Raw data review (QA1)

Raw data review

The raw data review seeks to identify the Level 1 data that satisfies a range of quality control criteria. Typical criteria used to identify possible bad data include:

1. Velocity limits
   1. Check for values outside the nominal measurement range for the instrument configuration
   2. Check for evidence of phase wrapping (ambiguity velocity) issues
2. Correlation coefficient
   1. minimum threshold
3. Echo intensity
   1. false target / “fish” detection
4. Percent good
   1. applies to measurement modes with in-instrument averaging across multiple pings per ensemble
5. Orientation (heading, pitch, roll) and depth (if sensor installed)
   1. deployment as planned?
   2. indentify specific changes or periodic motion
6. Along beam velocity
   1. data return rate
   2. phase wrapping for pulse-pulse coherent observations
   3. periodicity indicating waves or oscillatory motion
   4. distribution outliers
   5. burst variance spatial and temporal trends
7. Temperature and salinity (if sensors installed)
   1. indication of changes in local stratification and/or internal wave activity
8. Earth coordinate velocity
   1. may need to be derived from along-beam velocity
   2. bin mapping if ADCP orientation isn’t vertical
   3. error velocity from 4-beam instruments
   4. comparison with ambiguity velocity to check for possible phase wrapping
   5. burst variance spatial and temporal trends
   6. shear over observation range

is a comparison of data between beams, between bins and over time to determine possible anomalies. Note that consideration of spatial and temporal trends may be informed by data from other sensors e.g. meteorological, wave or CTD sensors. The following characteristics should be examined:

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