FLEX Bridge Study – Final Report

The FLEX Bridge Study kicked off on October 1, 2014 and concluded on September 30, 2015.
Our Final Review Meeting was held at ESA Headquarters (in Noordwijk, The Netherlands) in December 2015.
The Final Report package was published and released in January 2016.

  FLEX Bridge Study Project – Final Report

2014 FLEX/Sentinel-3 Tandem Mission FLEX Bridge Study – FINAL REPORT

PMT / Gina Mohammed – 2016-01-14

Gina H. Mohammed (Study Manager), Roberto Colombo, José Moreno, Christiaan van der Tol, Uwe Rascher;  Alexander Ač, Luis Alonso, Marco Celesti, Sergio Cogliati, Alexander Damm, Dominic Fawcett, José Gomez-Dans, Claudio Henry, Philip Lewis, Natasha MacBean, Federico Magnani, Jacques Malaprade, Maria Matveeva, Julie Olejnícková, Dan Pernokis, Francisco Pinto, Sabrina Raddi, Nastassia Rajh Vilfan, Juan Pablo Rivera, Micol Rossini, Neus Sabater, Anke Schickling, Carolina Tenjo, Wout Verhoef, Jochem Verrelst, Jorge Vicent Servera;  Matthias Drusch (ESA/ESTEC Technical Officer).

Acknowledgements:  Gustau Camps-Valls, Daniel Kovác, MaPilar Cendrero Mateo, Silvia Garbari, Luis Guanter, Ari Kornfeld, Jordi Muñoz-Marí, Caroline Nichol, Cinzia Panigada, Patrick Rademske, Fabian Schneider, Giulia Tagliabue, Sebastian Wieneke, and Mat Williams;  FLEX Mission Advisory Group, including Yves Goulas, Andreas Huth, Elizabeth (Betsy) Middleton, Franco Miglietta, and Ladislav Nedbal;  ESA: Stefan Kraft, Umberto Del Bello, and Dirk Schüettemeyer.


The FB Study has advanced approaches for retrieval & applications of solar-induced fluorescence (SIF) for assessment of photosynthesis & stress status in terrestrial vegetation, including development of a calibration/validation strategy for FLEX products.  Specific advances include:  (i) optimisation of SIF retrieval algorithms, formalisation of fluorescence-derived indices, and development of biophysical products;  (ii) SIF-photosynthesis model improvements and evaluation of data assimilation techniques;  (iii) testing of stress indices, extension of the range of potential applications, and evaluation of non-photochemical protection mechanisms;  and (iv) development of calibration/validation strategies, including metrics for validation error & product accuracies, definition of FLEX Level 2/3 products and their validation plan, and definition of a common protocol and state-of-the-art instruments to be used for estimation of fluorescence in the context of cal/val activities.  This activity now forms the foundation for subsequent science & applications development during FLEX mission development & deployment.

Whereas much of the space-based SIF detection to date has focused on the far-red fluorescence – owing to the fact that the sensors were not specialised for full fluorescence retrievals – current information is incomplete and limits the ability to derive important interpretive information for identifying & tracking stress effects and also for quantification of photosynthetic rates.  Both the visible and near-infrared spectra are important for retrieval of both red and far-red fluorescence peaks, peak wavelength positions & shifts, and ancillary indices such as PRI and NDVI (or EVI).


The FULL REPORT file contains the Abstract and Executive Summary (and the latest Errata sheet if applicable), although these are also provided as separate files.  The Cover Title Page is intended only for printing a cover on cardstock, so it is not included within the main document.

To download an item, right-click the VIEW link and use your web browser's "Save As" or "Save Link As" function.


The Final Report is laid out with page parity (all sections start on an odd page), so there are alternating blank pages at the very beginning of the PDF file.

PDF file (6.97 mb) – FULL REPORTView
PDF file (482 kb) – COVER TITLE PAGE Only (for cardstock)View
PDF file (716 kb) – EXECUTIVE SUMMARYView
PDF file (372 kb) – ABSTRACTView
PDF file (363 kb) – ERRATAView

About the FLEX Bridge Study...

The goal of the FLEX Bridge Study was to optimize approaches for SIF retrievals and applications in assessment of photosynthesis and stress status in terrestrial vegetation, including development of a calibration/validation strategy for FLEX products.  The study has advanced the work of the PS Study and PARCS projects with new and additional science to address priorities identified by these previous studies and in ongoing FLEX preparatory activities.  FLEX Bridge will form the foundation of subsequent science & applications development during mission development and deployment.  The study consolidated follow-on activities leading up to the User Consultation Meeting (UCM) held in Krakow, Poland, on September 15-16, 2015.  FLEX has now been selected as ESA's new Earth Explorer 8 mission.

For further information about the FLEX Bridge Study, click here.  To see a list of publications from the study, click here.