研究業績
論文(Refereed) Astafyeva, E., Bagiya, M. S., Förster, M.,& Nishitani, N., Unprecedented Hemispheric Asymmetries During aSurprise Ionospheric Storm: A Game of Drivers. Journal of Geophysical Research: Space Physics, 125, e2019JA027261, https://doi.org/10.1029/2019JA027261, 2020. Zhang, J. J., Wang, W., Wang, C., Lan, A. L., Yan, J. Y., Xiang, D., Zhang, Q.H., Ruohoniemi, J.M. , Kunduri, B.S.R, Nishitani, N., Shi, X., and Qiu, H.B., First observation of ionospheric convection from the Jiamusi HF radar during a strong geomagnetic storm. Earth and Space Science, 7, e2019EA000911, https://doi.org/10.1029/2019EA000911, 2020. Koustov, A.V., S. Ullrich, P.V. Ponomarenko, N. Nishitani, F.M. Marcucci, and W.A. Bristow, Occurrence of F region echoes for the polar cap SuperDARN radars, Earth Planets Space, 71:112, https://doi.org/10.1186/s40623-019-1092-9, 2019. Chakraborty, S., J.B.H. Baker, J.M. Ruohoniemi, B. Kunduri, N. Nishitani, and S.G. Shepherd, A Study of SuperDARN Response to Co-occurring Space Weather Phenomena, Space Weather, 17, 9, https://doi.org/10.1029/2019SW002179, 2019. Berngardt, O.I., J.M. Ruohoniemi, J.-P. St-Maurice, A. Marchaudon, M.J. Kosch, A.S. Yukimatu, N. Nishitani, S.G. Shepherd, M.F. Marcucci, H. Hu, T. Nagatsuma, and M. Lester, Global diagnostics of ionospheric absorption during X-ray solar flares based on 8- to 20-MHz noise measured by over-the-horizon radars, Space Weather, 17, 907-924, https://doi.org/10.1029/2018SW002130, 2019. Obana, Y., N. Maruyama, A. Shinbori, K.K. Hashimoto, M. Fedrizzi, M. Nosé, Y. Otsuka, N. Nishitani, T. Hori, A. Kumamoto, F. Tsuchiya, S. Matsuda, A. Matsuoka, Y. Kasahara, A. Yoshikawa, Y. Miyoshi, and I. Shinohara, Response of the Ionosphere- Plasmasphere Coupling to the September 2017 Storm: What Erodes the Plasmasphere so Severely?, Space Weather, https://doi.org/10.1029/2019SW002168, 2019. Nishitani, N., J. M. Ruohoniemi, M. Lester, J. B. H. Baker, A. V. Koustov, S. G. Shepherd, G. Chisham, T. Hori, E. G. Thomas, R. A. Makarevich, A. Marchaudon, P. Ponomarenko, J.A. Wild, S. E. Milan, W. A. Bristow, J. Devlin, E. Miller, R. A. Greenwald, T. Ogawa, and T. Kikuchi, Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF Radars, Prog. Earth Planet. Sci., 6:27, https://doi.org/10.1186/s40645-019-0270-5, 2019. Ozaki, M., K. Shiokawa, Y. Miyoshi, K. Hosokawa, S. Oyama, S. Yagitani, Y. Kasahara, Y. Kasaba, S. Matsuda, R. Kataoka, Y. Ebihara, Y. Ogawa, Y. Otsuka, S. Kurita, R. C. Moore, Y.-M. Tanaka, M. Nosé, T. Nagatsuma, M. Connors, N. Nishitani, Y. Katoh, M. Hikishima, A. Kumamoto, F. Tsuchiya, A. Kadokura, T. Nishiyama, T. Inoue, K. Imamura, A. Matsuoka, and I. Shinohara, Microscopic Observations of Pulsating Aurora Associated With Chorus Element Structures: Coordinated Arase Satellite-PWING Observations, Geophys. Res. Lett.,https://doi.org/10.1029/2018GL079812, 2018. Hori, T., N. Nishitani, S. G. Shepherd, J. M. Ruohoniemi, M. Connors, M. Teramoto, S. Nakano, K. Seki, N. Takahashi, S. Kasahara, S. Yokota, T. Mitani et al., Substorm-Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN-Arase Conjunction, Geophys. Res. Lett., https://doi.org/10.1029/2018GL079777, 2018. Kunduri, B. S. R., J. B. H. Baker, J. M. Ruohoniemi, N. Nishitani, K. Oksavik, P. J. Erickson, A. J. Coster, S. G. Shepherd, W. A. Bristow, and