HR: 0800h
AN: SA21A-06 [Abstracts]
TI: Equatorial Ionospheric Irregularities Observed in the South American Sector During the December 2006 Geomagnetic Storm
AU: * Sahai, Y
EM: sahai@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: de Jesus, R
EM: jesus.rodolfo@hotmail.com
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Guarnieri, F L
EM: guarnieri@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Fagundes, P R
EM: fagundes@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: de Abreu, A J
EM: alessandro_1000@hotmail.com
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Becker-Guedes, F
EM: fabio@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Abalde, J R
EM: abalde@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Brunini, C
EM: claudiobrunini@yahoo.com
AF: Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, La
Plata, BA , Argentina
AU: Gende, M
EM: mgende@fcaglp.unlp.edu.arg
AF: Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, La
Plata, BA , Argentina
AU: Cintra, T
EM: tuanapop@hotmail.com
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: de Souza, V
EM: vinicius@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Pillat, V
EM: valdirgp@univap.br
AF: Universidade do Vale do Paraiba, Av Shishima Hifumi 2911, Sao Jose dos Campos, SP
12244-000, Brazil
AU: Lima, W
EM: wlima@ulbra-to.br
AF: Centro Universitario Luterano de Palmas - CEULP, Universidade Luterana do Brasil -
ULBRA, Palmas, TO , Brazil
AB:
This investigation presents studies related to the observations of equatorial ionospheric irregularities in the
ionospheric F-region in the South American sector during the intense geomagnetic storm in December 2006,
during the period of low solar activity. The geomagnetic storm reached a minimum Dst of -147 nT at 0700 UT
on 15 December. In this work ionospheric sounding data obtained between 13 and 16 December 2006 at
Palmas (PAL; 10.2o S, 48.2o W; dip latitude 6.6o S) and São José dos Campos (SJC,
23.2o S, 45.9o W; dip latitude 17.6o S), Brazil, and Jicamarca (JIC, 12.0o S, 76.8o W;
dip latitude 0.05o S), Peru, have been used. Also, vertical total electron content (VTEC) and phase
fluctuations (TECU/min) from GPS observations obtained at Brasilia (BRAZ, 15.9o S, 47.9o W; dip
latitude 11.7o S), Presidente Prudente (PPTE, 22.12º S, 51.4º W; dip latitude 14,9º S), Curitiba (PARA,
25.43o S, 49.21o W; dip latitude 18.4o S), Santa Maria (SMAR, 29.71o S, 53.07o W; dip
latitude 19.6o S), Brazil, Bahia Blanca (VBCA, 38.7o S, 62.3o W; dip latitude 22.4o S) and
Puerto Deseado (PDES, 47.7o S, 65.9o W, dip latitude 27.1o S), Argentina, during the period 13
to 16 December are presented. An unusual uplifting of the F-region during pre-reversal enhancement (PRE) on
14 December was possibly associated with a prompt penetration of electric field of magnetospheric origin
after the storm sudden commencement (1414 UT on 14 December). On this geomagnetically disturbed night
of 14-15 December, intense equatorial ionospheric irregularities were observed up to southern most GPS
station PDES in Argentina. It should be mentioned that on the other nights viz., 12-13 and 13-14 December
(both nights before the storm), and 15-16 December (recovery phase), the ionospheric irregularities are limited
to only the Brazilian GPS stations. On the geomagnetically disturbed night of 14-15 December, strong
oscillations were observed in the F-region base height possibly associated with Joule heating at high latitudes
at SJC. Both JIC and PAL show unusual uplifting in the F-region base height on the night of 14-15 December.
The VTEC observations show a positive storm phase only at the Argentinean stations VBCA and PDES soon
after the storm sudden commencement (daytime). However, soon after this positive phase, all the stations in
Argentina and Brazil show negative storm phase during the night on 14-15 December.
DE: 2415 Equatorial ionosphere
DE: 2439 Ionospheric irregularities
DE: 2441 Ionospheric storms (7949)
DE: 2459 Planetary ionospheres (5435, 5729, 6026)
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA: Aeronomy [SA]
MN: 2009 Joint Assembly