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. These may involve comparison of data between beams, between bins and over time and be informed by data from other sensors e.g. meteorological, wave or CTD sensors. Typical criteria used to identify possible bad data include:

1. Correlation
   1. minimum threshold
2. Echo intensity
   1. false target / “fish” detection
3. Percent good
   1. applies to measurement modes with in-instrument averaging across multiple pings per ensemble
4. Orientation (heading, pitch, roll) and depth (if sensor installed)
   1. resolve location of observations
   2. indentify factors affecting location and any periodic motion
5. Along beam velocity
   1. variations in data return rate
   2. values outside the nominal measurement range for the instrument configuration
   3. evidence of phase wrapping (ambiguity velocity) in pulse-pulse coherent observations
   4. periodicity indicating waves or oscillatory motion
   5. distribution outliers
   6. burst variance spatial and temporal trends
6. Temperature and salinity (if sensors installed)
   1. indication of changes in local stratification and/or internal wave activity
7. 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

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