| Project/Area Number |
05640484
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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 |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
MATSUI Ichiro Atmospheric environment division, Reserch scientist, 大気圏環境部, 研究員 (30229398)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1994: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Raman lidar / Optical properties of the stratospheric aerosols |
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| Research Abstract |
The optical properties of the stratospheric aerosols are one of the most important parameters to understand the radiation transfer mechanisms in the stratosphere related to the global warming. They are also important to estimate the aerosol size distribution (surface area) which affects the degree of ozone depletion. The purpose of this study is to clarify the details of the stratospheric aerosol layr such as the vertical profiles of the aerosol size distribution by obtaining the vertical profiles of the optical properties of aerosols nsing a multiple-wavelength backscatter-Raman lidar. First, we modified our Mie lider system to enable to obtain the Raman scattering signals from the stratosphere. To obtain multiple wavelength information of the aerosol properties using a lider system with a simple configulation, we decided to obtain vibrational Raman scattering signals of Nitrogen molecules from the second (532 nm) and the third (355 nm) harmonics of a Nd-YAG laser. By comparing the Ra
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man signal with the the air density profiles obtained from the meteorological sonde measurements, the vertical profiles of the aerosol extinction coefficient can be obtained. Independently measured vertical profiles of the backscatter and extinction coefficient using the Mie scattering and Raman scattering respectively, we can calculate the vertical profile of the extinction-to-backscatter ratio. We examined the possibility to estimate the vertical profiles of the aerosol size distribution in the stratosphere from the measured two-wavelength vertical profiles of the extinction-to-backscatter ratios using Mie calculation. The results show that the wavelength dependence of the extinction-to-backscatter ratio is sensitive to the mode radii and the widths of the aerosol size distributions when the log-normal distribution is assumed. As the aerosol loading is not heavy now, it is difficult to obtain sufficient precision nsing the present system. However, this method is believed to be useful to obtain the information of the size distribution of the stratospheric aerosols by improving the sensitivity of the lider system. Less
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