E. S. Miller, A New Empirical Model of the Subauroral Polarization Stream, J. Geophys. Res., https://doi.org/10.1029/2018JA025690, 2018. Shinbori, A., Y. Otsuka, T. Tsugawa, M. Nishioka, A. Kumamoto, F. Tsuchiya, S. Matsuda, Y. Kasahara, A. Matsuoka, J. M. Ruohoniemi, S. G. Shepherd, and N. Nishitani, Temporal and Spatial Variations of Storm Time Midlatitude Ionospheric Trough Based on Global GNSS-TEC and Arase Satellite Observations, Geophys. Res. Lett., https://doi.org/10.1029/2018GL078723, 2018. Chakraborty, S., J. M. Ruohoniemi, J. B. H. Baker, and N. Nishitani, Characterization of Short-Wave Fadeout Seen in Daytime SuperDARN Ground Scatter Observations, Radio Sci., https://doi.org/10.1002/2017RS006488, 2018. Berngardt, O. I., J. M. Ruohoniemi, N. Nishitani, S. G. Shepherd, W. A. Bristow, and E. S. Miller, Attenuation of decameter wavelength sky noise during x-ray solar flares in 2013-2017 based on the observations of midlatitude HF radars, J. Atmos. Sol. Terr. Phys., https://doi.org/10.1016/j.jastp.2018.03.022, 2018. Zou, Y., B. M. Walsh, Y. Nishimura, V. Angelopoulos, J. M. Ruohoniemi, K. A. McWilliams, and N. Nishitani, Spreading Speed of Magnetopause Reconnection X-Lines Using Ground-Satellite Coordination, Geophys. Res. Lett., https://doi.org/10.1002/2017GL075765, 2017. Gallardo-Lacourt, B., Y. Nishimura, L. R. Lyons, E. V. Mishin, J. M. Ruohoniemi, E. F. Donovan, V. Angelopoulos, and N. Nishitani, Influence of Auroral Streamers on Rapid Evolution of Ionospheric SAPS Flows, J. Geophys. Res., https://doi.org/10.1002/2017JA024198, 2017. S.-I. Kim, K.-H. Kim, H.-J. Kwon, H. Jin, E. Lee, G. Jee, N. Nishitani, T. Hori, M. Lester, and J. R. Wygant, SC-Associated Electric Field Variations in the Magnetosphere and Ionospheric Convective Flows, J. Geophys. Res., https://doi.org/10.1002/2017JA024611, 2017. Lyons, L.R., B. Gallardo-Lacourt, Y. Zou, Y. Nishimura, P. Anderson, V. Angelopoulos, E.F. Donovan, J.M. Ruohoniemi, E. Mitchell, L.J. Paxton, and N. Nishitani, Driving of strong nightside reconnection and geomagnetic activity by polar cap flows: Application to CME shocks and possibly other situations, J. Atmos. Solar Terr. Phys., https://doi.org/10.1016/j.jastp.2017.09.013, 2017. Takahashi, N., Y. Kasaba, Y. Nishimura, A. Shinbori, T. Kikuchi, T. Hori, Y. Ebihara and N. Nishitani, Propagation and evolution of electric fields associated with solar wind pressure pulses based on spacecraft and ground-based observations, J. Geophys. Res.: Space Phys., DOI: 10.1002/2017JA023990, 2017. Kawano, H., A. S. Yukimatu, Y. Tanaka, S. Saita, N. Nishitani, and T. Hori, SC-triggered 1.6mHz waves including an interval with latitude-dependent phase shift, observed by the SuperDARN Hokkaido East Radar in mid latitudes: Possible global magnetospheric cavity-mode waves and their field-line resonance with poloidal Alfven-mode waves, Memoirs of the Faculty of Science, Kyushu University, Series D, Earth and Planetary Sciences, Vol. 34 (No. 1), pp. 1-15, Nov. 21, 2016. Hidehiko Suzuki, Kazuyo Sakanoi, Nozomu Nishitani, Tadahiko Ogawa, Mitsumu K. Ejiri, Minoru Kubota, Takenori Kinoshita, Yasuhiro Murayama and Yasushi Fujiyoshi, First imaging and identification of a noctilucent cloud from multiple sites in Hokkaido (43.2-44.4 