1. Introduction#

1.1 Context#

BIOMASS is ESA’s 7th Earth Explorer mission. The purpose of BIOMASS is to reduce the uncertainty in the worldwide spatial distribution and dynamics of forest biomass in order to improve current assessments and future projections of the global carbon cycle. This objective will be achieved by the implementation of a P-band SAR mission, providing global maps of forest biomass stocks, forest disturbance and growth.

The BIOMASS mission will also provide 3D views of forests through the tomographic phase and will support additional science needs arising from the opportunity to explore the Earth for the first time with a P-band SAR system from space, offering the possibility to see below vegetated areas and beneath bare soil or icy regions.

To achieve its challenging objectives, the BIOMASS mission requires a specific data processing strategy that combines different technologies at different processing levels in order to generate the final Above Ground Biomass global map.

1.2 Scope of the document#

The purpose of this document is to provide the Above Ground Biomass Algorithms Theoretical Baseline Document (ATBD) for the BIOMASS Processing Suite (BPS) project. This document is organised as follows:

Section	Content
1	Overview of the document
2	Brief introduction about BPS and Above Ground Biomass processing
3	Description of L2a Above Ground Biomass algorithms
4	Description of L2b/L3 Above Ground Biomass algorithms

1.3 Acronyms#

Acronym	Meaning
AD	Applicable Document
ADS	Annotation datasets
ACM	Average Covariance Matrix
AGB	Above-ground biomass
ARESYS	Advanced Remote Sensing and Systems
ATBD	Algorithm Theoretical Baseline Document
AUX	Auxiliary
BIODEMPP	Biomass DEM Prototype Processor
BPS	BIOMASS Processing Suite
CFI	Customer Furnished Items
CFM	Computed Forest Mask
CM	Covariance Matrix
CoSCS	Coregistered SCS
CP	co-polarization
DEM	Digital Elevation Model
DGG	Discrete Global Grid
DTM	Digital Terrain Model
ECSS	European Cooperation for Space Standardization
EO-CFI	Earth Observation Custom Furnished Items
ESA	European Space Agency
FD	Forest Disturbance
FH	Forest Height
FNF	Forest/Non-Forest Mask
GN	ground cancellation (Ground Notching)
GPP	Ground Processor Prototype
GPS	Global Positioning System
IERS	International Earth Rotation Service
InSAR	Interferometric Synthetic Aperture Radar
INT	Interferometric Phase
L0	Level-0 product
L1c	Level-1c product
L2a	Level-2a product
L2b	Level-2b product
L3	Level-3 product
LOS	Line Of Sight
LUT	Look-Up Table
PF	Processing Facility
PFD	Product Format Specification Document
RD	Reference Document
SAR	Synthetic Aperture Radar
SCS	Single-look Complex Slant-range
SKP	Sum of Kronecker Products
SNR	Signal-to-Noise Ratio
std	Standard deviation
TBD	To Be Defined
TBC	To Be Confirmed
TOM	Tomographic Phase
XML	eXtended Markup Language
XP	cross-polarization

1.4 Applicable documents#

Code	Title	Issue
`[AD1]`	BIOMASS Production Model, BIO-ESA-EOPG-EEGS-TN-0046	3.5
`[AD2]`	BIO-BPS-TN-PRODMOD, BIOMASS Production Model Technical Note	I/R 1/2/1
`[AD3]`	BIO-BPS-L1-PFD, BIOMASS L1a,b,c products format specification	I/R 1/2/2

1.5 Reference documents#

Code	Source
`[RD1]`	BIO-BPS-L1-STACK-ATBD, BIOMASS BPS L1c Stack ATBD, I/R 1/1/2
`[RD2]`	BIO-BPS-L1-SAR-ATBD, BIOMASS BPS L1 SAR ATBD, I/R 1/1/2
`[RD3]`	BIOMASS DEM Product Processor Prototype, DEM Processor Algorithm Theoretical Baseline Document, BIODEMPP-CoSCS-DEM-01, Issue 4.0, June 07th 2021
`[RD4]`	M. Mariotti d’Alessandro, S. Tebaldini, S. Quegan, M. J. Soja, L. M. H. Ulander and K. Scipal, “Interferometric Ground Cancellation for Above Ground Biomass Estimation,” in IEEE Transactions on Geoscience and Remote Sensing, vol. 58, no. 9, pp. 6410-6419, Sept. 2020
`[RD5]`	Snowdon, Peter. “A ratio estimator for bias correction in logarithmic regressions.” Canadian Journal of Forest Research 21.5 (1991): 720-724
`[RD6]`	Díaz-Francés, Eloísa, and Francisco J. Rubio. “On the existence of a normal approximation to the distribution of the ratio of two independent normal random variables.” Statistical Papers 54 (2013): 309-323
`[RD7]`	BIO-BPS- AUX-FMT, BPS Auxiliary Product Format, I/R 3/2
`[RD8]`	BIO-BPS-PPD, BIOMASS BPS Product Performance Description, I/R 3/0
`[RD9]`	L2-ATBD-ARE-011567, BIOMASS L2 Algorithm Theoretical Baseline Document, I/R 1/5
`[RD10]`	BIO-BPS-IODD, BIOMASS BPS IODD, I/R 3/0/2
`[RD11]`	Soja, Maciej J., et al. “Mapping above-ground biomass in tropical forests with ground-cancelled P-band SAR and limited reference data.” Remote Sensing of Environment 253 (2021): 112153