COMMISSION G: IONOSPHERIC RADIO AND PROPAGATION
G1. Ionospheric Observation Techniques
G1.1. Application of GPS to Ionospheric studies
dense GPS receiver network, GPS Earth Observation Network (GEONET), in which
about 1200 receivers cover
G1.2. Multiple Instruments and Campaigns
Institute of Information and Communications Technology (NICT) is conducting
Alaska Project in collaboration with Geophysical Institute,
TIDs and F-region ionospheric
irregularities were simultaneously observed in an observation campaign named
FRONT (F-region Radio and Optical measurement of the Nighttime TID). Saito et
al.  led the first FRONT campaign in May 1998. They employed the MU
radar, a GPS receiver network (GEONET), and a network of 630-nm all-sky
imagers. The observations were quite successful in finding a close relationship
between the wavelike structures of F-region field-aligned irregularities (FAIs) and medium-scale TIDs (MS-TIDs). There was the FRONT 2 campaign in August 1999 by
adding another 630-nm all-sky imager in
Iwagami et al.  conducted WAVE2000 (Waves
in Airglow Structures Experiment over
Coupling Processes in the Equatorial Atmosphere (CPEA)
A large VHF radar, Equatorial Atmosphere Radar (EAR), was installed in 2001 right on the equator in West Sumatra, Indonesia (0.20S, 100.32E) [Fukao et al., 2003a]. gCoupling Processes in the Equatorial Atmosphere (CPEA)h is a research program funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) as a Grant-in-Aid for Scientific Research on Priority Areas in the period from September 2001 to March 2007. CPEA studies dynamical coupling processes in the equatorial atmosphere by conducting various observations in the Indonesian equatorial region. EAR is the core facility for the program. As the geomagnetic latitude of the EAR site is 10.36N, it is a suitable location for investigating the low latitude ionosphere in the southern hemisphere [e.g., Fukao et al., 2003b].
(Sporadic-E Experiment over
On-going experiment and future plans
FERIX (F-region and E-region Coupling Study) is an on-going experiment to study electrodynamical coupling processes between ionospheric F- and E-regions. In June-August 2004, the MU radar observed the F-region FAIs and a portable radar observed the E-region FAIs. Both scattering volumes were connected with the same geomagnetic field line. The results showed clear correlation between FAIs in the both regions. In 2005 similar experiment continues with the MU radar and GEONET. Coordinated rocket-ground experiment in summer 2007 is proposed, which aims to study seeding mechanisms of MS-TIDs. Lithium-release from the rocket will be conducted to measure the neutral winds in the F-region. Mesosphere-Thermosphere-Ionosphere (MTI) satellite working group is planning a small-satellite mission to study MLT and F-regions at low- and midlatitudes by observing airglow emissions from the Earthfs upper atmosphere. The project was formally proposed to JAXA in January 2005.
G1.3. Other Techniques
were developments of radio/optical techniques to measure the ionosphere and MLT
regions. Maruyama  developed a technique to estimate in-situ electron
density in the topside ionosphere from the cosmic radio-noise intensity
measurements by the satellite. During the Leonid meteor shower in November
2001, Maruyama et al.  ran the ionosondes in a
rapid-run mode and found meteor-induced Es patches. Nakamura et al. 
conducted meteor echo observations with the MU radar, and showed that it is possible
to measure spatial changes in the wind velocity field by dividing the echoing
region into four azimuth sectors. Radar echoes from the mesosphere are not
fully understood. Kubo et al.  carefully analyzed the MU radar data and
constructed an empirical model for the mesospheric VHF radio wave scattering. Shiokawa et al. [2003c] developed a two-channel Fabry-Perot interferometer with thermoelectric-cooled CCD
detectors. The system is able to measure neutral winds in the mesopause region at 558 nm and in the thermosphere at 630
nm, automatically operated in the MU radar site in
G2. Ionospheric Structure and Disturbances
G2.1. Polar Ionosphere
Many studies using European Incoherent SCATter (EISCAT) radar has been published in this period. Fujii et al.  determined the characteristics of field-aligned ion motions in the E and F region ionosphere. Maeda et al.  investigated ion and neutral temperature profiles in the E-region between 105 and 115 km, and compared the results with precipitating particles observed with the DMSP satellite. Nozawa et al.  had a comparative study of the neutral wind in the polar upper mesosphere/lower thermosphere using two radars, EISCAT UHF radar and Tromso MF radar. Nozawa et al. [2003a] examined characteristics of the quasi 2-day waves in the polar mesosphere using the same set of instruments. Nozawa et al. [2003b] compared the quasi 2-day wave observed at Tromso and Poker Flat MF radars. Fujiwara et al.  estimated turbulent and electromagnetic energy dissipation rates in the altitude range of 98-116km using data obtained by the EISCAT radar.
