Geophysical Research Letters
American Geophysical Union
Bottom‐type spread F events were observed in the south American equatorial region by a VHF coherent radar and an ionosonde at São Luís (2.5°S, 44.3°W), an ionosonde at Fortaleza (3.9°S, 38.4° W) and an airglow OI 630.0 nm imager at Cariri (7.4°S, 36.5°W) and Brasilia (14.8°S, 47.6°W). In the evening of September 30, 2005, a long duration (∼70 minutes) bottom side scattering layer, confined in a narrow height region, was observed. At the same time all‐sky imager observed sinusoidal intensity depletions in the zonal plane extending more than 1500 km and elongated along the magnetic meridian. No strong spread F structures developed during the period. Subsequently well developed plasma bubbles were observed. This suggests that the observed bottom‐type spread F is an initial phase of the plasma bubbles. We report, for the first time, longitudinal and latitudinal extension of the bottom‐type spread F as diagnosed by optical imagers. Citation: Takahashi, H., et al. (2010), Equatorial ionosphere bottom‐type spread F observed by OI 630.0 nm airglow imaging.
Takahashi, H., M.A. Abdu, M.J. Taylor, P.-D. Pautet, E. de Paula, E.A. Kherani, A.F. Medeiros, C.M. Wrasse, I.S. Batista, J.H.A. Sobral, D. Gobbi, D. Arruda, I. Paulino, S. Vadas, and D.C. Fritts, Equatorial ionosphere bottom-type spread F observed by OI 630.0 nm airglow imaging, Geophys. Res. Lett. , 37, L03102, doi:10.1029/2009GL041802, 2010.