Commission G: Ionospheric Radio and Propagation (November 2010 – October 2013)
Edited by Mamoru Yamamoto
G1. Ionospheric irregularities
G1.1 Equatorial Spread F and Plasma Bubble
Simultaneous observations at Darwin of equatorial bubbles by ionosonde-based range/time displays
and airglow i maging to explain satellite traces of the ionogram (Lynn et al., 2011; 2013). Post-midnight
F-region field-aligned irregularities were investigated over Indonesia during solar minimum using a VHF
radar [Otsuka et al., 2012, 2013; Nishioka et al., 2012].
The so-called large scale wave structure (LSWS) at the base of F-layer is the earliest manifestation ofseed perturbation for the Rayleigh-Taylor (R-T) instability. It has been found to play deterministic role on
the development of equatorial plasma bubbles (EPBs) [Tsunoda et al., 2011]. Except for a few case studies,
a comprehensive investigation has not been conducted to determine the characteristics of LSWS. One
reason is that it is not straightforward with existing sensors to detect LSWS, particularly, in the spatial
domain. In this scenario, a comprehensive study was carried out, for the first time, on the spatial andtemporal characteristics of LSWS. Observations were made over the African and Southeast Asian sectors
during the year 2011. The observations confirm the findings from case studies, that these wave structures
can occur a few degrees west of E-region sunset terminator, and can grow significantly in amplitude atlongitudes east of sunset terminator [Sudarsanam et al., 2012; Thampi et al., 2012]. With the use ofadditional stations that are located on either side of dip equator, the phase fronts of these spatial structuresare shown to be aligned with geomagnetic field lines over a wide latitudinal belt of 500 - 600 km centeredon dip equator. The zonal wavelengths of these structures are found to vary from 100 to 700 km which isconsistent with the earlier reports. Tsunoda et al. [2013] showed relationship between multi-trace ofionograms is related to the LSWS. Recently there is a statistical finding that EPBs are consistently
observed when the amplitudes of LSWS are grown to sufficient strengths. These results provide better
insights on the underlying physical processes involved in excitation of LSWS in terms of important roles
being played by the E-region electrical loading and the polarization electric fields that are induced via
spatially varying dynamo current due to neutral wind perturbations associated with Atmospheric Gravity
Waves (AGWs).
The research project “Research Enhancement and System Establishment for Space Weather inIndonesia” is conducted during FY 2010-2012 under the framework of “Strategic Funds for the Promotionof Science and Technology” by MEXT (operation by Japan Science and Technology Agency (JST)). Thisis a joint project with RISH, Solar-Terrestrial Environmental Laboratory (STEL), Nagoya University, andNational Insititute for Information and Communications Technology (NICT). The counterpart in Indonesia
is LAPAN. Space weather is a program to observe, assess, and forecast the space environment, andregional observations and studies of the ionosphere are very important. Experiments for the project is not
limited in Indonesia, but spread over southeast Asian countries. RISH and LAPAN started the EAR
long-duration observation of the equatorial Spread-F (ESF) since July 2010 and archived huge amount ofdata for ESF occurrence and their spatial-time structures. They also expand observation network ofdual-band satellite beacon receivers for the study of ionospheric structures. STEL started the Fabry-Perot
interferometry experiment at the EAR site and Chiang Mai (Thailand) to measure thermospheric winds at
the geomagnetically conjugate points. NICT keeps operation of SEALION ionosonde network, andcollecting GPS-TEC data from the region of southeast Asia.
G2. Ionospheric DisturbanceG2.1 Ionospheric Storm
Sai et al. [2013] investigated the background magnetic field dependence of the saturated state of amagnetorotational instability (MRI) in an accretion disk by performing three-dimensional
magnetohydrodynamic simulations. We assume an unstratified disk by employing the local shearing box
approximation. Three different uniform background magnetic field configurations are treated for a wide1

range of field intensities. These simulations indicate that the time variations of the turbulent stress and themagnetic energy are altered by the presence of a poloidal component of the background field. We find thatthe saturation amplitude of the turbulent stress and the magnetic energy are determined by both thepoloidal and azimuthal components of the field. In particular, when the poloidal component has the same
intensity, the obtained turbulent stress for β y0 200 becomes smaller than those for a purely poloidal fieldcase. Despite the fact that the background field affects the MRI turbulence, the correlation between theobtained turbulent stress and the magnetic energy in the nonlinear stage is independent of the field
topology. Our results indicate that the saturated turbulent stress has a stronger correlation with the powerof the perturbed component of the magnetic field than with the power of the total magnetic field. These
results suggest that both the intensity and the direction of the background magnetic field significantly
affect the turbulent motion of the MRI in accretion disks.
By a series of self-consistent electron hybrid code simulations, Katoh and Omura [2013] studied theeffect of the background magnetic field inhomogeneity on the generation process of whistler-mode chorus
emissions. Chorus with rising tones are generated through nonlinear wave-particle interactions occurringaround the magnetic equator. The mirror force plays an important role in the nonlinear interactions, and thespatial inhomogeneity of the background magnetic field is a key parameter of the chorus generation
process. We have conducted numerical experiments with different spatial inhomogeneities to understandproperties of the chorus generation process. We assume the same initial condition of energetic electrons at
the magnetic equator in all simulation runs. The simulation results reveal that the spectral characteristics ofchorus significantly vary depending on the magnetic field inhomogeneity. Whistler-mode emissions are
generated and propagate away from the equator in all simulation runs, but distinct chorus elements withrising tones are only reproduced in the cases of small inhomogeneities. In the simulation that had thesmallest inhomogeneity, we find excitation of broadband hiss-like emission (BHE) whose amplitudes arecomparable to discrete chorus elements found in other simulation runs. The BHE consists of many wave
elements with rising tones nonlinearly triggered in the region close to the magnetic equator. We show thatthe small spatial inhomogeneity of the background magnetic field results in the small threshold amplitude
for the nonlinear wave growth and allows the triggering process of rising tone elements to emerge easily inthe equatorial region of the magnetosphere.
A campaign observation of auroras and VLF/ELF waves was carried out from January 28 to February
5, 2014 at Poker Flat, Alaska, in collaboration with an auroral rocket launch. Dual cameras were used todetermine the height of auroras. A loop antenna with a 20kHz-sampling portable recorder was tested for
VLF/ELF wave measurement at remote site without power line.
G2.2 Traveling Ionospheric DisturbancesFirst satellite-imaging observation of medium-scale traveling ionospheric disturbances were made by
FORMOSAT-2/ISUAL [Adachi et al., 2011]. Interesting disappearance of equatorial plasma bubble wasobserved after interaction with mid-latitude medium-scale traveling ionospheric disturbance [Otsuka et al.,2012]. Observation of nighttime medium-scale traveling ionospheric disturbances in 630-nm airglow
images over 7 years in equatorial latitudes at Kototabang, Indonesia [Fukushima et al., 2012].
Characteristic motion of high-latitude nighttime medium-scale traveling ionospheric disturbances werereported associated with auroral brightenings based on airglow-imaging observations at Tromsoe, Norway
and Athabasca, Canada [Shiokawa et al., 2012, 2013] and based on GPS network over Europe [Otsuka etal., 2013].
Shiokawa et al. [2012] reported the rapid oscillating motion of nighttime medium-scale travelingionospheric disturbances (MSTIDs) associated with an auroral brightening, based on airglow imaging
observations at Tromso (magnetic latitude: 67.1N), Norway. This observation indicates that the MSTID
oscillation was linked to auroral electric field in the ionosphere, implying that the observed MSTIDs areionospheric plasma structures. They suggest that the observed MSTIDs were created by atmosphericgravity waves at the beginning, left as fossil plasma structures even after the gravity wave packet
dissipated in the thermosphere.
Shiokawa et al. [2013] show statistical characteristics of occurrence rate, direction of motion, andwave parameters of high-latitude nighttime medium-scale traveling ionospheric disturbances (MSTIDs)
were reported based on observations by all-sky airglow imagers at Tromsoe (magnetic latitude: 67.1N),
2

Norway and at Athabasca (61.7N), Canada. The MSTIDs were observed mostly before midnight with an
occurrence rate of more than 30-50% of clear observation hours. The average wavelengths, phasevelocities, and periods of the observed MSTIDs were 150-200 km, 50-80 m/s, and 30-60 min, respectively.
Some MSTIDs at Tromsoe tend to show eastward motion in addition to the typical westward andsouthwestward motion at middle latitudes. At both stations, some MSTIDs showed characteristic changesof their phase velocity and directions in association with auroral activity, suggesting that they are plasma
structures affected by auroral electric field.
G3. Ionospheric Structure and Models
G3.1 Ionospheric Structure
There is a development of a new three-dimensional GPS ionospheric tomography technique that uses
total electron content (TEC) data from the dense Global Position System (GPS) receiver network, GPS
Earth Observation Network (GEONET) in Japan, and it will not require an ionospheric model as the initial
guess that will bias the reconstruction of electron density. The GEONET is operated by Geospatial
Information Authority of Japan and consists of more than 1200 receivers; this high density and wide
coverage helps to reconstruct the electron density distribution in the ionosphere with high spatial resolution.
This tomography technique uses a constrained least squares fit to reconstruct the three-dimensional
electron density distributions. This method is different to most other techniques as they require abackground ionospheric model as an initial guess that could bias the reconstructed electron density. It
rather uses a prior condition that the electron density should not exceed a certain value that is determinedby the restrain parameter, which is derived from the NeQuick model. Its independency of the initial guessfrom a model will make it useful even in disturbed conditions. This paper presents results that are obtainedby using this new tomographic technique. The reconstruction of three-dimensional ionospheric tomograms
is demonstrated using the GPS data, and the reliability and robustness are checked with simulated
tomograms obtained using the synthetic GPS-TEC data produced using NeQuick model.
G3.2 Ionosphere –Thermosphere Models
Jin et al. [2011] show a new Earth's atmosphere-ionosphere coupled model that treats seamlessly theneutral atmospheric region from the troposphere to the thermosphere as well as thethermosphere-ionosphere interaction including the electrodynamics self-consistently. The model is
especially useful for the study of vertical connection between the meteorological phenomena and the upper
atmospheric behaviors. As an initial simulation using the coupled model, a 30-day consecutive run in
September reveals that the longitudinal structure of the F-region ionosphere varies on a day-to-day basis ina highly complex way and that a four-peak structure of the daytime equatorial ionization anomaly (EIA)
similar to the recent observations appears as an averaged feature. The simulation reproduces and thus
confirms the vertical coupling processes proposed so far with respect to the formation of the averaged EIA
longitudinal structure; the excitation of solar nonmigrating tides in the troposphere, their propagation
through the middle atmosphere, and the modulation of ionospheric dynamo, which in turn affects EIA
generation. The simulation result indicates that not only the ionospheric averaged longitudinal structure but
also the day-to-day variation can be modulated significantly by the lower atmospheric effect. This newmodel is named as “GAIA (Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy)” andis now started for studies of various atmospheric/ionospheric phenomena. During this period of report,
Pancheva et al. [2012] and Jin [2012] used for the study of atmospheric tides, while Liu et al. [2013b] use
it for clarify vertical coupling process of the sudden stratospheric warming.
Model studies are also conducted for smaller-scale phenomena. Yokoyama [2013a] developed
hemisphere-coupled modeling to show an intriguing aspect of nighttime medium-scale travelingionospheric disturbances (MSTIDs) that they were simultaneously observed at magnetic conjugate
locations in the Northern and Southern Hemispheres. In order to study the hemisphere-coupledelectrodynamics, the numerical model has been upgraded to consist of two simulation domains for bothhemispheres in which the electrostatic potential is solved by considering electrodynamics in bothhemispheres. The simultaneous occurrence of MSTIDs at the magnetic conjugate stations has clearly been
reproduced when the F-region neutral wind satisfies the unstable condition in both hemispheres and a3

sporadic-E layer is given only at the Northern (summer) Hemisphere. On the other hand, Yokoyama[2013b] studied scale dependence of nighttime medium-scale traveling ionospheric disturbances (MSTIDs)
is studied with the midlatitude ionosphere electrodynamics coupling model by changing initial perturbation
scales. It is shown that both sporadic E (Es)-layer and Perkins instabilities have the scale dependence that ashorter wavelength mode tends to stop growing within a shorter period, whereas a very long wavelength
mode grows so slowly in the E region that it does not effectively seed the Perkins instability in the F region.
As a result, the typical wavelength of MSTIDs (100-200 km) can be spontaneously generated withoutscale-dependent forcing. It is also shown that long frontal structures of MSTIDs can be formed by thePedersen polarization process along the wavefront of MSTIDs by which the wavefront is forced to beuniformly distributed.
G4. Coupling with Atmosphere/LithosphereG4.1 Neutral Atmosphere-Ionosphere System
Nishioka et al [2013] detected clear concentric waves and short-period oscillations in the ionosphere
after the EF5 tornado hit Moore, Oklahoma, USA, on 20 May 2013 using a dense wide-coverage
ionospheric total electron content (TEC) observation in North America. These concentric waves were
non-dispersive waves with a horizontal wavelength of ~120 km and a period of ~13 minutes. They wereobserved for more than seven hours throughout North America. TEC oscillations with a period of ~4
minutes were also observed in the south of Moore for more than eight hours. Comparison between the
TEC observation and the infrared cloud image from the GOES satellite indicates that the concentric waves
and the short-period oscillations are caused by supercell-induced atmospheric gravity waves and acoustic
resonances, respectively. This observational result provides the first clear evidence of a severe
meteorological event causing atmospheric waves propagating upward in the upper atmosphere andreaching the ionosphere.
Maruyama et al. [2013] studied that geomagnetic disturbances from 7 to 12 November 2004 werequite intense, and the maximum excursion of Dst reached –374 nT. Unusual ionospheric phenomena havebeen observed around the world that have been associated with successive magnetic storms during thisperiod. The ionospheric total electron content (TEC) was increased at the longitudes of Japan within ashort time after sunset on 8 November, from 20 TEC units at 1830 JST to 97 TEC units at 2015 JST (JST =UT + 9 h). The enhanced TEC was significant over Hokkaido (43 deg N), and the center of the enhanced
region was well within the plasmasphere as an L value of approximately 1.5. The drift velocity of theplasma in the density-enhanced region measured by the Defense Meteorological Satellite Program (DMSP)
satellite was westward with a peak value of 250 m/s in the Earth’s frame, demonstrating a positive
correlation between density and drift velocity. A similar TEC event was observed after sunset on 10
November: TEC was enhanced, from 15 TEC units at 1830 JST to 45 TEC units at 2030 JST. During thesecond event, the ionosphere was highly structured and the rate of the TEC index (ROTI) increased. The
two-dimensional map of a ROTI-enhanced region exhibited the west to northwest transportation of plasma
in which density irregularities were entrained. A physical mechanism is proposed to explain these
disturbances, i.e., storm-induced plasma stream, which is different from a phenomenon calledstorm-enhanced density at midlatitudes.
The first comparison of the estimated meridional wind velocities with meridional wind observed withFPIs is conducted by the researchers at NICT. They analyzed data from the ionosondes and FPIs installed
at Chiang Mai, Thailand, and Kototabang, Indonesia, from 2010, and found that the estimated andobserved wind velocities were generally in good agreement on most nights, although on some nights, thewind velocities were different. The assumption that the meridional wind is equal anywhere between thetwo ionosonde stations would not be suitable for the days when the winds were not in good agreement. We
also investigated the seasonal dependence of the correlation between the estimated and observed
meridional winds. They were in good agreement from February to April and were not in good agreementfrom May to July.
G4.2 Effect of Thunderstorm and Meteorological Phenomenon

