Development of a Combined Polarimeter and Lidar Optimal Estimation Algorithm

We have developed a combined lidar and polarimeter retrieval algorithm to retrieve vertically-resolved profiles of aerosol microphysics properties. The new retrieval system is modular in design. It consists of three modules, a vertically-resolved aerosol profile retrieval module for lidar data, an aerosol and cloud/ocean retrieval module for polarimeter data, and a combined retrieval module for both lidar and polarimeter measurements. In addition to performing optimal estimation retrievals on various data sources, we have designed the system so that it can be used to carry out aerosol retrieval performance trade studies by changing the input characteristics of lidar and polarimeter data. We have tested Lidar-only algorithm using both simulated data and various field campaign data (DISCOVER-AQ, CHARMS, TCAP, and ORACLES). For polarimeter-only modules, we have done the same for SABOR, TCAP, NAMES, and ORACLES data. The simulated retrieval studies show that the combined lidar+polarimeter retrieval provides much higher information content relative to their individual counterpartsfor retrieving effective radius, particle concentrations, and absorption properties.