1998 Fiscal Year Final Research Report Summary
STUDY ON SPATIALAND TEMPORAL DISTRIBUTION OF SNOWMELT
| Project/Area Number |
09045050
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Field |
水工水理学
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| Research Institution | NAGAOKA UNIVERSITY OF TECHNOLOGY |
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Principal Investigator |
HAYAKAWA Norio Nagaoka University of Technology, Faculty of Engineering, Professor, 工学部, 教授 (70143815)
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| Co-Investigator(Kenkyū-buntansha) |
董 増川 河海大学, 環境水文学院, 教授
劉 新仁 河海大学, 環境水文学院, 教授
FUJII Hideyuki Nagaoka University of Technology, Faculty of Engineering, Research Associate, 工学部, 教務職員 (60293247)
陸 旻皎 地球フロンティア研究システム, 研究員
KOIKE Toshio Nagaoka University of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30178173)
LIU Xinren Hohai University, Institute of Environment and Hydrology, Professor
LU Minjiao Frontier Research System for Global Change Researcher
DONG Zengchuan Hohai University, Institute of Environment and Hydrology, Professor
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| Project Period (FY) |
1997 – 1998
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| Keywords | snowfall / snowcover / snowmelt / GIS / distributed model / temperature lapse rate / catch ratio of rain gage |
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| Research Abstract |
The study fields of this study are the Urumqi River Basin in the Tianshan mountains and the Naqi River Basin, the upstream reach of the Changjiang River, China. In this study, the meteorological and hydrological data are collected and the general features of these basins are described. The result, in short, is stated that these basins cover the high-altitude region and the climate is dry and cold with development of glaciers at the high altitude.
For the major part of this study, the distributed hydrological model is applied to these basins to obtain the high-accuracy rainfall-to-runoff model of these basins. In constructing the distributed hydrological model, the worldwide geographic information(GLOBE) is utilized. Input data to the model are precipitation and temperature and the output data of the basin runoff is compared with the observed discharge there.
The distributed hydrological model discretizes the basin topography to the square mesh points and the precipitation is inputted at
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each gid point. At each grid point, the precipitation is divided to the evaporation, direct runoff and the baseflow. The direct runoff, then, is routed through the flow network generated from the elevation data at the grid points to the basin outlet. Wile the baseflow is collectively converted to the basin runoff through a kind of the reservoir model.
In applying this distributed model, the precipitation data is treated either as rain or snow depending temperature and the amount of snowfall is calculated taking into account the catch ratio of the rain gage and the altitudinal dependence. If the snow is on the ground, the snowmelt calculation is conducted based of the degree-day method. In these calculations, temperature at each grid point is obtained with the data-fitted temperature lapse rate. The final verification of the model is conducted by selecting the parameters pertaining to the snowfall model, the calculated basin discharge reproduces the observed data satisfactorily, showing the validity of this model. Less
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