Conformity testing of satellite-derived quantitative surface variables

Reliable compliance information of quantitative Earth Observation products is a prerequisite for the usage of satellite-derived evidence in 1) regulatory initiatives dealing with climate and environment-relevant matters (among others), and 2) liability debates between customers and providers of value-added (quantitative) EO products. In this contribution the quality objectives compiled by the Global Climate Observing System (GCOS) for a series of biophysical essential climate variables (ECVs) are investigated from the point of view of conformity testing as used in legal metrology. Unlike current validation efforts, conformity testing requires that the maximum permissible uncertainty of the candidate and reference ECV estimates does not exceed a predefined fraction of the applicable tolerance interval. Given that the GCOS accuracy criterion is defined with respect to a local reference it is the uncertainty of both the in situ and the satellite ECV estimates that matter. Our findings suggest that, 1) current GCOS quality objectives must be complemented before they may serve as quality requirements for conformity testing, 2) a consensus on the choice of decision rule must be sought (between data providers and users) since this has a direct impact on what is deemed compliant, and 3) the uncertainty associated with current field validation methods for biophysical ECVs is unlikely to meet the ISO-13528 criteria. The latter thus challenges the eligibility of current field validation methods to provide the reference needed in efforts assessing the GCOS conformity of third party datasets.

WIDLOWSKI Jean-Luc; 

2016-01-08

ELSEVIER SCI LTD

JRC94548

1462-9011,   

http://www.sciencedirect.com/science/article/pii/S1462901115000672,    https://publications.jrc.ec.europa.eu/repository/handle/JRC94548,   

10.1016/j.envsci.2015.03.018,