1999 Fiscal Year Final Research Report Summary
Studies on water balance in the northern area of Okinawa Island
| Project/Area Number |
10660235
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
YOSHINAGA Yasutoshi Coll. of Agri. Prod. & Env. University of the Ryukyus, Ass. Prof., 農学部, 助教授 (80045129)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIJIMA Suguru Coll. of Sci. Physics & Earth Sci. University of the Ryukyus, Prof., 理学部, 教授 (50045184)
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| Project Period (FY) |
1998 – 1999
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| Keywords | air borne measurement / surface covering substances / emissivity of earth surface substances / air transmissivity / heat balance method / evapotranspiration / rainfall / water balance |
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| Research Abstract |
Measurements of the surface temperature of the northern area of Okinawa Island was made with the air borne INFRA IMAGER observation in three seasons, the first on 7 Feb.(Winter), on the second 13 July(Summer) and the last on 10 Dec., 1999. The area averaged uncorrected measured values of the earth surface temperature are 18.0, 30.4 and 19.5 and changes in the range of 6.3, 8.3 and 7.6 degree in centigrade, respectively.
Correction that should be made to the above uncorrected values due to the effects of the air transmissivity and the emissivity of the earth surface coverint substances underlying the aircraft is found to be an addition of 3 to 4 degree.
Water balance for an example case of 1997 showed for the same northern area showed that the averaged annual rainfall and evapotranspiration amount, respectively, to 2220mm and 1070mm, resulting in the discharge of water being about 50% of the rainfall.
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