Intercomparison of CALIOP Cloud and Aerosol Profiles with in situ Marine Stratocumulus Observations during ORACLES

The purpose of the ORACLES ( ObseRvations of Aerosols above CLouds and their intEractionS) field campaign that occurred during the months of August and September 2016 off the coast of Namibia is to measure the interactions of biomass burning aerosols (BBA) and clouds. In this region stratocumulus clouds are the dominant cloud type and are a critical component of Earth's radiation budget due to their high albedo and resulting cooling effect. They also impact the hydrological cycle through drizzle production. BBA are the predominant aerosol type in this region and also play multiple roles by modifying the atmospheric temperature structure through absorbing solar radiation and altering cloud properties by serving as CCN. These processes of aerosol-cloud interactions are poorly understood, thus the use of multiple measurement techniques, including space-borne remotely sensed data and in situ measurements, offer a more in depth look into these interactions. To address this complex system we combine satellite data from CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) and in situ data from the FPDR-PDI. CALIOP Level 2 Lidar Vertical Feature Mask (VFM) data was collected and analyzed for the years 2006-2015 to establish a climatological profile for aerosol and clouds in the region. Individual swaths observed during the 2016 field project are used to compare with in situ measurements. The VFM data provides aerosol and cloud types in categories based on their optical properties, along with their vertical structures in the atmosphere. To determine actual microphysical cloud properties we use a FPDR-PDI to measure instantaneous cloud drop size, cloud drop concentration, drop size distributions and liquid water content. This work compares average CALIOP aerosol and cloud profiles across the ORACLES region, including the stratocumulus to cumulus transition, with the in situ FPDR-PDI data to confirm cloud altitude and thickness and cloud-aerosol collocation.