Super Dual Auroral Radar
Network (SuperDARN) is an international collaborative
project based on the network of coherent HF radars in the Northern and
Ishii et al. [2002, 2003, 2004] studied thermosphere-ionosphere coupling (TI coupling), especially vertical winds in the thermosphere on the vicinity of aurora using Fabry-Perot interferometers. Oyama et al. [2001a,b] discussed possibilities that these TI coupling is a source of gravity waves. Oyama et al. [2003, 2004, 2005] discussed TI coupling from the observed ion motion with IS radars in the polar region. Kubota et al.  discovered a new type of auroras which do not change their shapes for several hours with high-sensitive all-sky imagers, and the phenomenon was named gco-rotating patchesh. Lummerzheim et al.  also used the instruments for understanding the mechanism of proton auroras. Mori et al.  studied characteristics of precipitating electrons with the energy range of 40-80 keV using a 16x16 imaging riometer.
Sakanoi et al.  investigated the generation
mechanisms of flickering auroras with a high-speed imaging photometer system. Shiokawa et al. [2005a] reported that a total of 20
low-latitude aurora events in
G2.2. Midlatitude Ionospheric Structure
Many types of variations in the Sq field such as seasonal, year-to-year, and day-to-day variations are known to exist. Takeda [2002a,b] studied seasonal and year-to-year variations of geomagnetic Sq field using the global equivalent current system. It was found that the Sq current intensity in the solar minimum period is about half that in the solar maximum period and its year-to-year variation is relatively smooth. Takeda et al.  examined relationships of the geomagnetic Sq field to the electric field, conductivity, and currents in the ionosphere.
F2 layer electron density strongly depends upon the solar EUV flux, thermospheric concentration, temperature, and wind. Zhang et al. [2002, 2003] explored a method for inferring solar EUV flux, atmospheric composition and wind using ionospheric electron density profile measurements. Incoherent scatter radar data from Millstone Hill and Shigaraki were assimilated into a theoretical model, which was used to derive EUV flux and [O]/[N2] from electron density profiles.
Kawamura et al.  studied the annual and semiannual variations of the midlatitude ionosphere under low solar activity using MU radar and a plasmasphere-ionosphere model. The study showed that the variations of the daytime midlatitude ionosphere near and above the ionospheric peak depend more on the neutral wind than on the thermospheric composition.
G2.3. Midlatitude Ionospheric disturbances
Signatures of upper atmospheric disturbances during a major magnetic storm were studied by the MU radar, MF radar, optical imager, and GPS-derived TEC [Balan et al., 2004]. Kutiev et al.  analyzed TEC data for 2000-2002, and found that TEC behavior during the storms is similar to that of foF2. While, Maruyama et al.  found that positive TEC and negative foF2 disturbances could simultaneously occur in some time intervals of storms. Tsurutani et al.  also analyzed global characteristics of ionospheric uplift and TEC changes during a large magnetic storm. Pavlov et al. [2004a] compared the electron density measured by the MU radar and modeled electron density during a magnetic storm.
Traveling ionospheric disturbances
Neutral wind fields associated with an equatorward traveling large scale TIDs (LS-TIDs) were investigated by using multiple instrumental technique [Shiokawa et al., 2002b, 2003d]. While, Tsugawa et al. [2003, 2004] clarified temporal and spatial characteristics of LS-TIDs based on the TEC data obtained by GEONET during the periods of geomagnetic disturbance.
Otsuka et al.  investigated another type of ionospheric disturbances called brightness wave, which propagated north-northeastward, using airglow images, Fabry-Perot interferometer (FPI), the MU radar, and the ionosonde network. Sahai et al.  observed mesoscale-enhanced airglow bands moving to the southwest direction.
