Comparison of cloud vertical structure from passive satellite measurements and ARM radar-lidar measurements
Poster PDF
Authors
Xiquan Dong — University of Arizona
Patrick Minnis — NASA - Langley Research Center
William L. Smith — NASA - Langley Research Center
Fu-Lung Chang — Science Systems and Applications, Inc.
Helen Yi — Science Systems and Applications. Inc./NASA - LRC
Baike Xi — University of Arizona
Kris M Bedka — NASA
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Category
Cloud Properties
Description
The vertical and horizontal structure of cloud fields is critical for characterizing the radiative and moisture budgets of the atmosphere. Measurements taken by active sensors at the surface provide a relatively detailed depiction of cloud depth, layering, and moisture content over the location where the measurements are taken. Typically, data from passive satellites have been used to monitor the horizontal distribution of cloud cover and cloud-top heights. Neither type of measurement has been able to adequately provide large-scale characterizations of 3D cloud fields. Recently, data from CloudSat and CALISPO have been used to develop global empirical methods to generate cloud thickness and water content profile information from passive satellite cloud retrieval products. Additionally, multilayer cloud retrieval methods have been developed, providing a means for adding more information about cloud vertical structure to the passive measurements. Thus, the potential to characterize cloud fields over large areas accurately has been increased. Determining how advanced such retrievals are requires independent validation, because the empirical techniques were developed for only one time of day and from somewhat limited data. The information about water content profiles and cloud base from CloudSat is reliable only above 1 km or higher. Furthermore, attenuation by upper-layer clouds sometimes affects the CloudSat retrievals of water content in the lower layers. The ARM lidars and radars provide an independent characterization of the cloud vertical structure and can be used to assess the passive retrievals. This paper presents comparisons of cloud thickness and water content profiles determined from GOES and MODIS data with similar data retrieved from active and passive sensors at one or more ARM sites. The results will be used to evaluate the empirical methods and perhaps refine them.
