How would cloud types affect the differences in multilayer cloud amounts retrieved from satellite and ARM ARSCL data?

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Description

Representation of the vertical structure of cloud amount is one of the central issues driving uncertainties in cloud modeling for weather predictions and climate simulations. The measurement of the cloud vertical representation requires large data volumes of spatial and temporal cloud observation data. In order to deliver improved cloud data, and therefore improved cloud modeling, it is important to evaluate large-scale multilayered overlapping cloud amount data that have been derived from available satellite and ground-based measurements. To this end, we examined two different multilayered overlapping cloud products that are retrieved separately from (1) space-borne U.S. Geostationary Operational Environmental Satellite (GOES) imager data and (2) ground-based U.S. DOE ARM active lidar and radar observations. This examination involved an innovative method developed by the authors for retrieving multilayer cloud properties using the GOES passive satellite data as well as MODIS data. It integrates the measurements from the CO2-absorption channel with other atmospheric window channels to quantitatively determine the overlapping cloud properties on a pixel-by-pixel basis. The ARM active lidar/radar data utilized in this study is the Active Remote Sensing of Clouds (ARSCL) cloud vertical mask data product. The resulting GOES multilayered cloud properties were analyzed over the ARM SGP Central Facility site for multiple years and are compared to temporal and spatially matched ARSCL data. It was found that generally good agreement exists between the two for well-defined multilayer cloud profiles. However, significant differences exist for various multilayered conditions. For instance, in some cases, the GOES method would miss multiple layered clouds that did not possess a sufficient layer altitude separation. For other cases, the ARSCL method would miss upper-level thin cirrus clouds that were above optically thick lower clouds. A summary report of agreement and differences will be discussed for different cloud types based on their physical and optical properties.