CEFLES2: the remote sensing component to quantify photosynthetic efficiency from the leaf to the region by measuring sun-induced fluorescence in the oxygen absorption bands

Abstract

Abstract. The CEFLES2 campaign during the Carbo Europe Regional Experiment Strategy was designed to provide simultaneous airborne measurements of solar induced fluorescence and CO2 fluxes. It was combined with extensive ground-based quantification of leaf- and canopy-level processes in support of ESA's Candidate Earth Explorer Mission of the "Fluorescence Explorer" (FLEX). The aim of this campaign was to test if fluorescence signal detected from an airborne platform can be used to improve estimates of plant mediated exchange on the mesoscale. Canopy fluorescence was quantified from four airborne platforms using a combination of novel sensors: (i) the prototype airborne sensor AirFLEX quantified fluorescence in the oxygen A and B bands, (ii) a hyperspectral spectrometer (ASD) measured reflectance along transects during 12 day courses, (iii) spatially high resolution georeferenced hyperspectral data cubes containing the whole optical spectrum and the thermal region were gathered with an AHS sensor, and (iv) the first employment of the high performance imaging spectrometer HYPER delivered spatially explicit and multi-temporal transects across the whole region. During three measurement periods in April, June and September 2007 structural, functional and radiometric characteristics of more than 20 different vegetation types in the Les Landes region, Southwest France, were extensively characterized on the ground. The campaign concept focussed especially on quantifying plant mediated exchange processes (photosynthetic electron transport, CO2 uptake, evapotranspiration) and fluorescence emission. The comparison between passive sun-induced fluorescence and active laser-induced fluorescence was performed on a corn canopy in the daily cycle and under desiccation stress. Both techniques show good agreement in detecting stress induced fluorescence change at the 760 nm band. On the large scale, airborne and ground-level measurements of fluorescence were compared on several vegetation types supporting the scaling of this novel remote sensing signal. The multi-scale design of the four airborne radiometric measurements along with extensive ground activities fosters a nested approach to quantify photosynthetic efficiency and gross primary productivity (GPP) from passive fluorescence.

Non-Invasive Spectral Phenotyping Methods can Improve and Accelerate Cercospora Disease Scoring in Sugar Beet Breeding

“…Optical measurements possess the advantage of objective and precise scoring [7]. Remote sensing signals can be collected by ground level and airborne measurements [8] based on the detection of reflected light or chlorophyll fluorescence of the vegetation canopy. The reflected light from the leaf surface is influenced by surface properties and physiological features, for example: trichomes, epicuticular waxes and leaf pigment composition [9,10].…”

Gross Primary Production of a Wheat Canopy Relates Stronger to Far Red Than to Red Solar-Induced Chlorophyll Fluorescence

“…As vegetation fluorescence is added to reflected light, it induces a small but detectable alteration of the absorption features, allowing the quantification of fluorescence. This "in-filling" approach has been successfully applied in the atmospheric absorption bands (namely, O 2 -A and O 2 -B) or in the solar Fraunhofer lines to detect vegetation fluorescence from various platforms at ground level [6,[9][10][11][12], from an airborne platform [13,14], from an unmanned aerial vehicle (UAV) [15], and from space [16,17]. Recently, the European Space Agency (ESA) selected the FLEX (FLuorescence EXplorer) mission to be the 8th Earth Explorer in the framework of the Living Planet Program [18].…”

Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence

“…SIF is an electromagnetic signal emitted in the 650-to 850-nm spectral window as a by-product of photosynthesis (e.g., refs. [17][18][19]. The first global maps of SIF were derived using data from the Greenhouse Gases Observing Satellite (GOSAT) (20)(21)(22)(23).…”