Numerical Simulation Discovery Metadata (aka NumSim)

The DIF? describes datasets at the discovery level, but where simulations are involved, discovery metadata needs more information than is available in the existing schema.

A new schema which is being trialled at the British Atmospheric Data Centre can be found here(xsd). The proposed schema should be accessible to both DIF? and ISO19115? parent discovery schema (as it evolves), although at the moment it's rather standalone.

The schema is documented primarily through the schema itself, but there is fairly comprehensive documentation in the documentation directory - although note that it tends to lag the schema by a bit - especially the pdf version.

See also example files: HiGEM control and HadCM3 Beowulf 500 year run.

Comments are welcome! Please note that this version has only just started to be trialled with data, so some changes are inevitable as described below.

You can either annotate this page, or join the mailing list at (mail the list at climate-model-doc@…). Or email bryan lawrence directly.

See also the  Numerical Model Metadata project which is aimed at producing a more complete set of numerical model metadata, albeit in a way probably more conducive to automatic production. However, we do plan convergence of these two projects, probably so that NumSim becomes a complete subset of NMM.


Two sets of email feedback on V005 have been received, and are documented on the NumSimFeedback page, and V00800 is now the current release following the Metadata meeting in Exeter. (NB: this is a pre-release of the official 0.8 version)

More responses welcome.

Technical Issues



  • Split into codebase and experiment between 006 and 007
  • See NumSim05to06 Changes.

Planned Changes

The outstanding tasks for milestone releases are listed below by milestone. However, note that not all the tickets listed below will definitely be done, you should look at the ticket status to be sure of what we currently are confirmed to do for each milestone.


More testing with major numerical model datasets held at BADC, including ECMWF and the operational NWP version of the UM (to be compared with the HiGEM version).

Convergence with  Numerical Model Metadata. What we want to be able to do is generate NumSim entries from NMM descriptions.

Complete ISO19139 compliance as an extension to the WMO core profile.

No results

NumSim related tasks against other NDG major milestones

No results

Other Issues

Generally these are things that might be issues, that are not raised as tickets against any milestone (yet).


  1. We could support individual members of the climate prediction ensembles by adding to the model element an optional <perturbed> element which could be a list made up of arg param pairs. These would appear in ensemble member descriptions but not in grand ensemble descriptions. The usual issue of what level in the D heirarchy should be exposed to the wider world will arise.
  2. Should we have the initial conditions as attributes (subelements) of the Model rather than as attributes of the simulation. This would help in some regards, but might break the future ability to inherit model descriptions ... Note that Response 2.4 is unkeen on this. This wont happen as originally concieved since we have split the description up into codebase and experiment ...


  1. Following response 2.3. Given that model has another understanding, in for example, geology, should we use a different word for model, e.g.: simulator?
  2. Should we suck any pages we link to down into the archive as copies? (This is a curation issue).