Quality control coding: Difference between revisions

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'''In progress
'''[In progress]
'''
'''


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'''Shear-probe quality-control flags'''
'''Shear-probe quality-control flags'''


The Q (quality control) flags associated with shear-probe measurements are not compatible with the Ocean Sites [http://www.oceansites.org/ Ocean Sites] for quality control (QC) coding.
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.
Every dissipation estimate from every probe must have Q flag.
The numerical values of the Q flags are as follows:
The numerical values of the Q flags are as follows:
      1, if FOM > FOM_limit
      2, if despike_fraction > despike_fraction_limit
      4, if |log(e_max)-log(e_min)|> diss_ratio_limit X \sigma_{\ln\varepsilon}
      8, if despike_iterations > despike_iterations_limit
      16, if variance resolved > 50%
      32, manual flag defined by user


{| class="wikitable"  
{| class="wikitable"  
|-
|-
! Flag Mask
! Flag Mask
! Bit
! Flag Meaning
! Flag Meaning
! Bit
! Example threshold value
! Example threshold value
| Ex: True =1  / False =0
| Ex: Q value
|-
|-
| 1
| 1
| if FOM > FOM_limit
| Bit 0
| Bit 0
| ?
| Poor figure of merit
| 1.15
| 0
| 0
|-
|-
| 2
| 2
| if despike_fraction > despike_fraction_limit
| Bit 1
| Bit 1
| ?
| Large fraction of data with spikes
| 5%
| 0
| 0
|-
|-
| 4
| 4
| if |log(e_max)-log(e_min)|> diss_ratio_limit X \sigma_{\ln\varepsilon}
| Bit 2
| Bit 2
| ?
| Anomalously large disagreement between dissipation estimates from probes
| 2.772
| 1
| 4
|-
|-
| 8
| 8
| if despike_iterations > despike_iterations_limit
| Bit 3
| Bit 3
| ?
| Too many iterations of despiking routine
| 8
| 0
| 0
|-
|-
| 16
| 16
| if variance resolved less than a threshold
| Bit 4
| Bit 4
| Insufficient variance resolved
| 50%
| 50%
| 1
| 16
|-
|-
| 32
| 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
| manual flag to be defined by user
| Bit 5
| N/A
| ?
| 0
| 0
|-
|
|
|
|
|
| Final Q = 20
|}
|}


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The Q flags are combined by their addition.
The Q flags are combined by their addition.
For example a Q value of 3 means that the dissipation estimated failed both FOM_limit test and the despike_fraction test.
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 15 means that all tests failed.
A value of 255 means that all tests failed.
A failure of any one test (<math>Q\ne0</math>) means that a dissipation test should not be trusted.
The reasons for a failure can be decoded by breaking the value of Q down to its powers of 2.
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]]
[[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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