Radarkartering av skogsbiomassa med

P-band Pol-InSAR

Lars Ulander, Maciej Soja, Gustaf Sandberg, och Daniel Murdin

Contents

• BIOMASS

• ESA candidate mission

• P-band satellite SAR

• Level-2 algorithm development

• Airborne SAR experiments

• Biomass retrieval evaluation

3

ESA:s Earth Explorers

• ESA has six Earth Explorers launched or under development in the Living Earth Program

• Launched: GOCE, SMOS, Cryosat-2

• Under development: ADM-Aeolus, Swarm, Earthcare

• 7th Earth Explorer

• Launched currently planned for 2016

• Three candidates in phase A: BIOMASS, CoreH20, Premiere

• Final mission selection with be in 2012

BIOMASS: First P-band SAR in space

Courtesy: ThalesAlenia Space

• Synthetic aperture radar 432-438 MHz ( = 0.7 m)

• Large deployable reflector antenna (diameter = 12 m)

BIOMASS: Challenges & solutions

• Large deployable antenna

• Heritage from communication antennas (e.g. Inmarsat-4)

• Ionospheric corrections

• Faraday rotation corrected by polarimetric analysis

• Algorithms for global biomass mapping

• Polarimetry and repeat-pass interferometry (main orbital phase)

• Multiple baselines, i.e. tomography (initial orbital phase)

Airborne P-band SAR experiments

• Objectives

• Temporal stability (correlation)

• Topography and moisture effects

• PolInSAR, tomography, P/L-band

• BioSAR (2007, 2008, 2010), Sweden

• Boreal forest at Remningstorp, and Krycklan

• TropiSAR (2009), French Guiana

• Tropical rain forest at Paracou and Nourages

Sweden

Finland

Norway

Denmark

Remningstorp

30°E

20°E

20°E

10°E

10°E0°

70°N70°N

65°N65°N

60°N60°N

55°N 55°N

Remningstorp

Krycklan

French Guiana

Paracou

Nourages

Sweden

BioSAR-1, 2007: Remningstorp

• Hemi-boreal forest in southern Sweden

• Stand-level biomass 10-290 tons/ha; Managed forest

• Topographic height variations are small (120-145 m)

Radar backscatter coefficient vs Biomass

Blue crosses: 58 training standsRed circles: 10 validation stands

HV HH VV

SAR data from one date (2 May); similar for other dates

Correlation with biomass is high for HV & HH but low for VV

BioSAR 2007: Height maps

Low-altitudehigh-resolution helicopter scanning lidar

0.25 m grid

Hei

ght

(m)

Airborne P-band repeat-pass PolInSAR

2 m resolution

BioSAR 2007: Biomass maps

Low-altitudehigh-resolution helicopter scanning lidar

0.25 m grid

Airborne P-band HV-polarisation

2 m resolution

Bio

mas

s [t

ons/

ha]

Biomass retrieval error

2 May, heading 200 deg

Retrieval based on HV-polarisation

Stable results for all dates

9 Mar 2 April 2 May

RMSE validation

32 t/h 35 t/h 42 t/h

RMSE cross-validation

33 t/h 34 t/h 34 t/h

Conclusions

• Phase-A for 7th Earth Explorer candidates ends 2011

• BIOMASS mission concept matured• Large deployable antenna

• Faraday rotation corrections

• Biomass retrieval algorithm

• Level-2 biomass algorithm needs further development• Current estimates indicate RMSE = 30-40 t/ha (10-290 t/ha)

• Topography and moisture corrections

• Combination estimates

• BIOMASS end-to-end-simulator