Abstract
Observations from an instrumented aircraft are used to study the small-scale structure of turbulence and convection in well-mixed boundary layers and the erosion processes in the nocturnally-formed inversions above them. The ways in which turbulence statistics for temperature, humidity and vertical velocity scale with height in the mixed layer are compared with the results of a three-dimensional model by Deardorff (1974a, b), and agreement is found in many aspects. Conditional sampling enables the statistics of thermals and their environment to be considered separately and, in particular, shows that the mode of the vertical velocity in thermals markedly decreases with height in the upper half of the mixed layer. Thermals may be recognized equally readily by either their excess of temperature or humidity. Transfers of heat and moisture through the nocturnal inversions influence the structure of the upper region of the mixed layer and there is strong evidence that these transfer processes are turbulent and not organized on scales similar to convective thermals.
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Coulman, C.E. Boundary-layer evolution and nocturnal inversion dispersal—Part II. Boundary-Layer Meteorol 14, 493–513 (1978). https://doi.org/10.1007/BF00121890
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DOI: https://doi.org/10.1007/BF00121890