The Valencia Anchor Station: 20 Years of Uninterrupted Scientific Activity on Validation of Low and Middle Resolution Earth Observation Remote Sensing Data and Products
Authors: Lopez-Baeza Ernesto , Garcia Rodriguez David , Albero Peralta Erika , Garcia-Celda Antonio , Asensi Ortega Victor , Catalan Alcober Domingo J. , Martinez Dura Juan J. 
Published: March 2022

&lt;p&gt;The &lt;em&gt;Valencia Anchor Station&lt;/em&gt; (VAS) was set up by the &lt;em&gt;University of Valencia&lt;/em&gt; at the very end of the year 2001 starting its operations on 1st January 2002. Since then, uninterruptedly, the &lt;em&gt;Climatology from Satellites Group&lt;/em&gt; (GCS) has developed a constant activity addressed to the difficult task of characterising an area sufficiently large as to also serve as a reference site for the scientific validation of current low and middle spatial resolution remote sensing instruments onboard the missions NASA CERES (&lt;em&gt;Clouds and the Earth&amp;#8217;s Radiant Energy System&lt;/em&gt;) and SMAP (&lt;em&gt;Soil Moisture Active and Passive&lt;/em&gt;), EUMETSAT GERB (&lt;em&gt;Geostationary Earth Radiation Budget&lt;/em&gt;), ESA SMOS (&lt;em&gt;Soil Moisture and Ocean Salinity&lt;/em&gt;), ESA-EUMETSAT EPS (&lt;em&gt;EUMETSAT Polar System&lt;/em&gt;) MetOp, EC-ESA Copernicus Sentinel-1, -2, -3 and is getting ready for the now close ESA-JAXA EarthCARE (&lt;em&gt;Earth Clouds, Aerosols and Radiation Explorer&lt;/em&gt;) launch and for the current GNSS-R, -iR terrestrial applications from the Galileo, BeiDou, GPS and GLONASS constellations. All these instruments have in common their middle/large footprint sizes for which a sufficiently large validation area up to about 50 x 50 km2 needs to be robustly equipped and fully characterised from different viewpoints such as soils, vegetation, atmospheric parameters, etc. This presentation shows the fundamentals of the methodologies used for the validation of surface radiation, soil moisture and biophysical vegetation parameters, and a brief summary of the field campaigns developed for the characterisation of the site in the context of the models used and some of the achievements so far obtained. Detailed account of the validation exercises for the different parameters under consideration is also given in different sessions of this EGU 22 Assembly. The paper also emphasises the role of the distributed soil measurements carried out over a large vineyard field in relation to the rest of significant parameters from a dense FAPAR (Fraction of Absorbed Photosynthetically Active Radiation) network and from an eddy-covariance station, together with the complete surface radiation network and land surface and atmospheric temperatures, also provided by the VAS. It is worth noting the role of the collaborative interdisciplinary international teams associated to the &lt;em&gt;Climatology from Satellites Group&lt;/em&gt; in the framework of the different Missions and Agencies above mentioned, the qualitative upgrading of the VAS as a GBOV (&lt;em&gt;Ground-Based Observations for the Validation of Copernicus Land Products&lt;/em&gt;) supersite and its future prospects by incorporating artificial intelligence and data semantics techniques. The VAS is currently jointly run by LISITT (&lt;em&gt;Integrated Laboratory of Intelligent Systems and Technologies of Traffic Information&lt;/em&gt;), a research and development group integrated into the IRTIC (&lt;em&gt;Research Institute on Robotics and Information and Communication Technologies&lt;/em&gt;) and by UV-ERS (&lt;em&gt;Environmental Remote Sensing Group&lt;/em&gt;) of the Faculty of Physics, both from the University of Valencia. This guarantees the envisaged new developments planned for the VAS to offer data and products in an optimum user-friendly format by using artificial intelligence and data semantics methods.&lt;/p&gt;