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VHF radar observations of nighttime F-region field-aligned irregularities over Kototabang, Indonesia

Earth, Planets and Space200961:BF03353159

https://doi.org/10.1186/BF03353159

Received: 6 December 2007

Accepted: 3 July 2008

Published: 14 May 2009

Abstract

We report, for the first time, continuous observations of the nighttime F-region field-aligned irregularities (FAIs) over Indonesia. A VHF radar with operating frequency of 30.8 MHz and peak power of 20 kW has been operated at Kototabang (0.20°S, 100.32°E; dip latitude 10.4°S), Indonesia since February 2006. Five beams were allocated between ±54° in azimuth around geographic south (126°–234°). From the continuous observation from February 2006 to November 2007, we found that FAIs appeared frequently at pre-midnight between March and May and at post-midnight between May and August. The pre-midnight FAIs coincided well with GPS scintillation observed at the same site. Seasonal and local time variations of the pre-midnight FAI occurrence are consistent with those of equatorial plasma bubbles reported in previous studies (e.g., Maruyama and Matuura, 1984). These results indicate that the pre-midnight FAIs could be associated with the equatorial plasma bubbles. On the other hand, seasonal and local time variations of the post-midnight FAIs were inconsistent with those of the plasma bubbles. The features of the post-midnight FAIs can be summarized as follows: (1) The post-midnight FAIs are not accompanied by GPS scintillations. (2) Most of the post-midnight FAI regions do not show propagation, but some of them propagate westward. (3) Echo intensity of the post-midnight FAIs was weaker than that of the pre-midnight FAIs. These features are similar to those of the FAI echoes that have been observed at mid-latitude (e.g., Fukao et al., 1991). At Kototabang, Fukao et al. (2004) have firstly observed FAIs that resemble those at mid-latitude. The present paper reports statistical characteristics of the mid-latitude-type FAIs observed at Kototabang.

Key words

Equatorial ionospherefield-aligned irregularityVHF radarGPSscintillation

Authors’ Affiliations

(1)
Solar-Terrestrial Environment Laboratory, Nagoya University, Japan
(2)
National Institute for Aeronautics and Space, Bandung, Indonesia
(3)
National Institute of Information and Communications Technology, Tokyo, Japan