4Schekotov et al. [2011] reported ULF impulsive magnetic response at mid-latitudes to lightning
activity, explaining that a pair of impulse causes the spectral resonance structure in the frequency-timeplots. Long-term variations in the tweek reflection height in the D- and lower E-region ionosphere has
been firstly shown by Ohya et al. [2011]. Correlation between pulsating aurora and chorus waves at Syowa
Station in Antarctica were reported for a case study by Ozaki et al. [2011].
Ohya et al. [2012] reported multi-point observations of daytime tweek atmospherics during the solar
eclipse of 22 July 2009 at Moshiri and Kagoshima, Japan, where the magnitudes of the solar eclipse were
only 0.458 and 0.966, respectively. The wide range of estimated tweek reflection heights at Kagoshima
also suggests a difference in electron density in the D- and lower E-regions between total and partial solar
eclipses.
Iyemori et al. [2013] showed that three rare occasions are introduced, where the excitation of verticalacoustic resonance between the ground and the ionosphere, and the resultant generation of a field-aligned
current, just after earthquakes are observationally confirmed. In the case of two inland earthquakes,
barometric observations very close to the epicenters (i.e., only 30 km apart) were available, and they
showed a sharp spectral peak which appeared within one hour after the origin time and lasted a few hours.
The observed periods of the spectral peaks around 260 seconds are close to the period of thetheoretically-expected fundamental mode of the resonance. On the other hand, magnetic observations on
the ground showed a dominant period at 220–230 seconds which corresponds to the first overtone among
theoretically-expected major resonance peaks. In the third case, i.e., during the 2010 Chile earthquake, along-period magnetic oscillation in the east-west direction, which has two major resonance periods at 265
and 190–195 seconds, was observed on the night-side magnetic dip equator in Peru, where the distance ismore than 2600 km from the epicenter, under a very quiet geomagnetic condition. The oscillation wasinterpreted as the effect of field-aligned current generated through a dynamo process in the ionosphere
over the epicenter caused by the resonance.
G4.3 Eathquake Effect on the Ionosphere
Ionospheric disturbances following the intense earthquake and tsunami such as the 2011 off the Pacificcoast of Tohoku Earthquake (2011 Tohoku EQ) were studied by GPS-TEC and ionosonde observations inJapan and numerical simulations. All the details of post-seismic ionospheric disturbances were firstobserved by a high-resolution two-dimensional GPS-TEC observation in Japan [Tsugawa et al., 2011]. The
initial ionospheric disturbance appeared as sudden TEC depletion about seven minutes after the earthquake
onset near the epicenter [Saito et al., 2011; Kakinami et al., 2012]. In the vicinity of the epicenter,
short-period oscillations with a period of about 4 minutes were also observed [Saito et al., 2011]. Off theepicenter, zonally-extended band-like structures and concentric wave trains appeared in the detrended TEC
maps about 15 minutes after the earthquake onset. The former band-like structure traveled equatorward
and also appeared in Taiwan [Chen et al., 2011]. The latter concentric waves with longer wavelengths andlarger propagation velocities appeared earlier [Tsugawa et al., 2011]. The center of the TEC depletion andconcentric waves, termed “ionospheric epicenter”, was located about 170 km from the epicenter in thesoutheast direction and consistent with estimated areas of the tsunami source. These ionosphericdisturbances were reproduced by numerical simulation with a time-dependent, two-dimensional, nonlinear,
non-hydrostatic, compressible and neutral numerical model [Matsumura et al., 2011]. Based on theseobservation and simulation results, it is considered that the first fast-propagating ionospheric concentric
wave with the propagation velocity of about 3.5 km/s was caused by the acoustic wave generated from the
propagating Rayleigh wave. The second and following concentric waves would correspond to theatmospheric gravity waves (AGWs) propagating in the ionosphere. These AGWs are considered to begenerated at the tsunami wavefronts and at the lower ionosphere above the tsunami source. Unusual
multiple-cusp signature (MCS) was observed in ionograms obtained by four ionosonde stations in Japan
about 15 minutes after the earthquake onset [Maruyama et al., 2011]. The real height analysis of the MCS
showed a vertical ionospheric structure with a scale size of 20∼30 km, indicating acoustic wave generated
from the propagating Rayleigh wave. The specific conditions of MCS appearance were statistically studied
based on MCS events observed in 8 or 43 earthquakes with a seismic magnitude of 8.0 or greater during
the period 1957 to 2011 [Maruyama et al., 2012]. Ogawa et al. [2012] reported giant ionospheric5

disturbances observed with the SuperDAN Hokkaido HF radar and GPS netwoork after the 2011 Tohoku
earthquake.
Shinagawa et al. [2013] showed that unusual ionospheric variations were observed in the M9.0
Tohoku-oki earthquake on 11 March 2011. Among various kinds of features in the ionosphere, significant
depletion of TEC near the epicenter was observed after the earthquake. Although previous studies havesuggested that the coseismic ionospheric variations are associated with atmospheric perturbation caused byvertical displacement of the sea surface, the mechanism of the TEC depletion has not been fully
understood. In this paper, a two-dimensional nonlinear nonhydrostatic compressible
atmosphere-ionosphere model is employed to investigate the ionospheric variations in the vicinity of theepicenter. The simulation results reveal that an impulsive pressure pulse produced by a sudden uplift of thesea surface leads to local atmospheric expansion in the thermosphere and that the expansion of thethermosphere combined with the effect of inclined magnetic field lines in the ionosphere causes the sudden
TEC depletion above the epicenter region.
G5. Polar Atmosphere-IonosphereG5.1 Studies with optical imagers
Several studies on various phenomena in the polar cap ionosphere have been conducted by using an
all-sky airglow imager (ASI) of OMTIs (Optical Mesosphere Thermosphere Imagers; operated by Nagoya
University) at Resolute Bay (74.73N, 265.07E). Hosokawa et al. [2011a] observed an unusual event inwhich a polar cap ionization patch stopped its anti-sunward motion and stayed within the field-of-view for
more than one hour. When the patch stagnated, its luminosity decreased gradually, which allows them toinvestigate how the patch plasma decayed in a quantitative manner. The decay of the patch can bequantitatively explained by the loss through recombinations of O+ with ambient N2 and O2 molecules, if
we assume the altitude of the optical patch to be around 295 km. The derived altitude of the patch around295 km is much higher than the nominal value at 235 km obtained from the MSIS-E90/IRI2007 models,
which suggests that we should employ higher emission altitude when we investigate optical patchestransported deep into the nightside polar cap. Hosokawa et al. [2011b] carried out a statistics of motion ofpolar cap arcs (i.e., auroral arcs in the polar cap latitudes) by using 5 years of optical data from Resolute
Bay. They identified 743 arcs by using an automated arc detection algorithm, and statistically examined
their moving velocities. They showed that polar cap arcs fall into two distinct categories, theIMF-dependent and IMF-independent (IMF: Interplanetary Magnetic Field) arcs. This implies that themechanism causing the arc motion is fundamentally different between these two types of arc. Thus, theirmagnetospheric source could also be different.
A highly sensitive all-sky EMCCD airglow imager has been operative in Longyearbyen, Norway(78.2N, 15.6E; AACGM latitude 75.3) since October 2011. The imager captures 630.0 nm all-sky images
with an exposure time of 4 sec, which is about 10 times shorter than that achieved by conventional cooled
CCD imagers. This allows us to visualize the structure of polar cap patches without blurring effects andbetter estimate their periodicities. Hosokawa et al. [2013] presented, as one of the first results from theimager, an event of successive appearance of patches on the night of December 21, 2011. A time-series ofthe optical intensity at zenith showed modulations having two distinguished periods, one at 40 min and theother at 5--12 min. One possible explanation is that such a coexistence of two different periodicities is amanifestation of simultaneous occurrence of patch generation processes on the dayside. Namely, the 40
min periodicity was created by large-scale reconfiguration of the dayside convection pattern while the 5-12
min modulations were closely associated with mechanisms driven by pulsed reconnection on the daysidemagnetopause. Such a combined effect of multiple patch generation processes may play a role instructuring patches; thus, it would be of particular importance for evaluating the space weather effects inthe trans-ionospheric communications environment in the polar cap.
A highly sensitive all-sky EMCCD airglow imager has been operative in Longyearbyen, Norway(78.2N, 15.6E; AACGM latitude 75.3) since October 2011. The imager captures 630.0 nm all-sky images
with an exposure time of 4 sec, which is about 10 times shorter than that achieved by conventional cooled
CCD imagers. This new equipment allows us to image the ongoing structuring of polar cap patches in 2-D
fashion. Hosokawa et al. [2013] reported a case in which faint undulations appeared along the trailing edgeof patches propagating in the central polar cap. The separation between the fingers in the undulations was
6about 50–100 km and the e-folding time of their growth was ~5 min. They suggested that the gradient-drift
instability (GDI) is one of the possible generation mechanisms of the undulating structures. The reasonsfor this interpretation are (1) the asymmetry in the preference of structuring between the leading andtrailing edges is qualitatively consistent with the GDI mechanism and (2) the linear growth rate of GDI
calculated by using electron density estimates from simultaneous European Incoherent Scatter Svalbard
radar observations is roughly consistent with the observed growth time of the fingers. Such “unstable polar
cap patches” could be important sources of seed irregularities, which would eventually be broken down tosmaller-scale density perturbations affecting the transionospheric satellite communications in the central
polar cap.
More recently, there are observations of regions of increased 630.0 nm airglow emission
simultaneously by dual all-sky imagers in the polar cap, one at Longyearbyen, Norway and the other at
Resolute Bay, Canada (74.7N, 265.1E). The Resolute Bay incoherent scatter radar observed clear
enhancements of the F region electron density up to 1012 m-3 within these airglow structures, whichindicates that these are optical manifestations of polar cap patches propagating across the polar cap. During
this interval of simultaneous airglow imaging, the nightside/dawnside (dayside/duskside) half of thepatches was captured by the imager at Longyearbyen (Resolute Bay). This unique situation enabled us toestimate the dawn-dusk extent of the patches to be around 1500 km, which was at least 60-70% of thewidth of the anti-sunward plasma stream seen in the SuperDARN convection maps. In contrast to the large
extent in the dawn-dusk direction, the noon-midnight thickness of each patch was less than 500 km. Theseobservations demonstrate that there exists a class of patches showing cigar-shaped structure. Such patches
could be produced in a wide range of local time on the dayside nearly simultaneously and spread across
many hours of local time soon after their generation.
High-latitude GPS TEC changes associated with a sudden magnetospheric compression and associatedwith polward-moving sun-aligned arcs were reported at high latitudes above the auroral zone
[Jayachandran et al., 2011; 2012].
G5.2 Studies with EISCAT Radars
By using EISCAT radars as well as instruments operated in northern Scandinavia, we have conductedfollowing studies: Nozawa et al. [2012] showed that lower thermosphere/Mesosphere wind wasinvestigated by the new meteor radar at Bear Island (74.5ºN, 19.0ºE) that started operation on November
2007. Seasonal variations of mean wind, diurnal and semidiurnal tides, and quasi-two day wave are foundto be similar to those at Tromsø (69.6ºN, 19.2ºN). Sato et al. [2012] studied first observations of auroralroar emissions near 4 times fce (electron cyclotron frequency) were conducted at Longyearbyen (78.2ºN,
16.0ºE). 4 fce roar emissions were detected from 5.27 to 5.70 MHz during moderate geomagnetic
disturbances in 22 days between May and September 2011 only from noon to evening, while no event
occurred during the winter season. The observations support the idea expanded from the most commonly
accepted generation mechanism of 2 fce and 3 fce roar: the origin of 4 fce roar is upper hybrid waves
favorably generated under the condition of fUH (upper hybrid resonance frequency) equal to 4 fce in theauroral F-region. Fujiwara et al. [2012] showed that variations of ion temperatures at Longyearbyen were
investigated using IPY long-run data obtained by EISCAT Svalbard radar and predictions by GCM. The
ion temperatures show significant seasonal variations. The amplitudes of the local time and seasonalvariations observed are much larger than the ones predicted by the IRI-2007 model. This study suggested
significant heat sources in the polar cap region even under solar minimum and geomagnetically quiet
conditions. Tsuda et al. [2011] showed that fine structure of a sporadic sodium layer (SSL) was observed
by a new sodium LIDAR, which started operation on October 1, 2010, at Tromsø on January 11, 2011. The
sodium lidar measurement with 5-sec time resolution revealed the details of dramatic sodium-density
increase as well as short-period wavelike structure in the SSL. The calculated power spectral densities arewell represented by power laws, implying the presence of the short-period waves and turbulence in thefrequency range of 10-4 – 10-1 Hz.
Fujii et al. [2012] studied a physical process for the latitudinal motion of an auroral arc based on thefour-side bound Cowling channel model is proposed. Assuming that an upward field-aligned current(FAC) is associated with the auroral arc that forms a Cowling channel with finite lengths not only
latitudinally but also longitudinally and that the upward FAC region is primarily embedded in a purely
7

