation of GNSS positioning accuracy. The measurement of wind and temperature of the thermosphere is essentially important to understand dynamic variation of the ionosphere, because collision withneutral atmosphere is a dominant force to cause ionospheric plasma variation. High-resolution interferometry of airglow emissions using Fabry-Perot or Michelson interferometers is the unique technique to make remote sensing of the thermospheric wind
and temperature from the ground. Since 2011, the Solar-Terrestrial Environment Laboratory (STEL), Nagoya University havebeen operating five Fabry-Perot interferometers (FPIs) at Shigaraki (Japan, FP00), Tromsoe (Norway, FP01), Chiang Mai (Thailand, FP02), Kototabang (Indonesia, FP03), and Darwin (Australia, FP04). They measure thermospheric wind and temperature
through Doppler shift of the 630-nm airglow emission that has an emission layer at altitudes of 200-300 km. The use of 70mmdiameter etalons for FP02-FP04 makes the cost of the FPIs about three times lower than those with 116mm-diameter etalons
for FP00 and FP01. By revising procedure of fringe-center determination we obtained reliable temperature of the thermospherewith accuracies of 10-40 K using these small-etalon FPIs. In this presentation, we show recent results of thermospheric andionospheric dynamics obtained by these five FPIs.
キーワード: 地上多点観測, 地上観測ネットワーク, ファブリ・ペロー干渉計, 熱圏, 電離圏, 超高層大気
Keywords: ground-based observation, ground-based network, Fabry-Perot interferometer, thermosphere, ionosphere, upper atmosphere

1/1

PEM10-16

会場:A01

時間:5 月 28 日 12:15-12:30

ICSWSE/ MAGDAS Research Project-極域-磁気赤道域電磁結合系の探査
ICSWSE/ MAGDAS Research Project-Exploration of global electromagnetic couplingfrom polar to equatorial ionosphere吉川 顕正 1∗
YOSHIKAWA, Akimasa1∗
1
1

九州大学国際宇宙天気科学・教育センター
International Center for Space Weather Science and Education, Kyushu University

International Center for Space Weather Science and Education (ICSWSE) has developed a real time magnetic data acquisition
system (the MAGDAS project) for space environment monitoring around the world. The number of observational sites is increasing every year with the collaboration of MAGDAS host countries. Now at this time, the MAGDAS Project has installed 73
real time magnetometers ? so it is the largest magnetometer array in the world. Using this global network data, we are developing
many research projects as following
Applying equivalent current method to this network data, we analyze a global ionospheric current system from polar to equatorial ionosphere. Our results suggest that Dp2 type disturbances excited by solar wind variation, Pi2 type pulsations accompanied
by aouroral substorm onset process and Pc3 type pulsations accompanied by dayside cavity type oscillation show the same typeof global current system, which are produced by primary bipolar electric field accompanied by field-aligned current system andHall polarization electric field excited at the dawn-dusk conductivity terminator and at the magnetic dip equator. We will discuss how the electromagnetic coupling between polar and equatorial ionosphere is regulated by the formation of global Cowlingchannel in the ionosphere.
In this talk, we will introduce our some interesting results obtained from above research project.
Keywords: ICSWSE, MAGDAS, Electromagnetic Coupling Process, Cowling channel

1/1

PEM10-17

会場:A01

時間:5 月 28 日 12:30-12:45

IUGONET メタデータデータベース、及び解析ソフトを用いた超高層大気の長期変動研究
Long-term variation of upper atmosphere using the IUGONET metadata database anddata analysis software (UDAS)
新堀 淳樹 1∗ ; 八木 学 2 ; 田中 良昌 3 ; 梅村 宣生 3 ; 上野 悟 5 ; 小山 幸伸 6 ; 阿部 修司 7 ;谷田貝 亜紀代 4
SHINBORI, Atsuki1∗ ; YAGI, Manabu2 ; TANAKA, Yoshimasa3 ; UMEMURA, Norio3 ; UENO, Satoru5 ;KOYAMA, Yukinobu6 ; ABE, Shuji7 ; YATAGAI, Akiyo4
1

京都大学生存圏研究所, 2 東北大学惑星プラズマ・大気研究センター, 3 国立極地研究所, 4 名古屋大学太陽地球環境研究所, 5 京都大学天文台, 6 京都大学地磁気センター, 7 九州大学国際宇宙天気科学・教育センター
1
Research Institute for Sustainable Humanosphere (RISH), Kyoto University, 2 PPARC, Tohoku University, 3 NIPR, 4 STEL,
Nagoya University, 5 Observatory, Kyoto University, 6 WDC for Geomagnetism, Kyoto University, 7 ICSWSE, Kyushu University