Sporadic E and irregularities
et al. [2002d] conducted simultaneous observation of E-region FAIs with the MU radar and Es layers with ionosondes. They found that quasi-periodic (QP) structures
of the FAIs were enhanced when foEs-fbEs
increased, which means that the FAI generation is closely related to localized density gradients within the Es layers. With the
MU radar, Hysell et al. [2002a] carried out imaging
observations of E-region FAIs, and found fine
structures of QP echoes. Kagan et al.  studied the
Doppler shift of FAI radar echoes, and determined contribution from the neutral
winds and electric fields. An observation campaign, SEEK-2 (Sporadic-E
Spatial structures of Es layers and polarization electric fields are important to know generation mechanism of the QP structures of the FAIs. Hysell et al. [2002b] simulated three-dimensional clouds of enhanced plasma density with a background electric field imposed by the F-region dynamo. If the clouds are smaller than about 1 km, the polarization electric field can be large enough for the FAI onset. Yokoyama et al.  conducted two-dimensional simulation with rod-like enhancements of plasma density and found that polarization electric fields are induced by the neutral winds as well as by the background electric field. They showed that the induced polarization electric field maps upward along the magnetic field line, and form secondary plasma structures up to 120 km altitudes. Yokoyama et al. [2004a] found that Pedersen conductivity of the F-region strongly affects the polarization mechanism in the E-region by the 3-D numerical simulations. Cosgrove et al.  studied the electrodynamical coupling processes and showed that the Perkins instability in the midlatitude F-region would be enhanced by the coexisting E-region instability with the same horizontal alignment.
G2.4. Equatorial Ionosphere
bubbles and ionospheric instability were studied by the Equatorial Atmosphere
Radar (EAR), airglow imager, and ionosondes. The 47-MHz
EAR located in West Sumatra, Indonesia has a capability of observing FAIs in multiple directions, in which radar beams
perpendicularly intersect the magnetic field lines. Range-time-intensity (RTI)
plots of radar backscattering for each beam revealed true spatial structure and
evolution of plasma bubbles. Onsets of plasma bubbles near sunset [Yokoyama et
al, 2004b] and sunrise [Fukao et al., 2003a]
terminators and spatial structure of evening bubbles [Fukao
et al., 2004] were diagnosed. Otsuka et al. [2004b]
compared the radar backscattering with all-sky airglow images and found
coexistence of small scale irregularities and airglow depletions. Optical
imaging technique was used for the study of plasma bubbles not only in the equatorial
region but also in the main islands of
G2.5. Ionosphere-Neutral Atmosphere Coupling
behavior of the MLT region is very important to understand physics in the
ionosphere. The all-sky imager of OH band (720-910 nm) and OI (557.7 nm)
nightglow is a powerful instrument to study gravity waves in the MLT region. Ejiri et al.  conducted dual-site imaging
observations and determined the true altitude of the nightglow layers.
Statistical studies of the gravity waves were carried out for
behavior of planetary waves with periodicities of 4-10 days was studied with a network
of MF and meteor radars [Isoda et al., 2002;
Lieberman et al., 2003]. Tsuda et al.  studied
long-term variations of the equatorial atmospheric waves, i.e., Kelvin waves,
by means of MF radars in the equatorial Pacific. Long-period wind data set from
the meteor radar in
G3. Ionospheric Modeling
G3.1. Earthfs Ionosphere
modeling is a useful tool for studying ionospheric disturbances. Pavlov et al.
[2004a,b] used a model of the low- and midlatitude ionosphere and plasmasphere to study the
ionosphere during magnetic storms. Mechanisms causing the morning and evening
peaks in the electron temperature were discussed. Zhang et al.  used a
one-dimensional high-latitude ionospheric model to study the conductivities in auroral regions where electrojets
exist. Shinagawa et al.  developed a nonhydrostatic
thermosphere-ionosphere model to study high-latitude disturbances.
