Longitudinal variation in Global Navigation Satellite Systems TEC and topside ion density over South American sector associated with the four-peaked wave structures

Autor(es)

Nogueira, P. A. B. ^[1] ; Abdu, M. A. ^[1] ; Souza, J. R. ^[1] ; Bailey, G. J. ^[2] ; Batista, I. S. ^[1] ; Shume, E. B. ^[3] ; Denardini, C. M. ^[1]

Afiliação do(s) autor(es)

^[1] Inst Nacl Pesquisas Espaciais, Div Aeron, Sao Jose Dos Campos - Brazil

^[2] Univ Sheffield, Dept Appl Math, Sheffield, S Yorkshire - England

^[3] CALTECH, Jet Prop Lab, Pasadena, CA - USA

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS; v. 118, n. 12, p. 7940-7953, DEC 2013.
• Citações Web of Science: 8

Resumo

Recent observations of the low-latitude ionospheric electron density revealed a four-peaked longitudinal structure in the equatorial ionization anomaly when plotted at a constant-local-time frame. It was proposed that neutral wind-driven E region dynamo electric fields due to nonmigrating tidal modes are responsible for this pattern. We examine the four-peaked structure in the observed topside ion density and its manifestation as longitudinal structures in total electron content (TEC) over South America. The strong longitudinal variation in TEC characterized by larger value over Brazilian eastern longitude sector as compared to that over the Peruvian western longitude is modeled using the Sheffield University plasmasphere-ionosphere model (SUPIM) aiming to identify the control factors responsible for the longitude variation. We found that the SUPIM runs using as input the existing standard models of vertical drift, and thermospheric winds do not explain the TEC longitudinal structure. Realistic values of these control parameters were generated based on the strong vertical drift longitudinal variation as determined from magnetometer and Digisonde data and appropriately adjusted winds (horizontal wind model). These realistic vertical drifts together with the modified thermospheric wind, when used as input to the SUPIM, are found to satisfactorily explain the longitudinal differences in the TEC and topside ion density (Ni) over South America. The study shows that the TEC in the whole latitude distribution is larger over the east coast than over the west coast of South America and that the vertical drift and thermospheirc winds control the longitudinal four wave structure in the TEC and Ni. (AU)

• Processo FAPESP: 12/08445-9 - Estudo da variabilidade dia-a-dia da mesosfera, termosfera e ionosfera em baixas latitudes e região equatorial, durante o ciclo solar 24
• Beneficiário: Paulo Roberto Fagundes
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/01924-1 - Estudo e Previsão do Conteúdo Eletrônico Total na Região da América do Sul.
• Beneficiário: Paulo Alexandre Bronzato Nogueira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado