Slovakia Dr. Junichi Watanabe National Astronomical Observatory of Japan, Japan Prof. This conference will be the fourth in a series of meteoroid meetings which have been held every few years since 1993, the last being in Tatranska Lomnica in 1998. Due to the high Leonid activity during recent years, much research has been devoted to these topics with both traditional and new optical, radar and in-situ methods from ground, airplane and spacecraft. In radar applications the data collection and signal processing techniques have developed hugely within a few years. With these extremely sensitive instruments, the mysterious head echo process can be studied with very high spatial and time resolution observing the effects on the background ionosphere simultaneously.
Radars are important tools for studying the various origins of the meteoroids.
New global problems such as indications of climate change are being tackled. Meteoric constituents have an effect on the physics and chemistry of the atmosphere at and below the deposition heights. Especially, it is important to understand the impact of these on the artificial constituents. Studies of how the addition of meteoric constituents affect different atmospheric phenomena such as noctilucent clouds and ozone chemistry have increased in interest. Studies of meteoroid chemical composition and the ablation processes can even provide information about the state of early conditions in the solar system.