Wind tunnel study of atmospheric dispersion in unstable stratified boundary layer

The unstable stratified boundary layer that was analogous to unstable atmospheric boundary layer was created in CRIEPI wind tunnel. The overall Richardson number was equall to -4.0 in the unstable flow condition in the wind tunnel and under this condition velocity and temperature fluctuation was measured. Auto-correlation coefficient and power spectram of velocity and temperature fluctuation were calculated and compared with those, of field experiments. Fothermore tracer gas diffusion experiment was mad in the wind tunnel and it's apparant that vertical plume spread in unstable condition was nearly equall to that of atmospheric stability B in Pasquill-Fifford chart. (author)