Quality control coding: Difference between revisions

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'''[In progress]
'''


'''Quality control coding'''


We suggest to follow [http://www.oceansites.org/ Ocean Sites] for QC coding. The flagging scheme is mostly compatible with the primary level flagging suggested by IOC
'''Shear-probe quality-control flags'''


The Q (quality control) flags associated with shear-probe measurements are bitwise flags with boolean values which are CF compliant. More information available here: https://mplnet.gsfc.nasa.gov/about-flags


{| class=wikitable style=height:14em
Every dissipation estimate from every probe must have Q flag.
The numerical values of the Q flags are as follows:
 
{| class="wikitable"
|-
! Flag Mask
! Bit
! Flag Meaning
! Example threshold value
| Ex: True =1  / False =0
| Ex: Q value
|-
| 1
| Bit 0
| Poor figure of merit
| 1.15
| 0
| 0
|-
| 2
| Bit 1
| Large fraction of data with spikes
| 5%
| 0
| 0
|-
| 4
| Bit 2
| Anomalously large disagreement between dissipation estimates from probes
| 2.772
| 1
| 4
|-
| 8
| Bit 3
| Too many iterations of despiking routine
| 8
| 0
| 0
|-
| 16
| Bit 4
| Insufficient variance resolved
| 50%
| 1
| 16
|-
|-
! Flag !! Meaning !! Comment
| 32
| Bit 5
| manual flag to be defined by user
| N/A
| 0
| 0
|-
|-
| 0|| unknown || No QC was performed.
| 64
|-
| Bit 6
| 1 || good data  || All QC tests passed.
| manual flag to be defined by user
| N/A
| 0
| 0
|-
|-
| 2 || probably good data || Data have failed one or more QC tests but visual examination suggests data is good.
| 128
|-
| Bit 7
| 3 || potentially correctable bad data || These data are not to be used without scientific correction or re-calibration (e.g. uncertain shear sensor sensitivity).
| manual flag to be defined by user
|-
| N/A
| 4 || bad data  || Data have failed one or more tests.
| 0
|-
| 0
| 5 || -  || Not used
|-
|-
|
| 6 || - || Not used
|
|-
|
| 7 || bad data  || Data were not observed but reported (e.g. instrument target depth.).
|
|-
|
| 8 || interpolated value || Missing data may be interpolated from neighboring data in space or time.
| Final Q = 20
|-
| 9 || missing value || This is a fill value
|}
|}
<br />
The Q flags are combined by their addition.
For example a Q value of 20 means that the dissipation estimated failed both dissipation ratio limit test and the resolved variance test.
A value of 255 means that all tests failed.
The reasons for a failure can be decoded by breaking the value of Q down to its powers of 2.
-----------------------------
return to [[Flow chart for shear probes]]
[[Category: Shear probes]]

Latest revision as of 09:18, 28 August 2023

[In progress]


Shear-probe quality-control flags

The Q (quality control) flags associated with shear-probe measurements are bitwise flags with boolean values which are CF compliant. More information available here: https://mplnet.gsfc.nasa.gov/about-flags

Every dissipation estimate from every probe must have Q flag. The numerical values of the Q flags are as follows:

Flag Mask Bit Flag Meaning Example threshold value Ex: True =1 / False =0 Ex: Q value
1 Bit 0 Poor figure of merit 1.15 0 0
2 Bit 1 Large fraction of data with spikes 5% 0 0
4 Bit 2 Anomalously large disagreement between dissipation estimates from probes 2.772 1 4
8 Bit 3 Too many iterations of despiking routine 8 0 0
16 Bit 4 Insufficient variance resolved 50% 1 16
32 Bit 5 manual flag to be defined by user N/A 0 0
64 Bit 6 manual flag to be defined by user N/A 0 0
128 Bit 7 manual flag to be defined by user N/A 0 0
Final Q = 20


The Q flags are combined by their addition. For example a Q value of 20 means that the dissipation estimated failed both dissipation ratio limit test and the resolved variance test. A value of 255 means that all tests failed. The reasons for a failure can be decoded by breaking the value of Q down to its powers of 2.

return to Flow chart for shear probes

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