Various kinds of atmospheric and ionospheric disturbances and long-term variation of the Earth’s upper atmosphere as seen
in several observation parameters (electric and magnetic fields, temperature, wind, density etc.) are caused by energy input
from solar radiation, solar wind, momenta and energies from the lower atmosphere via atmospheric waves, and chemical reaction. Such disturbance phenomena and long-term variation observed by various kinds of ground-based and satellite instruments
are the result of such complicated physical processes. Then, in order to investigate the mechanisms of the atmospheric disturbances and long-term variation of the upper atmosphere, researchers need to conduct comprehensive analyses with various
kinds of long-term observation data that have been continued by means of a global network of radars, magnetometers, opticalsensors, helioscopes, etc. The IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project initiated in2009 aims at the establishment of a cross-reference system for various kinds of ground-based observation data obtained fromdifferent techniques. The IUGONET participants consist of five universities/institutes: the National Institute of Polar Research(NIPR), Tohoku University, Nagoya University, Kyoto University, and Kyushu University. We have developed metadata database(MDB) and IUGONET data analysis software (UDAS) of ground-based observation data managed by these IUGONET universities/institutes with an international collaboration in order to promote a study on coupling process in the Sun-Earth system. The
MDB provides researchers in a wide range of disciplines with a seamless data environment to link databases spread across the
IUGONET universities/institutes. In particular, UDAS will be of great help in conducting integrated analyses and visualizationof various kinds of solar-terrestrial observation data to investigate the long-term variation in the upper atmosphere throughout the
Sun-Earth system. Then, the IUGONET products will greatly contribute to a study on coupling process in the Sun-Earth systemon the basis of integrated analysis of various kinds of long-term observation data covering a wide region from both the pole tothe equator. In this talk, we introduce a brief overview of the IUGONET project, and an application of the IUGONET products
to typical examples of upper atmospheric researches.
キーワード: 太陽活動, 超高層大気, IUGONET, メタデータデータベース, 解析ソフト
Keywords: Solar activity, Upper atmosphere, IUGONET, Metadata database, Data analysis software

1/1

PEM10-18

会場:A01

時間:5 月 28 日 14:15-14:30

GNSS network observations of medium-scale traveling ionospheric disturbances
GNSS network observations of medium-scale traveling ionospheric disturbances
大塚 雄一 1∗ ; 溝口 拓弥 1 ; 山脇 景太 1 ; 塩川 和夫 1 ; 齊藤 昭則 2 ; 津川 卓也 3 ; 西岡 未知 3
OTSUKA, Yuichi1∗ ; MIZOGUCHI, Takuya1 ; YAMAWAKI, Keita1 ; SHIOKAWA, Kazuo1 ; SAITO, Akinori2 ;TSUGAWA, Takuya3 ; NISHIOKA, Michi3
1

名古屋大学太陽地球環境研究所, 2 京都大学大学院理学研究科, 3 情報通信研究機構
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Graduate School of Science, Kyoto University, 3 National Institute of Information and Communications Technology

1

Recently, GNSS (Glbal Navigation satellite system) receiver is widely used to measure total electron content (TEC). Using densely spaced GPS receivers in Japan, Northern America, Europe, Alaska, and New Zealand, we have investigated twodimensional maps of TEC perturbations with a high spatial resolution to reveal the statistical characteristics of medium-scale
traveling ionospheric disturbances (MSTIDs). We found that MSTIDs can be categorized into three groups: daytime, nighttime,
and terminator MSTIDs. Daytime MSTIDs frequently occur in winter and tend to propagate equatorward and eastward in both
northern and southern hemispheres. We speculate that daytime MSTIDs are caused by atmospheric gravity waves in the thermosphere. Nighttime MSTIDs frequently occur in December and June solstices and propagate southwestward in the northernhemisphere and northwestward in the southern hemisphere. This propagation direction supports the notion that polarizationelectric fields could play an important role in generating nighttime MSTIDs. Terminator MSTIDs frequently occur in summer
and propagate eastward or north-northwestward. Comparing the MSTID occurrence rates at different longitudinal sectors, wehave found that occurrence rate of the nighttime MSTIDs is high around December solstice at European longitudinal sector andaround June solstice at Japan and American longitudinal sectors. From comparison with sporadic E activity, we can speculate that
activity Es layer in summer hemisphere control occurrence of the nighttime MSTIDs in both northern and southern hemispheres
through E and F region electrodynamical coupling. Longitudinal variation of the nighttime MSTIDs could be attributed to thatof the sporadic E activity.
キーワード: GNSS, ionosphere, GPS, MSTID, ionospheric disturbance
Keywords: GNSS, ionosphere, GPS, MSTID, ionospheric disturbance

1/1

PEM10-19

会場:A01

時間:5 月 28 日 14:30-14:45

Temporal change of the precise EIA asymmetry in Thailand-Indonesia sector observed bya beacon receiver network
Temporal change of the precise EIA asymmetry in Thailand-Indonesia sector observed bya beacon receiver network
WATTHANASANGMECHAI, Kornyanat1∗ ; YAMAMOTO, Mamoru1 ; SAITO, Akinori2 ; YOKOYAMA, Tatsuhiro3
WATTHANASANGMECHAI, Kornyanat1∗ ; YAMAMOTO, Mamoru1 ; SAITO, Akinori2 ; YOKOYAMA, Tatsuhiro3
1

