UV measurements at Marambio and Ushuaia during 2000–2010

Solar ultraviolet (UV) irradiances were measured with NILU-UV multichannel radiometers at Ushuaia (54° S) and Marambio (64° S) between 2000 and 2013. The measurements were part of the Antarctic NILU-UV network, which was started in cooperation between Spain, Argentina and Finland. The erythemally weighted UV irradiance time series of both stations were analyzed for the first time in this study. The quality assurance procedures included a traveling refence instrument to transfer the irradiance scale to the stations. The time series were homogenized and high quality measurements were available for the period 2000–2010. During this period UV indices of 11 or more were measured on 5 and 35 days at Marambio and Ushuaia, correspondingly. At Marambio, the peak daily maximum UV index of 12 and dailydoses of around 7 kJ/m 2 were measured in November 2007. Typically the highest UV daily doses were at both stations around 6 kJ/m 2 , and they occurred on time periods, when the station was inside the polar vortex with very low total ozone amount. At both stations, dailydoses of late November could even exceed those of summer. At Marambio, in some years, also dailydoses in October can be as high as those during the summer. At Ushuaia, the peak daily maximum UV index of 13 was measured twice: in November 2003 and 2009. Also during those days, the station of Ushuaia was inside the polar vortex.