Quantifying the carbon cycle is the most
important element in understanding climate
change and its consequences, yet is poorly
understood (Le Toan et al, 2004). Forests store
85% of terrestrial carbon, yet the amount of
carbon contained in the earth’s forests is not
known to even one significant figure, ranging
from 385 to 650 1015g carbon (Goodale et al.
2002, Houghton et al. 2009).
Recent publications on 3D vegetation
structure measurements have reiterated the
urgent need of developing new spaceborne
sensors capable of three dimensional structure
measurements to understand changes and trends
in terrestrial ecosystem function as carbon
sources and sinks, and to characterize the impact
of their changes on climate, habitat and
biodiversity. In particular, the authors concluded
that lidar profile samplers in combination with Lband polarimetric SAR data and ecosystem
modeling can be used to satisfy the vegetation
3D structure and biomass measurement
requirements (Hall et al. 2011).
These measurements of terrestrial
biomass and ecosystem structure have far
ranging societal, policy and management
implications. The anticipated economic and
societal burden that will result from unmitigated
rises in CO2 emissions and losses in ecosystem
services alone are estimated to be in the trillion
of dollars by mid-century (Stern Report, 2008).
Ongoing international carbon mitigation
initiatives, such as the UNFCCC’s Agreement on
Reduced Emissions from Deforestation and
Degradation (REDD+) need detailed, precise and
accurate measurements of carbon storage in
terrestrial and coastal ecosystems to be
successful.
Here were present a recent NASA effort
towards acquiring these critical measurements
with three unique and innovative NASA
Goddard Space Flight Center airborne sensors
that were flown as part of the Eco3D
measurement campaign in August-September of
2011: The L-band Digital Beamforming
Synthetic Aperture Radar (DBSAR), the Slope
Imaging Multi-polarization Photon-counting
978-1-4673-1159-5/12/$31.00 ©2012 IEEE 3387 IGARSS 2012Lidar (SIMPL) and the Cloud Absorption
Radiometer (CAR), capable of bidirectional
reflectance (BRDF) measurements.