Research Institute for Sustainable Humanosphere, Kyoto University, 2 Department of Geophysics, Graduate School of Science,
Kyoto University, 3 National Institute of Information and Communications Technology
1
Research Institute for Sustainable Humanosphere, Kyoto University, 2 Department of Geophysics, Graduate School of Science,
Kyoto University, 3 National Institute of Information and Communications Technology
To reveal a temporal change of the equatorial ionization anomaly (EIA) asymmetry, a multipoint satellite-ground beacon
experiment was conducted along the meridional plane of the Thailand-Indonesia sector. The observation includes one stationnear the magnetic equator and four stations at the off-equator latitudes. GRBR-TECs from 97 polar-orbit satellite passes in March2012 were analyzed in this study. Successive passes captured the rapid evolution of the EIA asymmetry especially during thegeomagnetic disturbances. The penetrating electric field during geomagnetic disturbed days is not the cause of an asymmetry.
Such rapid evolution of the EIA asymmetry was not seen during the nighttime when meridional wind mainly controlled theasymmetric structures. The EIA asymmetry had a quasi 3-day variation at 21 LT, which probably suggests the forcing fromthe lower atmosphere. Precise capturing of the crests’ locations and the asymmetry evolution enhances an understanding of thetemporal change of the EIA asymmetry in local scale. It leads to a future local modeling of the TEC prediction in Southeast Asia.
キーワード: EIA, asymmetry, geomagnetic disturbances, penetrating electric field, rapid evolution
Keywords: EIA, asymmetry, geomagnetic disturbances, penetrating electric field, rapid evolution

1/1

PEM10-20

会場:A01

時間:5 月 28 日 14:45-15:00

The Ionospheric Space Weather Mission of FORMOSAT-7/COSMIC-2
The Ionospheric Space Weather Mission of FORMOSAT-7/COSMIC-2
LIN, Charles1∗ ; RAJESH, P. K.1 ; CHEN, Chia-hung1 ; CHANG, Loren C.2 ; CHEN, Alfred B.3
LIN, Charles1∗ ; RAJESH, P. K.1 ; CHEN, Chia-hung1 ; CHANG, Loren C.2 ; CHEN, Alfred B.3
1

Department of Earth Science, National Cheng-Kung University, 2 Institute of Space Science, National Central University,
Chung-Li, Taiwan, 3 Institute of Space and Plasma Sciences, National Cheng-Kung University, Tainan, Taiwan
1
Department of Earth Science, National Cheng-Kung University, 2 Institute of Space Science, National Central University,
Chung-Li, Taiwan, 3 Institute of Space and Plasma Sciences, National Cheng-Kung University, Tainan, Taiwan
With the success of the satellite constellation performing radio occultation experiments of FORMOSAT-3/COSMIC (F3/C),
its follow-on mission, FORMOSAT-7/COSMIC-2 (F7/C2), has been planned and in progress of its construction. The follow-on
mission will have 12 microsatellites distributed at 24-degree and 72-degree inclination orbits taking radio occultation signals
from GPS, GLONASS and Galileo satellites. In addition to space-borne GNSS receivers, secondary payload opportunities forspace weather studies are available. The secondary payloads of the first six satellites of 24-degree inclination angle have beenplanned, and there is a possible opportunity for the second six satellites. In this study, we propose a multiple band imager forstudying the atmosphere-ionosphere perturbations and irregularities. As the radio occultation soundings provide global coverageof the ionosphere observations and give the large-scale view of the ionospheric space weather effects. The imagers proposed
here, on the other hand, provide opportunity to study the small-scale ionospheric space weather effects.
キーワード: Ionospheric Space Weather, FORMOSAT-3/COSMIC, FORMOSAT-7/COSMIC-2
Keywords: Ionospheric Space Weather, FORMOSAT-3/COSMIC, FORMOSAT-7/COSMIC-2

1/1

PEM10-21

会場:A01

時間:5 月 28 日 15:00-15:15

極域総合観測と GCM シミュレーションによる超高層大気研究
Studies of the polar upper atmosphere from comprehensive observations and GCM simulations
藤原 均 1∗ ; 野澤 悟徳 2 ; 小川 泰信 3 ; 片岡 龍峰 3 ; 三好 勉信 4 ; 陣 英克 5 ; 品川 裕之 5
FUJIWARA, Hitoshi1∗ ; NOZAWA, Satonori2 ; OGAWA, Yasunobu3 ; KATAOKA, Ryuho3 ; MIYOSHI, Yasunobu4 ;JIN, Hidekatsu5 ; SHINAGAWA, Hiroyuki51

成蹊大学 理工学部, 2 名古屋大学 太陽地球環境研究所, 3 国立極地研究所, 4 九州大学 大学院理学研究院, 5 情報通信研究機構
1
Faculty of Science and Technology, Seikei University, 2 Solar Terrestrial Environment Laboratory, Nagoya University, 3 National
Institute of Polar Research, 4 Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, 5 National Institute of Information and Communications Technology

