TropiSCAT : A MULTI-FREQUENCY POLINSAR DATA CAMPAIGN OF ACQUISITION FOR VEGETATION CHARACTERIZATION Clément ALBINET – Office National d’Etudes et de Recherches

TropiSCAT : A MULTI-FREQUENCY POLINSAR DATA CAMPAIGN OF ACQUISITION FOR

VEGETATION CHARACTERIZATION

Clément ALBINET – Office National d’Etudes et de Recherches Aérospatiales (ONERA)

Pierre BORDERIES – Office National d’Etudes et de Recherches Aérospatiales (ONERA)Thierry KOLECK – Centre National d’Etudes Spatiales (CNES)

Fabio ROCCA – Politecnico di Milano (POLIMI)Stefano TEBALDINI – Politecnico di Milano (POLIMI)

Thuy LE TOAN – Centre d’Etudes Spatiales de la BIOsphère (CESBIO)Ludovic VILLARD – Centre d’Etudes Spatiales de la BIOsphère (CESBIO)

Stéphane MERMOZ – Centre d’Etudes Spatiales de la BIOsphère (CESBIO)Dinh HO TONG MINH – Politecnico di Milano (POLIMI)

IGARSS 2011 VANCOUVER – Friday, July 29 – FR3.T02 The BIOMASS Mission

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• BIOMASS Mission, candidate for the ESA 7th Earth Explorer Mission

• First Synthetic Aperture Radar (SAR) at P-band

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Motivation and objectives

• Forest with high biomass density (>300ton/ha) → PolInSAR

High temporal coherence is necessary !

→ Airborne experiment : TropiSAR (2009)

→ Ground based experiment : TropiSCAT

(ESA and CNES founding)

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1. Experiment description

• Goal :• Polarimetric intensity• Polarimetric complex coherence• Polarimetric vertical imaging (tomography)

• Time scales :• Minutes• Daily• Monthly• Yearly

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• Equipment :

• VNA – Agilent A5061B :• With IF=1kHz, noise is less than -100 dBm.

• Antennas – SATIMO LP400 :• 400MHz – 1GHz• Adequate 3dB aperture : E - 50° / H - 65°.

• RF Switches :• Solid state switches.

• 70m Low loss cables :• Losses measured in laboratory range from

3 dB at 400 MHz to 5 dB at 1 GHz.

• Industrial Computer :• Compact design• Tropicalized motherboard• Waterproof

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• Location - Requirements :• High biomass density• High number of different tree species• High spot for radar measurement• Safe place for hardware

→ Guyaflux tower in Paracou, French Guiana

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• Location : 55 m high Guyaflux tower in

Paracou, French Guiana

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Primary forest

Continuously studied since the seventies Ground data are continuously collected

(weather, soil moisture, tree measurements)

Test site overflown by TropiSAR campaign (ONERA, August 2009)

view from the top of the tower :

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2. Instrument architecture

• Project evolution/planning :• October 2010 – Preliminary campaign with light equipment.• June 2011 – Setup of the automatic full-polarimetric backscattering and

coherence measurements.• September 2011 - Setup of the automatic tomographic measurements.

• Instrument architecture :• 4 antennas configuration

RF Transmit

RF Receive

RF switches box

Vector Network Analyzer

Control Unit

Control and Monitoring PC

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US

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Guyaflux tower

Internet Gateway(if available)

Antennas

Power line (24V)

Control line

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2. Instrument architecture

85cm

70cm

70cm

150cm

T-V T-H R-H R-V

Tower

Forest

• 4 antennas configuration :

Full polarization impulse responses

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3. TropiSCAT first results

• Extremely high coherence on tower

• Range gate on the tower at P band :

Validation of coherence measurements

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• Diurnal cycle & High coherence for one day interval• Strong decorrelation during storm, stronger for foliage only• Stronger decorrelation for full forest

High influence of soilProminent influence of soil moisture variation ?

Further analysis necessary with ground data

• Range gate on the forest at P Band :

24 hours

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• Foliage only at 2 bands :

• Stronger decorrelation at L band

• Stronger decorrelation on HH at L band

P band L band

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• Full forest at 2 bands :

• For HV : day night same order of decorrelation.

• Stronger decorrelation on VV at L band during the whole day, including same hour.• Stronger decorrelation at L band for HH.

P band L band

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• HH

• HV

• VV

• Vertical tomography :

Localization of the contributors

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Validation of tomograms

• Vertical tomography :

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4. TropiSCAT development

• Project evolution/planning :• October 2010 – Preliminary campaign with light equipment.• June 2011 – Setup of the automatic full-polarimetric backscattering and

coherence measurements.• September 2011 - Setup of the automatic tomographic measurements.

• Instrument architecture :• Antenna array configuration : 20 antennas

RF Transmit

RF Receive

RF switches box

Vector Network Analyzer

Control Unit

Control and Monitoring PC

Eth

ern

et lin

k

US

B link

Guyaflux tower

Internet Gateway(if available)

Antennas

Power line (24V)

Control line

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• The TropiSCAT experiment has been partially installed in French Guiana and is currently running

• The first measurements show that TropiSCAT experiment can achieve the scientific objectives

• The first results yield physical interpretation

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Conclusion

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TropiSCAT : A MULTI-FREQUENCY POLINSAR DATA CAMPAIGN OF ACQUISITION FOR VEGETATION CHARACTERIZATION

Thank you for your attention.

(360° panorama from the top of the tower)

[email protected]

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Modeling

• Comparisons between measurements and modeling : Interpret the temporal variations observed in the long term experiment.

• Situation of the plot :• West side of tower• Surface of 172 m²

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Modeling

• Comparisons between measurements and modeling : Comparisons with measurements from the TropiSAR airborne campaign

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Deforestation

Regeneration

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Introduction and Context

Carbon fluxes and its uncertainties [BIOMASS 08]

Biomass changes on tropical forests

P-band (435MHz) now available

Carbon Budget

Documents

TropiSCAT : A MULTI-FREQUENCY POLINSAR DATA CAMPAIGN OF ACQUISITION FOR VEGETATION CHARACTERIZATION Clément ALBINET – Office National d’Etudes et de Recherches