Evolution of the boundary layer - 3PM

3 PM:

  • surface heating is maximum

  • therefore, thermal turbulence is strongest at this time of the day - generate fair-weather cu

  • thermals mix down even stronger wind speeds to the surface - generates larger mechanical turbulence

  • surface winds are strongest at this time - breezy

  • boundary layer is about 1-1.5 km deep

  • air in the boundary layer is well-mixed (i.e., has uniform properties) due to thermal and mechanical turbulence