Thermospheric winds near a moving auroral arc were
simulated. Miyoshi and Fujiwara  developed a new general circulation
model (GCM), which contains the region from the ground surface to the exobase. The results showed that day-to-day variations of
the migrating diurnal tide are evident from the upper troposphere to the
thermosphere. Kamide et al.  described the
Global Environment Data Analysis System (GEDAS) developed at the
Solar-Terrestrial Environment Laboratory,
G3.2. Planetary Ionosphere
A two-dimensional global hybrid model was developed by Terada et al. [2002, 2004] to study kinetic processes associated with the solar wind interaction with the Venus ionosphere. The entire solar wind-Venus ionosphere region was included kinetically by applying boundary fitted coordinates to the particle-in-cell code. It was found that the Kelvin-Helmholtz instability occurred at the Venus ionopause plays an important role in the ion escape from the planet. Recent progress in modeling the planetary ionospheres was reviewed by Shinagawa  and Kallio and Shinagawa .
Balan, N., Y. Otsuka, T. Tsugawa, S. Miyazaki, T. Ogawa, K. Shiokawa, and G. J. Bailey , gPlasmaspheric electron content in the GPS ray paths over Japan,h Earth Planets Space, vol.54, pp.71-79.
Balan, N., S. Kawamura, T. Nakamura, M. Yamamoto, S. Fukao, K. Igarashi, T. Maruyama, K. Shiokawa, Y. Otsuka, T. Ogawa, H. Alleyne, S. Watanabe, and Y. Murayama , gSimultaneous mesosphere/lower thermosphere and thermospheric F region observations during geomagnetic storm,h J. Geophys. Res., vol.109, doi:10.1029/2003JA009982.
Cosgrove, R. B., R. T. Tsunoda, S. Fukao and M. Yamamoto , gCoupling of the Perkins instability and the sporadic E layer instability derived from physical arguments,h J. Geophys. Res., vol.109, A06301, doi:10.1029/2003JA010295.
Ejiri, M. K., K. Shiokawa, T. Ogawa, M. Kubota, T. Nakamura, and T. Tsuda , gDual-site imaging observations of small-scale wave structures through OH and OI nightglow emissions,h Geophys. Res. Lett., vol.29, no.10, 1445, doi:10.1029/2001GL014257.
Ejiri, M. K., K. Shiokawa, T. Ogawa, K. Igarashi, T. Nakamura, and T. Tsuda , gStatistical study of short-period gravity waves in OH and OI nightglow images at two separated sites,h J. Geophys. Res., vol.108, no.D21, 4679, doi:10.1029/2002JD002795.
Fujii, R., S. Oyama, S. C. Buchert, S. Nozawa, and N. Matuura , gField-aligned ion motions in the E and F region,h J. Geophys. Res., vol.107, doi:10.1029/ 2001JA900148.
Fujiwara, H., S. Maeda, M. Suzuki, S. Nozawa, and H. Fukunishi , gEstimates of electromagnetic and turbulent energy dissipation rates under the existence of strong wind shears in the polar lower thermosphere from the European Incoherent Scatter (EISCAT) Svarlbard radar observations,h J. Geophys. Res., vol.109, A07306, doi:10.1029/2003JA010046.
Fukao, S., H. Hashiguchi, M. Yamamoto, T. Tsuda, T. Nakamura, M. K. Yamamoto, T. Sato, M. Hagio, and Y. Yabugaki [2003a], gEquatorial atmosphere radar (EAR): System description and first results,h Radio Sci., vol.38, no.3, 1053, doi:10.1029/2002RS002767.
S., Y. Ozawa, M. Yamamoto, and R. T. Tsunoda [2003b],
gAltitude-extended equatorial spread F observed near sunrise terminator over
S., Y. Ozawa, T. Yokoyama, M. Yamamoto, and R. T. Tsunoda
, gFirst observations of spatial structure of 3-m-scale field-aligned
irregularities with the equatorial atmosphere radar in
Hocke, K. and K. Igarashi , gStructure of the Earthfs lower ionosphere observed by GPS/MET radio occultation,h J. Geophys. Res., vol.107, no.A5, 1057, doi:10.1029/2001JA900158.
K., T. Tsuda, and A. de la Torre
[2002a], gA study of stratospheric GW fluctuations and sporadic E at midlatitudes with focus on possible orographic
Hocke, K., K. Igarashi, and A. Pavelyev [2002b], gIrregularities of the topside ionosphere observed by GPS/MET radio occultation,h Radio Sci., vol.37, 1101, doi:10.1029/2001RS002599.
