Contemporary spatio-temporal patterns of snow cover over the Drakensberg

Abstract

Sixteen years of low-resolution Landsat 5 and 7 satellite images were used to construct Boolean images of snow cover over the Drakensberg through a GIS. Contemporary patterns of snow cover, including altitudinal variations, were determined for individual months and various seasons. The seasonal occurrence and spatial influence of various snow-producing weather systems were determined through remote sensing and the consultation of daily climate data and synoptic charts. A proportional relationship was found between altitude of snow-covered pixels and the number of occurrences that pixels were covered in snow. The highest incidence and most widespread snow cover occurred from June to August; spring snow occurred preferentially in the central and southern Drakensberg regions. Cold fronts and associated cut-off lows accounted for about 80% of snow cover over the Drakensberg.