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The purpose of this check is to test for trends in each of the input time series and send log messages whenever a trend is detected. Each time series is processed independently. One of the strengths of the Mann-Kendall check is that it can also be used when there are lots of missing values.
Unfortunately there is a limit on the number of non-missings that can be processed reasonably, since the calculation of the slopes requires memory for n * (n + 1) / 2 values. In practise this means a limit of some 6000 6300 time steps. It is therefore recommended to aggregate the values first when there are many values in the timeseries to be checked.
During the check, the threshold criteria for the check are first sorted. The most severe log message is processed first and when the log message is generated the less serious log message will not be generated.
TODO: Add some general information on the Mann-Kendall....
Configuration
- id: identifier of the check.
- checkRelativePeriod: The period to run the trend test for.
- variableDefinition: Definition of time series.
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