Editing IPCC:AR6/WGI/Chapter-Atlas (section)

=== Atlas.2.3 Accessibility, Reproducibility and Reusability (FAIR Principles) ===

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The accessibility and reproducibility of scientific results have become a major concern in all scientific disciplines ( [[#Baker--2016|Baker, 2016]] ). During the design and development of the Interactive Atlas, special attention was paid to these issues in order to ensure the transparency of the products feeding into the Interactive Atlas (which are all publicly available). Accessibility is implemented in collaboration with the IPCC Data Distribution Centre (DDC), since all products underpinning the Interactive Atlas, including the intermediate products required for the indices and CIDs (monthly aggregated data), are curated and distributed by the IPCC-DDC and include full provenance information as part of their metadata. Atlas products are generated using the open-source climate4R framework ( [[#Iturbide--2019|Iturbide et al., 2019]] ) for data processing (e.g., regridding, aggregation, index calculation, bias adjustment), evaluation and quality control (when applicable). Full metadata are generated for all final products using the METACLIP framework ( [[#Bedia--2019|Bedia et al., 2019]] ), based on the Resource Description Framework (RDF) standard to describe the datasets and data-processing workflow.

In summary, a number of actions have been conducted in order to implement open access, reproducibility and reusability of results, including:

* Use of standards and open-source tools.
* Open access to raw data and derived Atlas products via the IPCC-DDC.
* Provision of full provenance metadata describing the product generation workflow.
* Access to code through an online repository ( [[#Iturbide--2021|Iturbide et al., 2021]] ), including the scripts needed for calculating the intermediate datasets and for reproducing some of the figures of the Atlas chapter.
* Provision of annotated (Jupyter) notebooks describing key elements of the code to provide guidance and facilitate reusability.

All final products visualized in the Interactive Atlas can be exported in a variety of formats, including PNG and PDF for bitmap and vector information, respectively. Moreover, in the case of the global maps, the final data underlying these products can be downloaded in NetCDF and GIS format (GeoTIFF), thus facilitating reusability of the information. Note that the images are final IPCC products (covered by the IPCC terms of use), whereas the underlying data are distributed by the IPCC-DDC under a more flexible license which facilitates reusability. Moreover, a comprehensive provenance metadata description has been generated, including all details needed for reproducibility, from the data sources to the different post-processes applied to obtain the final product. In these cases, there is also the possibility to download a PNG file augmented with attached metadata information (in JSON format). This metadata information (including the source code generating the product) can be accessed and interpreted automatically using specific JSON software/libraries. However, for the sake of simplicity, a human-readable version of the metadata is accessible directly from the Interactive Atlas, describing the key information along the workflow.

Provenance is defined as a ‘record that describes the people, institutions, entities, and activities involved in producing, influencing, or delivering a piece of data or a thing’. This information can be used to form assessments about their quality, reliability or trustworthiness. In the context of the outcomes of the Interactive Atlas, having an effective way of dealing with data provenance is a necessary condition to ensure not only the reproducibility of results, but also to build trust on the information provided. However, the relative complexity of the data and the post-processing workflows involved may prevent a proper communication of data provenance with full details for reproducibility. Therefore, a special effort was made in order to build a comprehensive provenance metadata model for the Interactive Atlas products.

Provenance frameworks are typically based on RDF (Resource Description Framework), a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model ( [[#Candan--2001|Candan et al., 2001]] ). It is an abstract model that has become a general method for conceptual description of information for the Web, using a variety of syntax notations and serialization formats. METACLIP ( [[#Bedia--2019|Bedia et al., 2019]] ) exploits RDF through specific vocabularies, written in the Web Ontology Language (OWL), describing different aspects involved in climate product generation, from the data source to the post-processing workflow, extending international standard vocabularies such as PROV-O ( [[#Moreau--2015|Moreau et al., 2015]] ). The METACLIP vocabularies are publicly available in the METACLIP repository (Bedia and Martin, 2021).

METACLIP emphasizes the delivery of ‘final products’ (understood as any piece of information that is stored in a file, such as a plot or a map) with a full semantic description of its origin and meaning attached. METACLIP ensures ‘machine readability’ through reuse of well-defined, standard metadata vocabularies, providing semantic interoperability and the possibility of developing database engines supporting advanced provenance analytics. Therefore, this framework has been adopted to generate provenance information and attach it as metadata to the products generated by the Interactive Atlas. A specific vocabulary (‘ipcc_terms’) is created alongside the inclusion of new products in the Interactive Atlas and uses the controlled vocabularies existing from CMIP and CORDEX experiments. As an example, Figure Atlas.10 shows the semantic vocabularies needed to encode the information of the typical workflow for computing (from bias-adjusted data) any of the climate indices (extreme or CIDs) included in the Interactive Atlas.

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[[File:21269b047c37dcec9b45d1d7a6944874 IPCC_AR6_WGI_Atlas_Figure_10.png]]

'''Figure Atlas.10''' '''|''' '''Schematic representation of theInteractive Atlas workflow, from database description, subsetting and data transformation to final graphical product generation (maps and plots).''' Product-dependent workflow steps are depicted with dashed borders. METACLIP specifically considers the different intermediate steps consisting of various data transformations, bias adjustment, climate index calculation and graphical product generation, providing a semantic description of each stage and the different elements involved. The different controlled vocabularies describing each stage are indicated by the colours, with gradients indicating several vocabularies involved, usually meaning that specific individual instances are defined in ‘ipcc_terms’ extending generic classes of ‘datasource’. These two vocabularies, dealing with the primary data sources have specific annotation properties linking their own features with the CMIP5, CMIP6 and CORDEX Data Reference Syntax, taking as reference their respective controlled vocabularies. All products generated by the Interactive Atlas provide a METACLIP provenance description, including a persistent link to a reproducible source code under version control.

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