Investigações da maré atmosférica lunar na concentração de meteoros sobre o Brasil.

Abstract

The atmosphere works as a protector layer and all the time it is bombarded by meteoroids. When those meteoroids get in the atmosphere, they start to coliding with molecules and pass to disintegrate.This collision process, the meteoroids and the molecules found in its path produce vaporization, in which form ionized trails called meteors. These heated and ionized trails are quite important because they have the property to reĆect radio waves, becoming a fundamental tool in the atmosphere dynamic studies in the Mesosphere and Low Thermosphere region (MLT). Using collected data between 2000 and 2020 by two meteor radars located in Cachoeira Paulista (22.7° S; 45.0° W) and Sao Joao do Cariri (7.4° S; 36.5° W), diurnal and semidiurnal lunar atmospheric tides were studied in their meteor concentration peak and in the atmospheric layer width. To the determination of the meteors concentrarion peak, a Gaussian adjustment was used for the altitudes of the determined echoes with a three hour movable hourly window. A residual was calculated and the inĆuence of the solar components were remove from them. Then the conversion was made to the lunar time and it was applied a minimum squares method in compound months with every year to each location. The same procedure was made to the layer width study, which instead of the use of the meteors peak of concentration it was used the Full Width Half Maximum (FWHM) of the Gaussian adjustment made in the meteor distribution with altitude. The obtained results showed the inĆuence of the moon tide in the meteors concentration peak and the layer width. In the layer peak, the diurnal component was seen by two months in both locations on the solstices, yet the semidiurnal was seen by almost all the compound year, except the months in which the diurnal component was also detected, their biggest amplitudes occurred in the equinoxes months. In the layer width data, the lunar tides showed less inĆuence than the concentration peak. The lunar tide amplitudes were bigger for both peak and layer width were bigger to the data of less latitude in Sao Joao do Cariri.