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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Thermospheric Meridional Wind Control on Equatorial Scintillations and the Role of the Evening F-Region Height Rise, E x B Drift Velocities and F2-Peak Density Gradients

Texto completo
Autor(es):
Muella, M. T. A. H. [1] ; de Paula, E. R. [1] ; Fagundes, P. R. [2] ; Bittencourt, J. A. [1] ; Sahai, Y. [2]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Inst Nacl Pesquisas Espaciais, Div Aeron, Sao Paulo - Brazil
[2] Univ Vale Paraiba, IP&D, Lab Fis & Astron, Sao Paulo - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo de Revisão
Fonte: SURVEYS IN GEOPHYSICS; v. 31, n. 5, p. 509-530, SEP 2010.
Citações Web of Science: 11
Resumo

The possible role, on L-band scintillation activity, played by the nighttime magnetic meridional component of the thermospheric horizontal neutral winds, the post-sunset F-layer base height, the electrical field pre-reversal enhancement (PRE) and the latitudinal gradients of the F2-layer peak density is analyzed, considering different cases of scintillation occurrence (and their latitudinal extent) during August and September 2002. The meridional winds were derived over low-latitudes from a modified form of the nonlinear time-dependent servo-model. A chain of two scintillation monitors and three digital ionosondes was operational in Brazil and used to collect, respectively, global positioning system signal amplitude scintillation and ionospheric height (h'F; hpF2) and frequency (foF2) parameters. From the overall behavior in the 2 months analyzed, the results suggest that high near sunset upward vertical plasma drifts are conducive for the generation of spread-F irregularities, whereas large poleward meridional winds tend to suppress the development of plasma bubble irregularities and the occurrence of their associated scintillations. Even when generated, a reduced fountain effect, due to weak electric field PRE, acts for the bubbles to be expanded less effectively to higher latitudes. The results also reveal that high F-layer base and peak heights (at equatorial and off-equatorial latitudes), and intense gradients in the F2-peak density between the dip equator and the equatorial anomaly crests, are favorable conditions for the generation of F-region irregularities and increased scintillation activity. Other distinct features of the controlling factors in the cases of occurrence and non-occurrence of equatorial scintillations are presented and discussed. (AU)

Processo FAPESP: 08/05482-5 - Estudo da geração, evolução e dinâmica das irregularidades ionosféricas na região equatorial e baixas latitudes
Beneficiário:Paulo Roberto Fagundes
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 08/04892-5 - Estudo da dependência temporal e espacial entre as irregularidades do plasma e o conteúdo eletrônico total como fundamentos para o desenvolvimento de um modelo de cintilação ionosférica: investigação simultânea de radiotomografia ionosférica
Beneficiário:Marcio Tadeu de Assis Honorato Muella
Linha de fomento: Bolsas no Brasil - Pós-Doutorado