2005 Fiscal Year Final Research Report Summary
Development of a portable water vapor profiler in the lower troposphere using a small Raman lidar
| Project/Area Number |
15340156
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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 |
NAKAMURA Takuji Kyoto University, Research Institute for sustainable Humanosphere, Associate Professor, 生存圏研究所, 助教授 (40217857)
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| Co-Investigator(Kenkyū-buntansha) |
ABO Makoto Tokyo Metropolitan University, Graduate School of Engineering, Associate Professor, システムデザイン学部, 助教授 (20167951)
TSUDA Toshitaka Kyoto University, Research Institute for sustainable Humanosphere, Professor, 生存圏研究所, 教授 (30115886)
FURUMOTO Junichi Kyoto University, Research Institute for sustainable Humanosphere, Lecturer, 生存圏研究所, 講師(研究機関研究員) (10402934)
HASHIGUCHI Hiroyuki Kyoto University, Research Institute for sustainable Humanosphere, Associate Professor, 生存圏研究所, 助教授 (90293943)
HORINOUCHI Takeshi Kyoto University, Research Institute for sustainable Humanosphere, Research Associate, 生存圏研究所, 助手 (50314266)
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| Project Period (FY) |
2003 – 2005
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| Keywords | lidar / Raman scattering / water vapor profiling / troposphere / aerosol / radio acoustic sounding system / forest atmosphere / volcanic gas |
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| Research Abstract |
We have developed a transportable Raman lidar for water vapor profiling at around 200 m altitude, which is the lower boundary of a L-band wind profiler radar. A small Nd:YAG laser with a SHG of 532 nm is used for transmission and the same wavelength (532 nm), N2 Raman (607 nm) and H20 Raman (660 nm) scatters are received with a photon counting system, by means of a 35.5 cm telescope. The water vapor mixing ratio around 200 m could be observed both day and night, and the system was equipped at the Shigaraki MU observatory, Shiga, Japan for a long time. The system calibration factor did not change for more than 6 months within a deviation of 4 - 5 %. Water vapor could be profiled well for most of the times except for a rare case of the low altitude clouds or fogs. When we adjust the system to use a larger iris, water vapor mixing ratio profiles could be observed up to 3 - 4 km altitude. This lidar has been improved to be controlled remotely through a network. On the other hand, observations in a horizontal direction as well as a field observation on board a vehicle have been carried out. We found that fluctuations of waver vapor as large as 10 % over the national forest around Shigaraki observatory, as well as correlation with aerosol intensity. The measurement of water vapor content in the volcanic gas emitted from Nakadake, Mt. Aso has been successfully carried out, which is the first time of the remote-sensing measurement of H20 in the volcanic gas. As mentioned above, this study has achieved much more than we had expected at the beginning, as an application of a small Raman lidar.
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