Low-latitude equinoctial spread-F occurrence at different longitude sectors under low solar activity

• Autores: Pezzopane, M.; Zuccheretti, E.; Abadi, P.; de Abreu, A. J.; de Jesus, R.; Fagundes, P. R.; Supnithi, P.; Rungraengwajiake, S.; Nagatsuma, T.; Tsugawa, T.; Cabrera, Miguel Angel; Ezquer, Rodolfo Gerardo
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: IONOSPHERE; EQUATORIAL IONOSPHERE; IONOSPHERIC IRREGULARITIES; WAVE PROPAGATION
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We present the results of a comparative study of spread-F signatures over five low-latitude sites: Chiangmai (CGM; 18.8° N, 98.9° E, mag. Lat. 8.8° N), Thailand; Tanjungsari (TNJ; 6.9° S, 107.6° E, mag. Lat. 16.9° S), Indonesia; Palmas (PAL; 10.2° S, 311.8° E, mag. Lat. 0.9° S) and São José Dos Campos (SJC; 23.2° S, 314.1° E, mag. Lat. 14.0° S), Brazil; and Tucumán (TUC; 26.9° S, 294.6° E, mag. Lat. 16.8° S), Argentina. The investigation was based on simultaneous ionograms recorded by an FMCW (frequency-modulated continuous-wave) at CGM, an IPS-71 (digital ionosonde from KEL aerospace) at TNJ, a CADI (Canadian Advanced Digital Ionosonde) at PAL and SJC, and an AIS-INGV (Advanced Ionospheric Sounder – Istituto Nazionale di Geofisica e Vulcanologia) at TUC, during the equinoctial periods March–April (R12 = 2.0 and R12 = 2.2) and September–October (R12 = 6.1 and R12 = 7.0) 2009, for very low solar activity. Spread-F signatures were categorized into two types: the range spread-F (RSF) and the frequency spread-F (FSF). The study confirms that the dynamics and the physical processes responsible for these phenomena are actually complicated. In fact, the features that arise from the investigation are different, depending on both the longitude sector and on the hemisphere. For instance, TUC, under the southern crest of the ionospheric equatorial ionization anomaly (EIA), shows a predominance of RSF signatures, while both SJC, under the southern crest of EIA but in a different longitude sector, and CGM, under the northern crest of EIA, show a predominance of FSF signatures. Moreover, the spread-F occurrence over the longitude sector that includes CGM and TNJ is significantly lower than the spread-F occurrence over the longitude sector of PAL, SJC, and TUC.
Fil: Pezzopane, M.. Istituto Nazionale Di Geofisica E Vulcanologia; Italia;
Fil: Zuccheretti, E.. Istituto Nazionale Di Geofisica E Vulcanologia; Italia;
Fil: Abadi, P.. Indonesian National Institute of Aeronautics and Space. Space Science Center. Division of Ionosphere and Telecommunication; Indonesia;
Fil: de Abreu, A. J.. Universidade do Vale do Paraíba; Brazil;
Fil: de Jesus, R.. Universidade do Vale do Paraíba; Brazil;
Fil: Fagundes, P. R.. Universidade do Vale do Paraíba; Brazil;
Fil: Supnithi, P.. King Mongkut’s Institute of Technology Ladkrabang . Faculty of Engineering; Tailandia;
Fil: Rungraengwajiake, S.. King Mongkut’s Institute of Technology Ladkrabang . Faculty of Engineering; Tailandia;
Fil: Nagatsuma, T.. National Institute of Information and Communications Technology. Space Weather and Environment Informatics Laboratory; Japón;
Fil: Tsugawa, T.. National Institute of Information and Communications Technology. Space Weather and Environment Informatics Laboratory; Japón;
Fil: Cabrera, Miguel Angel. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Electricidad, Electrónica y Computación. Laboratorio de Telecomunicaciones; Argentina; Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación de Atmósfera Superior y Radiopropagación; Argentina;
Fil: Ezquer, Rodolfo Gerardo. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación de Atmósfera Superior y Radiopropagación; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Ionosfera; Argentina;