Context and objectives
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
Expected scientific results
The most important scientific deliverables will be:
- 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.
- 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.
Due to the basic science the project, potential users rise mainly from the research and engineering communities, and include the hydrologists (e.g., water research and agriculture research institutes), climate and biogeochemistry scientists (e.g. science contributors to the IPCC), ecologists, or satellite remote sensing experts.
|Project leader(s):||UGent - Laboratory of Hydrology and water management (LHWM)|