| Project/Area Number |
05640481
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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 | Kanazawa Institute of Technology |
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Principal Investigator |
KAWATA Yoshiyuki Kanazawa Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (70104768)
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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 |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Remote Sensing / Atmosphere-Ocean System / Multiple Scattering / Ocean Wind Speed / Ocean Wind Direction / Sea Surface Reflection / 偏光 / 大気・海洋系 / 反射 / 反射輝度 / 偏光度 / Cox-Munkモデル |
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| Research Abstract |
In this study we have made an analysis of the airborne POLDER data over the ocean by a multiple scattering model. Assuming an atmosphere-ocean system with a Cox-Munk type reflecting sea surface, the reflectance and degree of linear polarization, including contributions from multiple scatterings and reflections have been computed by using the adding and doubling method for several different atmospheric models. Our results based on this study are summarized as follows :
1) We found the oceanic aerosol model is not an appropriate aerosol model for Medimar data, but Junge type aerosol model with 3 < v < 5 is able to satisfy the observed polarization characteristics.
2) Based on the multiple scattering computations, the image reconstruction for the reflectance and degree of linear polarization was made, for the first time. We showed that many features in the observed reflectance and polarization images can be theoretically reconstructed by assuming a two layrs atmospheric model, composing of Rayleigh and aerosol particles with a Cox-Munk sea surface layr.
3) An isotropic Cox-Munk model should be rejected on the ground that it fails to explain the asymmetry in the observed reflectance curve with respect to the viewing zenith angle rheta=0 in the perpendicular plane. An anisotropic Cox-Munk model can explain such the asymmetry and it should be used in retrieving the surface wind field instead. We should point out here that the multiple scattering analysis for such a model is necessary for estimating the surface wind field accurately.
5) As a major unsolved problem conceming with polarization, a clear explanation of two polarization minimum points in a symmetric location to the principal plane is left in future.
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