Hosokawa, K, T. Iyemori, A. S. Yukimatu, and N. Sato , gSource of field-aligned irregularities in the subauroral F region as observed by the SuperDARN radars,h J. Geophys. Res., vol.106, no.A11, pp.24,713-24,731.
Hosokawa, K., E. E. Woodfield, M. Lester, S. E. Milan, N. Sato, A. S. Yukimatu, and T. Iyemori [2002a], gStatistical characteristics of Doppler spectral width as observed by the conjugate SuperDARN radars,h Ann. Geophys., vol.20, pp.1213-1223.
Hosokawa, K., M. Sugino,
M. Lester, N. Sato, A. S. Yukimatu, and T. Iyemori [2002b], gSimultaneous measurement of duskside subauroral
irregularities from the CUTLASS
Hosokawa, K., E. E. Woodfield, M. Lester, S. E. Milan, N. Sato, A. S. Yukimatu, and T. Iyemori , gInterhemispheric comparison of spectral width boundary as observed by the SuperDARN radars,h Ann. Geophys., vol.21, pp.1553-1565.
Hosokawa, K., S. Yamasita, P. Stauning, N. Sato, A. S. Yukimatu and T. Iyemori [2004a], gOrigin of the SuperDARN broad Doppler spectra: Simultaneous observation with Oersted satellite magnetometer,h Ann. Geophys., vol.22, pp.159-168.
Hosokawa, K., T. Ogawa, N. Sato, A. S. Yukimatu, and T. Iyemori [2004b], gStatistics of Antarctic mesospheric echoes observed with the SuperDARN Syowa radar,h Geophys. Res. Lett., vol.31, doi:10.1029/2003GL018776.
Hosokawa, K., T. Ogawa, N. F. Arnold, M. Lester, N. Sato, and A. S. Yukimatu , gExtraction of polar mesosphere summer echoes from SuperDARN data,h Geophys. Res. Lett., vol.32, doi:10.1029/2005GL022788.
D. L., M. Yamamoto, and
Hysell, D. L., M. Yamamoto, and S. Fukao [2002b], gSimulations of plasma clouds in the midlatitude E region ionosphere with implications for type I and type II quasiperiodic echoes,h J. Geophys. Res., vol.107, no.A10, 1313, doi:10.1029/2002JA009291.
Ishii M., S. Okano, E. Sagawa, Y. Murayama, S. Watari, M. Conde, and R. W. Smith , gDevelopment of CRL Fabry-Perot interferometers and observation of the thermosphere,h J. Comm. Res. Lab., vol.49, pp.173-184.
Ishii M., M. Conde, R. W. Smith, M. Krynicki, E. Sagawa, and S. Watari , gA comparison between vertical winds in the lower thermosphere and magnetic field perturbations on the ground,h Adv. Polar Upper Atmos. Res., no.17, pp.137-145.
Ishii M., M. Kubota, M. Conde, R. W. Smith, and M. Krynicki , gVertical wind distribution in the polar thermosphere during HEX campaign,h J. Geophys. Res., vol.109, A12311, doi:10.1029/2004JA010657.
Isoda, F., T. Tsuda, T. Nakamura, Y. Murayama, K. Igarashi, R. A. Vincent, I. M. Reid, A. Nuryanto, and S. L. Manurung , gLong-period wind oscillations in the mesosphere and lower thermosphere at Yamagawa (32 degrees N,131 degrees E), Pontianak (0 degrees N, 109 degrees E) and Christmas Island (2 degrees N, 157 degrees W),h J. Atmos. Sol.-Terr. Phys., vol.64, pp.1055-1067.
Iwagami, N., T. Shibaki, T. Suzuki, Y. Yamada, H. Ohnishi, Y. Takahashi, H. Yamamoto, H. Sekiguchi, K. Mori, Y. Sano, M. Kubota, Y. Murayama, M. Ishii, K-I. Oyama, R. Yoshimura, M. Shimoyama, Y. Koizumi, K. Shiokawa, N. Takegawa and T. Nakamura , gThe Wave2000 campaign: Overview and preliminary results,h J. Atmos. Sol.-Terr. Phys., vol.64, pp.1095-1104.
