TURBULENT FLUXES AT THE SURFACE AND AT THE INVERSION IN THE UNSTABLE BOUNDARY LAYER OVER COMPLEX HILLY TERRAIN (EVAPORATION, SENSIBLE HEAT, WATER VAPOR, ENTHOLPY, SWITZERLAND, SOUTH CHINA SEA)

Measurements were made of the profiles of mean wind velocity, V, of potential temperature, (theta), and of specific humidity, q, in the unstable atmospheric boundary layer (ABL) over rugged hilly terrain. These data were obtained from radiosonde observations in a calibrated watershed of 3.2 km('2) in the Pre-Alpine region of Switzerland during the summer of 1982.; The q-profile was found to be logarithmic over roughly half the ABL thickness (i.e., 0.5 h where h is the height of the ABL below the inversion). The data indicate that the shapes of the V-profile and q-profile are practically independent of the Monin-Obukhov parameter (z-d(,o))/L but they display some dependency on baroclinicity and the relative magnitude of z(,o)/h (where z(,o) is the roughness length). The profile method with V and q used to obtain hourly estimates of evaporation was found to give values which correlate reasonably well (R = 0.7) with the measured values.; The heat budget method usually overestimated the measured values of surface sensible heat flux, H. This is mainly attributed to radiative heating whose values were commonly the same order of magnitude as H. Several entrainment models based on the turbulent kinetic energy equation were tested with the estimated values of the inversion flux of virtual heat. It was found that a relatively simple equation of Tennekes (1973), which contains both a convective and mechanical term for entrainment, does as well as the more complicated parameterizations. In addition, the effect of water vapor on the magnitude of the buoyancy fluxes was observed to be important.; A general formulation based on first order closure assumptions to determine the gradient, (PAR-DIFF)g/(PAR-DIFF)z, in the mixed layer gave the best results when the shear velocity, u(,*), was included in the parameterizations of the eddy diffusivities. Similarly, two formulations were derived which gave reasonably good estimates for the inversion flux, again provided u(,*) was included.; Similar analyses on water vapor in the unstable ABL were performed with radiosonde data taken over the South China Sea. The best results for estimating (PAR-DIFF)q/(PAR-DIFF)z and the inversion flux were obtained with the convective velocity, w(,*).; Radiosonde data taken in the unstable boundary layer over rugged terrain and over the ocean suggest that the relative importance of mechanical-type as compared to convective-type turbulence on the fluxes of scalar quantities depends significantly on the size of the roughness obstacles, that is z(,o)/h.