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Statistical Quality Control of Moisture Data in GEOS DASA new statistical quality control algorithm was recently implemented in the Goddard Earth Observing System Data Assimilation System (GEOS DAS). The final step in the algorithm consists of an adaptive buddy check that either accepts or rejects outlier observations based on a local statistical analysis of nearby data. A basic assumption in any such test is that the observed field is spatially coherent, in the sense that nearby data can be expected to confirm each other. However, the buddy check resulted in excessive rejection of moisture data, especially during the Northern Hemisphere summer. The analysis moisture variable in GEOS DAS is water vapor mixing ratio. Observational evidence shows that the distribution of mixing ratio errors is far from normal. Furthermore, spatial correlations among mixing ratio errors are highly anisotropic and difficult to identify. Both factors contribute to the poor performance of the statistical quality control algorithm. To alleviate the problem, we applied the buddy check to relative humidity data instead. This variable explicitly depends on temperature and therefore exhibits a much greater spatial coherence. As a result, reject rates of moisture data are much more reasonable and homogeneous in time and space.
Document ID
19990064448
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Dee, D. P.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Rukhovets, L.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Todling, R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 18, 2013
Publication Date
January 1, 1999
Subject Category
Quality Assurance And Reliability
Meeting Information
Meeting: General Assembly
Location: The Hague
Country: Netherlands
Start Date: April 19, 1999
End Date: April 23, 1999
Sponsors: European Geophysical Society
Distribution Limits
Public
Copyright
Other

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