Lidar-sonde-radiometer based analysis of the inversion strength of the entrainment zone and its daytime evolution

The stability of the entrainment zone (EZ) is an important parameter for numerical forecast models. It restrains the growth rate and the amount of heat and moisture flux in and out of the atmospheric boundary layer (ABL). Information of its stability is routinely obtained only a couple times a day form radiosonde measurements at weather stations. This study uses aerosol scattering ratio (ASR) from a surface-based Raman Lidar system to infer continuous information of EZ stability for daytime fair weather ABLs. Entrainment Zone stability conditions are approximated through a spectral analysis of boundary layer height (zi) estimates and the skewness of zi versus the convective Richardson number (Ri) stability parameter. In addition, the gradient of ASR across the EZ is used to give stability information. The Raman Lidar observations are complemented by radiosondings and continuous observations from a surface-based microwave radiometer profiler (MWRP). The radiosonde and MWRP observations provide thermodynamic profiles of the ABL. Observations used for this study are collected at Howard University Beltsville, MD Research Campus (HUBC).