Abstract
Analysis of snow-melt mechanizm and discharge system is important, because snow-melt is the most important resource for supplying water for irrigation purposes in Hokkaido. The present paper addresses the observed data of snow-depth, snow-density, snow-melt, discharge amounts, radiation amounts and temperature in dry fields in the upland area. Using the data, this paper discusses the model of hourly snow-melt due to radiation and convection of warm air and hourly discharge.
The main results obtained herein are as follows:
1) Time of peak of hourly snow-melt observed under the snow deposit delays several hours are compared with the time estimated to the peak of snow-melt on the surface of snow deposit. The delay time is long in proportion to the snow depth.
2) Using the runoff distribution function built in the concentration time that is be reformabl depending on the snow depth, it is cleared that the calculated time-series of the discharge under the snow deposit was in good agreement with the observed data.
3) The reservoir-model can be applied in the estimation of interflow after a previous snow-melt and discharge process.
4) The simple model of snow-melt applied with hourly air temperature and hourly radiation data was in good agreement with the estimation model. The method was also explained to estimate the hourly radiation data from the time of sunshine. It was finally proven that the model of snow-melt and discharge used with the estimated hourly radiation coincied with the observed results.
