NUMERICAL STUDY OF PENETRATIVE AND SOLID LID NONPENETRATIVE CONVECTIVE BOUNDARY-LAYERS

A large eddy simulation model was used to generate and compare statist ics of turbulence during nonpenetrative and penetrative dry convection . In penetrative convection dimensionless vertical velocities in updra fts were found to have almost the same values as in the nonpenetrative case. The countergradient transport of heat and moisture was found to be present during nonpenetrative convection at z/z(i) > 0.6. For pene trative convection the countergradient transport of heat occurred only in a layer 0.5 < z/z(i) < 0.75, while the countergradient transport o f humidity was not present. During nonpenetrative convection, temperat ure and humidity were perfectly correlated. In penetrative convection the correlation coefficient was found to be less than unity, varying f rom about 0.9 near the surface to about -0.7 at the top of the mixed l ayer.