Forecasting snow and black ice growth from temperature and precipitation

Growth of ice and the type of ice that is formed have environmental impact on a lake. Although ice growth is reasonably well estimated by the degree-day method, this method does not allow to distinguish between different types of ice. In this paper, an algorithm or model is suggested for computing black and white ice growth and lake snowcover depth. Input is daily values of air temperature and precipitation. The model is applied to a water body in northern Sweden. Also, some theoretical situations are simulated. Total ice thickness is well computed through a freezing period, but white ice formation is not computed very accurately in the first one or two months after freeze-up, because of difficulties in estimating snow precipitation. Total ice thickness is well determined by the degree-day method, but where the winters are not very stable, it is difficult to estimate an § priori value of the degree-day coefficient.