Abstract.Two atmospheric trajectories have been determined by simultaneous observations with image intensifier-fitted TV cameras and conventional photographic cameras for two bright Leonid meteors (fireballs) in 1995 and 1996. Beginning heights recorded by the photographic method are lower than about 130 km, but those observed by the TV systems are closer to 160 km. The primary reason for this difference is the sensitivity of the observing systems. However, the difference in the sensitive wavelengths (up to 900 mn for the TV systems) could be another factor contributing to the large difference between the two methods. This suggests that the beginning heights of high speed bright meteors such as Leonid meteors are much higher than previously thought.
During the Leonid MAC 2002 airborne mission, we carried out a wide-field TV observation of the strong activity of the Leonid meteor shower from 03h30m UT through 11h50m UT on 2002 November 19. Two narrow peaks of the storm activities were observed at around 04h03m UT and 10h49m UT, with peak influx rates ($\mbox{mag} \leq +6.5$ mag$\leq +6.5$) of $1.63 \times 10^{-5} \,\mathrm{km}^{-2} \,\mathrm{s}^{-1}$ and $1.95 \times 10^{-5} \,\mathrm{km}^{-2} \,\mathrm{s}^{-1}$, respectively. Even in the full-Moon condition, the activity level of these twin peaks were comparable to that of the storm observed in 2001 over Japan. The first peak activity generated by the 7-revolution-old dust trail (ejection in 1767) was rich in bright meteors, including the fireball-class, compared to the second peak corresponding to the 4-revolution-old dust trail (ejection in 1866). The magnitude distribution indices ($-2.5 \leq$ mag$\leq +3.5$) were $1.70 \pm 0.10 $ in the first peak (7-rev) and $2.03 \pm 0.05$ in the second peak (4-rev). The correlation between the observed peaks and several theoretical predictions is discussed.
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