Particle Turbulent Mass Flux Retrievals Through Novel Remote Sensing Methodology

Active sensors such as lidars and radars can retrieve information on vertical velocity, aerosol extinction, and backscatter with a spatial and temporal resolution of about 50 m and 30 seconds, respectively. In this study, we report the application of a vertically pointing coherent Doppler Lidar (DL) and the University of Wisconsin High Spectral Resolution Lidar (UW-HSRL) for inferring aerosol vertical turbulent mass fluxes at different altitudes within the Planetary Boundary Layer (PBL) throughout the day. Aerosol number size distributions and mass fluxes at 12 m height above ground were measured using Printed Optical Particle Spectrometer (POPS) and a 3-D sonic anemometer. The field studies were conducted at the DOE ARM SGP site in Oklahoma in 2020 and at La Porte, Texas, during the TRacking Aerosol Convection interactions ExpeRiment (TRACER) in 2022. In this presentation, aerosol vertical turbulent mass fluxes at different heights within the PBL are compared with near-ground measurements for different relative humidity (RH) conditions. Preliminary analysis at the SGP site shows the DL mass fluxes in a range of -0.5 and 0.5 µg m-2 s-1 in the surface layer during mid-day, with upward fluxes occurring more often than downward fluxes. In addition to estimates of the aerosol mass flux, aerosol depolarization ratios reported by HSRL are used for inferring chemical proxies of aerosols. This study will also test the feasibility of using vertical flux profiles as a parameter to estimate the mixing layer height (MLH) as compared to using radiosondes and other techniques such as using a Haar wavelet covariance transform on airborne backscatter lidar data.