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

Size: px

Start display at page:

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

Luke Ross
5 years ago
Views:

EXPLORER (FLEX) MISSION Jose F. Moreno Depart.

1 Session WE International Spaceborne Imaging Spectroscopy Missions: Updates and News II GLOBAL MAPPING OF TERRESTRIAL VEGETATION PHOTOSYNTHESIS: THE FLUORESCENCE EXPLORER (FLEX) MISSION Jose F. Moreno Depart. Earth Physics and Thermodynamics Faculty of Physics University of Valencia, Spain IGARSS 2014 Quebec, Canada 16 July 2014

2 ESA s Earth Explorers GOCE Gravity Field and Steady-State Ocean Circulation Explorer SWARM The Earth Magnetic Field And Environment Explorer EarthCARE Earth Clouds and Radiation Explorer BIOMASS Biomass Establishment 17 MAR 2009 Nov 2013 Nov NOV APR 2010 Mid XX? SMOS Soil Moisture and Ocean Salinity CryoSat-2 Polar Ice Monitoring ADM-Aeolus Atmospheric Dynamics Mission Explorer 8 FLEX / CarbonSat

scale: - Coupling of carbon and water cycles (light use efficiency versus water use efficiency) CO 2 water (c) Vegetation stress monitoring: -

3 Science objectives (a) Global vegetation fluorescence, and derived photosynthesis, CO 2 fluxes, carbon assimilation: - Mapping photosynthetic efficiency - Activation/deactivation status of photosystems (b) Coupling of photosynthesis (carbon) and transpiration (water) at a global scale: - Coupling of carbon and water cycles (light use efficiency versus water use efficiency) CO 2 water (c) Vegetation stress monitoring: - Early indicators of environmental stresses (d) Anthropogenic impacts associated to land use changes and varying management practices (food security)

4 FLUORESCENCE De-excitation path ways absorption (a.u.) absorption (a.u.) light absorption lower energy fluorescence emission wavelength (nm) fluorescence (a.u.) fluorescence (a.u.)

5 DYNAMICS OF REFLECTANCE AND FLUORESCENCE

6 Fluorescence versus water stress Peak ratio changes through the day and between days as stress increases, changing the shape of the emission spectrum Fluorescence versus air polution stress FY: Upwelling Fluorescence Yield Low polution High polution Van Wittenberghe et al.,

Vegetation stress Water deficit Freezing

7 Vegetation stress Water deficit Freezing Chilling Heat Nutrient deficit Salinity Pests Weeds Elevated CO2 Herbicides Photosynthetic Strain Fluorescence tracks actual photosynthesis as regulated by vegetation stress Pollutants High light Insecticides UV Acid rain Heavy metal toxicity Ozone Direct impact on agricultural production, food security and optimization of food resources for the growing population

8 apparent reflectance actual reflectance

9 Determination of fluorescence from apparent reflectance apparent reflectance actual reflectance PS-II PS-I 0.3 FWHM / 0.1 nm sampling 300 m spatial resolution LIGHT LIGHT

SIF 687 & SIF 760 Initial SIF estimates at O 2 absorptions ρ 687, ρ 760 Requires (from Atmospheric Correction): TOC Total Irradiance E tot and Ê tot (modelled with no O 2 ) TOC Apparent Reflectance ρ

10 SIF 687 & SIF 760 Initial SIF estimates at O 2 absorptions ρ 687, ρ 760 Requires (from Atmospheric Correction): TOC Total Irradiance E tot and Ê tot (modelled with no O 2 ) TOC Apparent Reflectance ρ app (includes SIF) Estimated E tot Modelled no-o 2 E tot Estimated ρ app Interpolated no-o 2 ρ app True ρ F s = ρ aaa ρ aaa E ttt E ttt π(e ttt E ttt ) Estimated ρ app Interpolated no-o 2 ρ app True ρ No assumptions about true reflectance ρ (large source of error in other retrieval methods) Full Spectrum Retrieval Minimization function mmm (L TTT λ F λ ρ λ E ttt λ ) 2 λ n-parameters to be fitted initialization is required Fluorescence [mw.m -2.sr -1.nm] Pixel 1 TOTAL DATABASE Error@O 2 <3% Error@O 2 <2% Fluorescence [mw.m -2.sr -1.nm] Pixel 4 TOTAL DATABASE Error@O 2 <3% Error@O 2 <2% Fluorescence [mw.m -2.sr -1.nm] Pixel 5 TOTAL DATABASE Error@O 2 <3% Error@O 2 <2% Wavelength [nm] Wavelength [nm] Wavelength [nm]

11 The FLEX retrieval scheme produces as output the full shape of the actual reflectance plus the full spectral curve of fluorescence emission. This is a key element because it allows: (a) To derive fluorescence integral energy, peak-ratios, etc. (b) Biophysical parameters such as chlorophyll, LAI, etc. from the actual reflectance (actual red-edge)

12 Relation fluorescence-photosynthesis carbon-limited Light-limited

illumination at the time of overpass Local Solar

13 Orbit selection taking into account instantaneous illumination conditions and previous history of illumination at the time of overpass Local Solar Time [hours] Latitude [deg] Incoming light Longitude [deg]

