Overview

Every data value provided by CORIOLIX is accompanied by a set of quality flags. These flags are a combination of automated and manually-assigned flags. A brief summary of the flags are provided below for quick reference. Complete details may be found in the CORIOLIX QA/QC Manual.

CORIOLIX quality flags are based on IOOS QARTOD quality control flag conventions. QARTOD is the Quality-Assurance/Quality Control of Real-Time Oceanographic Data, a set of manuals by the U.S. Integrated Ocean Observing System (IOOS). The CORIOLIX flag set includes some of the key flags defined in QARTOD, plus a few additional flags such as "Port Status Test". More information about QARTOD flags is available here:
U.S. Integrated Ocean Observing System, 2020. Manual for the Use of Real-Time Oceanographic Data Quality Control Flags, Version 1.2. 24 pp. https://doi.org/10.25923/w8y6-d298

Flag Set Format

The CORIOLIX quality flag set is a string of 30 digits. Each digit in the string may take values of 0 (not applicable), 1 (pass), 2 (unknown), 3 (suspect), 4 (fail), or 9 (missing). The position of the digit within the flag set indicates which flag test it represents.

An example quality flag set might be:

11123114322222222222222222222

The above quality flag set indicates that the the Gap Test (the leftmost digit, in position 0) passed (1), however the Spike Test (the digit in position 7) failed (4).

Flag Changes

QA/QC happens at various stages throughout the data lifecycle. As a consequence, quality flags may change throughout a cruise.

Combined Flags

During data processing, such as temporal binning, it is sometimes necessary to combine the flags from different data points. In the case of binning, quality flags representing the binned data are a composite of all of the flags from that bin. To generate the combined flag set, the largest value found in each flag position is used.

For example:

Flag Set 1	111144000022222222111100000000
Flag Set 2	121122000033222222114400000000
Flag Set 3	321122000033222222114400000000
Combined	321144000033222222114400000000