Remedy 1: Operationalisation of a satellite – non-satellite matchups facility with appropriate discovery and user tools

The Virtual Observatory contains a still rudimentary data extraction capability that allows the export of co-located data from it in user-friendly, self-descriptive NetCDF format. The format also allows comparison data being amended by meta-data of the comparison, e.g., the used co-location criteria, etc., but this has not been realised within the lifetime of the GAIA-CLIM project. Such a format also supports analysis of the data in ways that may not be enabled, at least initially, in the final demonstrator version of the Virtual Observatory. Data extraction tools also are capable of sub-setting each data source contained in the co-location data base by ECV, time and location, observing system, and other boundary conditions such as surface type.

To exploit the co-location data base proposed as remedy 2 for gap G5.01, analysis tools must be developed to provide statistics and various indicators for a comparison that meet user needs as indicated by the GAIA-CLIM user survey outcomes. These analysis tools must have some flexibility, such as interchanging the reference in a comparison and the ability to perform analysis at different time and eventually space scales.

Visualisation tools need to be capable of displaying multiple co-located parameters to circumvent the complexity of comparing datasets of varying type and geometries, e.g. time series and instantaneous, spatially localised and large spatial extent observations, column-integrated observations, and vertical profiles, etc. Special attention must be paid to the specification of graphical representation of individual parameters and various uncertainty measures, including the smoothing uncertainty.

Tool development should look to benefit from existing elements and capabilities whenever possible. All developed tools need to be accessible via a GUI that also needs to be developed. GAIA-CLIM has developed a demonstrator facility with a limited number of static examples. Further development and operationalisation of the facility would be required to enable reliable near-real-time and delayed mode exploitation for a broader range of satellite instruments and ECVs.