Measurement of the characteristics of the intensity and polaristion of skylight at two different sites in Antarctica, differeing in albedo

The enhancement of UVB radiation falling onto the different land surfaces was investigated. Previous measurements (in the 1990 season) found low maximum polarisation of sky light and strong low azimuth back scattered light as two characteristic features of the Antarctic skies. Analyses of these features suggested that this occurs by multiple reflections from the snow-ice surfaces surrounding the Tent Island measuring site (and most of Antarctica). To test the theory that the distinctive features of skylight over ice (and snow) is due to the high albedo environment, two sites at essentially the same latitude and the same unpolluted air were measured to determine if the land surface was what was affecting the results. Enhanced UVB radiation was measured, and hence the properties of Antarctic skies, at two sites, one near Tent Island and the other at Lake Vanda, the first site being surrounded by sea ice, while the second site was surrounded over a substantial distance by bare rock. Using a sky monitor and polarisation spectrometer, the polarisation and sky light distribution was measured at both sites.