1993 Fiscal Year Final Research Report Summary
Seasonal variations of water loss due to evapotranspiration in an experimental watershed with various surface conditions
| Project/Area Number |
03455001
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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 |
広領域
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| Research Institution | Hokkaido University, Institute of Low Temperature Science |
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Principal Investigator |
ISHIKAWA Nobuyoshi Hokkaido University, Institute Low Temperature Science, Associate Professor, 低温科学研究所, 助教授 (70002277)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Daiji Hokkaido University, Institute Low Temperature Science, Professor, 低温科学研究所, 教授 (30001655)
MASTUDA Kyo Hokkaido University, College Experiment Forests, Associate Professor, 農学部・附属演習林, 助教授 (30002075)
SHIRASAWA Kunio Hokkaido University, Institute Low Temperature Science, Instructor, 低温科学研究所, 助手 (50196622)
ISHII Yoshiyuki Hokkaido University, Institute Low Temperature Science, Instructor, 低温科学研究所, 助手 (40222955)
KODAMA Yuji Hokkaido University, Institute Low Temperature Science, Instructor, 低温科学研究所, 助手 (70186708)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Heat Balance / Water Balance / Evapotranspiration / Watershed / Discharge / Snowemlt / Precipitation / Runoff Coefficient |
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| Research Abstract |
The aims of this investigation are :
1.Areal heat balance of an experimental watarshed
2.Estimations of evapotranspiration from various surfaces
3.Variations of soil water level
4.Characteristics of water balance of the watershed.
We observed meteorological factors at 6 different sites in a small watershed, and developed the method which could estimate the snowmelt of the whole watershed. We also measured evapotranspiration with three different methods : by the calculation with Penman equation : by the residual of the water balance, and by the weighing lysimeters, which surfaces were set by vegetated soil, water and snow.
The following are the results :
(1) The amount of snowmelt runoff was about 41-53% of the annual total runoff.
(2) The remarkable seasonal variation of evapotranspiration was observed. The evapotranspiration amount was large from May to August, became smaller in Stptember and October, and was kept to be zero through snow cover season.
(3) The proportion of evapotranspiration to the precipitation was 41-47% during summer and the annual mean was 15% in the three years of the whole year observations. The ratio of runoff to precipitation 50-60% in summer and 85% for a year.
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