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| Waves can modify an ice field in several ways. This webpage is focused mainly on ice in the MIZ, so will concentrate on the effects of waves on ice types that occur in the MIZ. Among other types of ice in the MIZ, there are the frazil, grease and pancake ice types. |
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In the MIZ and in leads, waves and wind herd frazil ice against more solid objects such as pack ice or even pancake ice. For our purposes, it is enough to say that the mechanism by which wind transfers momentum to the ice is that the wind exerts a viscous drag force on the ice surface. Also, the action of the wind on the surface of the ocean causes a current in the top layer of the ocean which pushes the ice in the general direction of the wind. There are a variety of proposed ways in which waves transfer momentum to ice. Without specifying a mechanism, it can quite generally be stated that waves transfer momentum to ice and hence the ice moves. |
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Image Source: http://www.gi.alaska.edu/~eicken/he_teach/GEOS615icenom/iceglossary/iceglossary.htm The progression of ice from frazil to pancake due to the action of wind and waves. |
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For our purposes, it is enough to give a general description of one possible progression of ice formation. Due to heat loss from the ocean to the atmosphere, frazil ice is formed. This can occur in a lead or in the open ocean. As the above series of pictures indicates, the waves and wind herd the frazil ice into a thicker layer and grease ice is formed. The grease ice becomes thicker because the wind and waves pile up more frazil ice against the existing grease ice. The waves damp the turbulent motion caused by the short waves and eventually through heat loss and wave action, the grease ice forms into distinct pancakes of ice. |
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| Last Modified: 12/12/2001 |