N), Japan, Earth, Planets and Space 2016 68:182, DOI: 10.1186/s40623-016-0562-6. Lyons, L.R., B. Gallardo-Lacourt, S. Zou, J. M. Weygand, Y. Nishimura, W. Li, M. Gkioulidou, V. Angelopoulos, E. F. Donovan, J. M. Ruohoniemi, B. J. Anderson, S. G. Shepherd and N. Nishitani, The 17 March 2013 storm: Synergy of observations related to electric field modes and their ionospheric and magnetospheric Effects, Journal of Geophysical Research: Space Physics, Volume 121, Issue 11, November 2016, Pages: 10,880-10,897, DOI: 10.1002/2016JA023237. Ying Zou, Yukitoshi Nishimura, Johnathan K. Burchill, David J. Knudsen, Larry R. Lyons, Kazuo Shiokawa, Stephan Buchert, Steve Chen, Michael J. Nicolls, J. Michael Ruohoniemi, Kathryn A. McWilliams and Nozomu Nishitani, Localized field-aligned currents in the polar cap associated with airglow patches, Journal of Geophysical Research: Space Physics, Volume 121, Issue 10, October 2016, Pages: 10,172-10,189, DOI: 10.1002/2016JA022665. Oinats, A.V., N. Nishitani, P. Ponomarenko, and K. Ratovsky, Diurnal and seasonal behavior of the Hokkaido East SuperDARN ground backscatter: simulation and observation, Earth, Planets and Space. 68:18, DOI: 10.1186/s40623-015-0378-9, 2016. Oinats, A.V., N. Nishitani, P. Ponomarenko, O. Berngardt, and K. Ratovsky, Statistical characteristics of medium-scale traveling ionospheric disturbances revealed from the Hokkaido East and Ekaterinburg HF radar data, Earth, Planets and Space. 68:8, DOI: 10.1186/s40623-016-0390-8, 2016. Yakymenko, K.N, A. V. Koustov, and N. Nishitani, Statistical study of midlatitude E region echoes observed by the Hokkaido SuperDARN HF radar, J. Geophys. Res., 120, 9959-9976, doi:10.1002/2015JA021685, 2015. Teramoto, M. N. Nishitani, Y. Nishimura, and T. Nagatsuma, Latitudinal dependence on frequency of Pi2 pulsations near the plasmapause, using THEMIS satellites and Asian-Oceanian SuperDARN radars, Earth Planets Space, 68:22, doi: 10.1186/s40623-016-0397-1, 2016. Hori T., A. Shinbori, S. Fujita, and N. Nishitani, IMF-By dependence of transient ionospheric flow perturbation associated with sudden impulses: SuperDARN observations, Earth, Planets Space, 67:190, doi: 10.1186/s40623-015-0360-62015, 2015. Ponomarenko, P., N. Nishitani, A.V. Oinats, T. Tsuya and J.-P. St.-Maurice, Application of ground scatter returns for calibration of HF interferometry data, Earth Planets Space, 67:138, doi: 10.1186/s40623-015-0310-3, 2015. Nagano, H., N. Nishitani, and T. Hori, Occurrence characteristics and lowest speed limit of Sub-Auroral Polarization Stream (SAPS) observed by the SuperDARN Hokkaido East radar, Earth Planets Space, 67:126, doi: 10.1186/s40623-015-0299-7, 2015. Oinats, A.V., V.I. Kurkin, and N. Nishitani, Statistical study of medium-scale traveling ionospheric disturbances using SuperDARN Hokkaido ground backscatter data for 2011, Earth Planets Space, 67, 22, doi:10.1186/s40623-015-0192-4, 2015. Teramoto, M., N. Nishitani, V. Pilipenko, T. Ogawa, K. Shiokawa, T. Nagatsuma, A. Yoshikawa, D. Baishev, and K. T. Murata, Pi2 pulsation simultaneously observed in the E and F region ionosphere with the SuperDARN Hokkaido radar, J. Geophys. Res, 119, 3444-3462, doi:10.1002/2012JA018585, 2014. Bea Gallardo-Lacourt, Y. Nishimura, L.R. Lyons, S. Zou, V. Angelopoulos, E. Donovan, K.A. McWilliams, J.M. Ruohoniemi, and