Shear probes quality control metrics

Spikes in epsilon estimates arise from a number of causes such as collisions of sensor tips with suspended particles (e.g. detritus, plankton, jelly fish, seaweed), electronic noise due to other sensors, or mechanical platform vibrations. This section describes quality control measures and its coding.

In a first step, epsilon estimates are flagged based on quality control matric and disagreement between dissipation estimates from redundant sensors.

1. Quality-control metrics (see also Processing Steps section V) that accompanied dissipation estimates are used to flag individual estimates. In particular, quality control thresholds for

   • figure of merit (FM)
   • fraction of shear-probe data altered by the de-spiking routine
   • number of iterations of the de-spiking routine required to clean the data
   • (more to be discussed)

2. Agreement between dissipation estimates from redundant sensors (i.e. two or more shear probes) does not exist.

Flagged data will receive quality control coding 4.

In a second step of quality control, a review of ensembles that have been flagged is performed. Individual shear spectra, associated tilt and acceleration data and microstructure thermistor data/spectra are visually examined for consistency. Previously flagged data that appears to be good data will receive quality control coding 2.

Details for QC coding can be found here.