Biomass MissionFLEX (Fluorescence Explorer) Mission

Large uncertainty in global / regional estimates of carbonbalance, in particular GPP (Gross Primary Production)

Terrestrial carbon cycle

coupling of carbonand water cycles

(vegetation stress)

Populationgrowth

More / bettercrop production

Optimalphotosynthesis

Direct impact on agricultural production,food security and optimization of foodresources for the growing population

Temperature

Reflectancechanges

Measured

Derived photosynthesis

Quantitative global mapping of actual photosynthetic activity of terrestrialecosystems, as a function of variable vegetation health status and environmental stress conditions

FLEX objectives

FLEX/Sentinel-3Tandem Mission

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600 650 700 750 800wavelength (nm)

abso

rptio

n (a

.u.) light

absorption

abso

rptio

n (a

.u.)

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

fluorescence (a. u.)

fluorescence emission

lower energy fluorescence (a.u.)

CHLOROPHYLL FLUORESCENCE

670 680 690 700 710 720 730 740 750 760 7700

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1

1.5

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3.5

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4.5

Wavelength [nm]

Fluo

resc

ence

[mW

.m-2

.sr-1

.nm

]

Pixel 5

TOTAL DATABASEError@O2<3%

Error@O2<2%

Information content in the shape and amplitude of fluorescence emission

Retrievalconcept

Very highspectral resolution absolutely needed

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0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Φ

P

ΦF

measured

Additional information is needed to disentangle

the ambiguity

Relationship between fluorescence and photosynthesis

F PaΦ ≈ Φ( )a f NPQ=

wavelength (nm)

refle

ctan

cech

ange

sDynamical reflectance changes associated to vegetation adaptation to stress conditions

Sent

inel

-3FL

EX

FLEX / Sentinel-3 spectral information

300 m spatial resolutionFLORIS:

Spectral resolution: 0.3 nmSpectral sampling: 0.1 nm

FLORIS instrument

DETECTOR

CALIBRATIONUNIT

LEVEL-2 PRODUCTS COMMENTS• Total fluorescence emission

(spectrally integrated value)• Peak values (F680 and F740)• PSI – PSII contributions

Integrated values at canopy level are the ones required by models.

for instantaneous observations.at 300 m original spatial resolution.

• Non-photochemical energy dissipationRegulated energy dissipation, accounts for the fraction of light absorbed by non-photochemical pigments (carotenoids / chlorophyll ratio and violaxanthin / zeaxanthin ratio, anthocyanin).

• Fluorescence quantum efficiency Ratio between energy emitted as fluorescence versus actual chlorophyll specific absorption.

• Photosynthesis rate Effective charge separation at PSII, interpreted as actual electron current.

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

( ) -2 -1 -10.2 mWm sr nmsFε ≤

LEVEL-3 PRODUCTS COMMENTS• Spatial mosaics Regional / continental / global maps

• Temporal composites Monthy / seasonal / annual composites• Activation / deactivation of photosynthetic

machinery Determines length of the growing season

LEVEL-4 PRODUCTS COMMENTS• Gross Primary Productivity (GPP) Carbon uptake, derived by data assimilation with usage of external inputs (meteo

data, land cover maps)• Dynamical vegetation stress Decoupling between different stresses through dynamical model

FLEX products