NORKLIMA III: Variability of Albedo Using an Unmanned Aerial Vehicle

A particularly important process in the Arctic surface energy budget is the snow/ice albedo feed-back which contributes considerably to polaramplification of global warming (Køltzow et al., 2007). This process, whereby increased temperatures cause melting of highly reflective snow/ice covered areas, increases absorption of solar radiation due to a decreased regional albedo. Further-more, several recent studies of pollutant transport, in particular black carbon, to the Arctic indicate that the deposition o f black carbon on snow/ice surfaces may have a significant effect on the energy balance. Currently, there are insufficient measurements to evaluate black carbon induced changes on albedo in a quantitative manner. Furthermore, satellite measurements are cu rrently not capable of measuring these changes with the required precision. Thus we propose an innovative solution relying upon state-of-the-art technology to acquire an improved assessment of Arctic albedo vari-ability as well as pollutant induced change s of albedo. Our measurement platform relies principally on the operational deployment of a proven Un-manned Aerial Vehicle (UAV). This platform will measure albedo over a wide range of Arctic ter-rain providing a valuable time series of baseline variabi lity. Furthermore, utilizing forecast products from the FLEXPART Lagrangian transport model, we will initiate Intensive Observing Periods (IOPs) during unique pollutant transport episodes in which it is suspected black carbon will be de-livered efficientl y to our sampling locations. The UAV will be flown operationally during two campaigns, each covering six months from March through August. The first campaign will take place in Svalbard, Norway with the objective of measuring snow albedo on polythermal gl aciers and over sea ice. A later campaign in Greenland will enable measurements over ice sheets. These two environments will provide an excellent opportunity for comparative measurements in the Arctic.