1. Using a Simple Knowledge Organization System to facilitate Catalogue and Search for the ESA CCI Open Data Portal EGU, 21 April 2016 Antony Wilson, Victoria Bennett, Steve Donegan, Martin Juckes, Philip Kershaw, Ruth Petrie, Ag Stephens, and Alison Waterfall

2. Overview ESA CCI and the open data portal Challenge – different data sources – provide a range of search and data services Solution – Use of linked data and SKOS

3. ESA Climate Change Initiative Earth observation data 13 essential climate variables (ECVs) Multiple sources Different scientific communities Heterogeneous data

4. The Challenge Produce an Open Data Portal Establish a central repository to bring together the data from multiple sources and make them available in a consistent way, in order to maximize their dissemination amongst the international user community

5. Data Reference Syntax A data reference syntax (DRS) was developed by the Earth System Grid Federation (ESGF) to support CMIP5 – Storage and discovery of model data Concept of DRS reused for CCI, but focussing on observation data Defines a number of grouping / facets common to all observations The CCI DRS was agreed and published in a standards document http://cci.esa.int/sites/default/files/CCI_Data_Requirements_Iss1.2_Mar2015.pdf data type institute platform sensor essential climate variable (ecv) product processing level time frequency

6. data scientist adds metadata cataloguing searching standards document output data

7. Cataloguing Data are archived at the Centre for Environmental Data Analysis (CEDA) – CEDA are responsible for the cataloguing of the data Data from 13 different providers Metadata encoded in: – The file name 2 different formats – Attributes of NetCDF files

8. data scientist adds metadata validation cataloguing searching vocabulary server machine interface human interface output data standards document Vocabulary Server

9. Single point of authority of the DRS The use of SKOS to represent the DRS is well suited to deal with its complexity and variety SKOS provides: – a means to represent controlled vocabularies – a way to represent relationships between similar terms used in different ECVs – a way to easily represent hierarchies and navigation up and down hierarchies of terms Data is stored in a triple store with a SPARQL endpoint

10. http://vocab-test.ceda.ac.uk/collection/cci/sensor a skos:Collection ; skos:prefLabel "Sensor"@en ; dc:title "Sensor" ; dc:description "The sensors that have been used in the collection of the data for the ESA Climate Change Initiative (CCI)." ; dc:creator "Science and Technology Facilities Council" ; dc:date "2016-03-22" ; dc:publisher "STFC"@en ; rdfs:comment "This collection represents the sensors used by the CCI project" ; skos:member, a skos:Concept ; skos:prefLabel "MERIS"@en ; skos:definition "Medium-Spectral Resolution, Imaging Spectrometer"@en ; cci:hasPlatform. SKOS

12. searching machine interface cataloguing data scientist adds metadata human interface output data validation MOLES (ISO19156) vocabulary server machine interface ESGF Publisher OGC CSW ISO19115 records machine interface search data files CCI Open Data Portal search datasets under development

14. http://vocab-test.ceda.ac.uk/collection/cci/sensor a skos:Collection ; skos:member,

15. a skos:Concept ; skos:prefLabel "MERIS"@en ; skos:definition "Medium-Spectral Resolution, Imaging Spectrometer"@en ; cci:hasPlatform.

16. /gmd:MD_Metadata keywordUri http://vocab-test.ceda.ac.uk/collection/cci/sensor/sens_meris ' http://csw1.cems.rl.ac.uk/geonetwork-CEDA/srv/eng/csw-CEDA-CCI

17. Conclusions Vocabulary server enables central management of – Controlled vocabularies – Definitions of terms – Relationships between term, internally and externally Assists in integrating multiple services, providing richer content Reuse by CLIPC project – Make use of NERC vocabulary server

18. Acknowledgements Telespazio VEGA UK University of Reading CGI Centre for Environmental Data Analysis Scientific Computing, RAL This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 607418