14 DYNAMICAL APPARENT REFLECTANCE CHANGES Fluorescence emission Actual measurements done under varying illumination conditions

band) Improved vegetation biophysical parameter estimation (Ca, LAI, fcover) 150 100 50 TOA radiance TOA radiance (at FLORIS spectral resolution) TOA fluorescence radiance x 10 λ = 2 nm 0

16 S-3 Spectral sampling of FLORIS + Sentinel 3/OLCI-SLSTR μm OLCI SLSTR o o o o L.ref (mw/m2/sr/nm) Improved quantification of aerosol effects Determination of atmospheric water vapor content (940 nm absorption band) Cloud screening, including cirrus (1375 nm dedicated band) Improved vegetation biophysical parameter estimation (Ca, LAI, fcover) TOA radiance TOA radiance (at FLORIS spectral resolution) TOA fluorescence radiance x 10 λ = 2 nm λ (nm) λ = 0.3 nm Spectral region Central Wavelengt h [nm] FLORIS FWHM [nm] Spectral Sampling [nm] PRI Chl O 2 -B ,7 0, ,3 0,1 Red-edge ,7 0, ,7 0,5 O2-A ,3 0, ,3 0, ,7 0,5

17 Altitude: ~815 km Local solar time: 10:00 LTDN Temporal co-registration: < 6s (G) / 15s (T) FLORIS (150 km) OLCI NADIR (1270 km) SLSTR NADIR (1420 km) SLSTR backward (750 km)

Data processing Sentinel-3 FLEX OLCI TOA Rad SLSTR TOA Rad Dual View FLORIS TOA Rad Coregistration Crosscalibration Spectral Calibration Atmospheric State Atmospheric Correction FLORIS TOC E tot

18 Data processing Sentinel-3 FLEX OLCI TOA Rad SLSTR TOA Rad Dual View FLORIS TOA Rad Coregistration Crosscalibration Spectral Calibration Atmospheric State Atmospheric Correction FLORIS TOC E tot FLORIS TOC Refl Fluorescence Retrieval L2 Fluo Map L2 Photosynthesis Cloud Mask OLCI / SLSTR TOC Refl Biophysical Retrieval L2 BIOPHYS Params The combined use of satellite data and models remains of crucial importance to interpret the data in a data assimilation scenario.

19 FLEX Level-2 products Target scientific community and levels of data users. LEVEL-2 PRODUCTS Total fluorescence emission (spectrally integrated value) Peak values (F680 and F740) PSI PSII contributions Non-photochemical energy dissipation Fluorescence quantum efficiency Photosynthesis rate Vegetation stress Vegetation productivity (GPP) COMMENTS Integrated values at canopy level are the ones required by models ε ( F s ) 0.2 mwm sr nm for instantaneous observations. 300 m original spatial resolution. Regulated energy dissipation, accounts for the fraction of light absorbed by nonphotochemical pigments (carotenoids / chlorophyll ratio and violaxanthin / zeaxanthin ratio, anthocyanin). Ratio between energy emitted as fluorescence versus actual chlorophyll specific absorption. Effective charge separation at PSII, interpreted as actual electron current. Defined as actual photosynthesis / potential photosynthesis Defined at Level-2, but recommended usage as Level-3 product LEVEL-3 PRODUCTS COMMENTS Spatial mosaics Regional / continental/ global maps Temporal composites Monthy / seasonal / annual composites Activation / deactivation of photosynthetic machinery LEVEL-4 PRODUCTS Dynamical vegetation stress Gross Primary Productivity (GPP) Determines length of the growing season COMMENTS Derived by data assimilation with dynamical vegetation model Derived by data assimilation with usage of external inputs (meteo data, land cover maps)

20 FLORIS Concept 1 FLORIS Concept 2 Launcher: Vega S/C Small satellite recurrent S/C bus Wet mass <1000 kg Power consumption <500 W Coverage Global (land + major islands, -56 to 75 degree latitude, coastal zones 50 km Revisit time up to 19 days P/L Power consumption ~120W Weight ~120 kg Data rate ~150 Mbps

21 FLORIS breadboards well advanced, Detector breadboard CCD being manufactured

22 CONCLUDING REMARKS - Plant photosynthesis is a key component of the global carbon cycle: fluorescence provides actual (not just potential) photosynthesis rates to constraint models of CO 2 assimilation (GPP) - Great potential for applications in agriculture / food production - New field instruments / airborne demonstrator (HyPlant) theoretical models (leaf/canopy - ecosystem - global), end-to-end mission simulator, ground validation networks - Many on-going activities involving a large science community, Welcome to join! FLEX Earth Explorer, tandem mission with Sentinel-3, Phase A / B1, Final decisión in 2015, launch for 2020+

23 Thank you for your attention! Questions?

GeoCarb. PI: Berrien OU (Leadership, science analysis)

GeoCarb. PI: Berrien OU (Leadership, science analysis) PI: Berrien Moore @ OU (Leadership, science analysis) Partner Institutions: Lockheed-Martin (instrument) CSU (Algorithms) NASA Ames (Validation) GeoCarb A NASA Earth-Ventures mission, awarded in Dec 2016,