northward electric field, the primary Hall current driven by the northward electric field accumulates
positive excess charges at the eastern edge of the channel and negative charges at the western edge. The
charges produce a westward secondary electric field. This secondary electric field moves the arc with its
magnetospheric source drifting together with the magnetospheric plasmas equatorward and simultaneously
produces the electric field outside the channel that moves the downward FAC equatorward of the upward
FAC region equatorward together with the upward FAC. Thus, the whole 3-D current system is expected
to move equatorward as often observed in the afternoon auroral zone.
Taguchi et al. [2012] showed that poleward-moving auroral forms (PMAF), the ionospheric signaturesof flux transfer events (FTEs), are intermittent phenomena observed in the cusp during negativeinterplanetary magnetic field intervals. We present initial results from a new high-sensitivity all-sky
imager installed at Longyearbyen, Norway in October 2011. The 630.0-nm all-sky images taken with atime resolution of 4 s reveal that one of the PMAFs that occurred with such typical separation times on 29
December 2011 comprises two consecutive auroral bursts. This observation provides evidence that one
PMAF could reflect double FTEs—there is not always a one-to-one correspondence between FTEs and
PMAFs.
Using a simultaneous and common-volume observation by a European incoherent scatter (EISCAT)VHF radar and a sodium lidar at Tromso, Norway (69.6 deg N, 19.2 deg E), the effect of pure particle
precipitation, excluding that of the electric field, on sodium density variations has been observed for the
first time [Tsuda et al., 2013]. The observation on 24-25 January 2012 showed that sodium atom density
decreased when there was no ion temperature enhancement (indicating a weak electric field) and theelectron density increased (indicating strong particle precipitation). From the results we have concluded
that auroral particle precipitation induced sodium atom density decrease in this event. Furthermore, a
discussion is provided regarding the time response of the decrease in sodium density.
Ionospheric ion upflow during an auroral substorm has been investigated using simultaneous EISCAT
radar and IMAGE satellite data [Ogawa et al., 2013]. Approximately 6 minutes after an initial brightening
identified with data from the IMAGE WIC instrument, ion upflow was seen and the electron temperature
became enhanced, too. The ion upflow, with a velocity of about 150 m/s, and the electron temperatureenhancement lasted for about 25 minutes. During the poleward expansion phase surges of large upward ion
velocity and flux, and high ion and electron temperatures occurred over Longyearbyen. The upward ion
flux reached 2×10^14 m-2s-1. Naturally enhanced ion-acoustic lines (NEIALs) were seen near thepoleward edge of the expanded auroral oval both near the end of expansion phase 17 minutes after onset
and also later in the recovery phase. The NEIALs seemed to be accompanied by another type of enhanced
echoes, obliquely to the local geomagnetic field. Data from the LENA instrument on the IMAGE satellite
show that energetic neutral oxygen reaches the IMAGE satellite about 40 minutes after the initialbrightening, and oxygen continues to get detected during the recovery phase. Ion upflow at the poleward
edge of the auroral oval during the expansion phase was proved to be related to ion/neutral outflow withenergy below 18-27 eV, whereas during the recovery phase of a substorm upward ions are accelerated up
to about 60 eV and flow out in the entire polar region.
Updates on EISCAT results are found at http://polaris.nipr.ac.jp/~eiscat/results.html
G5.3 Other studies of the polar region
Frequency-dependent polarization characteristics of Pc1 geomagnetic pulsations were observed bymulti-point ground stations at low latitudes [Nomura et al., 2011]. Polarization of Pc1/EMIC waves andrelated proton auroras were investigated in detail at subauroral latitudes [Nomura et al., 2012]. Sakaguchi
et al. [2012] visualized ion cyclotron wave and particle interactions in the inner magnetosphere using
THEMIS-ASI observations.
Morilka et al. [2012] examined AKR spectra using the long-term observation from the Polar satellite
to prove the comprehensive features of field-aligned auroral acceleration and to give observational
constraints to the theoretical mechanisms for acceleration at substorm. The remote observations of
substorm phenomena through auroral radio waves from the high altitude polar magnetosphere disclosed
some fundamental characteristics of the vertical auroral acceleration region and provided new informationon the formation process for field-aligned electric field at substorm onset. Furthermore, we reveal new

8

aspect of the relationship between the plasma state in the plasma sheet and the formation of auroral
acceleration.
Morioka et al. [2013] studied that auroral kilometric radiation (AKR) is known to be transientemissions generated by rapidly accelerated electrons together with sudden auroral activation in the polar
magnetosphere of the earth. In contrast, the characteristics and relationship with the auroral acceleration ofrather continuous AKR emissions are not well understood. We examine the emission using long-term data
and report that the continuous AKR emission frequency changes with universal time (UT) as the Earthrotates, indicating that the Earth is a spin-modulated variable radio source. The observed UT variation of
AKR frequency means that the acceleration altitude changes periodically with planetary rotation. The
observations indicate that the diurnal wobble of the tilted geomagnetic field in the solar wind flow alters
the magnetosphere-ionosphere (M-I) coupling state in the polar magnetosphere, giving rise to periodic
variation of auroral particle acceleration altitude. These observations of planetary radio wave properties
provide insight into the physics of planetary particle acceleration
Nishiyama et al. [2012] carried out ground-based observations, optimized to temporal and spatial
characteristics of pulsating auroras (PAs) in the micro/meso scale, using an electron multiplying charge
coupled device (EMCCD) camera with a wide field of view corresponding to 100 × 100 km at an altitudeof 110 km and a high sampling rate up to 100 frames per second. We focus on transient PAs propagating
southward around 1100 UT, in the early recovery phase of the substorm, on 4th March 2011. Three
independent patches (PA1–3) each with different periods between 4 and 7 s were observed, which meansthat the periodicity was not explained by the electron bounce motion and strongly depended on local
plasma conditions in the magnetosphere or in the ionosphere. One more insight is that only PA1 had also a
sharp peak of modulations around 1.5 Hz, with a narrow frequency width of 0.30 Hz, and the strong
modulations existed as a small spot in the center of PA1. We have also conducted cross spectrum analysis
and have obtained coherence and phase distributions for auroral variations between 0.1 and 3.0 Hz. The
results indicated that low frequency variations from 0.2 to 0.5 Hz inside PA1–3 propagated as a collective
motion in well-defined directions. The estimated horizontal propagation velocities ranged from 50 to 120
km/s at the auroral altitude. The velocities are almost consistent with the Alfven speed at the magnetic
equator, which suggests that compressional waves have an effect on PA via modulations of the ambient
plasma environment.
Sakanoi et al. [2012] studied that black aurora is a small-scale (typically a few to 10 km) black
structure seen in diffuse aurora, and its generation process has been studied with immense interest. We
report the precise characteristics of black aurora based on simultaneous image and particle measurement
data and possible generation process. Thirteen black auroral events are identified from the Reimei satellitedata, and the relationship between particle and auroral images around the satellite's magnetic footprints isinvestigated in detail. We found that a number of small-scale deficiencies were embedded in precipitating
electrons from the central plasma sheet with energies greater than 2–7 keV and that each deficiency
corresponded exactly to black arcs and black patches at the magnetic footprint. Therefore, black arcs andblack patches are not associated with a field-aligned potential (such as a divergent potential structure) but
probably originate from the suppression of pitch angle scattering. In the black auroral region, low-energy(2–5 keV) inverted-V-type downward electrons (spanning channels that are several tens of kilometerswide) often appear to overlap with high-energy (several keV) plasma sheet electrons.
G.6 Solar and planetary studies
Yoneda et al. [2013] studied that Jupiter’s sodium nebula showed an enhancement in late May throughthe beginning of June 2007. This means Io’s volcanic activity and the magnetosphere’s plasma content
increased during this period. On the other hand, Jupiter’s radio emission called HOM became quiet after
the sodium nebula enhancement. The HOM emission is considered to be related to the activity of aurorae
on Jupiter. These observation results therefore suggest that the increase in plasma supply from Io into
Jupiter’s magnetosphere weakens its field-aligned current, which generates the radio emissions and aurorae
on Jupiter. By comparing our observation results to recent model and observation results, we add
supporting evidence to the possibility that Io’s volcanism controls Jupiter’s magnetospheric activity.
Kodama et al. [2013] showed that observations of [OI] 630 nm emission in the Enceladus torus around
Saturn have been made at the summit of Mt. Haleakala in Hawaii using a high-dispersion echelle
9spectrograph coupled to a 40 cm telescope in the period of 13 May through 19 June 2011. A slit of thespectrograph was aligned perpendicular to the equatorial plane of Saturn and placed at a distance of 4
Saturn's radii (Rs) from the planetary center in the dawn side to put the Enceladus torus within the field ofview. As a result, [OI] 630 nm torus emission was detected with S/N ~ 7 for summed exposure of 20 hduring the observing period. The observed brightness has a maximum value of 4.1 ± 0.6 Rayleighs (R)near the equator, and it extends to north-south (N-S) direction with a full width at half maximum of 0.8 Rs.
We made estimation to explain mechanism of the observed brightness taking into account an excitation of[OI] 630 nm by electron impact and photodissociation of water group molecule (OH and H2O). Densities
of electron, O, OH, and H2O and electron temperature derived from data taken by Cassini and Hubble
telescope were used for the estimation. The observed brightness is reasonably explained, taking into
account an uncertainty of estimation depending on N-S distributions of species and quiet solar activity
conditions. The estimation also suggests that [OI] 630 nm emission is excited by photodissociation of OH
and H2O and by electron impact of O with their contributions of 50%, 30%, and 20%, respectively, forquiet solar activity. We also note that the intensity due to photodissociation has considerable variability
depending on the level of solar activity by a factor of 2.5.
Yagi et al. [2012] showed that a model of the martian exosphere is built for average solar conditions.
A Chamberlain's approach (Chamberlain, J.W. [1963]. Planet. Space Sci. 11, 901) is used to describe the O,
CO, CO2, and O2 thermal exospheric components. The average thermal oxygen density at 300 km in
altitude varies by about one order of magnitude with seasons. A Monte-Carlo test particle simulation is
also developed in order to estimate the non-thermal oxygen component of the exosphere. The seasonalvariation of the non-thermal oxygen average density is much less than the thermal component but displays
clear seasonal variations of its spatial distribution. The neutral oxygen atomic escaping flux varies from 2.9
to 5.3 x 1025 s―1 in good agreement with other studies. Mars's oxygen exosphere is thermal below 600
km and non-thermal above 700 km at all seasons. The typical scale height is ∼45 km for thermal O and ∼500 km for the non-thermal oxygen density. The total photoionization rate above 300 km corresponds to aCO•2 /O+ total production ratio between 0.004 and 0.02. When compared to the composition of theescaping flux measured by ASPERA-3/Mars Express, this suggests that ions formed below 300 km should
significantly contribute to the escaping ion flux and/or that a significant part of the newly O+ ionsreimpacts Mars. The simulated oxygen density profile is also compared to the recent observed profile by
Alice/Rosetta (Feldman, P.D. et al. [2011]. Icarus 214, 394-399). Although the scale height of oursimulated non-thermal oxygen exosphere and the transition from thermal to non-thermal dominatedexospheres are slightly higher than suggested by Feldman et al. [2011], a good agreement is found when
taking into account the uncertainties of Alice/Rosetta observations.
Io-Jupiter interaction leads to auroral emissions and Jovian decametric radiations (Io-DAM) [Matsuda
et al., 2013]. The longitudinal distribution of the Io-DAM occurrence probability has been considered to becontrolled by the footprint magnetic intensity of each hemisphere. Recent observations revealed that thebrightness of the main auroral spot is mainly modulated by Io's magnetic latitude. In the present study, we
propose that the Io-DAM occurrence probability is controlled by the north-south asymmetry of the
footprint magnetic intensity, in addition to Io's magnetic latitude. Hall magnetohydrodynamic equations
are solved in the corotating meridional plane, which includes the Jovian ionosphere of finite thickness. We
assume that the ionospheric Pedersen conductance is inversely proportional to the footprint magnetic
intensity; the conductance is nearly the same for both ionospheres at a longitude of 290°, while twice
higher for the south than for the north at a longitude of 110°. Above the northern ionosphere, the parallel
current density further than 20° downstream of the main spot is estimated to be 1.5–2.0 times larger for
290° than for 110°. This indicates that if the Io-DAM lead angle is large, the suppressed Io-DAM
occurrence probability for the northern hemisphere around 110° would be caused by the north-south
asymmetry of the footprint magnetic intensity. A large current density conducted into the south around110° would be the source of the Io-D component, radiated from the southern hemisphere. The observedbrightness of the Io-related auroras is discussed in the context of the intensity of the parallel current
density.
Ishiyama et al. [2013] investigated the geological conditions below two lava flow units throughdetermining the bulk permittivity and porosity in the uppermost basalt layer to depths of a few hundred
meters. We use a newly developed method based on three data sets obtained by the Lunar Radar Sounder(LRS), Multiband Imager (MI), and Terrain Camera (TC) onboard the Selenological and Engineering