References

  1. Basu, S., Su. Basu, J. Aarons, J. P. McClure, and M. D. Cousins, On the coexistence of kilometer- and meter-scale irregularities in the nighttime equatorial F region, J. Geophys. Res., 83, 4219–4226, 1978.View ArticleGoogle Scholar
  2. Bowman, G. G., Upper atmosphere neutral-particle density variations compared with spread-F occurrence rates at locations around the world, Ann. Geophys., 10, 676–682, 1992.Google Scholar
  3. Burke, W. J., L. C. Gentile, C. Y. Huang, C. E. Valladares, and S. Y. Su, Longitudinal variability of equatorial plasma bubbles observed by DMSP and ROCSAT-1, J. Geophys. Res., 109, A12301, doi:10.1029/2004JA010583, 2004.View ArticleGoogle Scholar
  4. Chandra, H., Som Sharma, M. A. Abdu, and I. S. Batista, Spread-F at anomaly crest regions in the Indian and American longitudes, Adv. Space Res., 31(3), 717–727, 2003.View ArticleGoogle Scholar
  5. Fukao, S., M. C. Kelley, T. Shirakawa, T. Takami, M. Yamamoto, T. Tsuda, and S. Kato, Turbulent upwelling of the mid-latitude ionosphere, 1. Observational Results by the MU radar, J. Geophys. Res., 96, 3725–3746, 1991.View ArticleGoogle Scholar
  6. Fukao, S., H. Hashiguchi, M. Yamamoto, T. Tsuda, T. Nakamura, M. K. Yamamoto, T. Sato, M. Hagino, and Y. Yabugaki, The Equatorial Atmosphere Radar (EAR): System description and first results, Radio Sci., 38(3), 1053, doi:10.1029/2002RS002767, 2003a.View ArticleGoogle Scholar
  7. Fukao, S., Y. Ozawa, M. Yamamoto, and R. T. Tsunoda, Altitude-extended equatorial spread F observed near sunrise terminator over Indonesia, Geophys. Res. Lett., 30(22), 2137, doi:10.1029/2003GL018383, 2003b.View ArticleGoogle Scholar
  8. Fukao, S., Y. Ozawa, T. Yokoyama, M. Yamamoto, and R. T. Tsunoda, First observations of the spatial structure of F region 3-m-scale field-aligned irregularities with the Equatorial Atmosphere Radar in Indonesia, J. Geophys. Res., 109, A02304, doi:10.1029/2003JA010096, 2004.Google Scholar
  9. Kelley, M. C., The Earth’s ionosphere, Plasma Physics and Electrodynamics, Academic, San Diego, Calif., 1989.Google Scholar
  10. Kotake, N., Y. Otsuka, T. Tsugawa, T. Ogawa, and A. Saito, Climatological study of GPS total electron content variations caused by mediumscale traveling ionospheric disturbances, J. Geophys. Res., 111, A04306, doi:10.1029/2005JA011418, 2006.Google Scholar
  11. Martinis, C., J. V. Eccles, J. Baumgardner, J. Manzano, and M. Mendillo, Latitude dependence of zonal plasma drifts obtained from dualsite airglow observations, J. Geophys. Res., 108, 1129, doi:10.1029/2002JA009462, 2003.View ArticleGoogle Scholar
  12. Maruyama, T. and N. Matuura, Longitudinal variability of annual changes in activity of equatorial spread F and plasma bubbles, J. Geophys. Res., 89, 10,903–10,912, 1984.View ArticleGoogle Scholar
  13. Ogawa, T., Y. Miyoshi, Y. Otsuka, T. Nakamura, and K. Shiokawa, Equatorial GPS ionospheric scintillations over Kototabang, Indonesia and their relation to atmospheric waves from below, Earth Planets Space, 61, this issue, 397–410, 2009.View ArticleGoogle Scholar
  14. Otsuka, Y., K. Shiokawa, T. Ogawa, T. Yokoyama, M. Yamamoto, and S. Fukao, Spatial relationship of equatorial plasma bubbles and field-aligned irregularities observed with an all-sky airglow imager and the Equatorial Atmosphere Radar, Geophys. Res. Lett., 31, L20802, doi:10.1029/2004GL020869, 2004a.View ArticleGoogle Scholar
  15. Otsuka, Y., K. Shiokawa, T. Ogawa, and P. Wilkinson, Geomagnetic conjugate observations of medium-scale traveling ionospheric disturbances at midlatitude using all-sky airglow imagers, Geophys. Res. Lett., 31, L15803, doi:10.1029/2004GL020262, 2004b.View ArticleGoogle Scholar
  16. Otsuka, Y., K. Shiokawa, and T. Ogawa, Equatorial ionospheric scintillations and zonal irregularity drifts observed with closely-spaced GPS receivers in Indonesia, J. Meteor. Soc. Jpn., 84A, 343–351, 2006.View ArticleGoogle Scholar
