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QC Overview
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Data received by the CIMIS computer are quality tested and flagged if they fall outside a set standard. Missing data are also flagged. Quality control is based on metric units.
Quality tested data are stored in a relational database for on-demand access by CIMIS users. The quality control flags identify specific data problems. While their immediate use is to inform users of data credibility as related to the set of standards, the flags are also used to monitor sensor performance on a daily basis and to observe long-term trends in data quality, and therefore, test the performance of specific stations. Local personnel examine the quality control program printout daily to detect potential malfunction of station sensors and schedule repair trips.
Prior to 1995, the quality control program data standards used were based on theoretical and historical data limits for the period 1982 through 1985. A new data quality control criteria program based on CIMIS historical data has been developed. Data means and standard deviations for each station, theoretical limits, and some of the procedures described by Meek and Hatfield (1994) were used to test data quality. For stations that have less than five years of historical data, regional statistics are used. The new quality control criteria took effect on January 1, 2001. We also quality tested and flagged historic data for the period 1995 through 2000 using the new criteria.
If you have questions, you may write or email Simon Eching or Bekele Temesgen:
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Bekele Temesgen
Department of Water Resources
Office of Water Use Efficiency
P.O. Box 942836
Sacramento, CA 94236-0001
temesgen@water.ca.gov
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Simon Eching
Department of Water Resources
Office of Water Use Efficiency
P.O. Box 942836
Sacramento, CA 94236-0001
seching@water.ca.gov
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