10Explorer (SELENE; Kaguya) spacecraft. The bulk permittivity of the uppermost basalt layer is calculated
as the ratio of the apparent radar depth to the thickness of the uppermost basalt layer. Its thickness can beconstrained from the excavation depths of two types of craters (haloed and nonhaloed craters). These
craters are identified on the basis of FeO and/or TiO2 maps created from the MI data. These excavation
depths are determined based on the measurement of the crater diameter using the TC data. The apparent
radar depth is derived from the time delay between the surface echo and subsurface echo measured by LRS
near the craters. The bulk permittivities are estimated to be 2.8–5.5 in a lava flow unit of Mare Humorumand 4.2–18.0 in a lava flow unit of Mare Serenitatis. These bulk permittivities are indicative of porous
basalt layers with the porosities of 19%–51% in the unit of Humorum and 0%–33% in the unit ofSerenitatis. The estimated porosities would be mainly explained by two different sources: intrinsic voids oflava and impact-induced cracks.
A new radio spectropolarimeter for solar radio observation has been developed at Tohoku University
and installed on the Iitate Planetary Radio Telescope (IPRT) at the Iitate observatory in Fukushima
prefecture, Japan [Iwai et al., 2012a]. This system, named AMATERAS (the Assembly of Metric-band
Aperture TElescope and Real-time Analysis System), enables us to observe solar radio bursts in thefrequency range between 150 and 500 MHz. The minimum detectable flux in the observation frequency
range is less than 0.7 SFU with an integration time of 10 ms and a bandwidth of 61 kHz. Both left andright polarization components are simultaneously observed in this system. These specifications areaccomplished by combining the large aperture of IPRT with a high-speed digital receiver. Observational
data are calibrated and archived soon after the daily observation. The database is available online. The
high-sensitivity observational data with the high time and frequency resolutions from AMATERAS will be
used to analyze spectral fine structures of solar radio bursts.
Iwai et al. [2012b] showed that the first coordinated observations of an active region using
ground-based radio telescopes and the Solar Terrestrial Relations Observatory (STEREO) satellites fromdifferent heliocentric longitudes were performed to study solar radio type-I noise storms. A type-I noise
storm was observed between 100 and 300 MHz during a period from 2010 February 6 to 7. During thisperiod the two STEREO satellites were located approximately 65° (ahead) and –70° (behind) from the
Sun-Earth line, which is well suited to observe the earthward propagating coronal mass ejections (CMEs).
The radio flux of the type-I noise storm was enhanced after the preceding CME and began to decrease
before the subsequent CME. This time variation of the type-I noise storm was directly related to thechange of the particle acceleration processes around its source region. Potential-field source-surface
extrapolation from the Solar and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI)
magnetograms suggested that there was a multipolar magnetic system around the active region from which
the CMEs occurred around the magnetic neutral line of the system. From our observational results, wesuggest that the type-I noise storm was activated at a side-lobe reconnection region that was formed after
eruption of the preceding CME. This magnetic structure was deformed by a loop expansion that led to thesubsequent CME, which then suppressed the radio burst emission.
Iwai et al. [2012c] showed that the relationships between solar radio type-I bursts and soft X-ray
activities were investigated using Hinode/XRT and a ground-based radio telescope belonging to Tohoku
University. Although a type-I burst is thought to be generated by high energy non-thermal electrons in thesolar corona, the counterpart of this radio burst in X-rays or EUV have yet to be identified. In this study,
we found some small scale soft X-ray activities on the XRT images around the onset time of the type-I
burst when 10 percent of the soft X-ray flux enhancement around the onset time of the radio burst is
defined as a burst-related activity. However, the causal relationship between the observed soft X-ray
activities and the onset of the type-I burst are unclear, and more simultaneous observations of radio bursts
and X-rays are needed to investigate the coronal counterpart of the type-I burst.
Iwai et al. [2013] showed that Solar radio type-I bursts were observed on 2011 January 26 by highresolution observations with the radio telescope AMATERAS in order to derive their peak flux
distributions. We have developed a two-dimensional auto burst detection algorithm that can distinguisheach type-I burst element from complex noise storm spectra that include numerous instances of radio
frequency interference (RFI). This algorithm removes RFI from the observed radio spectra by applying amoving median filter along the frequency axis. Burst and continuum components are distinguished by a
two-dimensional maximum and minimum search of the radio dynamic spectra. The analysis result showsthat each type-I burst element has one peak flux without double counts or missed counts. The peak flux

11

distribution of type-I bursts derived using this algorithm follows a power law with a spectral index
between 4 and 5.
G.7 Instruments and experiments
G7.1 PANSYPANSY (Program of the Antarctic Syowa MST/IS Radar) is a project which was started in 2000 tocomprehensively study the polar atmosphere with a large aperture atmospheric radar as the main
instrument combined with complementary observation techniques and also with numerical modeling andtheoretical works.
The PANSY project has been supported internationally by resolutions from international scientificbodies such as IUGG, URSI, SPARC, SCOSTEP, and SCAR. The scientific research objectives andtechnical developments have been frequently discussed at international and domestic conferences. The
project was authorized in 2008 as one of the main observation plans for the 6 year period of Japanese
Antarctic Research Expedition program (2011-2016), and funded by Japanese government in 2009. The
PANSY radar is the first Mesosphere-Stratosphere-Troposphere/Incoherent Scatter (MST/IS) radar in the
Antarctic region. It is a large VHF monostatic pulse Doppler radar operating at 47 MHz, consisting of anactive phased array of 1,045 Yagi antennas and an equivalent number of transmit-receive modules with a
total peak output power of 500 kW. Its first stage has been installed at Syowa Station (69°00’S, 39°35’E)
in early 2011, and is currently operating with 228 antennas and modules.
The radar aims to clarify the role of atmospheric gravity waves at high latitudes in the momentum
budget of the global circulation in the troposphere, stratosphere and mesosphere and the dynamical aspects
of unique polar phenomena such as polar mesospheric clouds (PMC) and polar stratospheric clouds (PSC).
The katabatic winds as a branch of Antarctic tropospheric circulation and as an important source of gravity
waves are also of special interest. Moreover, strong and sporadic energy inputs from the magnetosphere byenergetic particles and field-aligned currents can be quantitatively assessed by the broad height coverage ofthe radar extending from the lower troposphere to the upper ionosphere. Currently the radar is operatingwith about a quarter of the full system. Nevertheless, we have already obtained interesting results on the
Antarctic troposphere, stratosphere and mesosphere, such as observation of gravity waves and multiple
tropopauses associated with a severe snow storm in the troposphere and stratosphere, and polarmesosphere summer echoes. The first paper of these initial results was recently accepted and is now online[Sato et al., JASTP, 2013].
G7.2 Equatorial Atmosphere Radar
A receiver system for radars were developed based on the general-purpose software-defined radio
receiver referred to as Universal Software Radio Peripheral 2 (USRP2) under control of a PC. The receiveris able to collect received signals at intermediate frequency (IF) of 130 MHz with a sample rate of 10 MHz.
USRP2 digitizes IF received signals, produces IQ time series, and then transfers the IQ time series to PC
through the Gigabit Ethernet. PC receives the IQ time series, executes range sampling, carries out filteringin the range direction, decodes phase-modulated received signals, integrates the received signals in time,and finally stores processed data to the hard disk drive (HDD). Because only sequential data transfer from
USRP2 to PC is available, the range sampling is triggered by transmitted pulse leaked to the receiver. In
order to perform range imaging with multiple frequencies, the digital receiver executes real-time signal
processing for each of the time series collected at different frequencies. Further, in order to implement
oversampling, the receiver is able to decode phase-modulated oversampled signals by interleaving
oversampled signals in the range direction. Because program codes for real-time signal processing at PC iswritten in C++ language, the signal processing executed by the digital receiver is easy to be implemented,
reconfigured, and reused. Using the measurement result from a 1.3-GHz range imaging atmospheric radar,
we demonstrate that the digital receiver, which is capable of executing real-time signal processing forrange imaging and oversampling, is useful for resolving fine-scale structure of atmospheric turbulencewith a vertical scale as small as 100 m.

12

Equatorial Atmosphere Radar (EAR) is a big atmospheric radar located in West Sumatra, Indonesia.
The EAR was established in June 2001, and has continued long-term observations. Research Institute for
Sustainable Humanosphere (RISH), Kyoto University and National Institute of Aeronautics and Space(LAPAN) of Indonesia hold the 10th anniversary ceremony and symposium on September 22-23, 2011, at
Jakarta. The ceremony was attended by the Minister of Research and Technology of Indonesia, theMinister of the Embassy of Japan, and the representative from the Ministry of Education, Culture, Sports,
Science Technology (MEXT), and the Vice President of Kyoto University.
G7.3 Rocket experiments
Ionospheric Radio Wave: S-310-40 sounding rocket experiment was carried out at Uchinoura Space
Center (USC) at 23:48 JST on 19 December, 2011. The purpose of this experiment is the investigation ofcharacteristics of radio wave propagation in the ionosphere and the estimation of electron density structurein the lower ionosphere, when the intensity of radio wave measured on the ground was attenuate atnighttime. In order to measure the radio waves, a LF/MF band radio receiver (LMR) is installed on thesounding rocket. The LMR measured the propagation characteristics of four radio waves at frequencies of
60 kHz, 405 kHz, 666 kHz and 873 kHz in the region from the ground to the lower ionosphere. The LMR
could measure the relative attenuation of radio waves from the ground up to the ionosphere. Furthermore
the loop antenna consists of three loop antennas in order to measure three components of four radio waves.
Although the attenuation of intensity is seen near an altitude of 100 km, the amount of attenuation is lessthan usual. 100 dB or more is decreased in usual. Such observations are not obtained by past rocket
experiments. We investigate the unusual propagation characteristic of radio waves in the ionosphere at
winter nighttime. Then we will obtain the 3-dimensional structure of electron density in the lower
ionosphere by measuring the intensity of radio waves that propagate from the three different directions.
Electric field measurement with double probe: S-520-26 sounding rocket experiment was carriedout at Uchinoura Space Center (USC) in Japan at 5:51 JST on 12 January, 2012. The purpose of thisexperiment is the investigation of the bonding process between the atmospheres and the plasma in thethermosphere. S-520-26 sounding rocket reached to an altitude of 298 km at 278 seconds after the launch.
The S-520-26 payload was equipped with Electric Field Detector (EFD) with a two set of orthogonal
double probes to measure both DC and AC less than 200 Hz electric fields in the spin plane of the payload
by using the double probe method. Results of DC electric fields measured by the EFD have the large sine
waves that result from the payload rotation at the spin period. The largest contribution to the electric fieldmeasurements by double probes moving through the ionosphere at mid-latitudes is that due to the vxBfields created by their motion across the ambient magnetic field, where v is the rocket velocity in the
Earth-fixed reference frame and B is the ambient magnetic field. The sum of the squares of the twocomponents represents the magnitude of the DC electric field in the spin plane of the payload. These data
reveal abrupt, large-scale variations which can immediately be attributed to changes in the geophysicalelectric field since the vxB fields are slowly varying. The sum of the squares data also reveals
contributions at the spin frequency and its harmonics. These contributions result primarily from distortionsof the waveforms in the raw data.
There are number of waves in the mid-latitude ionosphere. One interesting phenomenon is
medium-scale traveling ionospheric disturbance (MSTID) in the F-region. The MSTID is the wave
structure with a wavelength of 100-200 km. These horizontal structures can be observed by using the total
electron content (TEC) from GEONET, Japanese dense network of GPS receivers. We conducted an
intensive experiment to study generation mechanism of the MSTID by the combination of sounding
rockets and ground observations. We monitored horizontal structures of the MSTID by using GPS-TEC
real-time monitor system. While active MSTID region appeared over south Kyushu, Institute of Space andAeronautical Science of JAXA (JAXA/ISAS) launched sounding rockets S-310-42 and S-520-27 from
Uchinoura Space Center (USC) at 23:00 JST and 23:57 JST, respectively. Ionospheric parameters, i.e.,
plasma density, electric field, density fluctuations, were measured by in-situ instruments on board of the
S-520-27 rocket. TMA (Tri-Methyl Aluminum) and Lithium were released from the S-31-42 and S-520-27
rockets, respectively, for measurement of the neutral winds. Their luminescent clouds were imaged fromthe JAXA experimental jet “Hisho” and from three ground sites. The Lithium experiment under the
moonlight was the world first trial, and was successful. Both rockets transmitted dual-band beacon signal
which was received at five ground sites. Preliminary analysis of from the experiment show that strong13