The polar upper atmosphere is the window on near-Earth space. Since the energy from the solar wind is poured into thepolar upper atmosphere through near-Earth space, we can obtain information of the outer world around the Earth from someobservations in the polar region. For example, the auroral phenomena are the typical ones which visualize the variations of thespace environments. The polar upper atmosphere is also the mirror for the climate change. Global cooling goes on in the upper
atmosphere while global warming is the advancing problem in the troposphere. Since the effects of the global warming propagate
upward with increasing their amplitudes with height, some people have tried to understand the global warming or climate change
from the signals in the upper atmosphere. In particular, remarkable phenomena, such as the noctilucent cloud, have appeared in
the polar upper atmosphere due to the changes in the troposphere. Furthermore, recent studies have clarified the effects of thesudden stratospheric warming (SSW) on temperature and wind variations in the mesosphere, thermosphere, and ionosphere. We
overview the relationships between external forcing from above and below and variations of the polar upper atmosphere. Then,the recent progress of our understandings from comprehensive observations and GCM simulations are shown. The future targets
in our research project will be also shown in this presentation.
キーワード: 熱圏, 電離圏, 中間圏, EISCAT, GCM, ナトリウムライダー
Keywords: thermosphere, ionosphere, mesosphere, EISCAT, GCM, Na lidar

1/1

PEM10-22

会場:A01

時間:5 月 28 日 15:15-15:45

EISCAT 3D Capabilities and Status
EISCAT 3D Capabilities and Status
HEINSELMAN, Craig1∗
HEINSELMAN, Craig1∗
1
1

EISCAT Scientific Association
EISCAT Scientific Association

The EISCAT Scientific Association has operated incoherent scatter radars in northern Norway, Sweden, and Finland for overthree solar cycles. At present, the EISCAT Associate nations include China, Finland, Japan, Norway, Sweden, and the United
Kingdom. EISCAT radars have provided new insights into a number of Geospace-related topics by directly measuring theinfluences of auroral particles on the ionosphere as well as the neutral atmosphere. While many discoveries have been made,there remains a good deal of uncertainty concerning the detailed aspects of the influences, especially at smaller spatial scales andshorter time scales. The EISCAT 3D project was initiated to address some of these issues. An extensive science case for the new
instrument is described in the document found at https://www.eiscat3d.se/content/deliverable-36-final-version-eiscat3d-sciencecase .
EISCAT 3D has new completed both a Design Study and a Preparatory Phase, both funded by the European Commission.
The funding for construction of the system is presently being pursued. In addition to describing the system and some of the new
Geospace research that it will enable, this presentation will describe the present state of this funding effort.

キーワード: Ionosphere, Aurora, Radar
Keywords: Ionosphere, Aurora, Radar

1/1

PEM10-23

会場:A01

時間:5 月 28 日 15:45-16:00

EISCAT 3D による北極域大気およびジオスペース研究の新展開 −日本の貢献−
A new perspective on atmospheric and geospace science in the Arctic with EISCAT 3D Japan’s contributions 宮岡 宏 1∗ ; 野澤 悟徳 2 ; 小川 泰信 1 ; 大山 伸一郎 2 ; 中村 卓司 1 ; 藤井 良一 2 ;ヘインゼルマン クレイグ 3
MIYAOKA, Hiroshi1∗ ; NOZAWA, Satonori2 ; OGAWA, Yasunobu1 ; OYAMA, Shin-ichiro2 ; NAKAMURA, Takuji1 ;FUJII, Ryoichi2 ; HEINSELMAN, Craig3
1

国立極地研究所, 2 名古屋大学太陽地球環境研究所, 3 EISCAT 科学協会
National Institute of Polar Research, 2 Solar-Terrestrial Environment Laboratory, Nagoya University, 3 EISCAT Scientific Association

1

The European Incoherent Scatter(EISCAT) radar system in northern Feno-Scandinavia and Svalbard have been playing a pivotal role in advancing cutting edge sciences in various area including atmospheric, ionospheric and geospace studies, space
weather and global change. Affiliated in the EISCAT scientific association in 1996, Japanese science community has jointly
contributed to understanding of the magnetosphere-ionosphere-thermosphere coupling processes using the coordinated groundbased and rocket/satellite simultaneous observations with EISCAT radars.
EISCAT 3D is the major upgrade of the existing EISCAT mainlamd radars, with a multi-static phased array system composedof one central active (transmit-receive) site and 4 receive-only sites to provide us 50-100 times higher temporal resolution thanthe present system. The core site will transmit signals at 233MHz with about 10MW power, and all five sites will have sensitive
receivers to detect the returned signal using phased-array antenna with10,000 elements.
The construction of EISCAT 3D is planned to implement by 4-staged approach, starting from the core site with half transmitting power about 5MW and 2 receiving sites at Bergfors (Sweden) and Karesuvanto (Finland) at the 1st stage. The transmitter
will be upgraded to full-scale of 10MW at 2nd stage, then another receiving sites will be constructed at Andoya (Norway) andJokkmokk (Sweden) at the 3rd and 4th stages.
In parallel to developing design studies and the science case for EISCAT 3D, associate member countries have been making
best efforts to secure their national fundings. The EISCAT 3D program in Japan was applied to the call for Master Plan 2014 asa part of ’Study of Coupling Processes in the Solar-Terrestrial System’ (PI: Prof. Tsuda, Kyoto Univ.). After granted as one of 27
high-priority programs of Master Plan 2014 and 10 new Roadmap 2014 programs, National Institute of Polar Research has madea funding proposal to MEXT for EISCAT 3D, collaborating with Solar-Terrestrial Environment Laboratory, Nagoya University.
In this paper, we will overview the current status of Japan’s national contribution to the EISCAT 3D program as well as thescientific targets which are focussed by the Japanese science community.

