G5.10

G5.10    Characterisation of different types of uncertainty has not been systematically addressed per ECV, e.g., for some ECVs a full measurement uncertainty chain has been established, but smoothing uncertainty has not been considered or vice versa. This prevents and potentially delays inclusion of various instrument/ECV combinations into the Virtual Observatory.

Gap detailed description

The development work of the Virtual Observatory was addressing the selection of reference data, available uncertainty estimates (measurements and smoothing) and the satellite data that shall be characterized. This exercise revealed that certain different types of uncertainty are not addressed systematically resulting in some cases in reference measurements that have quantified uncertainty but for which no means exist to address smoothing uncertainties and vice-versa. This leads to delays in integrating the full QA and validation chain into the Virtual Observatory. It can be expected that for other ECVs in atmospheric but also oceanic and terrestrial domains similar issues exist.

Activities within GAIA-CLIM related to this gap

For the ECVs dealt within GAIA-CLIM this issue is mitigated by focussing on a specific set of non-satellite reference measurements and satellite products and working out the full chain for them.

Gap remedy(s)

Gap remedy at full scale of the problem would be to assess for each GCOS ECV what elements of the uncertainty budget are quantified for pairs of reference measurements and satellite measurements/products and how the missing elements can be achieved. For the ECVs considered in GAIA-CLIM this has been completed.

Remedy #1

Specific remedy proposed

For the full scale problem international bodies such as the CEOS Cal/Val and WG Climate and the GCOS Secretariat should be involved to assess the status throughout the domains and to report to WMO and agency principals about the resulting issues. For the CEOS WG Climate cycles of updating ECV climate data record Inventories could be used to assess the quality of the validation activities in more depth than has been the case to date.

Measurable outcome of success

Knowledge of the status of uncertainty budget estimates for all GCOS ECVs.

Achievable outcomes

Technological viability: High

Organizational viability: medium to low

Indicative cost estimate: Low (<1 million)

Relevance

Implementing the proposed remedy would help to create awareness of the issue and if successful to make the use of more reference measurements and satellite products possible in a Virtual Observatory setting.

Timebound

Status assessment would take approximately 5 years including finding international acceptance for the action and executing it technically.

Remedy #2

For the establishment of the Virtual Observatory a systematic assessment of the considered ECVs is needed (and has partially been done) with respect to the available uncertainty budget elements.  In order to find practical solutions it needs to be considered what is the practical importance of smoothing uncertainty for different ECVs (having variability at different space time scales) in addition of different parts of the electromagnetic spectrum. For instance, smoothing uncertainty is of large importance in the visible spectrum but may be of negligible size in the microwave spectrum.

Measurable outcome of success

Successful implementation of the complete QA and validation chains in the Virtual Observatory.

Achievable outcomes

Technological viability: High

Indicative cost estimate: Low (<1 million)

Relevance

The remedy proposed here is in full agreement with the project plan of GAIA-CLIM and is key to success.

Timebound

The remedy proposed here is part of deliverables of GAIA-CLIM WP5 due (D5.3, D5.4 and D5.5) in months 24, 30 and 33, respectively.

Gap risks to non-resolution

 

Identified future risk / impact

Probability of occurrence if gap not remedied

Downstream impacts on ability to deliver high quality services to science / industry / society

If no assessment of the status of uncertainty budgets for ECVs would be undertaken uncertainties would continue not to be systematically addressed.

Medium

Continued uncertainty about the quality of satellite products for many ECVs used in service relevant applications.

If the implementation in the VO is failing the concept would need to be revisited.

Low

Satellite products used in science and services will have only limited characterisation of uncertainty in

 

Work package: 
WP6