wind shear and sporadic-E layers co-existed at around 100 km. Also the results infer large horizontal
inhomogeneity of F-region plasma density as well. Electric-field detector (EFD) on board of the rocket
S-520-27 measured a waveform of electric field at the frequency less than 6.4 kHz. Intensity from 4 kHz to
6 kHz are increased at the apex region during the period from 210 sec to 350 s. In the low frequency
components, we sound enhanced intensity of 40 Hz or less is clearly seen during the time of most of rocket
flight.
G7.3 MAGDASMAGDAS is the world network of magnetometer developed and maintained by International Center
for Space Weather Science and Education (ICSWSE), Kyushu University. MAGDAS network and its
observations are well maintained during this period. New installation of fluxgate magnetometer(MAGDAS 9) in 2012 is listed as follows.
- Jayapura, Indonesia. - Sicincin, Sumatra, Indonesia- Bengkulu, Sumatra, Indonesia- Liwa, Sumatra, Indonesia(Above three are for earthquake investigations in Sumatra).
- Jerusalem, Ecuador.
Many studies of atmospheric tides, sudden stratospheric warming, various ionospheric phenomena,and thermosphere-ionosphere coupling are published in international journals.
G7.4 VLF
The Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, started routine observationof VLF waves at Athabasca (54.72N, 246.69E, MLAT=61.3), Canada, using a loop antenna since February
16, 2012. The loop antennas measure east-west and north-south magnetic field variations with a sampling
rate of 100 kHz. Quick-look spectra are available at http://stdb2.stelab.nagoya-u.ac.jp/vlf/index.html
G7.5 GNSS receivers
Electronic Navigation Research Institute (ENRI) and National Institute of Information andCommunications Technology (NICT) developed a system to monitor ionospheric disturbances in realtime.
Observed data of 200 GPS receivers selected from the Japanese nationwide GPS reference network(GEONET) are transferred to ENRI in realtime with a sampling rate of 1 Hz. The data are processed to
produce a map of perturbation component of ionospheric total electron content (TEC) every 5 minutes witha typical time delay of 1-2 minutes. The realtime monitor will be utilized in the JAXA/ISAS sounding
rocket experiment for medium-scale traveling ionospheric disturbances to monitor occurrence of the target
phenomenon. (http://www.enri.go.jp/cnspub/susaito/rocket/recent_mstid.html).
The two-dimensional maps of absolute TEC, rate of TEC change index (ROTI), and loss of lock on
GPS signals (LOL) with 10-30 minutes delay are also available from NICT at the following URL;
http://seg-web.nict.go.jp/GPS/RT_GEONET/index_e.html
Several 100 km to 1,000 km scale ionospheric variations caused by equatorial plasma bubble and/or
travelling ionospheric disturbances can degrade single-frequency GNSS positioning and differential GNSS
positioning. However, these ionospheric disturbances have not been monitored enough due to the lack ofdense wide-coverage ionospheric observations. One of the most effective methods for such dense andwide-coverage ionospheric observations is two-dimensional TEC observations using a dense GNSS
receiver network. Dense GNSS receiver networks are now available only limited areas such as Japan,
North America, and Europe. It is needed to expand the GNSS-TEC observation area using all the available
GNSS receiver networks with international collaboration of ionosphere and space weather researchers in
the world. We propose a new data format, GNSS-TEC Exchange format (GTEX), to promote international
exchange and share of GNSS-TEC data. The main concept of the GTEX is to include slant TEC data fromeach GNSS receiver. By sharing slant TEC data which are not converted to vertical TEC, various
ionospheric studies may be possible without affected by specific analysis procedures such as

14

satellite/receiver bias estimation, or different mapping heights. The structure of GTEX is designed to be as
close to the format of GNSS observation data (RINEX) as possible, because RINEX is a de facto standard
in exchanging GNSS observation data and potential users of GTEX would be familiar with RINEX. Since
the 1st Asia-Oceania Space Weather Alliance (AOSWA) workshop held at Chiang Mai, Thailand during
22-24 February, 2012 (AOSWA, 2013), we have collaborated with several organizations researchingionosphere and space weather in Korea, Thailand, Indonesia, Malaysia, and China to share the GTEX dataof each country and to develop dense wide-coverage TEC maps in the Asia-Oceania region. The GTEX
has been adopted as the basis of ionospheric data sharing by Ionospheric Studies Task Force (ISTF)
established in the Asia-Pacific Region of International Civil Aviation Organization (ICAO), which is
working on ionospheric characterization for facilitation of GNSS implementation for aviation (ICAO/ISTF,
2012).
NICT, a delegate of Japan, proposed “GNSS-TEC exchange format (GTEX)” as a format to promoteinternational exchange and sharing of GNSS-TEC data in an input document to the meeting of Working
Group 3L-3 (trans-ionospheric propagation) of ITU-R held in Geneva from 19 to 26 June 2013. The
document was discussed in the larger context of the need to incorporate new digital products and SG3DB
databanks. As a result, the GTEX was included in a Chairman’s report towards the definition of new
digital products for transionospheric propagation.
In order to investigate drift velocities of the ionospheric irregularities at high-latitudes, threedual-frequency GNSS receivers with mutual distances of 172-242 m have been operated at EISCAT
Tromso radar site since September 2012. The receivers sample GNSS signals at a rate of 50 Hz. We
observed the ionospheric scintillation associated with aurora activities.
G7.6 Airglow imagers
The Solar-Terrestrial Environment Laboratory (STEL), Nagoya University is conducting various
optical and radio measurements of ionosphere and thermosphere at 13 ground-based stations over theworld. The STEL have started new routine measurements of VLF/ELF waves at Athabasca (54.7°N,
246.7°E), Canada since September 25, 2012, in collaboration with Kanazawa University and Athabasca
University. STEL also started routine measurements of ionospheric airglow emssions at 630-nm at
Haleakala, Hawai (20.7°N, 203.7°E) in March 2013 in collaboration with Kyoto University and Tohoku
University. These ground-based data are available from STEL web site.
Quick-look spectra are available at http://stdb2.stelab.nagoya-u.ac.jp/vlf/index.html
Another all-sky airglow imager has been operational in Longyeabyen, Norway (78.2N, 15.6E;
AACGM latitude 75.3) since October 2011 by University of Electro-Communications. The ASI isequipped with an EMCCD camera whose imaging part has 512x512 pixels. The imager has two different
passband interference filters for airglow measurements, one at 630.0 nm and the other at 557.7 nm, whichenables us to study various phenomena in the polar cap ionosphere, such as cusp aurora, polar cap aurora
and polar cap patches. The exposure time for 630.0 nm emissions is 4.0 s. Every 56 s (= 14 x 4 s) 557.7 nm
emissions are observed with an exposure time of 1.0 s by rotating the filter turret. Background continuum
emission from the sky is sampled every 10 min at a wavelength of 572.5 nm and is used to derive theabsolute intensity of the airglow lines. Optical images obtained by this ASI will be used for better
understanding the dynamic nature of polar cap ionospheric phenomena such as polar cap patches and polar
cap arcs in near future.
G7.7 Satellite observations
Airglow emissions at the lower-thermosphere (O2 762 nm, 95km alt.) and the upper-thermosphere (O630 nm, 250 km alt.) are measured with IMAP/VISI on the international space station. We find many
concentric gravity wave event in the O2 emission, and equatorial anomaly and plasma bubbles in O630 nm
emission. We are also conducting the ground-based all-sky imaging measurement at the summit of
Haleakala, Maui, Hawaii to carry out simultaneous measurement of airglow emissions with IMAP/VISI.

15

In order to monitor space environment and its temporal variations, JAXA Space Environment Grouphas been developing space radiation detectors as well as magnetometers and installing them on Low Earth
Orbit (LEO) satellites, Geostationary Orbit (GEO) satellites, Geostationary Transfer Orbit (GTO) satellite,
Quasi Zenith Orbit (QZO) satellite and Japanese Experimental Module (JEM) of the International Space
Station (ISS). We are using these space environment data to know the situation of space environment andto provide warning messages to the satellite operators as well as ISS/JEM manager, when the spaceenvironment will be harmful. Based on our observation data, we also have constructed an advanced
electron belt model for the use in satellite manufacturing. With space radiation data obtained by JAXA
satellites and ISS, some findings related to the space radiation environment have been obtained. We will
review our activities related to the space environment research and development in JAXA. [Obara, 2012a]
The Space Environment Data Acquisition equipment (SEDA), which was mounted on the Exposed
Facility (EF) of the Japanese Experiment Module (JEM, also known as “Kibo”) on the International Space
Station (ISS), was developed to measure the space environment along the orbit of the ISS. This payload
module, called the SEDA-Attached Payload (AP), began to measure the space environment in August
2009. This paper reports the mission objectives, instrumentation, and current status of the SEDA-AP.
[Obara, 2012b]
G7.8 Instruments for planetary sciences
IPRT (Iitate Planetary Radio Telescope) is a ground-based VHF-UHF radio telescope developed by
Tohoku University, which has been developed at the Iitate observatory in Fukushima prefecture Japan
since 2000 and dedicated for the observations of solar and planetary radio emissions. IPRT has two
distinctive radio receivers; one is a low noise and quite stable receiver tuned at 325MHz and 785MHz, andanother one is a 100-500MHz spectro-polarimeter, named AMATERAS (the Assembly of Metric-band
Aperture TElescope and Real-time Analysis System). The former is mainly used for observing Jupiter’s
synchrotron emission with the sensitivity of 0.1Jy, and enables us to investigate dynamical variations ofJupiter’s deep inner magnetosphere. The latter is used for observing solar radio bursts with 10ms
accumulation time and 61 KHz bandwidth, and enables us to clarify various micro structure ofwave-particle or wave-wave interactions generated in the solar corona region.
The Jovian and solar radio wave receiver system in HF range (15-40MHz) was continuously operated
at Iitate Observatory of Tohoku University. Spectrograms of Jovian and solar radio wave with a time
resolution of 0.5 sec were automatically archived and provided to the researchers through the internet. The
discussion on combining this data archive with that of Nancay observatory has started between the
researches of Paris Astronomical Observatory and Tohoku University. In addition, the operation of RF
waveform recording receiver system for the observation of Jovian decametric S-bursts was started at Iitate
Observatory since October 2013. The data will be useful for the analysis of the repetition of S-bursts,
which is caused by Jovian Ionospheric Alfven Resonator (IAR).

16

References--- 2011 --Adachi, T., Y. Otsuka, M. Yamaoka, M. Yamamoto, K. Shiokawa, A. B. Chen, and R. Hsu [2011], “First
satellite-imaging observation of medium-scale traveling ionospheric disturbances by
FORMOSAT-2/ISUAL,” Geophys. Res. Lett., 38, L04101, doi:10.1029/2010GL046268.
Bagiya, M. S., K. N. Iyer, H. P. Joshi, S. V. Thampi, T. Tsugawa, S. Ravindran, R. Sridharan, and B. M.
Pathan [2011], “Low-latitude ionospheric-thermospheric response to storm time electrodynamical
coupling between high and low latitudes,” J. Geophys. Res., 116, A01303,
doi:10.1029/2010JA015845.
Balan, N., M. Yamamoto, V. Sreeja, I. S. Batista, K. J. W. Lynn, M. A. Abdu, S. Ravindran, T. Kikuchi, Y.
Otsuka, K. Shiokawa, and S. Alex [2011], “A statistical study of the response of dayside equatorial F2
layer to the main phase of intense geomagnetic storms,” J. Geophys. Res., 116, A03323,
doi:10.1029/2010JA016001.
Balan, N., M. Yamamoto, J. Y. Liu, Y. Otsuka, H. Liu, and H. Luhr [2011], “New aspects ofthermospheric and ionospheric storms revealed by CHAMP,” J. Geophys. Res., 116, A07305,
doi:10.1029/2010JA016399.
Chen, C. H., A. Saito, C. H. Lin, J. Y. Liu, H. F. Tsai, T. Tsugawa, Y. Otsuka, M. Nishioka, and M.
Matsumura [2011], “Long-distance propagation of ionospheric disturbance generated by the 2011 off
the Pacific coast of Tohoku Earthquake,” Earth Planets and Space, 63, 881-884.
Furumoto, J., T. Shinoda, A. Matsugatani, and T. Tsuda [2011], “Measurements of Detailed Temperature
Profiles within the Radar Range Gate Using the Range Imaging Technique,” J. Atmos. Ocean. Tech.,
Volume 28, Issue 1, 22-36.
Hosokawa, K., J. I. Moen, K. Shiokawa, and Y. Otsuka [2011a], “Decay of polar cap patch,” Journal ofGeophysical Research, 116, doi:10.1029/2010JA016297.
Hosokawa, K., J. I. Moen, K. Shiokawa, and Y. Otsuka [2011b], “Motion of polar cap arcs,” Journal ofGeophysical Research, 116, doi:10.1029/2010JA015906.
Jayachandran, P. T., C. Watson, I. J. Rae, J. W. MacDougall, D. W. Danskin, R. Chadwick1, T. D. Kelly,
P. Prikryl, K. Meziane, and K. Shiokawa [2011], “High-Latitude GPS TEC Changes Associated witha
SuddenMagnetosphericCompression,”
Geophys.
Res.
Lett.,
38,
L23104,
doi:10.1029/2011GL050041.
Jin, H.; Miyoshi, Y.; Fujiwara, H.; Shinagawa, H.; Terada, K.; Terada, N.; Ishii, M.; Otsuka, Y.; Saito, A.
[2011], “Vertical connection from the tropospheric activities to the ionospheric longitudinal structure
simulated by a new Earth's whole atmosphere-ionosphere coupled model,” J. Geophys. Res., 116,
A01316, doi:10.1029/2010JA015925.
Kenpankho, P., P. Supnithi, T. Tsugawa, and T. Maruyama [2011a], “Variation of ionospheric slab
thickness observations at Chumphon equatorial magnetic location,” Earth Planets and Space, 63,
359-364.
Kenpankho, P., K. Watthanasangmechai, P. Supnithi, T. Tsugawa, and T. Maruyama [2011b],“Comparison of GPS TEC measurements with IRI TEC prediction at an equatorial latitude station,
Chumphon, Thailand,” Earth Planets and Space, 63, 365-370.
Liu, H., and M. Yamamoto [2011], “Weakening of the mid-latitude summer night anomaly during
geomagnetic storms,” Earth Planets and Space, 63, 371-375.
Liu, H., E. Doornbos, M. Yamamoto, S. T. Ram [2011a], “Strong thermosphere cooling during the 2009
major statratosphere warming,” Geophys. Res. Lett., 38, L12102, doi:10.1029/2011GL047898.
Liu, H., M. Yamamoto, S. Tulasi Ram, T. Tsugawa, Y. Otsuka, C. Stolle, E. Doornbos, K. Yumoto, T.
Nagatsuma [2011b], “Equatorial Electrodynamics and Neutral Background in the Asian Sector
During the 2009 Stratospheric Sudden Warming,” J. Geophys. Res., 116, A08308,
doi:10.1029/2011JA016607.

