Mesosphere-ionosphere coupling processes observed in the F-layer bottom-side oscillation

Hisao Takahashi, Instituto Nacional de Pesquisas Espaciais (INPE)
Sharon L. Vadas, NorthWest Research Associates
C. M. Wrasse, Universidade de Vale do Paraíba (UNIVAP)
Michael J. Taylor, Utah State University
Pierre-Dominique Pautet, Utah State University
A. F. Medeiros, Universidade Federal de Campina Grande (UFCG)
R. A. Buriti, Instituto Nacional de Pesquisas Espaciais (INPE)
Mangalathayil Ali Abdu, National Institute for Space Research, São José dos Campos
Inez S. Batista, National Institute for Space Research, São José dos Campos
I. Paulino, National Institute for Space Research, São José dos Campos
P. A. Stamus, NorthWest Research Associates
David C. Fritts, NorthWest Research Associates
Eurico R. de Paula, Instituto Nacional de Pesquisas Espaciais

Abstract

During the Spread FEx campaign, under the NASA Living with a star (ILWS) program which was carried out in the South American Magnetic Equatorial region from September to November 2005, we observed formation of the bottom-type spread F and simultaneous occurrence of mesospheric gravity wave events. The events were monitored by the ionosonde, coherent radar and airglow OI 630.0 nm and OH imager. It is found that the bottom-type scattering layer has a wave form generated most probably by local gravity waves. Reverse ray-tracing of the observed gravity waves indicate their possible sources in the troposphere or thermosphere. Forward ray-tracing indicates their penetration into the ionosphere. The present work summarizes the observational evidence and results of the data analysis and discusses the mesosphere–ionosphere coupling processes.