Quality Assessment

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R2R performs programmatic Quality Assessment (QA) for datasets from several routinely acquired high value devices including GPS, MBES, SBES, gravity, magnetics, CTD, and XBT sensors. QA is defined as documenting the quality of the data as originally delivered from vessels. It is important to note that R2R QA routines are intended to identify suspicious data, and do not indicate the scientific quality/value of data. During QA procedures, a series of quality tests are run on the data and a summary of the results is provided. Programmatic QA includes basic dataset level tests to evaluate that minimum appropriate metadata exists, that the expected data files exist, that file checksums match cruise manifest checksums, that files are readable and of the correct documented format. Additional device-specific tests are also run for which individual datafiles are opened and read to confirm data values are valid and within expected temporal and spatial bounds, as well as statistical tests to assess whether the instrument appears to be functioning properly. R2R QA routines do not alter the original data files.

The primary purpose of the QA is to more thoroughly document the dataset and potential quality issues related to data acquisition. This information may be useful for ship operators to help improve future acquisition and for science end users of the data to help identify data of interest for their applications and helps support FAIR principles for long-term data preservation. Results of the programmatic QA are summarized in an R2R Quality Assessment Certificate (QAC). Data that have not been quality assessed are documented as such. The results of QA is made publicly accessible on the R2R website in a QA Dashboard, via the Cruise Catalog, and Web services. The QAC provides essential file details including name, size, checksum and date, as well as additional data specific content.

For some data types, Quality Controlled data products are also created. These include meteorology station (MET) and thermosalinograph (TSG) data (delivered in real-time), as well as navigation, trackline geophysics (gravity and magnetics), and hydrographic (CTD and XBT). In Quality Control (QC), each value within a dataset is tested, and one or more sets of QC flags is incorporated into the data product that indicate whether that record or value passed or failed the quality test(s). Failing points are not removed, just flagged. The exact quality tests done vary by data type. Tests can include ensuring physically plausible relationships between observations, comparisons to historical values for a region (e.g., climatologies), identifying time reversals and missing data, and other tests that evaluate the scientific use of the data.

Information about QA tests perfomed by R2R can be found on the Quality Assessment Dashboard.

Additional documentation is available for Quality Assessment by data type and Quality Controlled Data Products.

VESSELS

50 RESEARCH CRUISES

10,067

DATA SETS ARCHIVED

61,063

DOWNLOADABLE FILES

23,573,045

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