Pantropical structure and biomass mapping using the fusion of GEDI and TanDEM-X data - Phase II: expansion to new regions and estimating change
Ralph Dubayah, University of Maryland, dubayah@umd.edu (Presenter)
John Armston, University of Maryland, armston@umd.edu
Konstantinos Papathanassiou, German Aerospace Center (DLR), kostas.papathanassiou@dlr.de
Matteo Pardini, German Aerospace Center (DLR), matteo.pardini@dlr.de
Wenlu Qi, University of Maryland, wqi@umd.edu
Adrian Pascual, University of Maryland, apascual@umd.edu
Paul May, University of Maryland, College Park, pbmay@umd.edu
Hao Tang, National University of Singapore, hao.tang@nus.edu.sg
Noelia Romero-Puig, German Aerospace Center (DLR), noelia.romeropuig@dlr.de
Andreas Huth, Helmholtz Centre for Environmental Research - UFZ, Germany, andreas.huth@ufz.de
Christian Giardina, USFS, christian.p.giardina@usda.gov
Julian Gonzalo Jimenez, The World Bank, jgonzalojimenez@worldbank.org
George Gaines, USFS, george.gaines@usda.gov
Rico Fischer, Helmholtz Centre for Environmental Research - UFZ Leipzig, rico.fischer@ufz.de
Rachel L Lamb, Maryland Department of Environment (DEP), rachel.lamb@maryland.gov
Responding to global need of monitoring forest biomass stocks and their changes through time NASA and the University of Maryland developed the Global Ecosystems Dynamics Investigation (GEDI), a waveform Lidar mission launched in late 2018 and deployed on the International Space Station (ISS). GEDI has provided orders of magnitude more space-based observations of forest structure data than currently exists. However, GEDI is a sampling mission, and there are large gaps between tracks, and other gaps in coverage caused by clouds and orbital considerations. The GEDI gridded biomass and forest structure products have a core resolution of 1 km (based on aggregation of footprint samples within 1 km cells) and even at this resolution, some cells have no GEDI tracks within them, even after four years on orbit. Furthermore, it is now clear that many stakeholders want gap-free maps at finer spatial resolution.
One way to eliminate gaps, and to provide higher resolution and accuracy for MRV applications, is to combine the sparse GEDI observations with data from other space-based sensors that provide wall-to-wall coverage, especially Synthetic Aperture Radar (SAR) because of its weather independence and sensitivity to canopy structure. We initiated such a study within NASA’s Carbon Monitoring System (CMS) program in 2019 to develop and apply methods for fusion of interferometric SAR data from TanDEM-X (TDX) and GEDI to produce wall-to-wall estimates of canopy height and biomass at fine spatial resolution for a large area of the pantropics. This Phase I included the creation of complex workflows, understanding the impacts of spatial variability in canopy structure on height retrievals, and incorporation of an innovative uncertainty framework based upon generalized model-based inference (GHMB).
In this Phase II we will provide change estimates for canopy height and biomass for the Pantropics region to support global efforts on MRV, the Paris Accords and its associated Global Stocktake and relevant stakeholder supporting our proposal such as the US Forest Service, the World Bank of ASEAN countries. TDX has provided complete forest coverage around two epochs: 2010-2015 and 2017-2020, and has planned new coverage for 2023-2025. There is thus the ability to measure changes in over a 15-year period. We will develop methods for estimating changes using TDX data combined with GEDI and using Landsat disturbance chrono-sequences to estimate biomass accumulation for pantropical countries after stand-replacement disturbances. he overall goal of our project 2022-funded CMS project is the continuing development and application of methods for mapping forest structure, carbon stock and their changes using fusion of GEDI and TDX data .We will work jointly with our DLR co-investigators to derive maps of height and biomass at 25 m, 100 m and 1 km resolutions, expanding to cover most of the pantropics and the US, specifically over US temperate forests in support of US Forest Service small area estimation and other synergies in the US states of Washington, Hawaii and Maryland and through established cooperation projects such as on old-growth mapping.
Our spatially resolved estimates of biomass and its changes though time will enable the USFS to provide greater accuracy at finer resolution as increasingly required by landowners in the US, support the World Bank to strengthen REDD+ policies and MRV programs with developing countries, and long-term support states and countries on climate policy requirements regarding climate mitigation. Our project also pave the way for enhanced biomass mapping from the NISAR and BIOMASS missions through the development of fusions algorithms that are directly applicable to SAR data from these missions as well as by providing unmatched data for calibration of algorithms and validation of products.
Associated Project(s):
Poster Location ID: 8
Presentation Type: Poster
Session: Poster Session 1
Session Date: Wednesday (9/27) 1:15 PM