N. Nishitani, Coordinated SuperDARN THEMIS ASI observations of mesoscale flow bursts associated with auroral streamers, J. Geophys. Res., 119,1,142-150, doi:10.1002/2013JA019245, 2014. Zou, Y., Y. Nishimura, L.R. Lyons, E.F. Donovan, J.M. Ruohoniemi, N. Nishitani and K.A. McWilliams, Statistical relationships between enhanced polar cap flows and PBIs, J. Geophys. Res., 119, 51-162, doi:10.1002/2013JA019269, 2014. Zou, Y., and N. Nishitani, Study of mid-latitude ionospheric convection during quiet and disturbed periods using the SuperDARN Hokkaido radar. J. Adv. Space Res., http://dx.doi.org/10.1016/j.asr.2014.01.011, 2014. Koustov, A.V., K. N. Yakymenko, N. Nishitani, and P. V. Ponomarenko, Hokkaido HF radar signatures of periodically reoccurring nighttime MSTIDs detected at short ranges, J. Geophys. Res., in press, doi:10.1002/2013JA019422, 2014. Ogawa, T., N. Nishitani, S. Kawamura, and Y. Murayama, Mesosphere summer echoes observed with the SuperDARN Hokkaido HF radar at Rikubetsu, Japan (43.5N), Earth Planets Space, 65, 1593-1597, 2013. Watanabe, D., and N. Nishitani, Study of ionospheric disturbances during solar flare events with the SuperDARN Hokkaido Radar, Adv. Polar Sci., 24, 12-18, 2013. Hori, T., N. Nishitani, Y. Miyoshi, Y. Miyashita, K. Seki, T. Segawa, K. Hosokawa, A. S. Yukimatu, Y. Tanaka, N. Sato, M. Kunitake, and T. Nagatsuma, An integrated analysis platform merging the SuperDARN data within the THEMIS tool developed by ERG-Science Center (ERG-SC), Adv. Polar Sci., 24, doi: 10.3724/SP.J.1085.2013.000692013, 69-77, 2013. Ichihara, A., N. Nishitani, T. Ogawa, and T. Tsugawa, Northward-propagating nighttime medium-scale traveling ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GEONET, Adv. Polar Sci., 24, 42-49, 2013. Hori, T., A. Shinbori, N. Nishitani, T. Kikuchi, S. Fujita, T. Nagatsuma, O. Troshichev, K. Yumoto, A. Moiseyev, and K. Seki, Evolution of negative SI-induced ionospheric flows observed by SuperDARN King Salmon HF radar, J. Geophys. Res., 117, A12223, 10.1029/2012JA018093, 2012. Mori, D., A.V. Koustov, P.T. Jayachandran, and N. Nishitani, Resolute Bay CADI ionosonde drifts, PolarDARN HF velocities, and cross polar cap potential, Radio Sci., 47, 3, doi:10.1029/2011RS004947, 2012. 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. Baishev, Magnetospheric responses to the passage of the interplanetary shock on 24 November 2008, J. Geophys. Res., 117, A10209, doi:10.1029/2012JA017871, 2012. Ogawa, T., N. Nishitani, T. Tsugawa, and K. Shiokawa, Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake, Earth Planets Space, 64, 12, 1295-1307, 2012. Koustov, A. V., K. Hosokawa, N. Nishitani, K. Shiokawa, and H. Liu, Signatures of moving polar cap arcs in the F-region PolarDARN echoes, Ann. Geophys., 30, 441-455, doi:10.5194/angeo-30-441-2012, 2012. Lyons, L. R., Y. Nishimura, H.-J. Kim, E. Donovan, V. Angelopoulos, G. Sofko, M. Nicolls, C. Heinselman, J. M. Ruohoniemi, and N. Nishitani, Possible connection of polar cap flows to pre- and post-substorm onset PBIs and streamers, J. Geophys. Res., 116, A12225, doi:10.1029/2011JA016850, 2011. Nishitani, N., T. Ogawa, Y. Otsuka, K. Hosokawa, and T. Hori, Propagation of large amplitude ionospheric disturbances with velocity dispersion observed by the SuperDARN Hokkaido radar after the 2011 off the Pacific coast of Tohoku Earthquake, Earth Planets Space, 63, 891-896, 2011. Miyashita, Y., Y. Kamide, K. Liou, C.