Vertical Velocity Field and Convective Plumes in the Atmospheric Boundary Layer as Observed with an Acoustic Doppler Sodar

摘要

The vertical velocity field and the convective plumes which are observed during the morning with the acoustic Doppler sounder are examined. Two points of view are presented: (1) microscopically the histogram of vertical velocity in the well mixed layer associated with conditional averaging shows the relations between the vertical velocity skewness and the convective velocity and gives an objective criterium for plume determination; (2) microscopically the predictions of the models and the plumes properties as observed by the Doppler Sodar are compared microscopically. It is shown that the convective plumes observed carry near 60% of the sensible heat flux at the top of the surface layer.