Summary
This metric counts the times this data quality flag is set from 0 (default) to 1 in the fixed section of the miniSEED header. A flag value of 1 indicates when electronics problems in the datalogger have lead to spikes or dropouts (glitches). Glitches are most common in analog recording. Not all dataloggers set this flag.
Uses
This metric can be used to identify data with large transients that may need to be removed before the data is used for research.
If using this metric with the rrds service, be aware that a value of 0 (zero) can either mean that
- the datalogger detected 0 instances of this condition, or
- the datalogger does not set this flag, so it is unknown whether or not this condition occurred.
Unless all channels in an rrds request are known to set this flag, requesting only data with a count of 0 will not necessarily omit all data for which this condition occurred.
Data Analyzed
Traces – one N.S.L.C (Network.Station.Location.Channel) per measurement
Window – 24 hours starting at 00:00:00 UTC
Data Source – IRIS miniSEED archive
SEED Channel Types – ?H?, ?L?, ?N?, ?G?, ?P?, VM? | High Gain, Low Gain, Accelerometer, Gravimeter, Geophone, Mass Channels
Algorithm
- Request 24 hours of data for a single N.S.L.C.
- Count and report the number times this binary flag is set to 1.
Metric Values Returned
value – number of times this flag is set to 1 that day
target – the trace analyzed, labeled as N.S.L.C.Q (Network.Station.Location.Channel.Quality)
start – beginning of the data day requested (00:00:00 UTC)
end – end of the data day requested (truncated as 23:59:59 UTC)
lddate – date/time the measurement was made and loaded into the MUSTANG database (UTC)
Notes
Not all dataloggers set this flag. For these instruments, a value of 0 does not necessarily mean that glitches are absent.