-C. Wu, A. Ieda, N. Nishitani, S. Machida, Y. Saito, and T. Mukai, Successive substorm expansions during a period of prolonged northward interplanetary magnetic field, J. Geophys. Res., 116, A09221, doi:10.1029/2011JA016719, 2011. Kitanoya, Y., T. Abe, A. W. Yau, T. Hori, and N. Nishitani, Localized electron density enhancements in the high-altitude polar ionosphere and their relationships with storm-enhanced density (SED) plumes and polar tongues of ionization (TOI), Ann. Geophys., 29, 367-375, 2011. Hosokawa, K., T. Tsugawa, K. Shiokawa, Y. Otsuka, N. Nishitani, T. Ogawa, M. Hairston, and L. J. Paxton, Dynamic temporal evolution of polar cap tongue of ionization during magnetic storm, J. Geophys. Res., 115, A12333, doi:10.1029/2010JA015848, 2010. Hosokawa, K., and N. Nishitani, Plasma irregularities in the duskside subauroral ionosphere as observed with midlatitude SuperDARN radar in Hokkaido, Japan, Radio Sci., 45, RS4003, doi:10.1029/2009RS004244, 2010. Hayashi, H., N. Nishitani, T. Ogawa, Y. Otsuka, T. Tsugawa, K. Hosokawa, and A. Saito, Large-Scale traveling ionospheric disturbance observed by SuperDARN Hokkaido HF radar and GPS networks on 15 December 2006, J. Geophys. Res., 115, A06309, doi:10.1029/2009JA014297, 2010. Kikuchi, T., Y. Ebihara, K.K. Hashimoto, R. Kataoka, T. Hori, S. Watari, and N. Nishitani, Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasi-periodic DP2 geomagnetic fluctuation event, J. Geophys. Res., 115, A05209, doi:10.1029/2008JA013948, 2010. Nishimura, Y., et al. (N. Nishitani as 10th author), Preonset time sequence of auroral substorms: Coordinated observations by all-sky imagers, satellites, and radars, J. Geophys. Res., 115, A00I08, doi:10.1029/2010JA015832, 2010. Koustov, A.V., N. Nishitani, K. Shiokawa, S. Suzuki, and B.M. Shevtsov, Joint observations of a traveling ionospheric disturbance with the Paratunka OMTI camera and the Hokkaido HF radar, Ann. Geophys., 27, 2399-2406, 2009. Sakanoi, T., H. Fukunishi, K. Igarashi, S. Okano, and N. Nishitani, Neutral-ion interaction in the auroral E region obtained from coordinated Fabry-Perot imager and VHF radar observations, J. Geophys. Res., 114, A09305, doi:10.1029/2008JA013956, 2009. Tsuda, T.T., et al. (N. Nishitani as 7th author), Acceleration mechanism of high-speed neutral wind observed in the polar lower thermosphere, J. Geophys. Res., 114, A04322, doi:10.1029/2008JA013867, 2009. Watari, S., et al. (N. Nishitani as 7th author), Measurements of geomagnetically induced current in a power grid in Hokkaido, Japan, Space Weather, 7, S03002, doi:10.1029/2008SW000417, 2009. Suzuki S., K. Hosokawa, Y. Otsuka, K. Shiokawa, T. Ogawa, N. Nishitani, T. F. Shibata, A. V. Koustov, and B. M. Shevtsov, Coordinated observations of nighttime medium-scale traveling ionospheric disturbances in 630-nm airglow and HF radar echoes at midlatitudes, J. Geophys. Res., 114, A07312, doi:10.1029/2008JA013963, 2009. Kataoka, R., K. Hosokawa, N. Nishitani, and Y. Miyoshi, SuperDARN Hokkaido radar observation of westward flow enhancement in subauroral latitudes, Ann. Geophys., 27, 1695-1699, 