IGOSS Flag Mapping

[DocOtak]

Jim is looking into an IGOSS to WHP flags (or digging up an old table).

Once we have that, the exchange format should be updated with the bi-directional mappings.

Follow up hopefully the week of 2022-06-27

[DocOtak]

From Jim Swift:

WOCE and IGOSS Quality Codes Note from J. Swift June 2022 (version 2, with a few corrections)

A. [Excerpt from document held by J. Swift and probably on line somewhere …]

In order that WHP data can best be used with other data, it may be advantageous for some users to translate the WOCE-specific quality codes into the more widely recognized IGOSS quality codes.

The WHP quality codes for the water bottle itself are:

Flag	Meaning
1	Bottle information unavailable.
2	No problems noted.
3	Leaking.
4	Did not trip correctly.
5	Not reported.
6	Significant discrepancy in measured values between Gerard and Niskin bottles.
7	Unknown problem.
8	Pair did not trip correctly. Note that the Niskin bottle can trip at an unplanned depth while the Gerard trips correctly and vice versa.
9	Samples not drawn from this bottle.

Flags 6, 7, and 8 apply primarily to large volume samplers.

The WHP bottle parameter data quality codes are:

Flag	Meaning
1	Sample for this measurement was drawn from water bottle but analysis not received. Note that if water is drawn for any measurement from a water bottle, the quality flag for that parameter must be set equal to 1 initially to ensure that all water samples are accounted for.
2	Acceptable measurement.
3	Questionable measurement.
4	Bad measurement.
5	Not reported.
6	Mean of replicate measurements (Number of replicates should be specified in the —.DOC file and replicate data tabulated).
7	Manual chromatographic peak measurement.
8	Irregular digital chromatographic peak integration.
9	Sample not drawn for this measurement from this bottle.

The WHP CTD data quality codes are:

Flag	Meaning
1	Not calibrated.
2	Acceptable measurement.
3	Questionable measurement.
4	Bad measurement.
5	Not reported.
6	Interpolated over >2 dbar interval.
7	Despiked.
8	Not assigned for CTD data.
9	Not sampled.

The WMO IGOSS observation quality codes are:

Flag	Meaning
0	No quality control yet assigned to this element
1	The element appears to be correct
2	The element is probably good
3	The element is probably bad
4	The element appears erroneous
5	The element has been changed
6 to 8	Reserved for future use
9	The element is missing

A perfect translation is probably not feasible, but the WHP Office [now the CCHDO] suggests the following WHP-to-IGOSS (not IGOSS-to-WHP) translation rules as reasonable:

Bottle:

WOCE	IGOSS
1	0
2	1
3	3 (see note 1)
4	4
5	0
6	4
7	4
8	4
9	9

water sample

WOCE	IGOSS
1	0
2	1
3	2 (see note 2)
4	4
5	0
6	2
7	2
8	2
9	9

ctd

WOCE	IGOSS
1	0
2	1
3	2 (see note 2)
4	4
5	0
6	2
7	2
9	9

B. Attempt to translate IGOSS Quality Codes to WOCE (corrected from version 1)

The IGOSS Quality Codes do not translate all that well to WOCE Quality Codes. Here is a suggestion:

bottle

IGOSS	WOCE
0	5
1	2
2	3
3	4
4	4
5	9
6	n/a
7	n/a
8	n/a
9	9

Water sample

IGOSS	WOCE
0	1
1	2
2	3
3	4
4	4
5	1
6	n/a
7	n/a
8	n/a
9	9

CTD

IGOSS	WOCE
0	1?
1	2
2	3
3	4
4	4
5	3
6	n/a
7	n/a
8	n/a
9	9

Footnotes

1. The WHP Office, in the interest of being conservative, has chosen to translate the WOCE bottle quality code 3 into IGOSS quality code 3. A leaking water sample bottle typically results in a discrepancy or error in gas samples, such as oxygen and CFCs, but less often results in data discrepancies for salinity and nutrients. It is suggested that data users who wish to import only "good" data not import any water sample data from bottles with a WOCE code 3 or IGOSS code 3. A data user who is willing to entertain slightly greater risk might choose to import non-gas sample data (e.g., salinity and nutrients) from a WOCE code 3 or IGOSS code 3 water sample bottle, and allow import of gas sample data (e.g. oxygens and CFCs) for bottles with IGOSS Code 2. (The WHP Office is not, however, currently assigning IGOSS code 2 to water sample bottles; but future data originators or data centers may wish to use code 2.) ↩

2. The WHP Office has noted that in general, data originators tend to be conservative and so in DQE reports many WHP code 3 ("questionable") water sample parameter data are deemed WHP code 2 ("good") by the examiners. The IGOSS code 2 ("probably good") seems to be a reasonable interpretation. The WHP Office is not currently assigning IGOSS code 3 ("probably bad") to WHP water sample data values. ↩ ↩²