User requirements for observation (OSCAR/Requirements)

The purpose of the Rolling Review of Requirements (RRR) process is to provide a systematic and transparent process to support the high-level design and evolution of WIGOS. The RRR process compiles information about requirements for observations, about observing system capabilities, and draws on experts and impact studies to provide guidance on the most important priorities for addressing the gaps between requirements and capabilities.

Ongoing management of the RRR process is undertaken by the WMO Commission for Observation, Infrastructure and Information Systems (INFCOM) through the Joint Expert Team on Earth Observing System Design and Evolution (JET-EOSDE), designated Earth System Application Category (ESAC) Coordinators and Application Areas (AA) Points of Contact (PoC), and supported by the WMO Secretariat staff in the Observing Networks and Measurement Division of the Infrastructure Department (More information).

This database is the official repository of requirements for the observation of geophysical variables in support of WMO Programmes and Co-sponsored Programmes. The requirements in the OSCAR/Requirements database pertain to AAs as important users of observational information, and the AAs are grouped into ESACs. Each ESAC is ‘owned’ by an identified body or expert group (Owner) representing the relevant user community. The Owner has the authority and responsibility to create, name and delete AAs in their ESAC, to nominate their PoC, for the specification of observation requirements, and for contributions to the Statements of Guidance (SoG) document. The SoGs are essentially gap analyses and include recommendation on how to address the identified gaps. The PoCs maintain the requirements in the database in collaboration with the ESAC Coordinators.

Browsing the database

To explore the database, you can use the "Quick Search" in the top right corner, when looking for a specific Variable or Application area. You can also consult the full tables accessible through the top menu, and use the filter options provided.

It is not unusual that requirements for observation of a given geophysical variable are expressed and recorded by several AAs, and that these requirements may differ. Browsing the database by ‘variable’ is therefore a supported functionality.

The database is open for consultation. Editing is only possible by designated Point of Contacts, after login.

For any questions or clarifications regarding the content of the database, please directly contact the respective Point of Contact that can be found on the Application Area page.

Note on the Uncertainty

The "uncertainty" quoted in the OSCAR/Requirement characterizes the estimated range of observation errors (Root-Mean-Square-Error - RMSE) on the given variable, with a 68% confidence interval (1 σ ). Providers of observations should interpret the RRR uncertainty requirement as bias and random error, combined in the root-mean square sense. Within the context of the Guide to Instruments and Methods of Observation (WMO-No. 8) and other related documentation, the term uncertainty is aligned to the International Vocabulary of Metrology – Basic and General Concept and Associated Terms, JCGM 200:2012, and JCGM 100:2008 GUM: Guide to the Expression of Uncertainty in Measurement. These publications define Expanded Uncertainty as a quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand, at a typical 95% confidence level. Within INFCOM this is the definition used when referring generally to uncertainty, rather than RMSE (68% confidence level) expressed here. It is important to take this difference of meaning into account when comparing similar information between OSCAR and INFCOM. It is also noted that most reputable manufacturers of instruments, also comply with the GUM, however, this needs to be checked on a case-by-case basis.

Using the database

Each requirement for an Application Area is expressed quantitatively as a specific geophysical variable to be observed, in a specific domain (vertical layer/s and horizontal coverage), with a performance level quantified in terms of up to eight criteria (attributes): uncertainty, horizontal resolution, vertical resolution, observing cycle, timeliness and stability (where appropriate) plus the two planned criteria “layer/s quality” and “coverage quality”. In addition, each requirement (for a geophysical variable) should be prioritized to indicate its relative importance for an Application Area (Application-dependent Technical Priority – ATP). Within each requirement, each criterion (attribute) should also be prioritized (Relative priority) to indicate its relative importance for the specific requirement.

For each of these criteria the table indicates 3 values determined by experts:

  • The "threshold" is the minimum requirement to be met to ensure that data are useful
  • The "goal" is an ideal requirement above which further improvements are not necessary
  • The "breakthrough" is an intermediate level between "threshold" and "goal" which, if achieved, would result in a significant improvement for the targeted application. Note that the concept of a "breakthrough" level is different to the concept of the optimum cost-benefit level, since it refers to a significant increase in the value or benefit of an observation, without reference to the costs involved.