2009. Ogawa, T., N. Nishitani, Y. Otsuka, K. Shiokawa, T. Tsugawa, and K. Hosokawa, Medium-scale traveling ionospheric disturbances observed with the SuperDARN Hokkaido radar, all-sky imager and GPS network, and their relation to concurrent sporadic-E irregularities, J. Geophys. Res., 114, A03316, doi:10.1029/2008JA013893, 2009. Koustov, A.V., K. Hosokawa, N. Nishitani, T. Ogawa, and K. Shiokawa, Rankin Inlet PolarDARN radar observations of duskward moving Sun-aligned optical forms, Ann. Geophys., 26, 2711-2723, 2008. Ebihara, Y., N. Nishitani, T. Kikuchi, T. Ogawa, K. Hosokawa, M. -C. Fok and M. F. Thomsen, Dynamical property of storm-time subauroral rapid flows as a manifestation of complex structures of the plasma pressure in the inner magnetosphere, J. Geophys. Res., 114, A01306, doi:10.1029/2008JA013614, 2008. Shiokawa, K., Y. Otsuka, N. Nishitani, T. Ogawa, T. Tsugawa, T. Maruyama, S. E. Smirnov, V. V. Bychkov, and B. M. Shevtsov, Northeastward motion of nighttime MSTIDs at middle latitudes observed by an airglow imager, J. Geophys. Res., 113, A12312, doi:10.1029/2008JA013417, 2008. Koustov, A.V., N. Nishitani, Y. Ebihara, T. Kikuchi, M.R. Hairston, and D. Andre, Subauroral polarization streams: observations with the Hokkaido and King Salmon SuperDARN radars and modeling, Ann. Geophys., 26, 3317-3327, 2008. Ishida, T., K. Hosokawa, T. Shibata, S. Suzuki, N. Nishitani, and T. Ogawa, SuperDARN observations of daytime MSTIDs in the auroral and mid-latitudes: Possibility of long-distance propagation, Geophys. Res. Lett., 35, L13102, doi:10.1029/2008GL034623, 2008. Ebihara, Y., N. Nishitani, T. Kikuchi, T. Ogawa, K. Hosokawa, and M.-C. Fok, Two-dimensional observations of overshielding during a magnetic storm by the Super Dual Auroral Radar Network (SuperDARN) Hokkaido radar, J. Geophys. Res., 113, A01213, doi:10.1029/2007JA012641, 2008. Shiokawa, K., G. Lu, Y. Otsuka, T. Ogawa, M. Yamamoto, N. Nishitani, and N. Sato, Ground observation and AMIE-TIEGCM modeling of a storm-time traveling ionospheric disturbance, J. Geophys. Res., 112, A05308, doi:10.1029/2006JA011772, 2007. Kataoka, R., N. Nishitani, Y. Ebihara, K. Hosokawa, T. Ogawa, T. Kikuchi, and Y. Miyoshi, Dynamic variations of a convection flow reversal in the subauroral postmidnight sector as seen by the SuperDARN Hokkaido HF radar, Geophys. Res. Lett., 34, L21105, doi:10.1029/2007GL031552, 2007. Miyashita, Y., et al. (N. Nishitani as 11th author), Plasmoids observed in the near-Earth magnetotail at X ~ -7 RE, J. Geophys. Res., 110, A12214, doi:10.1029/2005JA011263, 2005. Nishitani, N., and T. Ogawa, Model calculations of possible ionospheric backscatter echo area for a mid-latitude HF radar, Adv. Polar Upper Atmos. Res., 19, 55-62, 2005. Ogawa, T., S. Nozawa, M. Tsutsumi, N. F. Arnold, N. Nishitani, N. Sato, and A. S. Yukimatu, Arctic and Antarctic polar mesosphere summer echoes observed with oblique incidence HF radars: analysis using simultaneous MF and VHF radar data, Ann. Geophys., 22, 4049-4059, 2004. Nishitani, N., M. Lester, S. E. Milan, T. Ogawa, N. Sato, H. Yamagishi, A. S. Yukimatu, and F. J. Rich, Unusual ionospheric echoes with high velocity and very low spectral width observed by the SuperDARN radars in the polar cap during high geomagnetic activity, J. Geophys. Res., 