キーワード: 非干渉散乱, レーダー, 北極圏, ジオスペース
Keywords: incoherent scatter, radar, arctic, geospace

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PEM10-24

会場:A01

時間:5 月 28 日 16:15-16:45

Advancing Research of Coupling between Geospace Environment and Atmosphere by
the EISCAT 3D Incoherent Scatter Radar
Advancing Research of Coupling between Geospace Environment and Atmosphere by
the EISCAT 3D Incoherent Scatter Radar
TURUNEN, Esa1∗
TURUNEN, Esa1∗
1
1

SGO, University of Oulu, 2 STEL, Nagoya University
SGO, University of Oulu, 2 STEL, Nagoya University

Incoherent scatter (IS) the most advanced radio method to remotely sense the upper atmosphere and the near-Earth space.
Since 1981 the EISCAT IS radars in Northern Fennoscandia provide unique measurements from the upper atmosphere in the polar regions, where forcing both by solar activity and lower atmospheric phenomena are present. The facilities are maintained by
the EISCAT Scientific Association, an international research organisation registered in Kiruna, Sweden. The mainland EISCAT
system consists of high-power VHF (224 MHz) and UHF (930 MHz) radars and the ionospheric modification facility (3.85 8 MHz) in Tromso (Norway), as well as radar receiving sites in Kiruna (Sweden) and in Sodankyla (Finland). In addition, the
EISCAT Svalbard Radar (ESR) operates at 500 MHz in the polar region.
The new EISCAT 3D phased-array facility, to be built in near future, will be a 3-dimensionally imaging radar, distributed in
Norway, Sweden, and Finland. It will surpass all the current IS radars of the world in technology and act as a pathfinder for othertypes of radar facilities worldwide. EISCAT 3D will make continuous measurements of the geospace environment and its coupling to the Earth’s atmosphere in the polar region and at the southern edge of the polar vortex for the next 30 years. Planning of
the new IS radar facility started with the EU-funded Design Study (2005-2009). In December 2008, the European Strategy Forumon Research Infrastructures, ESFRI, selected EISCAT 3D to the Roadmap for Large-Scale European Research Infrastructures.
The preparation continued in the EU FP7 Preparatory Phase project (2010 - 2014). Currently EISCAT Scientific Association has
applied EU financing in order to study together with manufacturers, the industrial implementation of the technical solution for
EISCAT 3D. Construction of EISCAT 3D can start as soon as the international financing for EISCAT 3D will be in place.
The EISCAT 3D will be realised as a multi-sited infrastructure using phased-array antennas and a key aspect is the use ofadvanced software and data processing techniques. The science case of EISCAT 3D includes studies of atmospheric physics andglobal change, space and plasma physics, solar system research, space weather and other service applications, development of
new radar techniques, and methods for coding and analysis. Here we give a summary of the planned characteristics and science
goals of the proposed international research infrastructure, review the current status of preparations towards realizing EISCAT
3D, and give a more detailed perspective to one of the key science themes of EISCAT 3D: Coupling between geospace environment and atmosphere of Earth during high energy particle precipitation into the atmosphere.
キーワード: incoherent scatter, geospace environment, atmosphere, dynamic coupling, high-energy particle precipitation, chemistry of atmosphere
Keywords: incoherent scatter, geospace environment, atmosphere, dynamic coupling, high-energy particle precipitation, chemistry of atmosphere

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PEM10-25

会場:A01

時間:5 月 28 日 16:45-17:00

Meteor observations with large aperture radars - an outlook for EISCAT 3D and EMU
Meteor observations with large aperture radars - an outlook for EISCAT 3D and EMU
KERO, Johan1∗ ; NAKAMURA, Takuji2 ; PELLINEN-WANNBERG, Asta3 ; FUJIWARA, Yasunori4 ; ABE, Shinsuke5 ;WATANABE, Jun-ichi6
KERO, Johan1∗ ; NAKAMURA, Takuji2 ; PELLINEN-WANNBERG, Asta3 ; FUJIWARA, Yasunori4 ; ABE, Shinsuke5 ;WATANABE, Jun-ichi6
1

Swedish Institute of Space Physics, 2 National Institute of Polar Research, 3 Umea University, 4 SOKENDAI, 5 Nihon University,
National Astronomical Observatory of Japan1
Swedish Institute of Space Physics, 2 National Institute of Polar Research, 3 Umea University, 4 SOKENDAI, 5 Nihon University,
6
National Astronomical Observatory of Japan
6

