ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-27-1501-2009 Simultaneous observation of traveling ionospheric disturbances in the Northern and Southern Hemispheres Valladares C. E. 1 Villalobos J. 2 Hei M. A. 1 Sheehan R. 1 Basu Su. 3 MacKenzie E. 1 Doherty P. H. 1 Rios V. H. 4 Institute for Scientific Research, Boston College, Chestnut Hill, MA 02467, USA Department of Physics, Universidad Nacional de Colombia, Bogota, Colombia Center for Space Physics, Boston University, 725 Commonwealth Ave, Boston, MA 02215, USA Department of Physics, Universidad Nacional de Tucuman, Tucuman, Argentina 02 04 2009 27 4 1501 1508 Copyright: © 2009 C. E. Valladares et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/27/1501/2009/angeo-27-1501-2009.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/27/1501/2009/angeo-27-1501-2009.pdf

Measurements of total electron content (TEC) using 263 GPS receivers located in the North and South America continents are presented to demonstrate the simultaneous existence of traveling ionospheric disturbances (TID) at high, mid, and low latitudes, and in both Northern and Southern Hemispheres. The TID observations pertain to the magnetically disturbed period of 29–30 October 2003 also known as the Halloween storm. The excellent quality of the TEC measurements makes it possible to calculate and remove the diurnal variability of TEC and then estimate the amplitude, wavelength, spectral characteristics of the perturbations, and the approximate velocity of the AGW. On 29 October 2003 between 17:00 and 19:00 UT, there existed a sequence of TEC perturbations (TECP), which were associated with the transit of atmospheric gravity waves (AGW) propagating from both auroral regions toward the geographic equator. A marked difference was found between the northern and southern perturbations. In the Northern Hemisphere, the preferred horizontal wavelength varies between 1500 and 1800 km; the propagation velocity is near 700 m/s and the perturbation amplitude about 1 TEC unit (TECu). South of the geographic equator the wavelength of the TECP is as large as 2700 km, the velocity is about 550 m/s, and the TECP amplitude is 3 TECu. Concurrently with our observations, the Jicamarca digisonde observed virtual height traces that exhibited typical features that are associated with TIDs. Here, it is suggested that differences in the local conductivity between northern and southern auroral ovals create a different Joule heating energy term. The quality of these observations illustrates the merits of GPS receivers to probe the ionosphere and thermosphere.

 References Balthazor, R. L. and Moffett, R. J.: A study of atmospheric gravity waves and travelling ionospheric disturbances at equatorial latitudes, Ann. Geophys., 15, 1048–1056, 1997. Balthazor, R. L., Moffett, R. J., and Millward, G. H.: A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere, Ann. Geophys., 15, 779–785, 1997. Basu, Su., Basu, S., Makela, J. J., et al.: Two components of ionospheric plasma structuring at midlatitudes observed during the large magnetic storm of October 30, 2003, Geophys. Res. Lett., 32, L12S06, https://doi.org/10.1029/2004GL021669, 2005. Foster, J. C. and Rideout, W.: Midlatitude TEC enhancements during the October 2003 superstorm, Geophys. Res. Lett., 32, L12S04, https://doi.org/10.1029/2004GL021719, 2005. Hajkowicz, L. A.: Universal time effect in the occurrences of large-scale ionospheric disturbances, Planet. Space Sci., 40, 1093–1099, 1992. Hines, C. O.: On the nature of traveling ionospheric disturbances launched by low-altitude nuclear explosions, J. Geophys. Res., 72, 1877–1882, 1967. Ho, C. M., Manucci, A. J., Sparks, L., Pi, X., Lindqwister, U. L., Wilson, B. D., Iijima, B. A., and Reyes, M. J.: Ionospheric total electron content perturbations monitored by the GPS global network during two Northern Hemisphere winter storms, J. Geophys. Res., 103, 26409–26420, 1998a. Ho, C. M., Mannucci, A. J., Lindqwister, U. J., Pi, X., Tsurutani, B. T., Sparks, L., Iijima, B. A., Wilson, B. D., Harris, I., and Reyes, M. J.: Global ionospheric TEC variations during January 10, 1997 storm, Geophys. Res. Lett., 25(14), 2589–2592, 1998b. Hocke, K. and Schlegel, K.: A review of atmospheric gravity waves and travelling ionospheric disturbances: 1982–1995, Ann. Geophys., 14, 917–940, 1996. Hunsucker, R. D.: Atmospheric Gravity Waves Generated in the High-Latitude Ionosphere: A Review, Rev. Geophys., 20(2), 293–315, 1982. Mannucci, A. J., Tsurutani, B. T., Iijima, B. A., Komjathy, A., Saito, A., Gonzalez, W. D., Guarnieri, F. L., Kozyra, J. U., and Skoug, R.: Dayside global ionospheric response to the major interplanetary events of October 29–30, 2003 "Halloween Storms", Geophys. Res. Lett., 32, L12S02, https://doi.org/10.1029/2004GL021467, 2005. Mayr, H. G., Harris, I., Varosi, F., and Herrero, F. A.: Global excitation of wave phenomena in a dissipative multiconstituent medium, 1, Transfer function of the Earth's thermosphere, J. Geophys. Res., 89, 10929–10959, 1984a. Mayr, H. G., Harris, I., Varosi, F., and Herrero, F. A.: Global excitation of wave phenomena in a dissipative multiconstituent medium, 2, Impulsive perturbations in the Earth's thermosphere, J. Geophys. Res., 89, 10961–10986, 1984b. Nicolls, M. J., Kelley, M. C., Coster, A. J., González, S. A., and Makela, J. J.: Imaging the structure of a large-scale TID using ISR and TEC data, Geophys. Res. Lett., 31, L09812, https://doi.org/10.1029/2004GL019797, 2004. Richmond, A. D.: Gravity wave generation, propagation, and dissipation in the thermosphere, J. Geophys. Res., 83, 4131–4145, 1978. Richmond, A. D.: Large-amplitude gravity wave energy production and dissipation in the thermosphere, J. Geophys. Res., 84, 1880–1890, 1979. Saito, A., Iyemori, T., and Takeda, M.: Evolutionary process of 10 kilometer scale irregularities in the nighttime midlatitude ionosphere, J. Geophys. Res., 103(A3), 3993–4000, 1998. Shiokawa, K., Otsuka, Y., Ogawa, T., Balan, N., Igarashi, K., Ridley, A. J., Knipp, D. J., Saito, A., and Yumoto, K.: A large-scale traveling ionospheric disturbance during the magnetic storm of 15 September 1999, J. Geophys. Res., 107, 1088, https://doi.org/10.1029/2001JA000245, 2002. Shiokawa, K., Ihara, C., Otsuka, Y., and Ogawa, T.: Statistical study of nighttime medium-scale traveling ionospheric disturbances using midlatitude airglow images, J. Geophys. Res., 108(A1), 1052, https://doi.org/10.1029/2002JA009491, 2003. Tsurutani, B. T., Judge, D. L., Guarnieri, F. L., et al.: The October 28, 2003 extreme EUV solar flare and resultant extreme ionospheric effects: Comparison to other Halloween events and the Bastille Day event, Geophys. Res. Lett., 32, L03S09, https://doi.org/10.1029/2004GL021475, 2005. Valladares, C. E., Basu, S., Groves, K., Hagan, M. P., Hysell, D., Mazzella, A., and Sheehan, R.: Measurements of equatorial spread-F ionospheric conditions using a latitudinal chain of GPS receivers, J. Geophys. Res., 106, 29133–29152, 2001.