Estimating planetary boundary layer height using Doppler lidar

Abstract. The planetary boundary layer height (PBLh) is a key parameter in atmospheric modeling and observational applications, but is inconsistently defined in the literature and lacks a large, global ensemble of observations. Doppler lidar observational datasets, with high temporal resolution and deployability, provide an opportunity for long-term, high vertical and temporal resolution PBLh estimates to improve our understanding of atmospheric mixing. Using data collected by the Southern Ontario LIDar (SOLID) Mesonet, a network of Doppler lidar sites spanning 500 km across Southern Ontario, Canada, we present three methods for estimating the PBLh from Doppler lidar vertical wind speed and aerosol backscatter observations. We perform comparisons with PBLh estimates from the Global Environment Multiscale (GEM) model, the ECMWF Reanalysis 5 (ERA5), and nearby radiosonde flights at the Buffalo International Airport, New York, USA. We identify the vertical wind variance threshold method to be the estimate with the highest consistency with expected PBLh values and variation, comparisons to numerical and radiosonde measurement-derived estimates, and least sensitivity to noise in observations. However, each of the methods presented here show a general consistency with theoretical expectations and comparisons in appropriate conditions, affirming the validity of Doppler lidar-derived PBLh estimates in Southern Ontario.