Ionospheric Plasma Bubble Climatology Over Brazil Based on 22Years (1977-1998) of 630 nm Airglow Observations
Journal of Atmospheric and Solar-Terrestrial Physics
The frequency of occurrence of the large-scale ionospheric plasma depletions, or plasma bubbles, over Cachoeira Paulista—CP (45°W, 33°S, 28°S dip), with solar activity, season, and geomagnetic activity, during the period of 1977–1998, is studied here based on 934 days of scanning photometers and imagers data of the atomic oxygen View the MathML source nocturnal airglow. The bubble occurrence for the entire period of study shows maximum rate of 86% in January and 11% in May. The seasonal pattern of the bubble occurrence shows up as broad a maximum and a minimum centered around summer and winter months, respectively. While during the high-solar activity the maximum extends from September to April, for the low-activity period it extends from October to March. The average sunspot number for the solar maximum (minimum) for the data of this work is 129.9 (33.1). Significant increase of bubble occurrence (by ∼80%) from low to high solar activity levels is found to occur in the present analysis only during the equinoctial months of March–April and September–October. The post-sunset plasma bubble occurrence over Cachoeira Paulista is found to decrease with increase of Kp that precedes the sunset by View the MathML source, suggesting the role of disturbance dynamo electric field to inhibit its development. Increase of Kp during sunset hours can increase the bubble occurrence as a possible effect of prompt penetration electric field. These results are presented and discussed in this paper.
Sobral, J.H.A., M.A. Abdu, H. Takahashi, M.J. Taylor, E.R. dePaula, C.J. Zamlutti, M.G. deAquino, and G.L. Borba, Ionospheric plasma bubble climatology over Brazil based on 22 years (1977-1998) of 630 nm airglow observations, , J. Atmos. Solar-Terr. Phys., 64, 1517- 1524, 2002.