Meteoroids deliver various elements into the atmosphere and the meteoric dust particles are of great importance in the terrestrial atmosphere. They act as nuclei for condensation and clouds and affect various atmospheric phenomena in both physicaland chemical aspects. We present highlights and experiences from meteor head echo observations conducted with the tristatic
EISCAT radar and the interferometric middle and upper atmosphere (MU) radar of Kyoto University at Shigaraki, Japan. The
results are used in the context of providing an outlook for meteor observations with EISCAT 3D and the Equatorial MU radar(EMU).
MU radar observations demonstrate that meteors originating from any direction down to a few degrees above the local horizon
can be accurately detected with an interferometric phased array. The location of EMU at the equator therefore enables coverageof a large fraction of the celestial sphere during each diurnal cycle. A meteor observation programme at EMU operating inparallel with atmospheric measurements would give excellent overall coverage of the meteor activity and transient outbursts.
We present a coverage estimation based on observations conducted with MU and show how an observation programme at EMU
would complement observations with radar facilities at other latitudes.
EISCAT 3D will consist of multiple phased arrays located in northern Fenno-Scandinavia. The multi station- and interferometric design offers extended possibilities to investigate the fine details of meteoroid-atmosphere interaction processes, as wellas significantly increased accuracy of meteoroid orbit determination capabilities compared to currently available radar facilities.

キーワード: meteor, upper atmosphere, high power large aperture radar
Keywords: meteor, upper atmosphere, high power large aperture radar

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PEM10-26

会場:A01

時間:5 月 28 日 17:00-17:15

Study on ion upflow based on high latitude IS radars and future EISCAT 3D
Study on ion upflow based on high latitude IS radars and future EISCAT 3D
小川 泰信 1∗
OGAWA, Yasunobu1∗
1
1

国立極地研究所
National Institute of Polar Research

An important phenomenon of magnetosphere-ionosphere coupling is the formation of upwelling ions in the topside polar
ionosphere. These upflows can be a significant loss of atmospheric gasses into interplanetary space and a significant source ofmagnetospheric plasma, which may also affect the dynamics of the magnetosphere. Key processes for upward ion flows in thetopside ionosphere are suggested to be frictional heating, ambipolar diffusion driven by a heated electron gas, and transverse
ion acceleration produced by plasma waves. It is critical to determine the relative importance of the different mechanisms inoperation and to understand the 3D distribution and composition of the upflowing ions and neutrals. Moreover, there are severaltransitions of upflowing ions, for examples, from chemical to diffusion dominance at 500-800 km altitude, from subsonic tosupersonic flow at 1000-2000 km altitude, and from collisional to collisionless region at 1500-2500 km altitude.
The ion upflows have been investigated with incoherent scatter (IS) radars at high latitude. Future EISCAT 3D is one of themost suitable measurements to investigate such transitions because of its wider height coverage (up to about 2000 km) along thefield line. EISCAT 3D will have more transmitter power density and higher sensitivity than those of the current IS radars at highlatitude, and will give information of accurate thermal ion velocity, upward flux, and ion composition (O+, H+, and hopefullyNO+). A combination of the EISCAT 3D, ground-based optical instruments, and in-situ measurements is definitely essential tosolve several key questions of ion upflow and outflow study. In this paper, we show potential investigations of ion upflow andoutflow using the EISCAT 3D, and also discuss a desirable combination of the EISCAT 3D and its related observations for theion upflow and outflow study.
Keywords: EISCAT, incoherent scatter, EISCAT 3D, upper atmosphere

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PEM10-27

会場:A01

時間:5 月 28 日 17:15-17:30

人工衛星-地上観測による脈動オーロラの総合観測
Comprehensive observations on the pulsating aurora from satellite and ground-observations
三好 由純 1∗ ; 大山 伸一郎 1 ; 齊藤 慎司 1 ; 栗田 怜 1 ; 藤原 均 2 ; 片岡 龍峰 3 ; 海老原 祐輔 4 ;Kletzing Craig5 ; Reeves Geoff6 ; Santolik Ondrej7 ; Clilverd Mark8 ; Rodger Craig9 ; Turunen Esa10 ;土屋 史紀 11MIYOSHI, Yoshizumi1∗ ; OYAMA, Shin-ichiro1 ; SAITO, Shinji1 ; KURITA, Satoshi1 ; FUJIWARA, Hitoshi2 ;KATAOKA, Ryuho3 ; EBIHARA, Yusuke4 ; KLETZING, Craig5 ; REEVES, Geoff6 ; SANTOLIK, Ondrej7 ;CLILVERD, Mark8 ; RODGER, Craig9 ; TURUNEN, Esa10 ; TSUCHIYA, Fuminori11
1

名古屋大学太陽地球環境研究所, 2 成蹊大学, 3 国立極地研究所, 4 京都大学生存圏研究所, 5 アイオワ大学, 6 ロスアラモス
国立研究所, 7 Charles University in Prague, Czech Rep., 8 British Antarctic Survey, UK, 9 University of Otago, NZ, 10 Sodankyla
Geophysical Observatory, University of Oulu, Finland, 11 東北大学大学院理学研究科惑星プラズマ・大気研究センター
1
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Seikei University, 3 National Institute of Polar Research, 4 RISH,
Kyoto University, 5 University of Iowa, USA, 6 Los Alamos National Laboratory, USA, 7 Charles University in Prague, Czech
Rep., 8 British Antarctic Survey, UK, 9 University of Otago, NZ, 10 Sodankyla Geophysical Observatory, University of Oulu, Finland, 11 PPARC, Tohoku University

