Use of Tetroons to Investigate the Kinematics and Dynamics of the Planetary Boundary Layer

Discussed is the use of tctroons to obtain cstiinates of the Reynolds stresses, the rate of production of eddy kitictic energy through these stresses, thc coefficictit of eddy viscosity, and thc viscous dissipation within thc planetary boundary layer. At a n average height of about 3000 ft. (admittedly in thc upper portion of the boundary layer) the tetroons yield a mean value for the zonal Reynolds stress of 1.5 dyneslcmz. This value increascs by a factor of three as the lapse rate increases by a factor of one-half. The tetroons yield an avcrage value for the rate of production of eddy kinetic energy through Rcynolds stresses of 5.4 cm.Z/scc.3, but this value is probably an uiidcrestiiiiate hasmuch as the tetroons appear systematically to undercstimatc thc wind shear in the vertical. The rate of production of eddy kinetic energy through Reynolds strcsscs decreases radically with increase in lapse rate. On thc averagc, both of the above parameters increase tvith increase in the 3000-ft wind specd. The mean tetroon-derived value for the coefficient of eddy (dynamic) viscosity is 0.57X lo3 gm. cm.-* see.-’ This mean value appears soniewhat large (in accord with the abovc-mentioned underestimate of the vertical shcar) and thc scatter of inividual flight values suggests that this may be too sensitive a paramcter to estimate from the tetroon data. Equating the rate of production of eddy Itinctic energy through Reynolds stresses to thc dissipation appears to yicld too large a value for the dissipation. Consequently, buoyancy and flux divergence terms probably can not be neglected and i t may be ncccssary to place temperature instrurnents on the tetroons before acccptablc dissipatioii estimates can be obtained.