17

Luhr, H. H. Liu,J. Park [2011a], “New aspects of the coupling between thermosphere and ionosphere, withspecial regards to CHAMP mission results,” Aeronomy of the Earth's atmosphere and ionosphere, eds.
Abdu, M. A., Pancheva, D., Springer, 303-316.
Luhr, H. J. Park, P. Ritter, H. Liu [2011b], “In-situ CHAMP observations of the ionosphere-thermosphere
coupling,” Space Sci. Rev., doi:10.1007/s11214-011-9798-4.
Lynn, K. J. W., Y. Otsuka, and K. Shiokawa [2011], “Simultaneous observations at Darwin of equatorial
bubbles by ionosonde-based range/time displays and airglow imaging,” Geophys. Res. Lett., 38, 23,
doi:10.1029/2011GL049856.
Makela, J., and Y. Otsuka [2011], “Overview of Nighttime Ionospheric Instabilities at Low- and
Mid-Latitudes: Coupling Aspects Resulting in Structuring at the Mesoscale,” Space Sci. Rev.,
DOI:10.1007/s11214-011-9816-6.
Maruyama, T., T. Tsugawa, H. Kato, A. Saito, Y. Otsuka, and M. Nishioka [2011], “Ionospheric multiple
stratifications and irregularities induced by the 2011 off the Pacific coast of Tohoku Earthquake,”
Earth Planets and Space, 63, 869-873.
Matsumura, M., A. Saito, T. Iyemori, H. Shinagawa, T. Tsugawa, Y. Otsuka, M. Nishioka, and C. H. Chen
[2011], “Numerical simulations of atmospheric waves excited by the 2011 off the Pacific coast of
Tohoku Earthquake,” Earth Planets and Space, 63, 885-889.
Miyoshi, Y., H. Fujiwara, H. Jin, H, Shinagawa, H. Liu , K. Terada [2011], “Model study on the formationof the equatorial mass density anomaly in the thermosphere,” J. Geophys. Res., 116, A05322,
doi:10.1029/2010JA016315.
Nomura, R., K. Shiokawa, S. Pilipenko, B. Shevtsov [2011], “Frequency-dependent polarization
characteristics of Pc1 geomagnetic pulsations observed by multi-point ground stations at low
latitudes,” J. Geophys. Res., 116, A01204, doi:10.1029/2010JA015684.
Ohya, H., K. Shiokawa, and Y. Miyoshi [2011], “Long-term variations in the tweek reflection height in theD- and lower E-region ionosphere,” J. Geophys. Res., 116, A10322, doi:10.1029/2011JA016800.
Rao, N. V., T. Tsuda, S. Gurubaran, Y. Miyoshi, and H. Fujiwara [2011], “On the occurrence andvariability of the terdiurnal tide in the equatorial Mesosphere and Lower Thermosphere and its
comparison with the Kyushu-GCM,” J. Geophys. Res.,VOL. 116, D02117, 13 PP.
Rao, N. V., and T. Tsuda [2011], “Diurnal variation of short-period (20-120min.) gravity waves in theequatorial Mesosphere and lower Thermosphere and its relation to deep tropical convention,” Annales
Geophysicae, Volume 29, Number 4, 623-629, doi: 10.5194/angeo-29-623-2011,623-629.
Rao, N. V., N., Y. Shibagaki, and T.Tsuda [2011], “Diurnal variation of short-period (20-120 min) gravity
waves in the equatorial Mesosphere and Lower Thermosphere and its relation to deep tropicalconvection,” Annales Geophysicae, Volume 29, Number 4.
Saito, A., T. Tsugawa, Y. Otsuka, M. Nishioka, T. Iyemori, M. Matsumura, S. Saito, C. H. Chen, Y. Goi,
and N. Choosakul [2011], “Acoustic resonance and plasma depletion detected by GPS total electron
content observation after the 2011 off the Pacific coast of Tohoku Earthquake,” Earth Planets andSpace, 63, 863-867.
Schekotov A., V. Pilipenko, K. Shiokawa, and E. Fedorov [2011], “ULF impulsive magnetic response at
mid-latitudes to lightning activity,” Earth Planets Space, 63, 119-128.
Sudarsanam, Tulasi Ram, M. Yamamoto, H. Liu, B. Veenadhari and S. Alex [2011], “Comment on
Westward electric field penetration to the dayside equatorial ionosphere during the main phase of thegeomagnetic storm on 22 July 2009,” Journal of Geophysical Research, 116, A06315,
doi:10.1029/2011JA016634.
Thampi, S. V., M. Yamamoto, C. Lin, and H. Liu [2011], “Comparison of FORMOSAT-3/COSMIC radio
occultation
measurements
with
radio
tomography,”
Radio
Sci.,
46,
RS3001,
doi:10.1029/2010RS004431.

18

Thampi, S. V., N. Balan, C.-H. Lin, H. Liu, and M. Yamamoto [2011], “Mid-latitude Summer Night time
Anomaly (MSNA) Observations and Model Simulations,” Ann. Geophys., 29, 157-165.
Tsuda, T., L. Xian, H. Hayashi, and Noersomadi [2011], “Analysis of vertical wave number spectrum of
atmospheric gravity waves in the stratosphere using COSMIC GPS radio occultation data,” Atmos.
Meas. Tech., 4, 1627-1636, doi:10.5194/amt-4-1627-2011.
Tsugawa, T., A. Saito, Y. Otsuka, M. Nishioka, T. Maruyama, H. Kato, T. Nagatsuma, and K. T. Murata[2011], “Ionospheric disturbances detected by GPS total electron content observation after the 2011
off the Pacific coast of Tohoku Earthquake,” Earth Planets and Space, 63, 875-879.
Tsuda, T. T., S. Nozawa, T. D. Kawahara, T. Kawabata, N. Saito, S. Wada, C. M. Hall, S. Oyama, Y.
Ogawa, S. Suzuki, T. Ogawa, T. Takahashi, H. Fujiwara, R. Fujii, N. Matuura and A. Brekke [2011],“Fine structure of sporadic sodium layer observed with a sodium lidar at Tromso, Norway,” Geophys.
Res. Lett., 38 (18), DOI: 10.1029/2011GL048685.
Tsunoda, R. T., M. Yamamoto, T. Tsugawa, T. L. Hoang, S. Tulasi Ram, S. V. Thampi, H. D. Chau, and T.
Nagatsuma [2011], “On seeding, large-scale wave structure, equatorial spread F, and scintillations
over Vietnam,” Geophysical Research Letters, 38, L20102, doi:10.1029/2011GL049173.
Yamazaki, Y.; Yumoto, K.; Uozumi, T.; Cardinal, M. G. [2011], “Intensity variations of the equivalent Sq
current system along the 210° magnetic meridian,” J. Geophys. Res., 116, A10308,
doi:10.1029/2011JA016632.
Yokoyama, T., M. Yamamoto, Y. Otsuka, M. Nishioka, T. Tsugawa, S. Watanabe, and R. F. Pfaff [2011a],“On post-midnight low-latitude ionospheric irregularities during solar minimum: 1. Equatorial
Atmosphere Radar and GPS-TEC observations in Indonesia,” J. Geophys. Res., 116, A11325,
doi:10.1029/2011JA016797.
Yokoyama, T., R. F. Pfaff, P. A. Roddy, M. Yamamoto, and Y. Otsuka [2011b], “On post-midnight
low-latitude ionospheric irregularities during solar minimum: 2. C/NOFS observations andcomparison with Equatorial Atmosphere Radar,” J. Geophys. Res., 116, A11326,
doi:10.1029/2011JA016798.
--- 2012 --Ando, H., T. Imamura, and T. Tsuda [2012], “Vertical Wavenumber Spectra of Gravity Waves in theMartian Atmosphere Obtained from Mars Global Surveyor Radio Occultation Data,” J. Atmos. Sci.,
69-Issue9, pp.2906-2912.
Chang, L. C., W. E. Ward, S. E. Palo, J. Du, D.-Y. Wang, H.-L. Liu, M. E. Hagan, Y. Portnyagin, J.
Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, P. Batista, B. Clemesha, A. H.
Manson, D. M. Riggin, C.-Y. She, T. Tsuda and T. Yuan [2012], “Comparison of diurnal tide inmodels and ground-based observations during the 2005 equinox CAWSES tidal campaign,” Journalof Atmospheric and Solar-Terrestrial Physics, Volumes 78-79, Pages 19-30.
Dahlgren, H., J. L. Semeter, K. Hosokawa, M. J. Nicolls, T. W. Butler, M. G. Johnsen, a nd K. Shiokawa[2012a], “Direct Three-dimensional Imaging of Polar Ionospheric Structures with the Resolute Bay
Incoherent Scatter Radar,” Geophys. Res. Lett., Vol. 39, No. 5, L05104, doi:10.1029/2012GL050895.
Dahlgren, H., G. W. Perry, J. L. Semeter, J.-P. St.-Maurice, K. Hosokawa, M. J. Nicolls, M. Greffen, K.
Shiokawa, and C. Heinselman [2012b], “Space-time variability of polar cap patches: Direct evidence
for internal plasma structuring,” J. Geophys. Res., 117, A09312, doi:10.1029/2012JA017961.
Fujii, R., O. Amm, H. Vanhamäki, A. Yoshikawa, and A. Ieda [2012], “An application of the finite length
Cowling channel model to auroral arcs with longitudinal variations,” J. Geophys. Res., 117, A11217,
doi:10.1029/2012JA017953.
Fujiwara, H., S. Nozawa, S. Maeda, Y. Ogawa, Y. Miyoshi, H. Jin, H. Shinagawa, and K. Terada [2012],“Polar cap ionosphere and thermosphere during the solar minimum period: EISCAT Svalbard radarobservations and GCM simulations,” Earth Planets Space, 64 (6), 459-465,
doi:10.5047/eps.2011.05.023.

19

Fukushima, D., K. Shiokawa, Y. Otsuka, and T. Ogawa [2012], “Observation of equatorial nighttime
medium-scale traveling ionospheric disturbances in 630-nm airglow images over 7 years,” J. Geophys.
Res., 117, A10324, doi:10.1029/2012JA017758.
Iwai, K., F. Tsuchiya, A. Morioka, H. Misawa [2012a], “IPRT/AMATERAS: A New Metric Spectrum
Observation System for Solar Radio Bursts,” Solar Phys., 277, 2, 447-457,
10.1007/s11207-011-9919-y.
Iwai, K., Y. Miyoshi, S. Masuda, M. Shimojo, D. Shiota, S. Inoue, F. Tsuchiya, A. Morioka, and H.
Misawa [2012b], “Solar Radio Type-I Noise Storm Modulated by Coronal Mass Ejections,” ApJ 744
167 doi:10.1088/0004-637X/744/2/167.
Iwai, K., H. Misawa, F. Tsuchiya, A. Morioka, S. Masuda, and Y. Miyoshi [2012c], “Survey ofAccelerated Particles in a Solar Active Region Using Hinode/XRT and Ground-Based Type-I Radio
Burst Observations,” Hinode-3, ASP Conference Series, Vol. 454, 249-253.
Jin, H., Y. Miyoshi, D. Pancheva, P. Mukhtarov, H. Fujiwara, H. Shinagawa [2012], “Response of
migrating tides to the stratospheric sudden warming in 2009 and their effects on the ionospherestudied by a whole atmosphere-ionosphere model GAIA with COSMIC and TIMED/SABER
observations,” J. Geophys. Res., 117, A10323, DOI: 10.1029/2012JA017650.
Jayachandran, P. T., K. Hosokawa, K. Shiokawa, Y. Otsuka, C. W. Watson, S. C. Mushini, J. W.
MacDougall, P. Prikryl, R. Chadwick, and T. D. Kelly [2012], “GPS total electron content variations
associated with poleward moving sun aligned arcs,” J. Geophys. Res., 117, A5,
doi:10.1029/2011ja017423.
Kakinami, Y., M. Kamogawa, Y. Tanioka, S. Watanabe, A. R. Gusman, J.-Y. Liu, Y. Watanabe, and T.
Mogi [2012], “Tsunamigenic ionospheric hole,” Geophys. Res. Lett., 39, L00G27,
doi:10.1029/2011GL050159.
Kim, K.-H., D.-H. Lee, K. Shiokawa, E. Lee, J.-S. Park, H.-J. Kwon, V. Angelopoulos, Y.-D. Park, J.
Hwang, N. Nishitani, T. Hori, K. Koga, T. Obara, K. Yumoto, and D. G. Baishev [2012],“Magnetospheric responses to the passage of the interplanetary shock on 24 November 2008,” J.
Geophys. Res., 117, doi:10.1029/2012JA017871.
Kimura, T., B. Cecconi, P. Zarka, Y. Kasaba, F. Tsuchiya, H. Misawa, and A. Morioka [2012],“Polarization and arrival direction of Jovian Quasi-Periodic bursts observed by Cassini,” J. Geophys
Res., 117, doi:10.1029/2012JA017506.
Koustov, A. V., K. Hosokawa, N. Nishitani, K. Shiokawa, and H. Liu [2012], “Signatures of moving polar
cap arcs in the F-region PolarDARN echoes,” Ann. Geophys., 30, 441-455.
Kurita, S., Y. Katoh, Y. Omura, V. Angelopoulos, C. M. Cully, O. Le Contel, and H. Misawa [2012a],“THEMIS observation of chorus elements without a gap at half the gyrofrequency,” J. Gephys. Res.
Space Phys., 117 (A11), DOI:10.1029/2012JA018076.
Kurita, S., H. Misawa, C. M. Cully, O. Le Contel, and V. Angelopoulos [2012b], “Source location offalling tone chorus,” Geophys. Res. Lett., 39 (22), DOI:10.1029/2012GL053929.
KuniiI, M., H. Seko, M. Ueno, Y. Shoji, and T.Tsuda [2012], “Impact of Assimilation of GPS Radio
Occultation Refractivity on the Forecast of Typhoon Usagi in 2007,” J. Meteorol. Soc. Japan Vol. 90,
No. 2.
Matsuda, K., N. Terada, Y. Katoh and H. Misawa [2012], “A simulation study of the current-voltage
relationship of the Io tail aurora,” J. Geophys. Res., 117, doi:10.1029/ 2012JA017790.
Maruyama, T., M. Ishii, T. Tsugawa, H. Kato, and M. Nishioka [2012], “Rayleigh wave signature in
ionograms induced by strong earthquakes,” J. Geophys. Res., 117, A08306,
doi:10.1029/2012JA017952.
Miyoshi, Y., H. Fujiwara, H. Jin, H, Shinagawa, H. Liu [2012], “Numerical simulation of the equatorial
wind jet in the thermosphere,” J. Geophys. Res., 117, A03309, doi:10.1029/2011JA017373.

