| Full text | |
| Author(s): |
Muella, M. T. A. H.
[1]
;
de Paula, E. R.
[1]
;
Fagundes, P. R.
[2]
;
Bittencourt, J. A.
[1]
;
Sahai, Y.
[2]
Total Authors: 5
|
| Affiliation: | [1] Inst Nacl Pesquisas Espaciais, Div Aeron, Sao Paulo - Brazil
[2] Univ Vale Paraiba, IP&D, Lab Fis & Astron, Sao Paulo - Brazil
Total Affiliations: 2
|
| Document type: | Review article |
| Source: | SURVEYS IN GEOPHYSICS; v. 31, n. 5, p. 509-530, SEP 2010. |
| Web of Science Citations: | 11 |
| Abstract | |
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) | |
| FAPESP's process: | 08/05482-5 - Study of generation, evolution and dynamics of ionospheric irregularities at equatorial and low-latitude regions |
| Grantee: | Paulo Roberto Fagundes |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 08/04892-5 - Study of the temporal and spatial dependence between plasma irregularities and total electron content as a basis to the development of a ionospheric scintillation model: simultaneous investigation of ionospheric radiotomography |
| Grantee: | Marcio Tadeu de Assis Honorato Muella |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |