GPM Ground Validation Autonomous Parsivel Unit (APU) GCPEx guide provides data format information for the Autonomous Parsivel Unit (APU), an optical disdrometer based on single particle extinction that measures particle size and fall velocity. This APU consists of the Parsivel, which was developed by OTT in Germany, and its support systems, which were designed and built by the University of Alabama in Huntsville. The APU dataset for the GPM Cold-season Precipitation Experiment (GCPEx) provides precipitation data including raindrop size and counts, precipitation drop size, rate and amount and snowflake size, counts and distribution. The GCPEx APU data was collected from several sites in Canada during the Winter 2011-2012 period.
