Eddy transfer processes in the atmospheric boundary layer

Abstract In this work the influence of stratification (evaluated through the gradient Richardson number) on the eddy transfer of momentum and heat (Km and Kh) has been studied. A wide range of Richardson numbers (Ri) has been covered with data recorded in summer at Valladolid (Spain) from a 100 m high tower situated on a flat and homogeneous terrain. The results show how the eddy transfers are inhibited for high stabilities (Ri > 0.1), and the importance of the wind shear at night. Different mixing mechanisms have been studied (convection and shear). The ratio of eddy transfer coefficients shows no constant value and a sharp dependence on Richardson number. Finally the effect of surface thermal inversions on the turbulent transfer is analysed.

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