title: Ground-based optical measurements at European flux sites: a review of methods, instruments and current controversies.
abstract: This paper reviews the currently available optical sensors, their limitations and opportunities for deployment at Eddy Covariance (EC) sites in Europe. This review is based on the results obtained from an online survey designed and disseminated by the Co-cooperation in Science and Technology (COST) Action ESO903-"Spectral Sampling Tools for Vegetation Biophysical Parameters and Flux Measurements in Europe" that provided a complete view on spectral sampling activities carried out within the different research teams in European countries. The results have highlighted that a wide variety of optical sensors are in use at flux sites across Europe, and responses further demonstrated that users were not always fully aware of the key issues underpinning repeatability and the reproducibility of their spectral measurements. The key findings of this survey point towards the need for greater awareness of the need for standardisation and development of a common protocol of optical sampling at the European EC sites.
authors.affiliation: DIBAF-University of Tuscia, Via SC de Lellis, 01100 Viterbo, Italy. manuela.balzarolo@unitus.it
authors.forename: Manuela
authors.initials: M
authors.lastname: Balzarolo
authors.forename: Karen
authors.initials: K
authors.lastname: Anderson
authors.forename: Caroline
authors.initials: C
authors.lastname: Nichol
authors.forename: Micol
authors.initials: M
authors.lastname: Rossini
authors.forename: Loris
authors.initials: L
authors.lastname: Vescovo
authors.forename: Nicola
authors.initials: N
authors.lastname: Arriga
authors.forename: Georg
authors.initials: G
authors.lastname: Wohlfahrt
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Calvet
authors.forename: Arnaud
authors.initials: A
authors.lastname: Carrara
authors.forename: Sofia
authors.initials: S
authors.lastname: Cerasoli
authors.forename: Sergio
authors.initials: S
authors.lastname: Cogliati
authors.forename: Fabrice
authors.initials: F
authors.lastname: Daumard
authors.forename: Lars
authors.initials: L
authors.lastname: Eklundh
authors.forename: Jan A
authors.initials: JA
authors.lastname: Elbers
authors.forename: Fatih
authors.initials: F
authors.lastname: Evrendilek
authors.forename: Rebecca N
authors.initials: RN
authors.lastname: Handcock
authors.forename: Joerg
authors.initials: J
authors.lastname: Kaduk
authors.forename: Katja
authors.initials: K
authors.lastname: Klumpp
authors.forename: Bernard
authors.initials: B
authors.lastname: Longdoz
authors.forename: Giorgio
authors.initials: G
authors.lastname: Matteucci
authors.forename: Michele
authors.initials: M
authors.lastname: Meroni
authors.forename: Lenoardo
authors.initials: L
authors.lastname: Montagnani
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Ourcival
authors.forename: Enrique P
authors.initials: EP
authors.lastname: Sánchez-Cañete
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Pontailler
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Juszczak
authors.forename: Bob
authors.initials: B
authors.lastname: Scholes
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Martín
mesh_terms: D001703:Biophysics / Q000379:methods; D002138:Calibration; D002980:Climate; D057231:Climate Change; D003247:Conservation of Natural Resources; D003362:Cost-Benefit Analysis; D017753:Ecosystem; D001330:Electronic Data Processing; D004784:Environmental Monitoring / Q000379:methods*; D005060:Europe; D007391:International Cooperation; D008027:Light; D055095:Optics and Photonics; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013997:Time Factors