An assessment of CloudSat products using the Environment Canada observing network

This paper contains an evaluation of the CloudSat mission data products over Canada after the satellite's first full winter season of operation. The CloudSat products considered are the basic reflectivity cloud mask as well as derived macroscopic parameters such as cloud top, cloud thickness and an 8-class cloud type. Also assessed are precipitation occurrence, precipitation type, and experimental precipitation rate products.

Independent validation measurements are taken from the Environment Canada observing network. These include 31 C-band Doppler radars (one with dual polarization), +200 weather observing stations, and 15 Precipitation Occurrence Sensors Systems. Two enhanced measurement sites in central Ontario and in the high Arctic at Eureka include a cloud profiling radar and a dual channel lidar that provide additional high resolution cloud and precipitation data.

First results highlight the critical assumptions and reflectivity thresholds within the CloudSat algorithms. CloudSat data products are shown to be least reliable in scenes where multi-layer clouds, low clouds, or precipitation types with complex vertical temperature profiles exist. A thorough statistical treatment is currently underway to quantitatively characterize their errors. The analysis considers the offset distance of the ground observations from the satellite track to assess the representativeness of CloudSat data in higher level products that integrate the data in time and space.