Institute of Bio- and Geosciences (IBG)

Plant Sciences (IBG-2)

FLOX Systems

FLOX systems are used to measure top-of-canopy reflectance and solar-induced fluorescence (SIF) using high-performance spectrometers

The FLOX was developed by the IBG-2: Plant Sciences of the Jülich Research Center and the Remote Sensing of Environmental Dynamics Laboratory of the University Milano-Bicocca. In 2015, two members of the partners founded the new start-up company JB Hyperspectral http://jb-hyperspectral.com/wordpress/. The commercial versions of the FLOX Boxes are distributed by this young start-up company.
FLOX is measuring the sun-induced chlorophyll fluorescence (SIF) of plant canopies as a measure of plant photosynthetic capacity under natural light conditions. A QEPro spectrometer from Ocean Optics covering the Red/Near Infrared region (650 – 800 nm) measures chlorophyll fluorescence of plant canopies in the wavelength region of the two atmospheric oxygen absorption bands, O2B and O2A (689 nm and 760 nm, respectively), with a high spectral resolution. SIF of plant canopies can be constantly monitored by the comparison of sequential measurements of light reflected and emitted from the plant canopy using a downward fiberoptics and solar irradiance using an upward directed reference fiberoptics. The spectrometers are embedded in a temperature controlled housing to maintain a stable level of dark current of the spectrometers. An accurate automatic optimization of the measurement duration of both channels to prevailing light conditions is applied to maximize the signal-to-noise ratio and minimize acquisition time. Thereby, FLOX can be used to constantly monitor SIF under changing environmental conditions.

The Shoot group at IBG-2 currently operates 5 FLox systems, some of which are used as stationary systems to continuously record solar-induced fluorescence (SIF) and hyperspectral reflectance from selected study sites and which thus produce time-series of vegetation functioning over the season. Other FLOX systems ae integrated in sensor positioning platforms and are operated within various projects to measure SIF and vegetation reflectance across experimental field systems. One FLOX system ist currently being modified in cooperatin with the manufacturer to be mounted on a UAV platform to enable SIF measurements from low flying plattforms.

Additionally, we are operating 2 ROX systems, which are smaller versions consisting of only one spectrometer. The ROX systems measure canopy reflectance but cannot be used to retrieve solar-induced fluorescence. The ROX systems are used as small weight field spectrometers to record canopy and leaf reflectance.

FLOX and ROX can be combined with the leaf-clip FluoWAT, which is a custom made leaf clip to measure leaf-reflecance and transmittance as well as upwelling and down-welling solar induced fluorescence from single leaves in the field.

Publications

Naethe P., Julitta T., Chang C.Y.-Y., Burkart A., Migliavacca M., Guanter L. & Rascher U. (2022) A precise method unaffected by atmospheric reabsorption for ground-based retrieval of red and far-red sun-induced chlorophyll fluorescence. Agricultural and Forest Meteorology, 325, article no. 109152, doi: 10.1016/j.agrformet.2022.109152.

§ Wieneke S., Burkart A., Cendrero-Mateo M.P., Julitta T., Rossini M., Schickling A., Schmidt M. & Rascher U. (2018) Linking photosynthesis and sun-induced fluorescence at sub-daily to seasonal scales. Remote Sensing of Environment, 219, 247-258, doi: 10.1016/j.rse.2018.10.019.

§ Buman B. Hueni A., Colombo R., Cogliati S., Celesti M., Julitta T., Burkhardt A., Siegmann B., Rascher U., Drusch M. & Damm A. (2022) Towards consistent uncertainty assessments of in situ radiometric measurements for the validation of fluorescence satellite missions. Remote Sensing of Environment, 274, article no. 112984, doi: 10.1016/j.rse.2022.112984.

Martini D., Sakowska K., Wohlfahrt G., Pacheco-Labrador J., van der Tol C., Porcar-Castell A., Magney T.S., Carrara A., Colombo R., El-Madanay T., González-Cascón R., Martin M.P., Julitta T., Moreno G., Rascher U., Reichstein M., Rossini M. & Migliavacca M. (2022) Heat-wave breaks down the linearity between sun-induced fluorescence and gross primary production. New Phytologist, 233, 2415-2428; doi: 10.1111/nph.17920.

§ Acebron K., Matsubara S., Jedmowski C., Emin D., Muller O. & Rascher U. (2021) Diurnal dynamics of non-photochemical quenching in Arabidopsis npq mutants assessed by solar-induced fluorescence and reflectance measurements in the field. New Phytologist, 229, 2104-2119, doi: 10.1111/nph.16984.

§ Quirós-Vargas J., Bendig J., Mac Arthur A., Burkart A., Julitta T., Maseyk K., Thomas R., Siegmann B., Rossini M., Celesti M., Schüttemeyer D., Kraska T., Muller O. & Rascher U. (2020) Unmanned Aerial Systems (UAS)-based methods for Solar Induced Chlorophyll Fluorescence (SIF) retrieval with non-imaging spectrometers: State of the art. Remote Sensing, 12, article no. 1624, doi: 10.3390/rs12101624.

Links

The FLOX systems were originally developed by Shoot Dynamic and are now produced and marketed by JB Hyperspectral, which is an established start-up company of former PhD students from IBG-2 and the University of Milano-Biccoca.

The FLOX system is nowadays used worldwide to record the dynamics of solar-induced fluorescence. Additionally, the FLOX systems will be used as reference stations for the upcoming FLEX satellite mission of the European Space Agency (ESA).

Contact

Prof. Dr. Uwe Rascher

Institute of Bio- and Geosciences (IBG)
Plant Sciences (IBG-2)

Building 06.2 /
Room 406b

+49 2461/61-2638

E-Mail

Kevin Warstat

Institute of Bio- and Geosciences (IBG)
Plant Sciences (IBG-2)

Building 06.2 /
Room 421

+49 2461/61-9858

E-Mail

Last Modified: 30.01.2023