INTERNATIONAL FIELD CAMPAIGN ON SOLAR-INDUCED FLUORESCENCE SUCCESSFULLY COMPLETED
Researchers of IBG-2 have taken advantage of clear sky conditions in June and have measured solar-induced fluorescence (SIF) from the level of single leaves to the airborne scale to better understand the functional diversity of plants stress acclimation and to provide further data for the upcoming European satellite mission FLEX.
Solar-induced fluorescence (SIF) is a weak red glow that is emitted from green photosynthetic active vegetation as a byproduct of photosynthetic energy conversion. The intensity of this faint red glow changes in relation to the efficiency of actual photosynthesis and thus this red glow can be used as an indicator for the efficiency of photosynthesis. Severe environmental conditions such as drought or heat stress often cause an impairment of photosynthesis and as a consequence such environmental stresses may also be detected by changes of this fluorescence signal.
This versatile nature of SIF has triggered scientists for decades to measure this signal to gain insight into the regulatory properties of photosynthesis. Recently it also became feasible to measure this red fluorescence signal from remote platforms, such as airplanes and satellites.
Researchers at IBG-2 have pioneered this development since several years and currently the IBG-2 is operating the state-of-the art airborne sensor, which was designed to measure SIF from above. Data from this airborne sensor have been used to prepare the European Satellite mission FLEX [link: https://earth.esa.int/eogateway/missions/flex], which is currently being implemented by the European Space Agency (ESA) and which will be the first satellite mission, which measures SIF, on a high spatial resolution globally.
During this year’s field campaign a collaboration between researchers from IBG-2 have teamed up with scientists from the the Universities of Bonn, Köln, Zurich, and from the Czech Academy of Science to employ the airborne sensor HyPlant over several study sites across Germany, Switzerland and Czech Republic. On June 14 & 15 the team made use of the clear sky conditions in the region and acquired almost 100 flight lines over Campus Klein-Altendorf, the Selhausen area and from the newly established field sites of the Strukturwandel projects around Jülich. While SIF was mapped from the low-flying research aircraft several teams were measuring plant function and fluorescence on the ground to provide auxiliary data on plant function and to validate the airborne data products.
After two long and exhausting days in the sun the teams had acquired a large data set of diverse physiological and optical field data. Analysis of the data will take several weeks but after a first quality check the teams were convinced that all sensors were operational, and that the data were of high quality. We are now further evaluating and analysing the potential of solar-induced fluorescence as a novel remote sensing parameter, which shall enable us in the near future to measure actual plant photosynthesis from space and to detect early signs of environmental stress to trigger timely measures to mitigate the effects of human impact on plant primary productivity and to better manage our plant production systems in times of global change.
Further material on this topic
Article describing the airborne sensor HyPlant that is operated by IBG-2:
Overview article on solar-induced fluorescence:
Link to the research area shoot dynamics at IBG-2: Shoot Dynamics