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Description
Available from Delft-FEWS version 2023.02.
Computes from an ensemble the probability of occurence of an event.
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eventprobability range can consist of a lower and upper boundary (both are optional) and can be configured in 3 ways:
Boundary values directly as a value, an attribute or obtained from a timeseries.
<event><lower><value>10</value></lower></event>
<event><lower><value>@my_lower_bound@</value></lower></event> ,properties are also possible using $my_lower_bound$ instead
<event><lower><variableId>my_lower_bound_timeseries</variableId></lower></event>
Use <inclusive> true for strict lower and upper bounds (>= and <=)
Value:
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<transformation id="compute_probability_of_exceedance_of_spi_equal_to_two"> <statisticsEnsemble> <eventProbability> <inputVariable> <variableId>spi</variableId> </inputVariable> <includeMissingValues>false</includeMissingValues> <event> <lower><value>2</value></lower> <upper><value>5</value></upper> </event> <outputVariable> <variableId>probability_spi_gte_2</variableId> </outputVariable> </eventProbability> </statisticsEnsemble> </transformation> |
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<transformation id="compute_probability_of_exceedance_of_spi_equal_to_two"> <statisticsEnsemble> <eventProbability> <inputVariable> <variableId>spi</variableId> </inputVariable> <includeMissingValues>false</includeMissingValues> <event> <lower><attribute>lowerEvent<<lower><value>@lowerEvent@</attribute><value></lower> <upper><attribute>upperEvent<<upper><value>@upperEvent@</attribute><value></upper> </event> <outputVariable> <variableId>probability_spi_gte_2</variableId> </outputVariable> </eventProbability> </statisticsEnsemble> </transformation> |
Timeseries:
!! For use of timeseries lowerBoundaryEvent and upperBoundaryEvent tag have to be used. Not the <event><lower> and <event><upper> tags !!
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<transformation id="compute_probability_of_exceedance_of_spi_equal_to_two"> <statisticsEnsemble> <eventProbability> <inputVariable> <variableId>spi</variableId> </inputVariable> <lowerBoundaryEvent> <variableId>lower_boundaries</variableId> </lowerBoundaryEvent> <upperBoundaryEvent> <variableId>upper_boundaries</variableId> </upperBoundaryEvent> <includeMissingValues>false</includeMissingValues> <event> <!-- <lower><variableId><variableId>lower <lower><variableId>lower_boundaries</variableId></variableId></lower> --> <!-- <upper><variableId><variableId>upper<upper><variableId>upper_boundaries</variableId></variableId></upper> --> upper> </event> <outputVariable> <variableId>probability_spi_gte_2</variableId> </outputVariable> </eventProbability> </statisticsEnsemble> </transformation> |
Example
In below example, the probability of three events is computed.
- Event 1 is the event where Q.forecast < 10 m3/s
- Event 2 is the event where 10 <= Q.forecast < 20 m3/s
- Event 3 is the event where Q >= 20 m3/s.
In this example, the events are chosen in such a way that they are mutually exclusive and collectively exhaustive. The combined probability should therefore sum to 1. The configuration file for this example can be downloaded from here. A timeseries plot for the results is shown below.