Browsing by Author "Cóndor, P."
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Item Restricted Ionospheric effects of sudden stratospheric warming during moderate-to-high solar activity: Case study of January 2013(American Geophysical Union, 2013-09-24) Goncharenko, L.; Chau Chong Shing, Jorge Luis; Cóndor, P.; Coster, A.; Benkevitch, L.A major sudden stratospheric warming (SSW) occurred in January 2013 during moderate-to-high solar activity conditions. Observations during the winter of 2012/2013 reveal strong ionospheric disturbances associated with this event. Anomalous variations in vertical ion drift measured at the geomagnetic equator at Jicamarca (12°S, 77°W) are observed for over 40 days. We report strong perturbations in the total electron content (TEC) that maximize in the crests of equatorial ionization anomaly, reach 100% of the background value, exhibit significant longitudinal and hemispheric asymmetry, and last for over 40 days. The magnitude of ionospheric anomalies in both vertical drifts and TEC is comparable to the anomalies observed during the record-strong SSW of January 2009 that coincided with the extreme solar minimum. This observation contrasts with results of numerical simulations that predict weaker ionospheric response to the tidal forcing during high solar activity.Item Restricted The global thermospheric and ionospheric response to the 2008 minor sudden stratospheric warming event(American Geophysical Union, 2012-10-09) Korenkov, Y. N.; Klimenko, V. V.; Klimenko, M. V.; Bessarab, F. S.; Korenkova, N. A.; Ratovsky, K. G.; Chernigovskaya, M. A.; Shcherbakov, A. A.; Sahai, Y.; Fagundes, P. R.; De Jesus, R.; De Abreu, A. J.; Cóndor, P.This paper presents a study of thermospheric and ionospheric response to the 2008 minor sudden stratospheric warming (SSW) event. This period was characterized by low solar and geomagnetic activity. The study was performed using the Global Self-consistent Model of Thermosphere, Ionosphere, and Protonosphere (GSM TIP). Model results were compared with ionosonde data from Irkutsk, Kaliningrad, Sao Jose dos Campos, and Jicamarca. The SSW event was modeled by specifying the temperature and density perturbations at the lower boundary of the GSM TIP (80 km altitude). GSM TIP simulation allowed the reproduction of the lower thermosphere temperature disturbances (the occurrence of the quasi-wave 1 structure at 80–130 km altitude with a vertical scale of 40 km), the negative response of F2 region electron density and the positive response of electron temperature at 300 km during the 2008 minor SSW event. The main formation mechanism of the global ionospheric response is due to the disturbances (decrease) in the n(O)/n(N2) ratio. The change in zonal electric field is another important mechanism of the ionospheric response at low latitudes.