Travaux prévus en pré-phase A

1. Robustesse et généralité des algorithmes:
différentes forêts et conditions: données existantes, campagne, modélisation comparaison bande L

2. Consolider techniques avancées
polarimétrie, interférométrie, PolInSAR
effets ionosphériques
comparaison bande L

3. Démontrer l'apport de la biomasse dans les estimations de Carbone
modélisation, estimation des incertitudes

4. Démontrer objectifs secondaires
pénétration sol, glace, océan?, humidité du sol?

Mission requirements

The mission will provide estimates for above-ground biomass up to 120-150 tons/ha, covering the entire range of biomass in boreal forests, the biomass of regenerating tropical forests up to 10-20 years after fire or abandonment, and a large part of the temperate zone forests. The mission will be able to detect biomass variation of 10-12 tons/ha, which represents the average biomass increase every 2 years in regenerating tropical forests, and the biomass increase in 4-5 years in the faster growing boreal forests. The mission lifetime of 5 years, with a repeat cycle of 55 days, will provide timely information about disturbances (deforestation, fires), will contribute to statistics on deforestation rate and fire occurrence, and will give information on permanent and seasonal forest inundation.

Science Objectives	Measurement	Accuracy	Resolution	Duration	Revisit
Boreal and temperate forest biomass	10 t / ha level	20%	100 m	3-5 years	2 / year
Tropical regrowth : biomass and biomass change	14 t / level	20%	100 m	4-5 years	2 / year
Forest area deforestation and burnt area mapping	Much improved estimates particularly tropical deforestation	< 10%	100 m	4-5 years	2 / year
Forest inundation extent	Inundated area and change	10 %	100 m	4-5 years	1 /month during season
Arid soil penetration	1 - 5 m penetration	1 m	100 m	4-5 years	1 coverage

Initial instrument definition (Alcatel Alenia Space)

We propose a P-band (432-438 MHz) polarimetric SAR on an orbital platform, and providing data for estimating the above-ground biomass worldwide, with emphasis on regions considered as the most critical in terms of the global carbon balance.

Duration	5 years	For deforestation rate and biomass change
Timing	2013-2018 (optimum)	Period of minimum solar activity
Spatial coverage	Global, 80°N - 80° S 100 km swath	Prioritising boreal and tropical forests
Repeat cycle	25 days	Monthly global monitoring of forest disturbance & inundation; construction of a biomass map every year (and one map of arid and polar regions during the satellite lifetime)
Spatial resolution	50 m (4 looks)	Giving disturbance & inundation monitoring at 50-100 m resolution, biomass at 100- 200 m resolution
Orbit	Dawn/dusk heliosynchro-nous orbit at ~580 km	Trade-off between power constraints and minimising ionospheric effects.
Polarisation	Full polarimetry and/or dual polarised: HH & HV	Biomass retrieval, monitoring disturbance & inundation (retrieving subsurface features in arid regions and ice)
Incidence angle	~30°	Biomass retrieval; canopy & surface penetration
Performance	1 dB relative, 1-2 dB absolute calibration	Mapping and retrieval accuracy

Science question ?

How global change will affect the Earth system and feedback in this system ?

The status, dynamics and evolution of the terrestrial biosphere are the least understood and the most uncertain in the Earth system (atmosphere,ocean and land)

	In the global carbon budget, the greatest uncertainties are the CO2 uptake by land. The annual flux of carbon to the atmosphere 1859-1990 (HOUGHTON, 1999) is which the unidentifined sink is assigned to uptake by the land.

Primary P-band Measurements

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Backscatter
Branch biomass, Basal Area, Volume

Biomass mapping in boreal forest
figure 1
figure 2
figure 3

Interferometry
Forest Height

Height measurement by SAR polarimetric Interferometry
figure 4 and figure 5 (Garestier et al., 2006)

Combined with Allometry:
Total Above Ground Live Biomass

Temporal Sampling:
Biomass Change, Wetland Inundation

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BIOMASS Key mission objectives

The spatial distribution and dynamics of biomass provided by BIOMASS will primarily be used to assess biomass in those huge regions of the Earth without adequate inventory and to replace or update existing regional and global inventories in carbon accounting. It will also be integrated with models, ground data and other remote sensing data, to quantify and reduce the uncertainty in carbon stocks and carbon flux estimates at local, regional and continental scales. This will significantly improve the basis for quantifying the role of terrestrial systems in the carbon cycle.

Important secondary objectives of the BIOMASS mission arise from this first chance to explore the Earth's environment with a long wavelength satellite SAR: a P-band SAR is expected to provide new information on polar ice, soil moisture, ocean salinity, sub-surface structures and paleohydrology in arid areas.

 

Mission objectives	Carbon cycle science questions	Human dimension
To develop consistent global high-resolution gridded estimates of above-ground biomass	Estimates of terrestrial carbon stocks and fluxes	Assessment of habitat, quality and biodiversity, forest ressource management, ecosystem services (including impact of forests on water cycle) and carbon accounting.
To monitor and quantify disturbance and recovery of forests	Estimates of change in terrestrial sources and sinks
To monitor and quantify areas of wetlands and forest inundation	Estimates of methane emission

Forest biomass information represents a key parameter which will improve our present assessments and future projections of the carbon cycle

 

BIOMASS Biomass monitoring mission for Carbon Assessment
		Selected by ESA in the Second Call for Earth Explorer Opportunity Missions March 2, 2009
A proposal in response to the ESA Second Call for Earth Explorer Core Missions Thuy Le Toan (Centre d'Etudes Spatiales de la Biosphère, France ) and Shaun Quegan (Centre for Terrestrial Carbon Dynamics, UK )
A P-band SAR payload is proposed to provide the spatial distribution and dynamics of forest biomass. This proposal was proposed in response to the ESA Second Call for Earth Explorer Opportunity Missions in March 2005. Climate change and its consequences constitute the most important environmental problem of the 21st century. The most critical element in understanding climate change is the quantification of the carbon cycle, of which a crucial component is the terrestrial biosphere. However, the status, dynamics and evolution of the terrestrial biosphere are the least understood and most uncertain elements in the carbon cycle, at all scales. Information on vegetation biomass is urgently needed to assess the present terrestrial carbon distribution. It is also essential, in combination with ecological models and other data sources, in order to identify carbon sources and sinks and their variation over time; to predict how these may change in the future; and to develop indicators of the status of the global climate system. On 23 May 2006, ESA has announced the shortlist of new Earth Explorer mission proposals within its Living Planet Programme. This is part of the selection procedure that will eventually lead to the launch of the fourth Earth Explorer Core mission during the first half of the next decade. The six missions cover a range of environmental issues with the aim of furthering our understanding of the Earth system and changing climate. The BIOMASS project to take global measurements of forest biomass was ranged number one. The role of remote sensing in forestry and ecological studies of the Carbon cycle For any questions or comments on this project, please contact  thuy.letoan@cesbio.cnes.fr