Abstract

Cold air drainage is a characteristic of hilly or mountainous terrain and can have significant impact on agricultural or horticultural activities. This paper considers a range of synoptic and topographic factors that could affect the phenomenon of cold air drainage, through an exploration of its characteristics in the Peak District of central England, showing that cold air drainage events can occur at any time of the year, with summer events being even more frequent than those usually noticed in winter. The occurrence of such events is related to the local topography, and particularly the correspondence to hollows and local valleys on the scale of 0.5-1 km, rather than on the scale of the principal drainage routes in the region. In contrast to some previous studies, synoptic and local weather conditions were not found to be strong indicators of cold air drainage events. It is also shown that under suitable conditions cold air drainage can overcome the effects of the urban heat island. © 2012 Royal Meteorological Society.