PSC Distributions and Composition Based on CALIOP Measurements From 2006-2018

Even though the role of polar stratospheric clouds (PSCs) in stratospheric ozone depletion is well established, important questions remain unanswered that have limited our understanding of PSC processes and how to accurately represent them in global models. This has called into question our prognostic capabilities for future ozone loss in a changing climate. A more complete picture of PSC processes on polar vortex-wide scales has emerged from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) instrument on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite that has been observing PSCs at latitudes up to 82 degrees in both hemispheres since June 2006. In this paper, we present a state-of-the-art climatology of PSC spatial and temporal distributions and particle composition constructed from the more than 13-year CALIOP spaceborne lidar dataset. The climatology also includes estimates of particulate surface area density and volume density to facilitate comparisons with in situ data and measurements by other remote sensors, as well as with theoretical models relating PSCs to heterogeneous chemical processing and ozone loss. Finally, we compare the CALIOP PSC data record with the 1979-1989 SAM II (Stratospheric Aerosol Measurement II) solar occultation PSC record to investigate possible multi-decadal changes in PSC occurrence.