(Elsevier) Pimenta, Alexandre Alvares; Batista, Paulo Prado; Andrioli, Vania Fatima; Fagundes, Paulo Roberto; Batista, Inez Staciarini
Our observations show that on some occasions an influx of meteor ablation possibly contributes to appearance of a sudden enhancement in mesospheric sodium density. On July 05, 2013, all-sky images with a narrow sodium filter in the 589 nm emission, operating at Cachoeira Paulista (22.7 S, 45 W) and lidar observations of the mesospheric sodium layer, operating at Sa˜o Jose´ dos Campos (23.1 S, 45.9 W), both observatories in Brazil, show a possible relationship of meteor disintegration and appearance of sodium enhancements on the background layer. After the meteor impact, the all-sky images showed a sodium cloud that was seen for about 10 min through the images in the NaD 589 nm emission, with initial dimensions of approximately 36 km 9 km and initial speed of about 90 m/s southward. In addition, our observations show that the movement of sodium cloud in the horizontal plane around 90 km is relatively anisotropic and change the dimensions with time