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Validation and Determination of Ice Water Content - Radar Reflectivity Relationships during CRYSTAL-FACE: Flight Requirements for Future ComparisonsIn order for clouds to be more accurately represented in global circulation models (GCM), there is need for improved understanding of the properties of ice such as the total water in ice clouds, called ice water content (IWC), ice particle sizes and their shapes. Improved representation of clouds in models will enable GCMs to better predict for example, how changes in emissions of pollutants affect cloud formation and evolution, upper tropospheric water vapor, and the radiative budget of the atmosphere that is crucial for climate change studies. An extensive cloud measurement campaign called CRYSTAL-FACE was conducted during Summer 2002 using instrumented aircraft and a variety of instruments to measure properties of ice clouds. This paper deals with the measurement of IWC using the Harvard water vapor and total water instruments on the NASA WB-57 high-altitude aircraft. The IWC is measured directly by these instruments at the altitude of the WB-57, and it is compared with remote measurements from the Goddard Cloud Radar System (CRS) on the NASA ER-2. CRS measures vertical profiles of radar reflectivity from which IWC can be estimated at the WB-57 altitude. The IWC measurements obtained from the Harvard instruments and CRS were found to be within 20-30% of each other. Part of this difference was attributed to errors associated with comparing two measurements that are not collocated in time an space since both aircraft were not in identical locations. This study provides some credibility to the Harvard and CRS-derived IWC measurements that are in general difficult to validate except through consistency checks using different measurement approaches.
Document ID
20070035753
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Sayres, D. S. (Harvard Univ. MA, United States)
Smith, J. B. (Harvard Univ. MA, United States)
Pittman, J. V. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Weinstock, E. M. (Harvard Univ. MA, United States)
Anderson, J. G. (Harvard Univ. MA, United States)
Heymsfield, G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Fridland, A. M. (Maryland Univ. Baltimore County MD, United States)
Ackerman, A. S. (Maryland Univ. Baltimore County MD, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2007
Subject Category
Meteorology And Climatology
Funding Number(s)
CONTRACT_GRANT: NAG5-8779
CONTRACT_GRANT: NAG1-01095
CONTRACT_GRANT: NAG5-11548
CONTRACT_GRANT: NAG5-115487
Distribution Limits
Public
Copyright
Public Use Permitted.

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