  17. Pimenta, A. A., P. R. Fagundes, Y. Sahai, J. A. Bittencourt, and J. R. Abalde, Equatorial F-region plasma depletion drifts: latitudinal and seasonal variations, Ann. Geophys., 21, 2315–2322, 2003.View ArticleGoogle Scholar
  18. Rino, C. L., R. T. Tsunoda, J. Petriceks, R. C. Livingston, M. C. Kelley, and K. D. Baker, Simultaneous rocket-borne beacon and in situ measurements of equatorial spread-F—intermediate wavelength results, J. Geophys. Res., 86, 2411–2420, 1981.View ArticleGoogle Scholar
  19. Saito, A., M. Nishimura, M. Yamamoto, S. Fukao, T. Tsugawa, Y. Otsuka, S. Miyazaki, and M. C. Kelley, Observations of traveling ionospheric disturbances and 3-m scale irregularities in the nighttime F-region ionosphere with the MU radar and a GPS network, Earth Planets Space, 54, 31–44, 2002.View ArticleGoogle Scholar
  20. Shiokawa, K., Y. Otsuka, M. K. Ejiri, Y. Sahai, T. Kadota, C. Ihara, T. Ogawa, K. Igarashi, S. Miyazaki, and A. Saito, Imaging observations of the equatorward limit of midlatitude traveling ionospheric disturbances, Earth Planets Space, 54, 57–62, 2002.View ArticleGoogle Scholar
  21. Shiokawa, K., Y. Otsuka, C. Ihara, T. Ogawa, and F. J. Rich, Ground and satellite observations of nighttime medium-scale traveling ionospheric disturbance at midlatitude, J. Geophys. Res., 108(A4), 1145, doi:10.1029/2002JA009639, 2003.View ArticleGoogle Scholar
  22. Shiokawa, K., Y. Otsuka, and T. Ogawa, Quasi-periodic southward-moving waves in 630-nm airglow images in the equatorial thermosphere, J. Geophys. Res., 111, A06301, doi:10.1029/2005JA011406, 2006.Google Scholar
  23. Subbarao, K. S. V. and B. V. Krishna Murthy, Seasonal variations of equatorial spread-F, Ann. Geophys., 12, 33–39, 1994.Google Scholar
  24. Swartz, W. E., M. C. Kelley, J. J. Makela, S. C. Collins, E. Kudeki, S. Franke, J. Urbina, N. Aponte, M. P. Sulzer, and S. A. Gonzalez, Coherent and incoherent scatter radar observations during intense mid-latitude spread F, Geophys. Res. Lett., 27, 2829–2832, 2000.View ArticleGoogle Scholar
  25. Tsunoda, R. T., Backscatter measurements of 11-cm equatorial spread-F irregularities, Geophys. Res. Lett., 7, 848–850, 1980a.View ArticleGoogle Scholar
  26. Tsunoda, R. T., Magnetic-field-aligned characteristics of plasma bubbles in the nighttime equatorial ionosphere, J. Atmos. Terr. Phys., 42, 743–752, 1980b.View ArticleGoogle Scholar
  27. Tsunoda, R. T., On the spatial relationship of 1-m equatorial spread F irregularities and plasma bubbles, J. Geophys. Res., 85, 185–190, 1980c.View ArticleGoogle Scholar
  28. Tsunoda, R. T., On the generation and growth of equatorial backscatter plumes 2. Structuring of the west walls of upwellings, J. Geophys. Res., 88, 4869–4874, 1983.View ArticleGoogle Scholar
  29. Tsunoda, R. T., Control of the seasonal and longitudinal occurrence of equatorial scintillations by the longitudinal gradient in integrated E region Pedersen conductivity, J. Geophys. Res., 90, 447–456, 1985.View ArticleGoogle Scholar
  30. Tsunoda, R. T., R. C. Livingston, J. P. McClure, and W. B. Hanson, Equatorial plasma bubbles: Vertically elongated wedges from the bottomside F layer, J. Geophys. Res., 87, 9171–9180, 1982.View ArticleGoogle Scholar
  31. Valladares, C. E., R. Sheehan, S. Basu, H. Kuenzler, and J. Espinoza, The multi-instrumented studies of equatorial thermosphere aeronomy scintillation system: Climatology of zonal drifts, J. Geophys. Res., 27, 26,839–26,850, 1996.View ArticleGoogle Scholar
  32. Woodman, R. F. and C. LaHoz, Radar observations of F-region equatorial irregularities, J. Geophys. Res., 81, 5447–5466, 1976.View ArticleGoogle Scholar
  33. Yokoyama, T., S. Fukao, and M. Yamamoto, Relationship of onset of equatorial F -region irregularities with sunset terminator observed with the Equatorial Atmosphere Radar, Geophys. Res. Lett., 31, L24804, doi:10.1029/2004GL021529, 2004.View ArticleGoogle Scholar

Copyright

© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB. 2009

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