11.19 Cold-Climate Aeolian Environments

Cold-climate environments include periglacial environments where the mean annual air temperature is less than +3 °C and seasonally cold environments where the coldest mean monthly temperatures are below −3 °C. In these environments, temperature and moisture conditions significantly affect the efficacy of sediment transport by wind. Specific wind conditions operating in cold-climate environments that promote aeolian processes include frontal winds, pressure-gradient winds, katabatic winds, and foehn winds, as well as large-scale pressure gradient winds associated with persistent stationary high-pressure cells centered over ice sheets. Sediment source supply is a limiting factor in present-day cold-climate aeolian environments, particularly within formerly glaciated regions of North America and Europe. In addition, in cold-climate environments, even though the wind speed may be high, entrainment and transport of sediment may not occur because surface soil moisture and phase-state conditions, vegetation cover, or other factors including organic matter content or soluble salts limit the availability of sediment. Aeolian processes and features within cold-climate environments include deflation, loess and dust, sand dunes and sand sheets, as well as niveo-aeolian processes, sand wedges, ventifacts and oriented lakes. Four major settings where cold-climate aeolian processes occur include cold-polar environments, glacially proximal environments, cold high-altitude environments, and seasonally-cold environments. In addition, although contemporary cold-climate aeolian environments are largely restricted in extent, even at high latitudes, relict cold-climate aeolian environments were considerably more extensive during full glacial and early Holocene times.