A new parameterization of temperature structure parameter in entraining convective boundary layer

Temperature structure parameter (CT2) controls the propagation of electromagnetic and acoustic waves in the atmospheric boundary layer (ABL), but it is difficult to be measured, especially in the upper part of the ABL. In this paper, optical turbulence is simulated in a laboratory convective tank, and CT2 profiles in the tank are measured by using laser beam patterns. Simulation results show that the Wyngaard’s scaling relationship for CT2 in the entrainment layer is only valid for large convective Richardson number (Ri > 40) cases. When Ri < 40, a new scaling relationship is proposed based on the laboratory and field measurements. The application of these relationships in estimating optical turbulence in the entrainment layer is discussed.