Sublimation and aeolian sand movement from a frozen surface: experimental results from Presquʹile beach, Ontario

Recent aeolian literature has indicated that sand movement can and does take place on frozen surfaces. The winter aeolian process is influenced by the pore ice which binds the sand grains together and increases the surface resistance to wind action. Sublimation of the frozen moisture provides loose grains of sand which subsequently can be entrained by the wind. Field experiments carried out on the Presquʹile Beach, Ontario in the 1992–1993 winter provide some data on variables which affect sand loss from frozen surfaces because of sublimation. Sand moisture content determines the resistivity of the surface to sublimation-induced sand loss: frozen surfaces with higher moisture contents experience less sand loss. The existing literature has indicated that temperature plays an important role in the occurrence of sublimation: higher temperatures (i.e., temperatures which are closer to 0°C) result in higher rates of sublimation. However, the Presquʹile experiments show that wind speed is more strongly correlated with sublimation-induced particle loss than temperature or relative humidity. Higher wind speeds allow sand from the surface and sublimation-produced water vapour to be removed from the area, thus providing an incentive for further sublimation and sand loss to take place. Information on the variables which affect sublimation-induced sand loss from frozen surfaces can be used to increase understanding of the processes involved in sand movement on frozen surfaces under subzero temperatures.