アンカーアイスが結氷河川の物質循環に与える影響

抄録

This study was conducted to clarify the mechanism of anchor ice formation on the river bed and to understand the impact of anchor ice on material transport in ice-covered river. Field observations indicated that anchor ice formation was significantly affected by the air temperatures and water temperatures as well as by the hydraulic conditions, such as the water depth and the flow velocity. We tried to simulate anchor ice formation in the actual river. The simulation results showed that accurate estimation of the temperature of river bed material that incorporated the influence of solar radiation and ground heat was critical for enhancing calculation precision. We could estimate that the anchor ice pulled away the algae from the river bed and flushed them to downstream, similar to a bed load transport in summer flood. This study proved that the river used for simulation had a specific material circulation due to frazil ice and anchor ice.