Photosynthesis Study – Task Descriptions
The Photosynthesis Study kicked off on July 5, 2012 and concluded on July 31, 2014.
Tasks, Milestones, and Deliverables
Seven organizations from seven countries were involved in the FLEX Photosynthesis Study, necessitating
an effective strategy for overall management and coordination of activities. The study was divided into
seven tasks and thirty-four workpackages, summarized here and detailed in the sections below.
Fourteen deliverables were scheduled. Findings from the Photosynthesis Study formed
the basis of advice and recommendations developed throughout the project, eventually culminating
in the final package assembled under Task 7.
TASK 1. Management and coordination of activities
Key aspects included in Task 1 were: establishment of a study website to provide project updates
and document sharing; overall coordination and management of the study to meet the specified
deliverables; and provision of an effective interface between the Photosynthesis Study and other
FLEX studies and campaign activities.
Further, it was important to keep the FLEX Mission Advisory Group (MAG) informed, in order to support
its advisory role to ESA in the completion of the Phase A/B1 assessments.
TASK 2. Data sets & model availability review:
Model/module assessment, comparison, and gap analysis
Task 2 generated and quality-checked a database of coupled photosynthesis-fluorescence (or
GPP-canopy fluorescence) data for model/module verification at different scales. (The database
itself contained the necessary input data to force the models/modules and the output data to calibrate and
validate the individual model components or the canopy-level model as a whole.) The database was then
used to assess individual modules and to compare alternative modules whenever possible (alternative
leaf-level A-SIF modules, for example). The exercise also developed a gap analysis,
highlighting processes not currently well-represented.
No ex-novo module development was planned for this stage.
This task also addressed interfacing of the various modules, their functionalities, and the compatibility
of the associated basic data sets. These activities resulted in the recommendation of a suitable model
design in joint agreement with Task 3 (implementation).
TASK 3. Model implementation, validation, sensitivity analysis and error quantification
Taking as inputs the modules designed and developed in Task 2, a full modular forward model was
developed and implemented in Task 3, combining the modules and sub-modules available.
Potential limitations identified in Task 2 were addressed through new module developments or revisions
of existing components, making possible the integration of modules with the corresponding interfaces.
TASK 4. Analysis of F-GPP relationships
Task 4 was to explore – by means of numerical simulations and from the results of previous field campaigns and
studies – how canopy level fluorescence as retrieved from the FLEX mission can be related to
photosynthesis in the vegetation canopy. This Task was suspended at ESA's request
before start-up and was not revived.
TASK 5. Algorithm development based on models
The objective of Task 5 was the development of a Level 2 prototype algorithm that could derive
measures of photosynthesis (represented by GPP or eventually by any other relevant parameter) from the
observations obtained from the FLEX/S3 Tandem Mission and eventual auxiliary data (if needed).
The work of this task relied heavily on the work undertaken during the previous tasks.
TASK 6. Fluorescence as an indicator of vegetation health and stress resilience
The updated database – together with consideration of applicable information from the modelling Tasks
(as they became available) – was used to forecast the strength of the novel signal to detect carbon
assimilative potential and/or vegetation stress. Conclusions were developed about the CF signal's
capacity to detect stress when the SIF is spectrally resolved. The final goal of Task 6
was to outline the potential and (subsequently) the methodological concept for using the FLEX
remotely-sensed sun-induced chlorophyll fluorescence signal as an indicator of vegetation carbon sink
capacity, health status, and stress resilience.
TASK 7. Conclusions and recommendations
This last task prepared and submitted the final deliverables to ESA. (The deliverables from
all of the previous tasks were used as inputs to create the Final Report, its Abstract,
and the Executive Summary.)
The Final Presentation, which offers an overview of all the work done in the study and its findings,
provided an opportunity to receive feedback from ESA. Submission of the
Technical Data Package – containing all science and software deliverables – completed the
contractual requirements of the PS Study.
About the FLEX Photosynthesis Study...
This study targetted the linkage between solar-induced chlorophyll fluorescence and photosynthesis
in terrestrial vegetation. A dedicated photosynthesis model based on state-of-the-art existing modules was developed
and implemented. We also developed and tested a prototype algorithm that can derive photosynthesis from FLEX tandem
mission measurements. The Photosynthesis Study was part of the package of parallel study activities needed for
assessment of the FLEX candidate mission.
For further information about the PS Study, click here.
To read or download the Final Report, click here.
To see a list of publications from the PS Study, click here.