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***Special Statement Regarding the GHCN-Daily***

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Source/Author: Natalie Umphlett - High Plains Regional Climate Center 09/05/13

Please read the following statement about important changes to ACIS:

Most climate data management systems focus on the storage of climate data and, at best, provide the means to access data subsets or simple pre-defined summaries from single datasets. ACIS is unique among climate data management systems because it focuses on producing customer-driven, value-added products that can be easily derived from MULTIPLE datasets. Product quality is assured through rigorous definition of station and individual station element capability through a well-managed metadata database.

In order to incorporate multiple datasets, the RCC development team has a priority list for those datasets. For instance, if the first dataset has missing values, then the next dataset is queried, and so on. The RCC program strives to provide a high quality dataset which has the official archive of the National Climatic Data Center (NCDC). Because of the implementation of the Global Historical Climatology Network - Daily (GHCN-Daily) at NCDC, ACIS will move to a new hierarchy of dataset priorities with the GHCN-Daily as the highest, beginning September 3, 2013. Please be aware that you may see changes in the ACIS database:

  • GHCN-Daily always provides "original" values, whereas ACIS previously included "replacement" values from the TD32xx datasets, when available. Reasons for the generation of these replacement values included shifting of observations to correct day of observation and automated or manual generation of replacements for values failing QC procedures in place at that time.
  • When data from both TD3200 and TD3210 are available, GHCN-Daily gives preference to TD3200, whereas ACIS previously gave preference to TD3210.
  • Possible changes in source data introduced by NCDC's conversion from the use of COOP and WBAN ids to GHCN ids.
  • If you would like to compare datasets, please see the Northeast Regional Climate Center's ACIS Dataset Comparison Tool.

    Should you find anything in error, please either contact NCDC directly or if you have an account, please submit a change using the Datzilla tool. If you have questions about ACIS, please contact us here.

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