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@Korina said in A difference between reference time and update time:

A difference between reference time and update time
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Korina
21 Feb 2020, 18:28

Each model has a different update time and it could be confusing what connection does it have with the update time.

Here is the explanation:

Reference time - is the time when a model starts a new forecast block.
It consists of:

Initialisation - data are entered into the model, this creates Initial conditions (initialisation time) and then model starts calculating conditions.
Assimilation - normalisation on data and assembling data for computation.
Computation - calculating the future atmospheric rates of change in time increments.
Data extraction - extracting data into regular forecast intervals.
Data storage - data are stored and written in accessible format.
Data postprocessing - special postprocessing routines

For example model ECMWF has an update interval 12 hours (or 6 hours interval for Premium users), that means the first reference time will be 00:00:00Z (Zulu time) and second one 12:00:00Z.

Update time is time between the reference time and the actual update.
The whole process of data computation takes approximately from 8 to 9 hours.
So for ECMWF model the update times are 07:15:00Z and 19:15:00Z.
See the exact update times here - When and how often are the weather data updated?.

Where to find info about reference and update time:

Thanks for the clarification! The distinction between reference time and update time makes a lot more sense now. It’s interesting to see how much processing goes into generating accurate forecasts.