Bipolar long-term high temporal resolution broadband measurement system for incoming and outgoing solar UV radiation, and snow UV albedo, at Sodankylä (67°N) and Marambio (64°S)

Abstract. The polar regions of the Earth are characterized with low solar elevation angles, cold temperatures and large amount of snow and ice. Under the harsh polar conditions, good quality in situ measurements of incoming and outgoing solar radiation, and surface albedo, is a major challenge. Both in the Arctic and Antarctic, the solar radiation at the wavelengths of ultraviolet (UV) has been of particular interest due to the polar stratospheric ozone depletion, which increases UV radiation on the ground (with multiple effects, such as UV-induced DNA-damage). In the presence of light absorbing impurities (OC/BC/dust) in snow, albedo can be most affected at the wavelengths of UV. Here we provide, for the first time, the description, comparison and evaluation of our bipolar measurement design, instrumentation and data system, calibration assessment, as well as challenges, for measuring incoming and outgoing UV radiation (from which snow albedo is calculated) at the Sodankylä Arctic Research Centre (67°N) and at the Marambio Antarctic Research Station (64°S). Both stations are members of the Global Atmosphere Watch GAW programme of the World Meteorological Organization WMO and have personnel available year-round. The Sodankylä snow UV albedo measurements were started in 2007, as part of the International Polar Year IPY (2007–2008). The Marambio surface UV albedo measurements, since February 2013, are part of the Argentinian-Finnish scientific co-operation on meteorological and atmospheric observations. The paper aims to give a comprehensive insight into our bipolar measurement system, and to create an understanding needed for a successful scientific utilization of these data, including satellite and modeling approaches. We also present a literature review of our previous publications on Sodankylä snow UV albedo data.