Retrieval of polar mesospheric cloud properties from CIPS: Algorithm description, error analysis and cloud detection sensitivity

The Cloud Imaging and Particle Size (CIPS) instrument has been in operation on the NASA Aeronomy of Ice in the Mesosphere (AIM) satellite since May 2007. CIPS is a multi-camera UV imager that makes unprecedented hemispheric-scale measurements of polar mesospheric clouds (PMC). The primary CIPS data products are cloud frequency, albedo, mean particle radius, ice water content and vertical column particle density. These quantities are retrieved at 25 km2 resolution at latitudes between ~55° and 84° over a range of local times in the summer hemisphere. CIPS has obtained data for six Northern Hemisphere and five Southern Hemisphere PMC seasons to date and is still in operation and performing flawlessly. The CIPS data are made available to the scientific community in a variety of formats and spatial and temporal resolution, including full-resolution single-orbit level 2 data files and images, daily (hemispheric) albedo maps and images, and full-season latitude-binned summary files. In this paper we describe the CIPS measurement strategy and sampling characteristics, calibration and the Version 4.20 processing algorithms and retrievals. We also provide a quantitative evaluation of the CIPS cloud detection sensitivity and estimated random and systematic errors of the V4.20 cloud data products.