Vegetation stress from satellite observations of fluorescence (STR3S)

Start-End 01/12/2015 -  31/12/2017
Programme STEREO 3
Contract SR/02/329
Objective May vegetation stress be derived from satellite observations? Because the temperature of vegetation should increase with stress, various efforts have been made to estimate this stress from infrared land-surface temperature; however, the use of temperature as an indirect diagnostic has often been deemed impractical. Yet, satellites may already be measuring a closer proxy of vegetation stress, namely chlorophyll fluorescence. Recent use of these data has focussed on deriving primary productivity. Here we propose to exploit its potential for the derivation of vegetation stress and transpiration. GLEAM (www.gleam.eu), a simple land surface model running on satellite data, will be applied for this purpose. 

The project has two core objectives:

- To explore the satellite fluorescence signal and its potential to capture the dynamics of vegetation stress
- To gain understanding into the variability of global transpiration
Method WP1–2 deal exclusively with the management, coordination, assessment of end-user requirements, and dissemination of results, WP3 and WP4 comprise the core of the analyses.

WP3 – Exploration: This phase comprises a series of in situ validation experiments of the GOME-2, OCO-2 and TROPOMI fluorescence data, and comparisons to satellite datasets of related variables (NDVI, fAPAR, VOD, soil moisture, surface temperature) with the goal of forming a vegetation stress dataset.

WP4 – Application: This phase concentrates on the incorporation of the new stress data into GLEAM in order to study the value of fluo¬rescence observations in constraining modelled transpiration fluxes.
Result EXPECTED SCIENTIFIC RESULTS

The most important scientific deliverables will be:

1.    A dataset of vegetation stress based on fluorescence observations, including validation statistics and information on the uncertainty and quality of the satellite-based fluorescence signal rom different sensors. This will be the main scientific output of WP3 and it is scheduled for April 2017.
2.    A dataset of global transpiration, which will be based on the incorporation of our fluorescence-based stress factor into GLEAM. This will be the main scientific output of WP4 and it is scheduled for March 2018.

EXPECTED PRODUCTS AND SERVICES

Our results on the effects of vegetation stress on the Earth's climate will be highly relevant to the atmospheric and hydrological science communities. We will also ensure that our findings on fluorescence retrievals connect to the activities of ESA in preparation for the FLEX mission, using our ongoing ESA projects as a platform.


Website link
Team
Team Member: GENTINE Pierre Columbia University - Department of Earth and Environmental Engineering
Team Member: DORIGO Wouter Vienna University of Technology - GEO Department
Coordinator: MIRALLES Diego Ugent (Universiteit Gent)
Coordinator: VERHOEST Nico Ugent (Universiteit Gent)
Team Member: STEPPE Kathy Ugent (Universiteit Gent)
Location
Sensors used
Applications
Related presentations BEODay 2016 - 21. STR3S: Can satellite-observed fluorescence be used to map transpiration?
Related publications STR3S - La fluorescence comme indicateur de stress de la végétation
Datasets used