From AMS Glossary
The property of turbulence within one air mass that occurs at some times and some places and does not occur at intervening times or places.
Whereas the classical theory of homogeneous turbulence relies on the assumption that the turbulence energy dissipation rate ε is constant in space, in reality ε is not always constant. Those inhomogeneities may lead to intermittent turbulence. To predict a turbulent or nonturbulent (laminar) behavior within an air mass properly, the complete vertical profiles of either the virtual potential temperature or the buoyancy must be known. Turbulence is often intermittent in the stable boundary layer (e.g., nocturnal) and in the entrainment zone capping the convective mixed layer (e.g., daytime).