Kagan, L. M., S. Fukao, M. Yamamoto, and P. B. Rao , gObservation of neutral winds and electric fields using backscatter from field-aligned irregularities,h Int. J. Geomagn. Aeronom., vol.5, GI1003, doi:10.1029/2003GI000056.
Kallio, E., and H. Shinagawa, Editors , gPlanetary Atmospheres, Ionospheres, and Plasma Interactions,h Adv. Space Res., vol.33, no.2, pp.121-241.
Kamide, Y., S. Masuda, H. Shirai, H.-J. Kim, T. Ogino, H. Shinagawa, M. Kojima, E. A. Kihn, and A. J. Ridley , gThe Geospace Environment Data Analysis System,h Adv. Space Res., vol.31, no.4, pp.807-812.
Kawamura, S., N. Balan,
Y. Otsuka, and
Koizumi, Y., K.-I. Oyama, and Y. Murayama , gSmall-scale atmospheric gravity wave observed by foil chaff experiment in the mesopause region,h ISAS Research Note 758.
Koizumi Y., M. Shimoyama, K. Oyama, Y. Murayama, T. Tsuda, and T. Nakamura , gFoil chaff ejection systems for rocket-borne measurement of neutral winds in the mesosphere and lower thermosphere,h Rev. Sci. Inst., vol.75, pp.2346-2350.
Kubo K., T. Sugiyama, and S. Fukao , gEvaluation of mesospheric VHF echoes observed with the middle and upper atmosphere radar,h Radio Sci., vol.37, no.1, 1002, doi:10.1029/2000RS002556.
Kubota M., S. Oyama, M. Ishii, and Y. Murayama , gRecent results and future plans of atmospheric study using CRL all-sky imagers,h J. Comm. Res. Lab., vol.49, pp.161-172.
Kubota, M., T.
Y. Murayama , gEvening co-rotating
patches: A new type aurora observed by high sensitivity all-sky cameras in
Lieberman, R. S., D. M. Riggin, S. J. Franke, A. H. Manson, C. Meek, T. Nakamura, T. Tsuda, R. A. Vincent, and I. Reid , gThe 6.5-day wave in the mesosphere and lower thermosphere: Evidence for baroclinic/barotropic instability,h J. Geophys. Res., vol.108, no.D20, 4640, doi:10.1029/2002JD003349.
M. Galand, and M. Kubota , gOptical Emissions from Proton
Ma, G. and T. Maruyama , gDerivation
of TEC and estimation of instrumental biases from GEONET in
Ma, X. F., T. Maruyama, G. Ma, and T. Takeda [2005a], gDetermination of GPS receiver differential biases by neural network parameter estimation method,h Radio Sci., vol.40, doi:10.1029/2004RS003072.
Ma, X. F. T. Maruyama, G. Ma, and T. Takeda [2005b], gThree-dimensional ionospheric tomography using observation data of GPS ground receivers and ionosonde by neural network,h J. Geophys. Res., vol.110, doi:10.1029/2004JA010797.
Maruyama, T. , gRetrieval of in situ electron density in the topside ionosphere from cosmic radio noise intensity by an artificial neural network,h Radio Sci., vol.37, no.5, 1077, doi:10.1029/2001RS002509.
Maruyama T., K. Nozaki, M. Yamamoto, and S. Fukao , gIonospheric height changes at two closely separated equatorial stations and implications in spread F onsets,h J. Atmos. Sol.-Terr. Phys., vol.64, pp.1557-1563.
Maruyama T. H. Kato, and M. Nakamura , gIonospheric effects of the Leonid meteor shower in November 2001 as observed by rapid run ionosondes,h J. Geophys. Res., vol.108, no.A8, 1324, doi:10.1029/2003JA009831.
Maruyama. T., G. Ma, and M. Nakamura , gSignature of TEC storm on
Miyoshi, Y. and H. Fujiwara , gDay-to-day variations of migrating diurnal tide simulated by a GCM from the ground surface to the exobase,h Geophys. Res. Lett., vol.30, no.15, 1789, doi:10.1029/2003GL017695.
