| Summary: | Current understanding of small-scale physical processes, such as mixing, in tropical
water bodies is lacking and observations are scarce at best. This study sheds more
light on these processes through a combined observational-modeling approach. For
this purpose, observations were made in Valle de Bravo's freshwater reservoir, about
100 km west of Mexico City and at an elevation of 1830 m above sea surface. Turbulence
kinetic energy dissipation (TKED) rates were estimated by fitting a theoretical
Batchelor spectrum to the temperature gradient spectrum. From similarity scaling of
dissipation rates, it was found that in the surface layer, winds were the main driving
force in generating turbulence during the day, while convective forces were responsible
during the night. Bottom boundary layer (BBL) mixing was mainly driven by internal
wave (first vertical and first horizontal mode) breaking at the bottom. Lognormality
of turbulence dissipation rates is also discussed for surface, intermediate and bottom
boundary layers. For our modeling efforts, a state-of-the-art one-dimensional turbulence
model was used and forced with the observed surface meteorology to obtain
simulated temperature and dissipation rate profiles. The model results were found to
be in good agreement with the observations, though minor differences in dissipation
rates were found in the vicinity of the thermocline and the BBL.
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