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Takahashi Yukihiro

Institute:
Hokkaido University.
Sapporo, Japan

EFFECTS OF LIGHTNING ACTIVITY ON ATMOSPHERE, IONOSPHERE AND MAGNETOSPHERE

Authors: Yukihiro Takahashi, Mitsuteru Sato, Kozo Yamashita, Dept. Cosmosciences, Hokkaido University

It has been revealed that the lightning and thunderstorm activity are closely related to the upper atmosphere, ionosphere and magnetosphere via various kinds of dynamical, chemical and electromagnetic processes as mentioned below. These are to be examined quantitatively with the latest observations, such as by spacecrafts and ground-based networks, and numerical modelings. 1) Thunderstorm causes gravity waves and mesoscale vertical circulation, which reach the middle atmosphere. These dynamical motions of the atmosphere may cause wave-4 structure observed in the upper atmosphere and ionosphere. 2) Lightning discharge induces significant increase or decrease of electron density in the ionosphere and the enhancement of chemical reactions in the lower and middle atmosphere. 3) Although the hypothesis of global electric circuit model was proposed almost 100 years ago, understanding of this model is still poor. Taking into account the latest observational dataset and numerical modeling will redraw this model with some essential qualitative revisions. 4) A part of high energy electrons detected in the magnetosphere could be provided by lightning discharges. Also the high energy electrons may initiate high altitude discharges such as sprites. On the other hand, high energy particles including radiation belt particles, and galactic and solar cosmic-rays could ionize the atmospheric molecules and atoms, which may result in generation of cloud particles as well as modification of atmospheric conductivity. 5) One of the important scenarios to explain the relationship between solar a
lightning, thunderstorm, Wave-4, electron density, chemical effect, global electric circuite, Sun-ea

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