GEWEX cloud assessment: A review

Claudia Stubenrauch, William B. Rossow, Stefan Kinne, Steve Ackerman, Gregory Cesana, Hélène Chepfer, Larry Di Girolamo, Brian Getzewich, Anthony Guignard, Andy Heidinger, Brent Maddux, Paul Menzel, Patrick Minnis, Cindy Pearl, Steven Platnick, Caroline Poulsen, Jérôme Riedi, Andrew Sayer, Sunny Sun-Mack, Andi WaltherDave Winker, Shen Zeng, Guangyu Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Clouds cover about 70% of the Earth's surface and play a dominant role in the energy and water cycle of our planet. Only satellite observations provide a continuous survey of the state of the atmosphere over the entire globe and across the wide range of spatial and temporal scales that comprise weather and climate variability. Satellite cloud data records now exceed more than 25 years; however, climatologies compiled from different satellite datasets can exhibit systematic biases. Questions therefore arise as to the accuracy and limitations of the various sensors. The Global Energy and Water cycle Experiment (GEWEX) Cloud Assessment, initiated in 2005 by the GEWEX Radiation Panel, provides the first coordinated intercomparison of publicly available, global cloud products (gridded, monthly statistics) retrieved from measurements of multi-spectral imagers (some with multi-angle view and polarization capabilities), IR sounders and lidar. Cloud properties under study include cloud amount, cloud height (in terms of pressure, temperature or altitude), cloud radiative properties (optical depth or emissivity), cloud thermodynamic phase and bulk microphysical properties (effective particle size and water path). Differences in average cloud properties, especially in the amount of high-level clouds, are mostly explained by the inherent instrument measurement capability for detecting and/or identifying optically thin cirrus, especially when overlying low-level clouds. The study of long-term variations with these datasets requires consideration of many factors. The monthly, gridded database presented here facilitates further assessments, climate studies, and the evaluation of climate models.

Original languageEnglish (US)
Title of host publicationRadiation Processes in the Atmosphere and Ocean, IRS 2012 - Proceedings of the International Radiation Symposium (IRC/IAMAS)
Number of pages4
StatePublished - 2013
EventInternational Radiation Symposium: Radiation Processes in the Atmosphere and Ocean, IRS 2012 - Berlin, Germany
Duration: Aug 6 2012Aug 10 2012

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


OtherInternational Radiation Symposium: Radiation Processes in the Atmosphere and Ocean, IRS 2012


  • Climate data record
  • Cloud properties
  • Satellite observations

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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