20

Morioka, A. and Y. Miyoshi [2012], “Two-step acceleration of auroral particles at substorm onset as
derived from auroral kilometric radiation spectra,” in Auroral Phenomenology and Magnetospheric
Processes: Earth and Other Planets, Geophys. Monogr.Series 197, AGU, Washington, DC.,
doi:10.1029/2011GM001160.
Morioka, A., Y. Miyoshi, N. Kitamura, H. Misawa, F. Tsuchiya, J. D. Menietti, and F. Honary [2012a],“Fundamental characteristics of field-aligned auroral acceleration derived from AKR spectra,” J.
Geophys. Res., 117, A02213, doi:10.1029/2011JA017137.
Morioka, A., Y. Miyoshi, N. Kitamura, H. Misawa, F. Tsuchiya, J. D. Menietti, and F. Honary [2012b],“Fundamental characteristics of field-aligned auroral acceleration derived from AKR spectra,” J.
Geophys. Res., 117., A02213, doi:10.1029/2011JA017137.
Muraki, Y., K. Koga, T. Goka, H. Matsumoto, T. Obara, O. Okudaira, S. Shibata and T. Yamamoto [2012],“Measurement by FIB on the ISS: Two Emissions of Solar Neutrons Detected?,” Advances in
Astronomy, 1-14, doi:10.1155/2012/379304.
Nishoka, M., Y. Otsuka, K. Shiokawa, T. Tsugawa, Effendy, P. Supnithi, T. Nagatsuma, and K. T. Murata[2012], “On post-midnight field-aligned irregularities observed with a 30.8-MHz radar at a low
latitude: Comparison with F-layer altitude near the geomagnetic equator,” J. Geophys. Res., 117, A8,
A08337, doi:10.1029/2012JA017692.
Nishiyama, T., T. Sakanoi, Y. Miyoshi, R. Kataoka, D. Hampton, Y. Katoh, K. Asamura, and S. Okano[2012], “Fine scale structures of pulsating auroras in the early recovery phase of substorm using
ground-based EMCCD camera,” J. Geophys. Res., 117, A10229, doi:10.1029/2012JA017921.
Nomura, R., K. Shiokawa, K. Sakaguchi, Y. Otsuka, and M. Connors [2012], “Polarization of Pc1/EMIC
waves and related proton auroras observed at subauroral latitudes,” J. Geophys. Res., 117, A02318,
doi:10.1029/2011JA017241.
Nozawa, S., C. M. Hall, M. Tsutsumi, A. Brekke, Y. Ogawa, T. T. Tsuda, S. Oyama, S., R. Fujii [2012],“Mean winds, tides, and quasi-2 day waves above Bear Island,” J. Atmos. Solar-Terr. Phys., 90,
26-44, DOI:10.1016/j.jastp.2012.05.002.
Obara, T. [2012a], “Space weather research and application for a long-term sustainability of the outerspace activities,” JSTS, 26 (2), 1-17.
Obara, T. [2012b], “Space Environment Measurements by JAXA satellites and ISS,” Acta Astronautica,
pp.1-10, doi:10.1016/j.actaastro.2011.08.009.
Obara, T. [2012c], “Space Environment Measurement by ISS / SEDA-AP,” Electronics andCommunications in Japan, 95 (9), 10-16, doi:10.1002/ecj.11418.
Ogawa, T., N. Nishitani, T. Tsugawa, and K. Shiokawa [2012], “Giant ionospheric disturbances observedwith the SuperDAN Hokkaido HF radar and GPS netwoork after the 2011 Tohoku earthquake,” Earth
Planets Space, 64, 1295-1307.
Ohya, H., F. Tsuchiya, H. Nakata, K. Shiokawa, Y. Miyoshi, K. Yamashita, and Y. Takahashi [2012],“Reflection height of daytime tweek atmospherics during the solar eclipse of 22 July 2009,” J.
Geophys. Res. Space Phys., 117 (A11), DOI: 10.1029/2012JA018151.
Otsuka, Y., K. Shiokawa, and T. Ogawa [2012a], “Disappearance of equatorial plasma bubble after
interaction with mid-latitude medium-scale traveling ionospheric disturbance,” Geophys. Res. Lett.,
39, L14105, doi:10.1029/2012GL052286.
Otsuka, Y. [2012b], “Seasonal and Local Time Variations of E-Region Field-Aligned Irregularities
Observed with 30.8-MHz Radar at Kototabang, Indonesia,” Special issue of International Journal ofGeophysics, “Low-latitude Mesosphere, Thermosphere and Ionosphere,” vol. 2012, 695793,
doi:10.1155/2012/695793.
Otsuka, Y., K. Shiokawa, M. Nishioka and Effendy [2012c], “VHF Radar Observations of Post-Midnight
F-Region Field-Aligned Irregularities over Indonesia during Solar Minimum,” Indian Journal ofRadio and Space Physics (IJRSP), 41, 199-207.

21

Oyama, S., J. Kurihara, B. J. Watkins, T. T. Tsuda, and T. Takahashi [2012], “Temporal variations of theion-neutral collision frequency from EISCAT observations in the polar lower ionosphere during
periods of geomagnetic disturbances,” J. Geophys. Res., 117, A05308, doi:10.1029/2011JA017159.
Ozaki, M., S. Yagitani, K. Ishizaka, K. Shiokawa, Y. Miyoshi, A. Kadokura, H. Yamagishi, R. Kataoka, A.
Ieda, Y. Ebihara, N. Sato, and I. Nagano [2012], “Observed correlation between pulsating aurora andchorus waves at Syowa Station in Antarctica: a case study,” J. Geophys. Res., 117, A08211,
doi:10.1029/2011JA017478.
Pancheva, D.; Miyoshi, Y.; Mukhtarov, P.; Jin, H.; Shinagawa, H.; Fujiwara, H. [2012], “Global responseof the ionosphere to atmospheric tides forced from below: Comparison between COSMIC
measurements and simulations by atmosphere-ionosphere coupled model GAIA,” J. Geophys. Res.,
117, A07319, doi:10.1029/2011JA017452.
Patra, A. K., P. P. Chaitanya, N. Mizutani, Y. Otsuka, T. Yokoyama, M. Yamamoto [2012], “A
comparative study of equatorial daytime vertical E x B drift in the Indian and Indonesian sectors
based on 150 km echoes,” J. Geophys. Res., 117, A11312, doi:10.1029/2012JA018053.
Rao, N. V., T. Tsuda, D. M. Riggin, S. Gurubaran, I. M. Reid, and R. A. Vincent [2012], “Long-term
variability of mean winds in the mesosphere and lower thermosphere at low latitudes,” J. Geophys.
Res., 117, A10312.
Rao, N. V., T. Tsuda and Y. Kawatani [2012], “A remarkable correlation between short period gravity
waves and semiannual oscillation of the zonal wind in the equatorial mesopause region,” Ann.
Geophys., 30, 703-710.
Sakaguchi, K., T. Nagatsuma, T. Ogawa, T. Obara, O. A. Troshichev [2012a], “Ionospheric Pc5 plasma
oscillations observed by the King Salmon HF radar and their comparison with geomagnetic pulsations
on the ground and in geostationary orbit,” J. Geophys. Res., 117, A03218,
doi:10.1029/2011JA016923.
Sakaguchi, K., Y. Miyoshi, E. Spanswick, E. Donovan, I. R. Mann, V. Jordanova, K. Shiokawa, and M.
Connors, J. C. Green [2012b], “Visualization of ion cyclotron wave and particle interactions in the
inner magnetosphere via THEMIS-ASI observations,” J. Geophys. Res., 117 (A10), A10204,
doi:10.1029/2012ja018180.
Sakanoi, T. Y. Obuchi, Y. Ebihara, Y. Miyoshi, K. Asamura, A. Yamazaki, Y. Kasaba, M. Hirahara, T.
Nishiyama, and S. Okano [2012], “Fine-scale characteristics of black aurora and its generation
process,” in Auroral Phenomenology and Magnetospheric Processes: Earth and other Planets, AGU
Geophysical Monograph 197, edited by A. Keiling et al., Amer. Geophys. Union, Washington, D. C.,
271-278.
Sarma, T. V. C., P. Srinivasulu, and T.Tsuda [2012], “Preliminary observation of temperature profiles byradio acoustic sounding system (RASS) with a 1,280 MHz lower atmospheric wind profiler atGadanki, India,” Atmos. Meas. Tech. Discuss., 5, pp4447-4472.
Sato, Y., T. Ono, N. Sato, and Y. Ogawa [2012], “First observations of 4fce auroral roar emissions,”
Geophys. Res. Lett., 39 (7), DOI: 10.1029/2012GL051205.
Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, and S. Nozawa [2012], “Motion of high-latitude nighttime
medium-scale traveling ionospheric disturbances associated with auroral brightening,” J. Geophys.
Res., 117, A10316, doi:10.1029/2012JA017928.
Sudarsanam, Tulasi Ram, M. Yamamoto, R. T. Tsunoda and S. V. Thampi [2012], “On the application ofdifferential phase measurements to study the zonal large scale wave structure (LSWS) in theionospheric electron content,” Radio Science, 47, RS2001, doi:10.1029/2011RS004870.
Sudarsanam, Tulasi Ram, M. Yamamoto, B. Veenadhari and Sandeep Kumar [2012], “Corotating
Interaction Regions (CIRs) at sub-harmonic solar rotational periods and their impact on
Ionosphere-Thermosphere system during the extreme low solar activity year, 2008,” Indian Journal ofRadio and Space Physics, 2011-SP-IJRSP-001, 41, 294-305.

