抄録
In recent years, cyclic steps are discovered in a variety of environments, such as deep ocean floors and ice floors on planets other than the earth. Water can exists only in the form of ice in the extraterrestrial environments, where temperature is commonly by far lower than that on the earth. Therefore, cyclic steps in the extraterrestrial environments are expected to be often found on ice. In order to obtain basic knowledge on the formation of ice steps, we have performed a series of experiments in a cold room of Institute of Low Temperature Science, Hokkaido University, and reproduced ice steps migrating in the downstream direction. In this paper, we formulated the formation process of ice steps, and provide a reasonable explanation of the downstream migrating ice steps based on the experimental results.