D5.2 Metadata and controlled vocabularies specification for data, quality control and uncertainties
The aim of this deliverable is to describe in detail the use of metadatametadata
Information about meteorological and climatological data concerning how and when they were measured, their quality, known problems and other characteristics. and controlled vocabularies for data, quality control and uncertaintyuncertainty
Lack of precision or unpredictability of the exact value at a given moment in time. It does not usually imply lack of knowledge. Often, the future state of a process may not be predictable, such as a roll with dice, but the probability of finding it in a certain state may be well known (the probability of rolling a six is 1/6, and flipping tails with a coin is 1/2). In climate science, the dice may be loaded, and we may refer to uncertainties even with perfect knowledge of the odds. Uncertainties can be modelled statistically in terms of pdfs, extreme value theory and stochastic time series models. information within CLIPC.
Since it is the aim of the portal to provide harmonised data search across a variety of different types of climate data records (e.g. climate model simulationsclimate model simulations
these are numerical solutions of sets of equations that represent the most relevant processes describing the climate system. Climate models can be of very different levels of complexity but the most elaborated ones appear to be able to realistically reproduce the key meteorological and climatological phenomena., re-analyses and observational data) it is important that the discovery metadata is complete and fully descriptive.
Controlled vocabularies play an important role in ensuring consistency across the different communities involved with CLIPC. Where different vocabularies are required or already exist, mapping relationships between the terms will enrich the data and facilitate the harmonisation of data access.
The wide range of formal and informal conventions in the different communities providing climate data presents users with a bewildering kaleidoscope of formats.
Whilst climate model datasets produced in the Coupled Model Intercomparison Project, Phase 5 (CMIP5) conform to agreed data reference syntax (DRS) and controlled vocabularies, additional datasets considered and included in the CLIPC platform have required these DRS and vocabularies to be developed, and mapped to existing systems. Much progress has been made with the DRS, controlled vocabularies and mappings for a range CLIPC datasets, and in particular the European Space Agency (ESA) Climate ChangeClimate Change
Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use. Note that the United Nations Framework Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: 'a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods'. The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition, and climate variability attributa Initiative (CCI) data.
The metadata for uncertainties across datasets is not consistent. A case study of CCI data products is included here, and a potential way forward is proposed. Further progress on improving consistency and creating standard vocabularies for uncertainty will be made at an Uncertainties workshop in Hamburg in February 2016. It would be beneficial to include additional controlled vocabularies on the quality and commentary metadata, this work will be pursued early in 2016.
Further work is also required on the metadata, DRS and controlled vocabularies for climate impactclimate impact
See Impact Assessment indicators, for which a workshop is planned in Toulouse in February 2016 to help resolve outstanding issues.