The pulsating aurora are caused by intermittent precipitations of tens keV electrons. The modulation for the pitch angle scattering take place at the magnetosphere via whistler mode wave-particle interactions. Usually, it is not possible to detect theelectron flux modulation at the magnetosphere because of the small loss cone angle. On the other hand, an integration of several
ground instruments provides the data for precipitating electrons. Here, we report an ideal observation for the pulsating aurora inNovember 2012. During the period,the pulsating aurora are observed at Tromso, Norway. The VHF radar obtained the heightresolved electron density profile during the period, which can be used to estimate the electron energy spectrum. As a result of
the EISCAT observations, we identify at least 200 keV electrons precipitate simultaneously associated with the pulsating aurora.
The riometer and subionospheric radio wave networks support this observation, and the radio wave network identified that theenergetic electron precipitation occurred from 01 MLT to 07 MLT. During this period, the footprint of the Van Allen Probe-A
satellite was very close to Tromso and the satellite observed rising tone emissions of the lower-band chorus (LBC) waves near
the equatorial plane. Using the satellite observed LBC and trapped electrons as an initial condition, we conducted a computer
simulation of the wave-particle interactions. The simulation showed simultaneous precipitation of electrons at both tens of keV
and a few hundred keV. And the simulated energy spectrum is consistent with that derived from the EISCAT observation. Froma comparison between the simulation and the observations, we specified the strong diffusion at ˜100 keV, and the propagating
whistler mode waves cause further precipitation at ˜200 keV. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora.
キーワード: 脈動オーロラ, EISCAT, 高エネルギー粒子降下Keywords: pulsating aurora, EISCAT, high energy electron precipiation

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PEM10-28

会場:A01

時間:5 月 28 日 17:30-17:45

トロムソにおけるナトリウムライダーを中心に用いた上部中間圏・下部熱圏変動の研究
Study of the upper mesosphere and the lower thermosphere by using the sodium LIDAR
at Tromsoe
野澤 悟徳 1∗ ; 津田 卓雄 2 ; 藤原 均 3 ; 小川 泰信 4 ; 川原 琢也 5 ; 斎藤 徳人 6 ; 和田 智之 6 ; 堤 雅基 4 ;鈴木 臣 1 ; 川端 哲也 1 ; 高橋 透 1 ; 日比野 辰哉 1 ; 滝田 真太郎 1 ; 安里 早稀 1 ; ホール クリス 7 ;ブレッケ アスゲイル 8
NOZAWA, Satonori1∗ ; TSUDA, Takuo2 ; FUJIWARA, Hitoshi3 ; OGAWA, Yasunobu4 ; KAWAHARA, Takuya5 ;SAITO, Norihito6 ; WADA, Satoshi6 ; TSUTSUMI, Masaki4 ; SUZUKI, Shin1 ; KAWABATA, Tetsuya1 ;TAKAHASHI, Toru1 ; HIBINO, Tatsuya1 ; TAKITA, Shintaro1 ; ASATO, Saki1 ; HALL, Chris7 ;BREKKE, Asgeir81名古屋大学太陽地球環境研究所, 2 電気通信大学, 3 成蹊大学理工学部, 4 国立極地研究所, 5 信州大学工学部, 6 理化学研
究所光量子工学研究領域, 7 トロムソ大学 TGO, 8 トロムソ大学理学部
1
STEL, Nagoya University, 2 The University of Electro-Communications, 3 Faculty of Science and Technology, Seikei University,
4
National Institute of Polar Research, 5 Faculty of Engineering, Shinshu University, 6 Advanced Photonics Technology Development Group, RIKEN, 7 Tromso Geophysical Observatory, The Arctic University of Tromsoe, 8 Faculty of Science, The Arctic
University of Tromsoe

