NMM – Numerical Model Metadata

1. NMM – Numerical Model Metadata Loïs Steenman-Clark Katherine Bouton plus Rosalyn Hatcher Ian Henderson with help from The Curator team, PRISM, FLUME, Geniefy, and the potential METAFOR team

2. The NMM schema is largely semantic metadata • Semantic metadata is necessarily a representation of whatever content it describes. NMM therefore selects and summarises, reducing the description of numerical models to a more compact and easily manipulable form. • What purpose does semantic metadata serve ? • promote understanding • encourage interoperability • develop curation policies • enable re-use • NMM aims to serve all these purposes with semantic metadata that describes the provenance of numerical model data. NMM does not document the numerical model but the manner in which it was used to produce data. • How is semantic metadata collected? - human intervention, forms etc • - automatic tools • NMM aims to facilitate metadata collection and avoid ambiguity and inaccuracy • by providing a well defined glossary of all terms and attributes in the schema.

3. Where does this semantic metadata fit with other metadata? Ontology is ‘the specification of the conceptualisation of a knowledge domain’, i.e. how all the semantic and syntactic metadata is conceptually related. RDF, from - Data Centres - Curator - METAFOR ontology NMM:model semantic metadata gridspec PRISM: SMIOC syntactic metadata CF DATA

4. build Common Information Model Metadata take metadata schema Projects like Curator have helped refine NMM and potential projects like METAFOR (if funded) will improve the relationship between semantic and syntactic metadata METAFOR wants to link to data at different data centres develop a relational data base of semantic and syntactic metadata design harvesting tools design ‘translation’ tools to move between different metadata environments enable metadata queries

5. Because NMM metadata will be used by external agencies wanting to • present the metadata in a defined manner • exploit the metadata to derive further products, using the metadata in a relational database to facilitate enquiries • NMM aims to group the schema into logically related properties • NMM aims to relate different elements of the schema • So the NMM glossary needs • to encapsulate these abstract concepts • to be generic to apply to all Earth System Models • to be independent of the practical nature of the model work flow

6. Science Numerical Technical I/O NMM:component gridspec:tile PRISM:PMIOD Science Numerical Technical I/O NMM:component gridspec:tile PRISM:PMIOD Science Numerical Technical I/O NMM:component gridspec:tile What is the relationship between an NMM model and NMM components? gridspec:mosaic Information NMM:model PRISM:SMIOC, SCC NMM:model information properties, as well as having the usual identity information, also provides semantic metadata relating the coupling of NMM:components

7. An Earth System Modelling component could be • a stand alone, self contained model code • eg an atmosphere GCM or a radiation model • a sub - component of a component • eg a chemistry scheme or an sea ice parameterisation • a data set • eg atmospheric fields derived from ERA40 • A NMM component is a semantic concept, not necessarily a code or • framework or workflow concept. How does this concept fit with the reality of Earth System Modelling? Is this a problem for metadata harvesting?

8. What is an NMM component with respect to IPCC AR4 models? Q can the NMM glossary definition explain this?

9. NMM GLOSSARY NMM: Component A component of a modelled system is any subsection of the numerical model. The level of granularity of this subsection can be variable however in an Earth System Modelling context it is expected that a component has sufficient functionality to enable it to be coupled to one or many other components. NMM component therefore contains both semantic and syntactic metadata with technical, numerical, science and input/output property groups. Examples of NMM components could be an Earth System Modelling coupler or a stand-alone radiation model or an atmospheric general circulation model code. NMM: Model A model is a numerical representation of the system being modelled made up of one or more components which may be coupled together. NMM model therefore contains the information properties pertaining to the inclusion of NMM components and the coupling of these components. An example of a model might be a dynamical core component coupled to an atmospheric physics package component and a radiation model component to form an atmospheric model. Another example for Earth System Modelling might be an atmospheric model component coupled with a coupling component to an ocean model component.

10. What is the relationship between an NMM application and NMM models? NMM:application Information NMM:model information properties, as well as having descriptive information, also provides semantic metadata describing the relationship of the NMM:models NMM:model CF:data There could be many different NMM:applications for the same group of NMM:models and the data they produce NMM:model CF:data NMM:model CF:data

11. What is an NMM application with respect to IPCC AR4? NMM:application IPCC Scenarios Models Ensemble CF: Data Q can the NMM glossary definition explain this?

12. NMM GLOSSARY NMM: Application An application of a modelled system is a grouping of different instances of a model. NMM application therefore contains the information properties of the model instances and their relationship. An example of an application could be an ensemble of seasonal forecast model runs where the model instances differ only in variations of the input to the model components. Another example of an application would be the IPCC AR4 set of modelling experiments where different models had a set of model instances where the relationship between those instances were determined by the IPCC scenarios.

13. Semantic metadata is about information gathering • Glossary terms must therefore • be understandable by the community using the metadata schema • (do we need more community discussion as with CF standard names?) • be meaningful for building tools to harvest metadata within workflows and frameworks • (we need different examples of these tools to measure this) • continue to be meaningful as modelling develops so it should be relevant for IPCC AR5 • (how possible is this?) • be clear, accurate and up-to-date with the schema version • (implement mechanisms to manage and maintain this) • NMM will use SKOS (Simple Knowledge Organization System) to embed • the NMM glossary definitions into the NMM schema. • be understandable outside the producer/user community • (ontologies!!!)