Mori H., Y. Murayama,
M. Ishii, M. Yamamoto, and Hans C. Stenbaek-Nielsen
, gImaging riomater database developed in cooperation
Mori H., M. Ishii, Y. Murayama, M. Kubota, K. Sakanoi, M. Yamamoto, Y. Monzen, D. Lummerzheim, and B. J. Watkins , gEnergy distribution of precipitating electrons estimated from optical and cosmic noise absorption measurements,h Ann. Geophys., vol.22, pp.1613-1622.
Motoba T., T. Kikuchi, T. Okusawa, and K. Yumoto , gDynamical response of the magnetosphere - ionosphere system to a solar wind dynamic pressure oscillation,h J. Geophys. Res., vol.108, no.A5, 1206. doi:10.1029/2002 JA009696.
Murayama Y., H. Mori, M. Ishii, M. Kubota, S. Oyama, M. Yamamoto, K. Seki, K. Mizutani, S. Ochiai, T. Kikuchi, K. Nozaki, K. Igarashi, H. Masuko, T. Itabe, R. W. Smith, M. Conde, B. J. Watkins, R. L. Collins, H. C. Stenbaek-Nielsen, W. R. Simpson, V. Bedford, J. Harrison, F. Williams, and S. -I. Akasofu , gCRL Alaska Project - international collaborations for observing arctic atmosphere environment in Alaska -,h J. Comm. Res. Lab., vol.49, no.2, pp.143-152.
Nakamura, T., T. Aono, T. Tsuda, A. G. Admiranto, E. Achmad, and Suranto , gMesospheric gravity waves over a tropical convective region observed by OH airglow imaging in Indonesia,h Geophys. Res. Lett., vol.30, no.17, 1882.
Nakazawa, Y., T. Okada, and K. Shiokawa , gUnderstanding the "SEKKI" phenomena in Japanese historical literatures based on the modern science of low-latitude aurora,h Earth Planets Space, vol.56, pp.e41-e44.
Nishitani, N., V. Papitashvili, T. Ogawa, N. Sato, H. Yamagishi, A.S. Yukimatu, and F. J. Rich , gInterhemispheric asymmetry of the high latitude ionospheric convection on May 11-12, 1999,h J. Geophys. Res., vol.108, no.A5, 1184, doi:10.1029/2002JA009680.
Nishitani, N., M. Lester, S. E. Milan, T. Ogawa, N. Sato, H. Yamagishi, A. S. Yukimatu, and F. J. Rich , gUnusual ionospheric echoes with high velocity and very low spectral width observed by the SuperDARN radars in the polar cap during high geomagnetic activity,h J. Geophys. Res., vol.109, no.A2, A02311, doi:10.1029/2003JA010048.
Nozawa, S., A. Brekke, A. Manson, C. M. Hall, C. Meek, K. Morise, S. Oyama, K. Dobashi, and R. Fujii , gA comparison study of the auroral lower thermospheric neutral winds derived by the EISCAT UHF radar and the Tromso radar,h J. Geophys. Res., vol.107, doi:10.1029/2000JA007581.
Nozawa, S., S. Imaida, A. Brekke, C. Hall, C. Meek, A. Manson, S. Oyama, K. Dobashi, and R. Fujii [2003a], gThe quasi 2-day wave observed in the polar mesosphere,h J. Geophys. Res., vol.108, no.D2, 4039, doi:10.1029/2002JD002440.
Nozawa, S., H. Iwahashi, A. Brekke, C. M. Hall, C. Meek, A. Manson, S. Oyama, Y. Murayama, and R. Fujii [2003b], gThe quasi 2-day wave observed in the polar mesosphere: Comparison of the characteristics observed at Tromso and Poker Flat,h J. Geophys. Res., vol.108, no.D24, 4748, doi:10.1029/2002JD003221.
Ogawa, T., N. Balan, Y. Otsuka, K. Shiokawa, C. Ihara, T. Shimomai, and A. Saito [2002a], gObservations and modeling of 630 nm airglow and total electron content associated with traveling ionospheric disturbances over Shigaraki, Japan,h Earth Planets Space, vol.54, pp.45-56.
Ogawa, T., N. Nishitani, N. Sato, H. Yamagishi, and A. S. Yukimatu [2002b], gUpper mesosphere summer echoes detected with the Antarctic Syowa HF radar,h Geophys. Res. Lett., vol.29, no.7, doi:10.1029/2001GL014094.
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(compiled by T. Maruyama and M. Yamamoto)