THE EO CALVAL PORTAL Goryl, Philippe (1) ; Brockmann, Carsten (2) , Block, Thomas (2) ; Riazanoff, Serge (3) ; Santer, Richard (4) (1) ESRIN, Via Galileo Galilei, 00044 Frascati, Italy; philippe.goryl@esa.int (2) Brockmann Consult, Max-Plankc-Str.2, 21502 Geesthacht, Germany, tom.block@brockmann-consult.de (3) Visio Terra, 7 rue Galilée, 75116 Paris, France, Serge.Riazanoff@visioterra.com (4) LISE Université du Littoral Côte d'Opale, 32 Avenue Foch, Wimereux, F62930, France, santer@univ-littoral.fr ABSTRACT The exploitation of Earth Observation data depends with increasing importance on multi-source intercalibrated data, as demonstrated, for example, in the ESA DUE GlobColour project. The subgroup on Calibration and Validation of the Committee on Earth Observing System (CEOS) formulated a recommendation during the plenary session held in China at the end of 2004, with the goal of setting-up and operating an internet based system to provide sensor data, protocols and guidelines for the purposes of efficiently supporting senor calibration, intercalibration and product validation. ESA has taken the initiative and launched the version 1.0 of the CalVal Portal in October 2006. This version is providing EO data from MERIS, AATSR, PRISM and AVNIR2 over internationally agreed diagnostic sites together with selected radiometric in-situ data. A methodology for calibration of optical and infrared sensors is described in detail and tools are made available to apply it. The supported sensors are described in SensorML language (SensorML 2004), a standard implemented in XML to technically describe measurement instruments. All elements are inter-coordinated to provide a complete and complementary set of information and tools. The upcoming version 2 of the CalVal Portal will include the functionality and data which have been provided by the WGISS Test Facility, operated by USGS until autumn 2006. 1. 1. 1. 1. INTRODUCTION The CEOS Working Group on Calibration and Validation has recommended to “initiate an activity to document a reference methodology to predict top of atmosphere radiance for which currently flying and planned wide swath sensors can be intercompared … Also create and maintain a fully accessible Web page containing … links to all instrument characteristics needed for intercomparisons as specified above, ideally in a common format. In addition, create and maintain a database … of instrument data for specific vicarious calibration sites in a common format. Each agency is responsible for providing data for their instruments in this common format.” [CEOS working group on Calibration and Validation, 18 th plenary meeting, Beijing, November 2004. Doc No 12.1]. This recommendation fits to the importance that calibration, sensor intercomparison and validation has in the context of GMES, which will be Europe’s contribution to a better coordinated Global Earth Observing System (GEOS). GMES relies on EO data access, interoperability, long-term data preservation, and definition of standards. Applications in the GMES context are based on multi sources data and can be addressed only if the calibration and validation process is well defined and controlled through common standards. GMES requires fusion of similar sensor data to guarantee the sustainability of the services. The EO CalValPortal is needed to ease and strengthen the calibration process and therefore will increase the comparability of similar instrument’s data, helping top match the above key GMES objectives. 2. 2. 2. 2. EO CalVal Portal Project In summer 2004 the European Space Agency took the initiative to launch the development of a Web Portal which will accomplish the CEOS-WGCV requirement. Version 1 of the Portal has been released October 2006 and is at a point where many of the CEOS requirements are implemented in software, where calibration methods are documented and a general understanding in supporting sensor calibration could be gained. The Portal includes description of methodologies for calibration, sensor intercalibration and validation. Version 2 is currently under development and will be completed by the end of 2007. It will include US sensors currently part of the WGIS test facility, address non IVOS sensors and support validation activities. 2.1. 2.1. 2.1. 2.1. Project elements The project includes studies to collect user requirements, to define reference methodologies for sensor calibration and intercalibration, to compile sensor technical data and to design and implement the Web Portal software. The Portal includes • Description of methodologies for o Calibration o Sensor intercalibration o Validation _____________________________________________________ Proc. ‘Envisat Symposium 2007’, Montreux, Switzerland 23–27 April 2007 (ESA SP-636, July 2007)