CATS Comparison with CPL Retrievals Over North America

The Cloud Aerosol Transport System (CATS) is a lidar designed for operation on the International Space Station (ISS).  CATS had significant heritage from the Cloud Physics Lidar (CPL), which operates at three wavelengths (355, 532, 1064 nm) and flies on high-altitude aircraft such as the NASA ER-2. Since its launch in January 2015, the CATS has provided space-based lidar measurements of cloud/aerosol types and optical properties using two modes of operation. To verify and improve the CATS data products and processing algorithms, comparisons with CPL have been conducted. CPL flights under the CATS instrument as well as statistical comparisons using multiple CPL field campaigns over North America show good agreement between 1064 nm backscatter from both instruments. The CATS-CPL comparisons are used to improve the accuracy of the CATS 532nm backscatter and depolarization ratio calibrations in CATS Mode 7.1 operation. CPL data were also utilized to determine the CATS multiple scattering factors, improving the CATS Level 2 data products.