Calibration and Validation of BIOMASS Products Using Airborne and Field Data in Indonesian Rainforests
Figure: credit ESA/ATG medialab CC-BY-SA 3.0 IGO.
Suggested elective course: Radar Remote Sensing
The topic is also suitable for GEM students in track 3 – GEM for Ecosystems & Natural Resources.
Tropical lowland rainforests in Sumatra have been extensively degraded through logging and conversion to oil palm plantations, resulting in major ecological and biophysical changes. Understanding how ecosystem functions such as biomass storage, biodiversity, and microclimate are altered during this transformation is essential. In the EFForTS project, detailed field inventories and airborne laser scanning (ALS) campaigns have provided high-quality measurements of canopy structure and above-ground biomass (AGB) across more than 100 plots monitored between 2012 and 2022. These datasets offer a unique opportunity to evaluate the potential of the ESA BIOMASS mission for large-scale ecosystem monitoring.
This thesis aims to assess and validate BIOMASS products in heterogeneous tropical landscapes and explore how well they capture changes along the gradient from intact forest to plantations. Spaceborne BIOMASS data will be compared and calibrated using ALS and field measurements, and further contrasted with GEDI, TanDEM-X, and Sentinel-based products to examine consistency and scaling behavior. The work will produce spatial maps of AGB and potentially additional ecological indicators, contributing to mission exploitation and improving tropical forest monitoring. Overall, the project seeks to demonstrate the capability of BIOMASS data for assessing forest transformation processes and supporting environmental modelling at regional scale.
This thesis will evaluate the potential of ESA BIOMASS mission data to monitor ecological changes in tropical lowland forests undergoing transformation into tree crops, particularly oil palm, in Jambi, Sumatra. The EFForTS project provides an ideal testbed with extensive field data (>100 plots) and high-resolution airborne laser scanning (ALS) and hyperspectral imagery, collected between 2012–2022. Previous work shows that ALS and spaceborne GEDI and TanDEM-X data can accurately estimate forest structure and above-ground biomass (AGB), enabling landscape-scale upscaling. Building on this foundation, the thesis will calibrate and validate BIOMASS products using EFForTS field and ALS datasets, and assess their ability to quantify AGB and other ecological indicators linked to biodiversity, microclimate, and ecosystem functioning.
Potential methodologies
- Compile and harmonize field, ALS, hyperspectral, GEDI/TanDEM-X, and BIOMASS datasets.
- Derive forest structure metrics (canopy height, cover, AGB) from ALS and use them as reference for BIOMASS calibration.
- Validate BIOMASS outputs on different product levels and assess error patterns across forest–plantation gradients.
- Test local calibration strategies to improve BIOMASS estimates for tropical mosaic landscapes.
- Produce spatial wall-to-wall maps of biomass and ecological function proxies, enabling regional environmental assessments.
Schlund, M., Scipal, K., Quegan, S., 2018. Assessment of a Power Law Relationship Between P-Band SAR Backscatter and Aboveground Biomass and Its Implications for BIOMASS Mission Performance. IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens. 3538–3547. http://dx.doi.org/10.1109/JSTARS.2018.2866868.
Quegan, S., Le Toan, T., Chave, J., Dall, J., Exbrayat, J.F., Minh, D.H.T., Lomas, M., D’Alessandro, M.M., Paillou, P., Papathanassiou, K., Rocca, F., Saatchi, S., Scipal, K., Shugart, H., Smallman, T.L., Soja, M.J., Tebaldini, S., Ulander, L., Villard, L., Williams, M., 2019. The European Space Agency BIOMASS mission: Measuring forest above-ground biomass from space. Remote Sens. Environ. 227, 44–60. http://dx.doi.org/10.1016/j.rse.2019.03.032.