A Study of Ice Thickness during Ice Breakup on the Teshio River

In this study, continuous non-contact measurement of ice thickness prior to its breakup was conducted to clarify the nature of the breakup process. An ice thickness calculation model using heat flux was also constructed to clarify the variation factors relating to the measured ice thickness. The calculation results revealed that these factors were increased ice thickness due to shortwave radiation, longwave radiation, evapo-condensation flux and conductive heat transfer or due to the transformation of accumulated snow into ice, and decreased ice thickness due to turbulent heat transfer from the water to the ice cover. In addition, a simple, practical ice thickness calculation model using air and water temperature and the water depth from the riverbed to the bottom ice surface as independent variables was developed based on the heat flux model.