What are reforecasts
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- Real-time ensemble forecasts can be calibrated using historical sets of reforecasts (also known as hindcasts)
- Reforecasts are forecasts run using the same model version as the real-time forecast for a number of past dates
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The way to produce reforecasts is not unique
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- In this case reforecasts are produced at the same time as the real-time forecasts.
- Each reforecast refers to a real-time forecast.
Main Concepts
Realtime Date
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Model Version Date
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- It is the version of the model used to produce the reforecasts.
- Because the version of the model is time-stamped with a date, the term "Model Version Date" is used instead.
- It is very important that the version of the model used to produce the reforecasts AND the version of the model used to produce the real-time forecast are the same. One CANNOT calibrate a real-time forecast with reforecast that has been produced by a different version of the model.
- In the MARS system, this is expressed with the keyword "date".
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Hindcast Date
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- It refers to a start date for any of the past dates of the reforecast.
- In the MARS system, this is expressed with the keyword "hdate".
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Examples
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reforecast
configuration
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realtime
date
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model version
date
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reforecast
length
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reforecast
frequency
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number of hindcast
dates available for a
model version date
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hdate=19810101/19810106/19810111/19810116/19810121/19810126/../
20131201/20131206/20131211/20131216/20131221/20131226
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