| Project/Area Number |
11440142
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TSUDA Toshitaka Kyoto University, Radio Science Center for Space and Atmosphere, Professor, 宙空電波科学研究センター, 教授 (30115886)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Atsushi National Institute for Environmental Studies, Research Associate, 研究員
HORINOUCHI Takeshi Kyoto Univeraily. Radio Science Center for Space and Atmosphere Research Associate, 宙空電波科学研究センター, 助手 (50314266)
NAKAMURA Takuji Kyoto University Radio Science Center for Space and Atmosphere, Associate Professor, 宙空電波科学研究センター, 助教授 (40217857)
YOSHIHARA Takayuki Kyoto University, Radio Science Center for Space and Atmosphere, JSPS Fellow(PD), 宙空電波科学研究センター, COE研究員
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2001: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2000: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1999: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | atmospheric gravity waves / GPS / middle atmosphere / ionosphere / sporadic E layer / radar / mountain waves / lidar / 重力波 / GPS掩蔽法 / スポラデイックE層 / 積雲対流 / GPS気象学 / 成層圏 / 中間圏 / 大気重力波全球分布 / ラジオゾンデ / 大気の光学観測 |
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| Research Abstract |
1. Analyses of the gravity waves with the GPS occultation technique
The global distribution of the atmospheric gravity waves was investigated with temperature data obtained by using the occultation technique for the GPS (Global Positioning System)signals. This study revealed the global distribution of the amplitude of gravity waves for the first time [Tsuda et al., 2000a]. We could also observe gravity waves from mountain ranges [Hocke et al., 2002]. Also revealed is the global morphology of the tropopause [Nishida et al., 2000]. We could further show that the occurrence of the ionospheric sporadic E layer is correlated with the activity of gravity waves in the stratosphere [Hocke et al., 2002].
2. Radar observations
The results with the GPS observations mentioned above was confirmed with the MU radar at Shigaraki and the White Sands radar in the United States [Nastrom, 2000]. We further showed that the breaking of gravity waves sometimes cause a large spatial variation of wind speed in a short distance [Nakamura et al., 2002]. Gravity waves in low latitudes were investigated with the MF radar in Indonesia to show their inter-annual and ultra-seasonal variability [Isoda, et al., 2002; Tsuda et al.,2002]. Methods to infer gravity wave excitation using meteorological radars were investigated as well [Horinouchi, 2002].
3. Radio sonde observations
Long-term observational data in Indonesia was analyzed to show seasonal variability of the gravity waves in the upper troposphere [Shimizu et al.,2001]. Latitudinal variation of the gravity wave amplitude was also investigated [Alexander et al., 2002].
4. Optical observation
Gravity waves in the mesopause-lower thermosphere region were investigated with CCD imagers,and the seasonal variation of their dominant propagation direction was revealed [Tsuda et al., 2000b, Nakamura, 200l].
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