Author(s): Takashi Nakao; Kimiteru Sado; Ichiro Sugiyama
Linked Author(s):
Keywords: Heat balance; Freezing river; Ice-cover ratio; Multiple regression model; Surface velocity
Abstract: Research was performed to clarify the changes in the ice-cover ratio on a river, based on an ice cover surveys conducted in the 1981/82 winter at four observation points in Kitami City. The ice cover was categorized according to the maximum ice-cover ratio defined as the maximum percent of river width covered with ice, the cumulative numbers of freeze-ups and break-ups, and the completely ice covered period as a share of the observation period. To estimate the ice-cover ratio, multiple regression equations were obtained that use meteorological elements and water levels. It was found that daily average temperature and degree-days of frost had the most significant effect on the ice-cover ratio. Changes in the total heat balance of river water were also clarified from the measured heat balance. Several multiple regression models for the total heat balance were developed. Using the estimated total heat loss and surface flow velocity as parameters, a diagram was produced to show the relationship between the ice cover condition and the two parameters.
Year: 2006