Special issue  

The main objective of the COST Action ES0903 "EUROSPEC" is to develop common protocols and new instruments within a larger European network for optical measurements, bringing together scientists and industries in order to increase the reliability, value and cost-efficiency of the existing spectral observations within the European flux network. In the last 3 years, the Action has focused on proximal sensing, which can be considered a fundamental tool in monitoring Biophysical Parameters and which acts as a "bridge" between the flux tower and the remote sensing community. In fact, the EUROSPEC activities actively involved researchers from the FLUXNET, SPECNET, ICOS, ABBA networks.

Four Working Groups have been active within EUROSPEC, organizing meetings, field campaigns, experiments and summer schools:

• WG1 focused on the state of the art of the optical sampling network, database issues and building a common platform for storing, sharing, visualizing spectral data.
• WG2 on instrument intercomparison, characterisation, standardisation, intercalibration and measurement protocol issues.
• WG3 dealing with upgrading instruments for continuous measurements at the Eddy Covariance towers.
• WG4 focused on scaling Biophysical Parameters and fluxes from the ecosystem at upper levels.