We will overview latest results obtained with the sodium LIDAR at Tromsoe (69.6N, 19.2E) in northern Scandinavia. The
sodium LIDAR at Tromsoe has been operated since October 2010 for five winter seasons (October-March). About 2800 hours
of neutral temperature and sodium density data, and about 1800 hours of wind data between 80 and 110 km are obtained. Byutilizing the datasets, we have studied several phenomena occurring in the polar upper mesosphere/lower thermosphere. We
will present results about (1) altitude variations of the semidiurnal tide, (2) sporadic sodium layer, (3) response of the upper
mesosphere/lower thermosphere to sudden stratospheric warmings (SSW), (4) comparison of the neutral temperature and the ion
temperature, and (5) probablity of instabilities.
We have investigated altitude variations of the semidiurnal tide using wind and temperature data, whose temporal length islonger than or equal to 12 hours, obtained by the sodium LIDAR for 62 nights. There appear two typical altitude profiles of theamplitude. We will discuss its causes. Sporadic sodium layer (SSL) is a thin (about 1 km) and dense sodium layer in the normal
sodium layer with a wide horizontal extent (typically, about 300 km or so). The generation mechanisms are not well understood,in particular, in the polar upper mesosphere. We have made a case study, and will present the results. Sudden StratosphericWarming (SSW) is a large disturbance phenomenon occurring in the stratosphere in winter due to breaking of planetary waves.
We have analyzed variations of the temperature and wind above Tromsoe during the 2012 SSW interval using sodium LIDAR
data, meteor radar data, and EISCAT radar data in the upper stratosphere, mesosphere, and lower thermosphere. We will present
those results and discuss differences of timing of the changes at different altitudes. Over five winter observational seasons between 2010 and 2015, simultaneous observations of the sodium LIDAR and the EISCAT UHF radar at altitudes between 100
and 110 km were conducted for 43 nights (about 250 hours). We have compared the neutral temperature obtained by the sodium
LIDAR with the ion temperature by the EISCAT UHF radar between 100 and 110 km. We will present the comparison results
and also discuss contributions of the Joule heating. By using temperature and wind data, we have investigated probability of theconvective and dynamical instabilities in the polar upper mesosphere and lower thermosphere. We will present the results andcompare them with published results at middle latitudes. We will also discuss expected improvements by the EISCAT 3D tothese kinds of researches.

キーワード: ナトリウムライダー, 北極域上部中間圏・下部熱圏, EISCAT レーダー, 流星レーダー, トロムソ
Keywords: Sodium LIDAR, polar upper mesosphere/lower thermosphere, EISCAT radar, meteor radar, Tromsoe

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PEM10-29

会場:A01

時間:5 月 28 日 17:45-18:00

Height-dependent ionospheric variations in the vicinity of nightside poleward expanding
aurora after substorm onset
Height-dependent ionospheric variations in the vicinity of nightside poleward expanding
aurora after substorm onset
大山 伸一郎 1∗ ; 三好 由純 1 ; 塩川 和夫 1 ; 栗原 純一 2 ; 津田 卓雄 3 ; Brenton J. Watkins4
OYAMA, Shin-ichiro1∗ ; MIYOSHI, Yoshizumi1 ; SHIOKAWA, Kazuo1 ; KURIHARA, Junichi2 ; TSUDA, Takuo3 ;WATKINS, Brenton J.4
1

名古屋大学太陽地球環境研究所, 2 北海道大学大学院理学院宇宙理学専攻, 3 電気通信大学情報理工学部, 4 GeophysicalInstitute, University of Alaska Fairbanks
1
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Department of Cosmosciences, Graduate School of Science,
Hokkaido University, 3 Department of Information and Communication Engineering, University of Electro-Communications,4Geophysical Institute, University of Alaska Fairbanks

Polar ionospheric responses to a substorm onset are among the most widely studied phenomena of space physics. An initialbrightening appears at the very first phase of the substorm and tends to take place at magnetic midnight or slightly earlier in theauroral oval or at its lower latitudes. After initial brightening of the aurora that is located at the most poleward side of the oval,near the polar cap boundary, the oval expands poleward and then a westward traveling surge forms.
Auroral morphology and some ionospheric parameters responding to substorm onsets have been studied with various instruments, such as the Super Dual Auroral Radar Network radars, incoherent scatter radars, and satellites, generally focusing on
spatiotemporal developments of the auroral forms, the ionospheric plasma convection, and the auroral particle spectra. By contrast, this paper addresses other ionospheric parameters such as the electron density in the F region, electron and ion temperatures,and the relationships of the large-scale time-dependent aurora and electric-field structures. This approach is important for achieving further understanding of the energy budget in the magnetosphere-ionosphere-thermosphere coupled system. The analysis isdirected to the height dependency of the ionospheric variations, because the ionization rate and the collision frequency significantly change with heights.
Statistical analysis was made of data from the European Incoherent Scatter UHF radar at Tromsφ, Norway, and International
Monitor for Auroral Geomagnetic Effects magnetometer for finding common features in electron density, ion and electron temperatures and relating these to currents and associated heating. This paper particularly focused on the height dependencies.
Results show clear evidences of large electric field with corresponding frictional heating and Pedersen currents located just outside the front of the poleward expanding aurora, which typically appeared at the eastside of westward traveling surge. At the
beginning of the substorm recovery phase, the ionospheric density had a large peak in the E region and a smaller peak in the
F region. This structure was named as C form in this paper based on its shape in the altitude-time plot. The lower altitudedensity maximum is associated with hard auroral electron precipitation probably during pulsating aurora. We attribute the upper
F region density maximum to local ionization by lower energy particle precipitation and/or long-lived plasma that is convectedhorizontally into the overhead measurement volume from the dayside hemisphere.

キーワード: 電離圏, サブストーム, 極域, 非干渉散乱レーダー, オーロラ, ジュール加熱
Keywords: ionosphere, substorm, polar region, incoherent scatter radar, aurora, Joule heating

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