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www.ann-geophys.net/22/4061/2004/
doi:10.5194/angeo-22-4061-2004
© European Geosciences Union 2004
Bottom-type scattering layers and equatorial spread F
1Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA
2Radio Observatorio de Jicamarca, Instituto Geofísico del Perú, Lima, Peru
Abstract. Jicamarca radar observations of bottom-type coherent scattering layers in the post-sunset bottomside F-region ionosphere are presented and analyzed. The morphology of the primary waves seen in radar images of the layers supports the hypothesis of kudeki+bhattacharyya-1999 that wind-driven gradient drift instabilities are operating. In one layer event when topside spread F did not occur, irregularities were distributed uniformly in space throughout the layers. In another event when topside spread F did eventually occur, the irregularities within the pre-existing bottom-type layers were horizontally clustered, with clusters separated by about 30km. The same horizontal periodicity was evident in the radar plumes and large-scale irregularities that emerged later in the event. We surmise that horizontal periodicity in bottom-type layer irregularity distribution is indicative of large-scale horizontal waves in the bottomside F-region that may serve as seed waves for large-scale Rayleigh Taylor instabilities.
Key words. Ionosphere (equatorial ionosphere; ionospheric irregularties; plasma waves and instabilities)
Full Article (PDF, 7647 KB)
Citation: Hysell, D. L., Chun, J., and Chau, J. L.: Bottom-type scattering layers and equatorial spread F, Ann. Geophys., 22, 4061-4069, doi:10.5194/angeo-22-4061-2004, 2004. Bibtex EndNote Reference Manager XML
