Application of the QA4EO Guidelines to the Sentinel-2 Radiometric Uncertainty Analysis and Radiometric Uncertainty Tool
Gorrono, Javier1; Gascon, Ferran2

The launch of Sentinel-2, one of ESA's Sentinel missions, is expected in early 2014 and will cover the Land Monitoring, Emergency Response, and Security GMES services. The S2 mission will provide high-resolution optical observations over global terrestrial surfaces. The images provided will include an associated uncertainty of the pixel value. This paper presents a radiometric uncertainty analysis report (R-UAR) and a radiometric uncertainty tool (S2-RUT) for the S2 mission. The objective is to provide a tool capable of providing per-pixel absolute radiometric uncertainty values for the S2 Level-1C products (TOA reflectance/radiance). The analysis starts from the description of the S2 radiometric model and associated parameters separating the acquisition from the ground processing chain. From each of the parameters, different uncertainty contributions can be identified and characterised in order to produce a combination of all the uncertainty sources. The methodology follows the guidelines proposed by the Quality Assurance Framework for Earth Observation (QA4EO) and aims to provide a transparent and traceable radiometric uncertainty analysis for users of S2 data. The S2-RUT tool is implemented based on the uncertainty schematic and the uncertainty methodology proposed in the R-UAR report.