| Project/Area Number |
62550200
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電力工学
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| Research Institution | Nagoya University |
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Principal Investigator |
KITO Yukio Nagoya University, Dpt. of Electrical Engineering, Professor, 工学部, 教授 (00023044)
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| Co-Investigator(Kenkyū-buntansha) |
SAKURANO Hitoshi Ishikawa College of Technology, Dpt. of Electrical Engineering, Associate Profes, 電気工学科, 助教授 (50042932)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1989: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Lightning discharge / Summer lightning discharge / Winter lightning discharge / Point discharge current / Space-electric-field meter / Ground flash / Regional distribution of electric field / Early warning of lightning strokes / 雷撃予測 / 対地雷放電 |
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| Research Abstract |
Obtained results in this project are summarized as the following seven items ; 1. Simultaneous observation of the electric field intensity on the ground have been performed at several sites inside Kahoku-gata, a reclaimed land located in the northern suburbs of Kanazawa in winter, and Kisozaki, a reclaimed land in the western suburbs of Nagoya in summer. 2. A graphical method was developed to presume regional distribution of the electric field under the winter thundercloud on the basis of observed records. 3. Large pulsive components found on recorded waveforms of the point discharge current were identified as the large electric field change associated with lightning discharges. 4. The regional distribution of the electric field on the ground were stored in our data-base with respect to 61 natural lightnings in winter around Kahoku-gata. A number of natural lightning discharges with different polarities may occur when more than 30% of the total area of Kahoku-gata is occupied by the negative intensity of the electric field. 5. The accurate stroke locations were determined by the double-quarter VTR observations with respect to eleven cloud-to-ground natural flashes. These have struck positions within distance of about 1 km from the boundary between the positive and the negative areas of the electric field on the ground. 6. The summer lightning discharge around Nagoya only occurs in the afternoon, but the.winter one around Kanazawa occurs in day and night. 7. According to the records obtained by a developed battery-saving type Space-electric-field meter, order of a few nC/m^3 is produced around ground under the strong thundercloud in winter and it changes with a certain time lag with increasing or decreasing of the electric field on the ground. The space electric field close to the top of a vertical rod electrode, 10m high, is reduced to about half compared with that of the same height.
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