Ground-based optical measurements at European flux sites: A review of methods, instruments and current controversies

M. Balzarolo (1) , K. Anderson (2) , C. Nichol (3) , M. Rossini (4) , L. Vescovo (5) , N. Arriga (1) , G. Wohlfahrt (6) , J.-C. Calvet (7) , A. Carrara (8) , S. Cerasoli (9) , S. Cogliati (4) , Fabrice Daumard (10) , L. Eklundh (11) , J.A. Elbers (12) , F. Evrendilek (13) , R.N. Handcock (14) , J. Kaduk (15) , K. Klumpp (16) , B. Longdoz (17) , G. Matteucci (18) , M. Meroni (4, 19) , L. Montagnani (20, 21) , J.-M. Ourcival (22) , E.P. Sánchez-Cañete (23) , J.-Y. Pontailler (24) , R. Juszczak (25) , B. Scholes (26) , M. Pilar Martín (27)

1 DIBAF, University of Tuscia, Via S.C. de Lellis, 01100 Viterbo, Italy
2 University of Exeter
3 School of Geosciences [Edinburgh]
4 UNIMIB - Università degli Studi di Milano-Bicocca = University of Milano-Bicocca
5 CRI, Fondazione E. Mach, Viote del Monte Bondone, Trento, Italy
6 Universität Innsbruck [Innsbruck]
7 CNRM - Centre national de recherches météorologiques
8 Fundacion CEAM, Parque Tecnologico, Calle C.R. Darwin, Paterna, SP-46980, Valencia, Spain
9 Forest Research Centre, School of Agriculture, Technical University of Lisbon, Tapada da Ajuda, 1349-017, Lisboa, Portugal
10 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
11 Department of Earth and Ecosystem Sciences [Lund]
12 Alterra, ESS-CC Group, PO Box 47, 6700 AA Wageningen, Netherlands
13 Department of Environmental Engineering, Abant Izzet Baysal University, Gölköy Campus, 14280 Bolu, Turkey
14 CSIRO, Private Bag 5, Wembley, WA, 6913, Australia
15 Department of Geography [Leicester]
16 UREP - Unité de recherche sur l'Ecosystème Prairial
17 EEF - Ecologie et Ecophysiologie Forestières [devient SILVA en 2018]
18 CNR, Institute for Agricultural and Forestry Systems in the Mediterranean, Via Cavour, 4-6 I-87036, Rende, Italy
19 IES - JRC Institute for Environment and Sustainability
20 Forest Services and Agency for the Environment, Autonomous Province of Bolzano, Bolzano, Italy
21 Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
22 CEFE - Centre d’Ecologie Fonctionnelle et Evolutive
23 IAA - Instituto de Astrofísica de Andalucía
24 Laboratoire d'Ecologie Végétale, Université Paris Sud-Orsay, CNRS URA 1492 Bât. 362, 91405 Orsay Cedex, France
25 Dept. of Meteorology, Poznan University of Life Sciences, Piatkowska 94, 60-649 Poznan, Poland
26 CSIR - Council for Scientific and Industrial Research [Pretoria]
27 CCHS - Centro de Ciencias Humanas y Sociales

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 ofoptical 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. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Mots clés: european flux networks; protocol standardization; optical measurements; spectral reflectance; photosynthetic efficiency; ndvi measurements; resolution ndvi; carbon dioxide; ecosystem; validation

Mots clés: sensors; vegetation indexes; co2 fluxes; calibration

Domaines: Sciences de la Terre; Optique [physics.optics]

M. Balzarolo, K. Anderson, C. Nichol, M. Rossini, L. Vescovo, et al.. Ground-based optical measurements at European flux sites: A review of methods, instruments and current controversies. Sensors, 2011, 11 (8), pp.7954-7981. ⟨10.3390/s110807954⟩. ⟨hal-01134125⟩