109(A2), A02311, doi:10.1029/2003JA010048, 2004. Ogawa, T., K. Hosokawa, N. Nishitani, N. Sato, H. Yamagishi, and A.S. Yukimatu, Characteristics of polar mesosphere summer echoes observed with oblique incidence HF radars at Syowa Station, Advances in Polar Upper Atmosphere Research, 17, 13-29, 2003. Nishitani, N., V. Papitashvili, T. Ogawa, N. Sato, H. Yamagishi, A.S. Yukimatu, and F.J. Rich, Interhemispheric asymmetry of the high latitude ionospheric convection on May 11-12, 1999, J. Geophys. Res., 108(A5), 1184, doi:10.1029/2002JA009680, 2003. Ogawa, T., N.F. Arnold, S. Kirkwood, N. Nishitani, and M. Lester, Finland HF and Esrange MST radar observations of polar mesosphere summer echoes, Ann. Geophys., 21, 1047-1055, 2003. Ogawa, T., N. Nishitani, N. Sato, H. Yamagishi, and A.S. Yukimatu, E region echoes observed with the Syowa HF radar under disturbed geomagnetic conditions, Advances in Polar Upper Atmosphere Research, 16, 84-98, 2002. Makarevitch, R.A., A.V. Koustov, K. Igarashi, K. Ohtaka, T.Ogawa, N. Nishitani, N. Sato, H. Yamagishi, and A. S. Yukimatu, Comparison of flow angle variations of E-region echo characteristics at VHF and HF, Advances in Polar Upper Atmosphere Research, 16, 59-83, 2002. Ogawa, T., N. Nishitani, N. Sato, H. Yamagishi, and A.S. Yukimatu, Upper mesosphere summer echoes detected with the antarctic Syowa HF radar, Geophys. Res. Lett., 29, 10.1029/2001GL014094, 2002. Nishitani, N., T. Ogawa, N. Sato, H. Yamagishi, M. Pinnock, J.-P. Villain, G. Sofko, and O. Troshichev, A study of the dusk convection cell's response to an IMF southward turning, J. Geophys. Res., 107, 10.1029/2001JA900095, 2002. Danskin, D.W., A.V. Koustov, T. Ogawa, N. Nishitani, S. Nozawa, S.E. Milan, M. Lester, and D. Andre, On the factors controlling occurrence of F-region coherent echoes, Ann. Geophys., 20, 1385-1397, 2002. Koustov, A.V., D.W. Danskin, M. V. Uspensky, T. Ogawa, P. Janhunen, N. Nishitani, S. Nozawa, M. Lester, and S.E. Milan, Velocities of auroral coherent echoes at 12 and 144 MHz, Ann. Geophys., 20, 1647-1661, 2002. Ogawa, T., N. Nishitani, N. Sato, H. Yamagishi, and A.S. Yukimatu, Implications of statistics of near-range Doppler velocity observed with the Syowa East HF radar, Advances in Polar Upper Atmosphere Research, 15, 82-102, 2001. Ogawa, T., S.C. Buchert, N. Nishitani, N. Sato, and M. Lester, Plasma density suppression process acound the cusp revealed by simultaneous CUTLASS and EISCAT Svalbard radar observations, J. Geophys. Res., 106, 5551-5564, 2001. Shue, J.-H., Y. Kamide, R. Elphinstone, and N. Nishitani, Intense growth phase events of substorms, J. Geophys. Res., 105(A3), 5357-5371, 2000. Fukumoto, M., N. Nishitani, T. Ogawa, N. Sato, H. Yamagishi, and A.S. Yukimatu, Statistical study of Doppler velocity and echo power around 75 deg magnetic latitude obtained with the Syowa East HF radar, Advances in Polar Upper Atmosphere Research, 14, 93-102, 2000. Nishitani, N., T. Ogawa, M. Pinnock, M.P. Freeman, J.R. Dudeney, J.