What do the Wave Error Codes mean?Follow
The Wave Error Codes provide an indication of when a wave burst measurement may be unreliable. Even though these are designated as "Error" codes, they may be more thought of as a type of warning.
The Error Codes are bit-coded so that multiple error types in a given burst can be determined. For example, a value of 139 would translate to 0000 1000 1011. This states that there is No Pressure, Low Pressure, White Noise, and Directional Ambiguity. This probably indicates the AWAC was not in the water, and is commonly noted at the beginning and end of data files.
Sometimes the burst is still useable and valid, but the user may wish to verify this themselves with further inspection. One example is the Directional Ambiguity warning; while this indicates that the directional estimates may be unreliable, the other estimates may be perfectly fine.
The following is a list of the error codes and a description of the detected error. A value of 0 indicates no detected data errors. Note that some warnings are particular to the AWAC and therefore will not occur with PUV processing.
No Errors (0)
Processing of burst was successful and had no detectable errors.
No Pressure (0000 0001) = 1
This would appear if the pressure is too low, and indicates that the instrument was most likely out of the water or unreasonably close to the surface.
Low Pressure (0000 0010) = 2
This error suggests that there was no dynamic pressure detected in the time series, and means that the waves are not measurable (i.e. a constant pressure). This would occur if the instrument was deployed at a depth that is too deep to measure the waves or simply that there were no measurable waves.
Low Amplitude (0000 0100) = 4
This indicates that the amplitude of the Doppler signal was too low to measure the orbital velocity.
White Noise Test (0000 1000) = 8
This test is to determine if the estimated spectrum is purely white noise. Such a spectrum does not contain information about the surface waves.
Unreasonable Estimate (0001 0000) = 16
If it appears that there is an unreasonable estimate then the burst is flagged as bad. Such estimates that wound be considered unreasonable are:
Hs > 20 meters
Tm02 > 35 seconds or Tm02 < 0.5 seconds
Tp > 50 seconds or Tp < 0.5 senods
Never Processed (0010 0000) = 32
The wave processing cleans up some corrupt data (ie checksum errors) however if number of bad points exceeds 10% of the burst data, then the data is not processed and it is tagged with this error message. Usually this error message suggests that the wave burst was incomplete or damaged
AST Out of Bounds (0100 0000) = 64
Since many of the estimates are based on the zerocrossing from the AST, there is a check to make certain none of these estimates are unreasonable. At the moment these bounds are as follow:
H3 > 20.0 m
H10 > 25.0 m
Hmax > 35.0 m
Tmean > 35.0 sec or Tmean < 0.5 sec
Tpeak > 30 sec
Directional Ambiguity (1000 0000) = 128
This is a test for the possibility that the directional estimate at the peak period is ambiguous. This may occur if the projected array is too large relative to the wave length associated with the peak period.
No Pressure Peak (1 0000 0000) = 256
This test checks to see if there is a peak in the spectrum. This commonly occurs if waves on the surface are very small and the water depth is large. This represents more of a problem for PUV measurements and not so much for AST/AWAC measurements.
Close to clipping (10 0000 0000) = 512
This indicates if the surface track is close to reaching the extent of its range. Such a situation would clip the crest of the waves an underestimate the wave height estimates. A fast value of 0.25 meters has been chosen to indicate this situation.
High AST Data Loss (100 0000 0000) = 1024
This indicates that the too many points were lost during the data clean-up or despiking steps. The level at which the data loss in the AST time series is considered excessive is 10% of the data.
Excessive tilt (1000 0000 0000) = 2048
This indicates that the too much tilt and almost exclusively effects the AST measurements, unless it is extreme. The test is 10 degrees from vertical.
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