22

Tadokoro, H. H. Misawa, F. Tsuchiya, Y. Katoh, A. Morioka, and M. Yoneda [2012], “Effect of thephoto-dissociations on the spreading of OH and O cloud in Saturn's inner magnetosphere,” J.
Geophys Res. 117,doi:10.1029/2011JA017492.
Taguchi, S., K. Hosokawa, Y. Ogawa, T. Aoki, and M. Taguchi [2012], “Double bursts inside a
poleward-moving auroral form in the cusp,” J. Geophys. Res., 117, A12301,
doi:10.1029/2012JA018150.
Thampi, S. V., and Mamoru Yamamoto [2012], “Evolution of plasma bubbles over Vietnam region
observed using the CERTO beacon on 1 board C/NOFS satellite,” Indian Journal of Radio and Space
Physics, 2011-SP-IJRSP-004, 41, 233-239.
Uno, T., T. Sakanoi, C. Tao, and Y. Kasaba [2012], “The thermosphere of Jupiter investigated byground-based near infrared observations,” (in Japanese), Planetary People (Yuu-Sei-Jin), 21 (1),22-28.
Watthanasangmechai, K., P. Supnithi, S. Lerkvaranyu, T. Tsugawa, T. Nagatsuma, and T. Maruyama[2012], “TEC prediction with neural network for equatorial latitude station in Thailand,” Earth
Planets and Space, 64, 473-483.
Wichaipanich, N., P. Supnithi, T. Tsugawa, and T. Maruyama [2012], “Thailand low and equatorial
F2-layer peak electron density and comparison with IRI-2007 model,” Earth Planets and Space, 64,
485-491.
Yagi, M., F. Leblanc, J.Y. Chaufray, F. Gonzalez-Galindo, S. Hess, R. Modolo [2012], “Mars exospheric
thermal and non-thermal components: Seasonal and local variations,” Icarus, 221 (2), 682-693.
Yamagiwa, Y., A. Takagi, N. Yoshimura, M. Matsui, K. Tanaka, T. Abe, H. Sahara, and H. Fujii, Hironori[2012], “Verification Experiment of Bare Electrodynamic Tether Operation and Charged Particle
Collection Theory by Using Sounding Rocket,” (in Japanese), Aerospace Technology Japan, 11, 7-14,
doi:10.2322/astj.11.7.
Yamazaki, Y.; Richmond, A. D.; Yumoto, K [2012a], “Stratospheric warmings and the geomagnetic lunar
tide: 1958-2007,” J. Geophys. Res., 117, A04301, doi:10.1029/2012JA017514.
Yamazaki, Y.; Yumoto, K.; McNamara, D.; Hirooka, T.; Uozumi, T.; Kitamura, K.; Abe, S.; Ikeda, A.
[2012b], “Ionospheric current system during sudden stratospheric warming events,” J. Geophys. Res.,
117, A03334, doi:10.1029/2012JA017453.
Yoshikawa, I., F. Tsuchiya, and N. Terada [2012], “Small Scientific Sattelite No.1 Sprint-A/EXCEED
Project summary,” (in Japanese), Planetary People (Yuu-Sei-Jin), 21 (1), 16-21.
Yoshioka, K., I. Yoshikawa, F. Tsuchiya, M. Kagitani, G. Murakami, K. Sakai, and T. Homma [2012],“Feasibility study of EUV spectroscopic observation of the Io plasma torus from the Earth-orbiting
satellite EXCEED,” Planetary Space Science, 62, 1, 104-110, 10.1016/j.pss.2011.12.016.
--- 2013 --Hosokawa, K., J. I. Moen, K. Shiokawa, and Y. Otsuka [2013a], “Decay of polar cap patch,” Journal ofGeophysical Research, 117, doi:10.1029/2012JA018165.
Hosokawa, K., S. Taguchi, Y. Ogawa, and J. Sakai [2013b], “Two-dimensional direct imaging ofstructuring of polar cap patches,” Journal of Geophysical Research, 118, doi:10.1002/jgra.50577.
Ishiyama, K., A. Kumamoto, T. Ono, Y. Yamaguchi, J. Haruyama, M. Ohtake, Y. Katoh, N. Terada, and S.
Oshigami [2013], “Estimation of the permittivity and porosity of the lunar uppermost basalt layer
based on observations of impact craters by SELENE,” J. Geophys. Res. Planets, 118, 1453-1467,
doi:10.1002/jgre.20102.
Iwai, K., S. Masuda, Y. Miyoshi, F. Tsuchiya, A. Morioka, and H. Misawa [2013], “Peak flux distributionof solar radio Type-I bursts from highly resolved spectral observations,” Astrophys. J., 768:L2,
doi::10.1088/2041-8205/768/1/L2.

23

Iyemori, T., Y. Tanaka, Y. Odagi, Y. Sano, M. Takeda, M. Nose, M. Utsugi, D. Rosales, E. Choque, J.
Ishitsuka, S. Yamanaka, K. Nakanishi, M. Matsumura, and H. Shinagawa [2013], “Barometric andmagnetic observations of vertical acoustic resonance and resultant generation of field-aligned current
associated with earthquakes,” Earth Planets Space, 65, 901–909, doi:10.5047/eps.2013.02.002.
Katoh, Y. and Y. Omura [2013], “Effect of the background magnetic field inhomogeneity on generation
processes of whistler-mode chorus and hiss-like broadband emissions,” J. Geophys. Res. Space
Physics, 118, 4189-4198, doi:10.1002/jgra.50395.
Kimura, T., L. Lamy, C. Tao, S. V. Badman, S. Kasahara, B. Cecconi, P. Zarka, A. Morioka, Y. Miyoshi,
D. Maruno, Y. Kasaba, and M. Fujimoto [2013], “Long-term modulations of Saturn’s auroral radio
emissions by the solar wind and seasonalvariations controlled by the solar ultraviolet flux,” J.
Geophys. Res. Space Physics, 118, 7019?7035, doi:10.1002/2013JA018833.
Kita, H., H. Misawa, F. Tsuchiya, C. Tao, A. Morioka [2013], “Effect of solar UV/EUV heating on theintensity and spatial distribution of Jupiter's synchrotron radiation,” Journal of Geophysical Research,
Vol 118, Oct 2013, 6106-6115.
Kodama, K., M Kagitani, S. Okano and N. M. Schneider [2013], “First detection of [OI] 630 nm emission
in the Enceladus torus,” Geophys. Res. Lett., 40, 4177-4181, doi:10.1002/grl.50799.
Li, Guozhu, Baiqi Ning, M. A. Abdu, Yuchi Otsuka, T. Yokoyama, M. Yamamoto and Libo Liu [2013],“Longitudinal characteristics of spread F backscatter plumes observed with the EAR and Sanya VHF
radar in Southeast Asia,” J. Geophys. Res. Space Phys., 118 (10), 6544-6557, DOI:
10.1002/jgra.50581.
Liu, H., T. Hirano, S. Watanabe [2013a], “Empirical model of the thermospheric mass density based on
CHAMP satellite observations,” J. Geophys. Res., 118, 843-848, doi:10.1002/jgra50144.
Liu, H., H. Jin, Miyoshi, Y., H. Fujiwara, H, Shinagawa [2013b], “Upper atmosphere response to
stratosphere sudden warming: Local time and height dependence simulated by GAIA model,”Geophys. Res. Lett., 40, 635-640, doi:10.1002/grl.50146.
Lynn, K. J. W., Y. Otsuka, K. Shiokawa [2013], “Ionogram-based range-time displays for observing
relationships between ionosonde satellite traces, spread F and drifting optical plasma depletions,” J.
Atmos. Solar-Terr. Phys., 98, 105-112, doi:10.1016/j.jastp.2013.03.020.
Maruyama, T., G. Ma, and T. Tsugawa [2013], “Storm-induced plasma stream in the low-latitude to
midlatitude ionosphere,” J. Geophys. Res. Space Physics, 118, doi:10.1002/jgra.50541.
Matsuda, K., Y. Katoh, N. Terada, and H. Misawa [2013], “A simulation study of Io-related Jovian
decametric radiation: Control factor of occurrence probability,” J. Geophys. Res. Space Physics, 118,
5082-5098, doi:10.1002/jgra.50493.
Morioka, A., Y. Miyoshi, S. Kurita, Y. Kasaba, V. Angelopoulos, H. Misawa, H. Kojima, and J. P.
McFadden [2013], “Universal time control of AKR: Earth is a spin-modulated variable radio source,”
J. Geophys. Res. Space Physics, 118, 1123-1131, doi:10.1002/jgra.50180.
Muraki, Y., K. Koga, H. Matsumoto, O. Okudaira, S. Shibata, T. Goka, T. Obara, T. Yamamoto [2013],“Measurement of High-Energy Solar Neutrons with SEDA-FIB onboard the ISS,” Proc. 33rd
International Cosmic Ray Conference, pp.6,[astro-ph.IM] arXiv:1307.5376.
Nishioka, M., T. Tsugawa, M. Kubota, and M. Ishii [2013], “Concentric waves and short-period
oscillations observed in the ionosphere after the 2013 Moore EF5 tornado,” Geophys. Res. Lett., 40,
doi:10.1002/2013GL057963.
Obara, Takahiro, Ray Williamson, Jim Head, Werner Schmutz, Dalmiro Maia, Karel Kudela, Ken Murata,
Vladimir Kuzentsov, Jerome Lafeuille, and Ian Mann [2013], “Report and proposed candidate
guidelines of expert group C: Space Weather,” UN COPUOS Report, pp.53,
A/AC.105/C.1/2013/CRP.13.
Ogawa, Y., M. Sawatsubashi, S. C. Buchert, K. Hosokawa, S. Taguchi, S. Nozawa, S. Oyama, T. T. Tsuda,
and R. Fujii [2013], “Relationship between auroral substorm and ion upflow in the nightside polar
ionosphere,” J. Geophys. Res. Space Phys., 118 (11), 7426-7437, DOI:10.1002/2013JA018965.
24

Otsuka, Y., K. Suzuki, S. Nakagawa, M. Nishioka, K. Shiokawa, and T. Tsugawa [2013a], “GPSObservations of Medium-Scale Traveling Ionospheric Disturbances over Europe,” Ann. Geophys., 31,
163-172.
Otsuka, Y., N. Mizutani, K. Shiokawa, A. Patra, T. Yokoyama, and M. Yamamoto [2013b], “Drift
Velocities of 150-km Field-Aligned Irregularities Observed by the Equatorial Atmosphere Radar,”
Antarctic Record, 57(No.3), 369-378.
Otsuka, Y., N. Mizutani, K. Shiokawa, A. Patra, T. Yokoyama, and M. Yamamoto [2013], “Study of drift
velocity of 150-km height field-aligned irregularity structures by using the Equatorial Atmosphere
Radar,” (in Japanese), Arctic Record (ISSN 0085-7289), 57 (3), 369.
Nishioka, M., T. Maruyama, Y. Otsuka, T. Tsugawa, H. Ishibashi, K. Shiokawa, M. Ishii [2013],“Comparison of meridional thermospheric winds observed by ionosondes and Fabry-Perot
interferometers,” (in Japanese), Arctic Record (ISSN 0085-7289), 57 (3), 357.
Sai, K., Y. Katoh, N. Terada, and T. Ono [2013], “Effect of Background Magnetic Field on Turbulence
Driven by Magnetorotational Instability in Accretion Disks,” Astrophys. J., 767, 165,
doi:10.1088/0004-637X/767/2/165.
Saito, S., S.-I. Asasofu, S. Watari, N. Sato and H. Misawa [2013], “Geomagnetic storms and their sourceson the sun: the rising phase of the sunspot cycle,” Antarctic Record, 57 (1), 1-15.
Sato, K., M. Tsutsumi, T. Sato, T. Nakamura, A. Saito, Y. Tomikawa, K. Nishimura, H. Yamagishi, T.
Yamanouchi [2013], “Program of the Antarctic Syowa MST/IS radar (PANSY),” J. Atmos.
Solar-Terr., Physics, doi:10.1016/j.jastp.2013.08.022 , in print,. (accepted for publicaton in August,2013).
Sato, K., E. Realini, T. Tsuda, M. Oigawa, Y. Iwaki, Y. Shoji, and H. Seko [2013], “A High-Resolution
Precipitable Water Vapor Monitoring System Using a Dense Network of GNSS Receivers,” Journalof Disaster Research, Vol.8, No.1, Feb.2013, pp.37-47.
Shiokawa, K., M. Mori, Y. Otsuka, S. Oyama, S. Nozawa, S. Suzuki, and M. Connors [2013],“Observation of nighttime medium-scale travelling ionospheric disturbances by two 630-nm airglow
imagers near the auroral zone,” J. Atmos. Solar-Terr. Phys., 103, 184-194.
Shinagawa, H., T. Tsugawa, M. Matsumura, T. Iyemori, A. Saito, T. Maruyama, H. Jin, M. Nishioka, andY. Otsuka [2013], “A simulation study of ionospheric variations in the vicinity of the epicenter of the
Tohoku-oki earthquake on 11 March 2011,” Geophys. Res. Lett., 40, 5009–5013,
doi:10.1002/2013GL057627.
Sureshbabu, V. N., Anandan, V. K., Tsuda, T.，Furumoto, J., Rao, S. V. [2013], “Performance Analysis of
Optimum Tilt Angle and Beam Configuration to Derive Horizontal Wind Velocities by Postset Beam
Steering Technique,” IEEE Transactions on Geoscience and Remote Sensing, Volume: 51, Issue: 1
Page(s): 520-526, doi:10.1109/TGRS.2012.2200256.
Tanaka, Y., A. Shinbori, T. Hori, Y. Koyama, S. Abe, N. Umemura, Y. Sato, M. Yagi, S. UeNo, Satoru, A.
Yatagai, Y. Ogawa, and Y. Miyoshi [2013], “Analysis software for upper atmospheric data developedby the IUGONET project and its application to polar science,” Advances in Polar Science, 24(4-English), 231-240.
Tsuda, T. T., S. Nozawa, T. D. Kawahara, T. Kawabata, N. Saito, S. Wada, Y. Ogawa, S. Oyama, C. M.
Hall, M. Tsutsumi, M. K. Ejiri, S. Suzuki, T. Takahashi, and T. Nakamura [2013], “Decrease insodium density observed during auroral particle precipitation over Tromso, Norway,” Geophys. Res.
Lett., 40 (17), 4486-4490, DOI:10.1002/grl.50897.
Tsunoda, R. T., S. V. Thampi, T. T. Nguyen, and M. Yamamoto [2013], “On validating the relationship of
ionogram signatures,” J. Atmos. Solar-Terr. Phys., 103, 30-35, doi:10.1016/j.jastp.2012.11.003.
Yokoyama, T. [2013a], “Hemisphere-coupled modeling of nighttime medium-scale traveling ionosphericdisturbances,” Adv. Space Res., doi:10.1016/j.asr.2013.07.048.

25

Yokoyama, T. [2013b], “Scale dependence and frontal formation of nighttime medium-scale travelingionospheric disturbances,” Geophys. Res. Lett., 40, doi:10.1002/grl.50905.
Yoneda, M., F. Tsuchiya, H. Misawa, Bonfond B., Tao C., M. Kagitani and S. Okano [2013], “Io’s
volcanism controls Jupiter’s radio emissions,” Geophys. Res. Lett., 40, 671–675,
doi:10.1002/grl.50095.
Yoshioka, K., G. Murakami, A. Yamazaki, F. Tsuchiya, M. Kagitani, T. Sakanoi, T. Kimura, K. Uemizu,
K. Uji, I. Yoshikawa [2013], “The extreme ultraviolet spectroscope for planetary science, EXCEED,”
Planetary and Space Science, Volume 85, Pages 250-260, ISSN 0032-0633.

26