Structure of the Atmospheric Boundary Layer at Ny-Alesund: Statistics and Case Studies

The Amundsen-Nobile Climate Change Tower (CCT) at Ny Alesund - Svalbard is a 33 m high observation platform particularly suited for investigating the thermodynamic characteristics the planetary boundary layer (PBL) at multiple levels using fast and slow response instruments. A set of four conventional meteorological sensors positioned at 2, 5, 1O and 33 m and three sonic anemometers at 3.7, 7.5 and 21 m of height is the main atmospheric equipment. Radiation and snow height sensors are also installed as well as instruments to estimate the heat flux into the snow and to measure the radiation fluxes and balance at the surface. For some periods a tethered balloon equipped with meteorological sensors was operational to provide temperature, humidity and wind up to 600-700 m. Selected period with optimal data coverage, for different seasons, have been investigated to test the literature profiles based on the Monin-Obukhov Similarity Theory (MOST).,The shape of the similarity function is evaluated in different stability conditions. By using the set of three sonic anemometers, the vertical structure of the boundary layer above the surface layer is also investigated