This page documents the steps to follow when a data provider plans to implement changes to their system, such as a new version of their model or a change in the configuration.

There can be two types of changes:

  1. A change that  does not affect the number of fields to in the database, for example, a change in resolution or an improved version of the model producing the same fields.
  2. A change in the configuration that affects the number of fields. This could be in the form of:
    1. change to the frequency of time-steps or extend/shorten the length of the forecast
    2. addition/removal of parameters
    3. change to the number of ensembles
    4. change to the frequency of the forecast (eg, from once a week to twice a week), etc...

In both cases, data providers must update the documentation with what has changed, so users are able to follow the history of a model

Changes to the configuration

When a change affects the number of fields, we ask data providers to:

  • Notify in advance ECMWF and CMA,
  • Provide test data (if required)
  • Update the documentation.

Notify in advance ECMWF and CMA

  • ECMWF
    • describe the change via ECMWF Service Desk form: https://www.ecmwf.int/en/about/contact-us
      • Subject:: select last option "Other"
      • Message: "system change for S2S archive"  + description of the change
    • it will result in creation of a Service Desk ticket which should be used in the following for all further communication (test data, docs update etc..)
  • CMA: TBD

Provide test data (if required)

If the change affects how fields are encoded, it is recommended to test the new encoding by ingesting test data in the S2S database, so ECMWF and CMA could adapt the ingestion suites if required.

This is achieved by naming files as test instead of prod, and by setting in the GRIB header Production status of data to 7:

table 1.3 Production status of data

6: S2S operational products
7: S2S test products

Once you have a full cycle of test data (whether real-time and/or reforecast), contact  S2S support team for checking it.

Update the documentation

Models are documented in two places:

  • Models summary, which contains an overview of the latest configuration
  • A page describing in detail each model (for example, changes in ECMWF Model), where one would keep details of previous configurations, in particular the date of the change.

For changes to the configuration for the same model (increase frequency, extend reforecast, addition of parameters), a note could be added to the model page (for example, see changes in UKMO Model)