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A combined observational-modeling study was conducted to investigate turbulence mixing, and the relation to surface forcing, in the surface boundary layer (SBL) of a tropical, high-altitude, freshwater reservoir. A suite of vertical profiles of temperature microstructure, collected at three different stations of one-day duration each, provided estimates of dissipation rates of turbulence kinetic energy, ϵ, and temperature variance, χ. Numerical simulations of ϵ and χ, using state-of-the-art, public domain, two-equation turbulence closure models, compared favorably with the observations and reproduced the dynamics of daytime wind mixing as well as the vertical and temporal turbulence structure during nighttime convective conditions. Two independent estimates of vertical eddy diffusivities in the stably stratified (daytime) SBL, computed from the microstructure measurements, agreed closely, and the near surface heat and …