Estudo da variação na altitude de máxima ocorrência de meteoros e a sua relação com o ciclo solar

Abstract

In this paper, data from the heights of maximum occurrence of meteor echoes were used to investigate a possible relationship between variations in the height of meteors and solar flux at low latitudes during the solar cycle 23. The heights of meteors were obtained from measurements by SKiYMET meteor radar system at Cachoeira Paulista (22.7 ° S, 45.0 ° W). The data used include measurements taken from March 1999 to July 2006 and from September 2007 to October 2008. The echo of the reach and the zenith angle with respect to each radar echo are used for the heights of occurrence of meteors. The maximum height of daily occurrence was obtained from the Gaussian distribution through vertical adjustment. The series of height data of peak occurrence of meteors was subjected to multiple linear regression analysis to investigate the trend and possible variations induced by solar activity. The results showed a downward trend of approximately 68 m / year at the time of maximum occurrence of meteor and 447 m / 100sfu using monthly data after removal of the solar effect, resulting in a decrease in the peak height of approximately 248 m for all observation period after the time trend removal. Considering only the period of decline of the solar cycle (2002-2008) the decline was approximately 1054 m using monthly data in the analysis. The decrease of the meteors occurrence height can be attributed, in part, the effects of solar activity. Knowing that the atmosphere expands with the growth of solar activity the neutral density shows a downward trend over time.