Author(s): Spyros Beltaos
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Abstract: Many rivers of cold, and even temperate, regions of the globe are covered with ice for a part of the year. Dynamic phenomena during the transitory periods of freezeup and breakup and the more stable condition of a complete ice cover during the winter, all have major and varied impacts on stream ecology, safety of people and infrastructure, transportation, and hydro-power generation. In the past fifty years or so, remarkable progress has been made in understanding and quantifying many of the complex thermodynamic, hydraulic, and structural processes that govern the ice regime of rivers. Yet, many problems posed by river ice remain unsolved or partly addressed, while some are just as intractable now as in the past. The practical answer to this situation has been to rely on empirical relationships, developed from historical data at specific sites. Implicit in such empiricism is the assumption of a “stationary” climate, that is, the statistical properties of local climatic variables do not change over time. This assumption is becoming increasingly untenable in view of already-experienced and anticipated climatic changes, which also tend to be more pronounced in a northerly direction and during the winter months. Numerous changes to the ice regimes of the world’s rivers have already been recorded, and some general projections can be made for the future. However, it is not possible to make specific predictions because our physical understanding remains incomplete. Thus, the main challenge is how to accelerate the pace of discovery and bridge the major knowledge gaps. Discussion of current opportunities indicates that river ice researchers can now obtain plentiful field data and perform sophisticated analyses by exploiting recent technological developments. These tools include new remote-sensing instrumentation, GPR systems, satellite imagery and processing algorithms, as well as advanced numerical models, whose scope is continuously expanding as computing power increases.
Year: 2008