2017 IEEE International Geoscience and Remote Sensing Symposium July 23–28, 2017 Fort Worth, Texas, USA

Session MO3.L12 - International Spaceborne Imaging Spectroscopy Missions: Updates and News I

QUANTITATIVE GLOBAL MAPPING OF TERRESTRIAL VEGETATION PHOTOSYNTHESIS: THE FLUORESCENCE EXPLORER (FLEX) MISSION

Jose F. Moreno Laboratory for Earth Observation Depart. Earth Physics and Thermodynamics Faculty of Physics, University of Valencia, Spain [email protected] on behalf of the FLEX team Presentation outline

- Introduction: mission objectives and mission implementation - Retrieval aspects: link between scientific requirements and technical solutions - News and updates about mission status and developments - Mission products - FLEX in the context of international Imaging Spectroscopy Missions

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission ESA Earth Explorer • Addressing high level science topics Missions • Advanced innovative techniques GOCE SWARM EarthCARE BIOMASS Gravity Field and Steady-State The Earth Magnetic Field Earth Clouds and Biomass Ocean Circulation Explorer And Environment Explorer Radiation Explorer Establishment

2022

SMOS CryoSat-2 ADM-Aeolus Soil Moisture and Polar Ice Monitoring Atmospheric FLEX Ocean Salinity Dynamics Mission Vegetation fluorescence

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission FLEX objectives Quantitative global mapping of actual photosynthetic activity of terrestrial ecosystems, as a function of variable vegetation health status and environmental stress conditions

Derived photosynthesis

Measured

Temperature

reflectance changes

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Very high spectral resolution absolutely O apparent 2 needed reflectance solar

H2O true reflectance

solar

O2 Retrieval concept

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission FLEX/Sentinel-3 Tandem Mission

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission IGARSS 300 m m 300 L.ref (mW/m2/sr/nm) FLEX / Sentinel / FLEX 100 150 50 0 500 - FLORIS spatial , Fort Worth,Fort Texas,2017, USA TOA fluorescence radiance x 10 x radiance fluorescence TOA (at resolution) spectral radiance FLORIS TOA radiance TOA

resolution 575

∆λ

= 2 nm = λ (nm) 650 - 3 spectral3 information - July 23 – July ∆λ 28, 28,

= 0.3 nm = 725 2017 2017 800 Red Spectral Spectral region FLuorescence O2 O PRI Chl - 2 edge - - B A

Wavelength 686 677 697 740 769 762 759 755 500 600 Central [nm

– – – – – – – – – –

697 686 740 755 780 769 762 759 600 677 ] EXplorer

FWHM FWHM [nm 0,3 0,7 0,7 0,7 0,3 0,3 0,7 2 3 3

(FLEX) Mission

]

Sampling Spectral Spectral [nm 0,1 0,5 0,5 0,5 0,1 0,1 0,5 1 2 2

]

Sentinel-3 FLEX

FLORIS instrument

CALIBRATION UNIT

DETECTOR

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission 300 m spatial sampling

PSF DEMANDING INSTRUMENT • High spectral resolution • High spatial resolution • High SNR • Very good calibration • Spectral stability

INSTRUMENTAL EFFECTS PERTURBING THE SIGNAL ISRF • Polarization effects • Spectral / radiometric calibration strategy • Straylight effects: - Optical element roughness - Contamination effects - Ghost for each optical element (baffle, telescope, grating,…)

0.3 nm resolution / 0.1 nm sampling

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Baffle effects Straylight kernels High Resolution Spectrometer O2-B: (677 nm–697 nm) O2-A: (740 nm–780 nm) FOCAL PLANE

10-2 PSF straylight

10-3

10-4

10-5

10-6

10-7

-4 -3 -2 -1 0 1 2 3 4 wavelength (nm)

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission STRAYLIGHT EFFECTS

160 0.50 0.30 TOA radiance F_TOA_error 140 straylight 0.40 0.25 total straylight 120

0.20 100 0.30

80 0.15

0.20 60 0.10

40 0.10 0.05 20

0.00 0 0.00 680 700 720 740 760 780 680 700 720 740 760 780 wavelength (nm) wavelength (nm) 5.0 straylight

4.0 nominal true

3.0

2.0

1.0

0.0 680 700 720 740 760 780 wavelength (nm) IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Relationship between fluorescence and photosynthesis

0.035 Additional information is needed 0.030 to disentangle the ambiguity

0.025 Φ F 0.020 measured 0.015 measured 0.010

0.005 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Φ P IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Impact of local time of observation in the retrieval of dynamical variables

Diurnal cycle of ΦP , ΦF

Changes in instantaneous illumination conditions and previous history of illumination hours at the time of overpass IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Dynamical reflectance changes associated to vegetation adaptation to stress conditions

changes

changes

reflectance reflectance

wavelength (nm) wavelength (nm) IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission FLEX products LEVEL-2 PRODUCTS COMMENTS • Integrated values at canopy level are the ones required by models. Total fluorescence emission -2 -1 -1 ε ≤ (spectrally integrated value) (Fs ) 0.2 mWm sr nm for instantaneous observations.at 300 m original spatial resolution. • Peak values (F680 and F740) • PSI – PSII contributions Regulated energy dissipation, accounts for the fraction of light absorbed • Non-photochemical energy dissipation by non-photochemical pigments (carotenoids / chlorophyll ratio and violaxanthin / zeaxanthin ratio, anthocyanin). Ratio between energy emitted as fluorescence versus actual chlorophyll • Fluorescence quantum efficiency specific absorption. • Photosynthesis rate Effective charge separation at PSII, interpreted as actual electron current.

• Vegetation stress Defined as “actual photosynthesis / potential photosynthesis”

LEVEL-3 PRODUCTS COMMENTS • Spatial mosaics Regional / continental / global maps • Temporal composites Monthy / seasonal / annual composites • Activation / deactivation of Determines length of the growing season photosynthetic machinery LEVEL-4 PRODUCTS COMMENTS Carbon uptake, derived by data assimilation with usage of external inputs

• Gross Primary Productivity (GPP) (meteo data, land cover maps) • Dynamical vegetation stress Decoupling between different stresses through dynamical model

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission CONCLUDING REMARKS

FLEX IN THE CONTEXT OF IMAGING SPECTROSCOPY MISSIONS

I. State-of-the-art technology for very high spectral resolution measurements, with relatively high spatial resolution and very high SNR to detect changes in an small signal like fluorescence and subtle changes in reflectance.

II. Data processing aspects: atmospheric correction, spectral calibrations, straylight corrections, retrievals taking full advantage of all the spectral information, going from raw data to high-level products.

III. Optimal specific exploitation of spectral information: fluorescence derived from spectral changes in apparent reflectance, small reflectance changes used for sensitivity to stress conditions and plant adaptations: link between dynamical reflectance changes and dynamics of leaf pigments.

IV. Modelling aspects: sophisticate modelling of the radiometric signal, coupled with physiological processes, into dynamical vegetation models.

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission Thank you.

Questions?

IGARSS-2017, Fort Worth, Texas, USA - July 23–28, 2017 FLuorescence EXplorer (FLEX) Mission