Transitions in the Boundary Layer, Looking at Sensible Heat Flux

Wind speed, optical laser scintillation and acoustic backscatter where simultaneously measured to calculate sensible heat flux and investigate looking at transitions in the Arctic summer boundary layer. Scale dependent sensible heat (HS) fluxes were determined by combining sonics anemometers, scintillometer and acoustic vertical profiles of the Planetary Boundary Layer (PBL) under different PBL regimes through the summer June-July, 2010. Differences have been observed between the temporal series of horizontally integrated HS deduced from scintillometry and HS calculated using eddy-covariance from sonic anemometers. Major divergences have been observed during transitions in the PBL diurnal cycle (i.e, developing convection and or developing a stable phase) due to the scale-representation of each instruments compared to the turbulent scale dominating the fluxes in the surface layer. Retrievals of vertical sensible heat fluxes through sodar measurements correlates with surface measurements depending on the development and vertical grow of the PBL.