-P. Villain, K.B. Baker, N. Sato, H. Yamagishi, and H. Matsumoto, A very large scale flow burst observed by the SuperDARN radars, J. Geophys. Res., 104, 22469-22486, 1999. Nishino, M., N. Nishitani, N. Sato, H. Yamagishi, M. Lester, and J.A. Holtet, A rectified response of daytime radio wave absorption to southward and northward excursions during northward interplanetary magnetic field: A case study, Advances in Polar Upper Atmosphere Research, 13, 139-153, 1999. Yamamoto, T., S. Inoue, M. Ozaki, and N. Nishitani, Distortion of the outer boundary of the closed region in the Tsyganenko magnetic field model, Advances in Polar Upper Atmosphere Research, 13, 89-104, 1999. Fukumoto, M., N. Nishitani, T. Ogawa, N. Sato, H. Yamagishi, and A.S. Yukimatu, Statistical analysis of echo power, Doppler velocity and spectral width obtained with the Syowa South HF radar, Advances in Polar Upper Atmosphere Research, 13, 37-47, 1999. Ogawa, T., N. Nishitani, M. Pinnock, N. Sato, H. Yamagishi, and A.S. Yukimatu, Antarctic HF radar observations of irregularities associated with polar patches and auroral blobs: A case study, J. Geophys. Res., 103, 26547-26558, 1998. Nishitani, N., T. Ogawa, N. Sato, H. Yamagishi, A. Sessai Yukimatu, and M. Watanabe, Averaged pattern of ionospheric echo region and convection: Initial results from the Syowa Station HF radar, Proc. of NIPR Symposium on Upper Atmosphere Physics, 10, 42-49, 1997. Shiokawa, K., K. Yumoto, N. Nishitani, K. Hayashi, T. Oguti, D. J. McEwen, Y. Kiyama, F. J. Rich, and T. Mukai, Quasi-periodic poleward motions of Sun-aligned auroral arcs in the high-latitude morning sector: A case study, J. Geophys. Res., 101(A9), 19789-19800, 1996. Yamamoto, T., S. Inoue, N. Nishitani, M. Ozaki, and C.-I. Meng, A theory for generation of the paired region 1 and region 2 field-aligned currents, J. Geophys. Res., 101, 27199-27222, 1996. Nishitani, N., G. Hough and M.W.J. Scourfield, Spatial and temporal characteristics of giant undulations, Geophys. Res. Lett., 21, 2673-2676, 1994. Nishitani, N., Magnetic field line connection between the ionosphere and the magnetosphere - Auroral activity and relevant magnetic field variations at geosynchronous orbit - , Ph-D Thesis, Nagoya University, 1992. Oguti, T., N. Nishitani, and R. Nakamura, Auroral activity and its connection with magnetospheric processes - Magnetic field conjugacy between the polar ionosphere and the magnetosphere -, J. Geomag. Geoelectr., 43, Suppl., 353-368, 1991. Nishitani., N., and T. Oguti, Auroral activity and corresponding magnetic signatures at geosynchronous orbit, J. Geomag. Geoelectr., 40, 423-445, 1988. Oguti, T., K. Hayashi, T. Yamamoto, J. Ishida, T. Higuchi, and N. Nishitani, Absence of hydromagnetic waves in the magnetospheric equatorial region conjugate with pulsating auroras, J. Geophys. Res., 91, 13711-13715, 1986. 論文(Non-refereed) Nishitani, N., T. Nagatsuma, A.S. Yukimatu, H. Hu, and T. Sakanoi, Preface of the Special issue "Coupling of the high and mid latitude ionosphere and its relation to geospace dynamics", Earth Planets Space, 68:168, 2016. Nishitani, N., T. Ogawa, N. Sato, H. Yamagishi, M. Pinnock, J.-P. Villain, and G. Sofko, Dynamics of ionospheric convection and current system following a sudden southward turning of the IMF, 23.1-23.4, Proceedings of the SuperDARN Annual Meeting, Iceland, 1999. Nishitani, N., G. Hough, and M.W.J. Scourfield, Fine-scale structure of the undulation forms on the equatorial edge of the diffuse auroral region, Proceedings of Eighth International Symposium on Solar Terrestrial Physics, 125, 1994.
