1997 Fiscal Year Final Research Report Summary
Study on Dependence of Hydrological Quantities on Their Temporal-Spatial Scales
| Project/Area Number |
07650593
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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 |
水工水理学
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| Research Institution | Yamanashi University |
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Principal Investigator |
SUNADA Kengo Yamanashi University, Dept.of Civil and Environmental Eng., Professor, 工学部, 教授 (20020480)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Runoff processes / temporal scale / spatial scale / evapotranspiration / remote sensing data / digital elevation model / direct runoff / concentration time |
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| Research Abstract |
Based on the preliminary study on literature survey in 1995, and on the distribution of evapotranspiration from the paddy field having area of 1km^2 and the concentration times estimated from the runoff models with different catchment element sizes in 1996, the following investigation was carried out in 1997.
At first, evapotranspiration in the east-Japan region was estimated by using NOAA/AVHRR data and GPV (Grid Point Value) data. The result does not show good estimation in mountainous areas because of incompleteness of radiation estimation and extreme variability of land surface in the areas. However it is shown that estimation in flat area is fairly good. It is pointed out that a method for good aggregation of land surface heterogeneity should be developed.
In the next, the dependency of runoff model parameters on catchment element scale was examined. The concentration times of direct runoff from two catchment models having different element sizes in which lattice sizes of the digital elevation map are 250m and 500m. The result shows that average concentration time along channel is almost same in the two models, however average concentration time at catchment slope should be changed with catchment element scale.
The scale effects were focused on evapotranspiration and direct runoff as representative processes of hydrologic cycle. Some fundamental characteristics of the scale problems have been clarified in this investigation.
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