1994 Fiscal Year Final Research Report Summary
Analysis of Evapotranspiration Process for Working System Planning in Water Resources Conservation
| Project/Area Number |
04454080
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
林学
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
SHIBANO Hirofumi The University of Tokyo, University Forest, Lecturer, 農学部(材), 講師 (00143412)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIO Kunihiko Tokyo University of Agriculture, Forestry, Professor, 農学部, 教授 (60011938)
SHUIN Yasuhiro The University of Tokyo, Forestry, Assistant Professor, 農学部, 助手 (60221305)
SUZUKI Masakazu The University of Tokyo, Forestry, Associate Professor, 農学部, 助教授 (10144346)
OHTA Takehiko The University of Tokyo, Forestry, Professor, 農学部, 教授 (50134797)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Water Resources Conservation / Evapotranspiration / Discharge Duration Curve / Eddy Correlation Method / Growth of Forest / Trend / Experimental Watershed |
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| Research Abstract |
In this study three methods were adopted to analyze evapotranspiration fundamentally. The first one is a study analyzing actual data with eddy correlation method to measure directly evapotranspiration, the second is a study to apply short term water balance method to daily precipitation and daily runoff, and the last is a study to analyze discharge duration curve on daily discharge rate.
1.Measurement was conducted to turbulent transport on forest crown which locate on rolling terrain in two study sites, University Forest in Aichi and Kinomoto Town in east side of Biwa Lake. Turbulent flux of momentum tau and sensible heat H which was measured by eddy correlation method were used to check goodness of fit on bulk method. The result shows that as to the correlation between u^* from tau and U,the data plots of the forest site were scattered widely, and were closely related to stability, however, the flat field data satisfied the linear correlation.
2.Attempt has been made to identify trends in a long series of discharge duration curve for describing the effect of gradual change in physical processes with forest growth using 56-year discharge records in two small experimental watersheds in the University Forest in Aichi. It was found that the 6th to 220th day discharge on the discharge duration curve linearly increased over the course of several decades in both watersheds using comparative analysis with simple regression models.
3.Short term water balance method was applied to the data of daily discharge and precipitation to get evapotranspiration. After correcting the difference caused by watershed wetness with simple model, good relationship between stand stock of forest and indication value on evapotranspiration was found in three watersheds.
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