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Funded Research

Detecting Changes of Forest Biomass from Fusion of Radar and Lidar: Developing DESDynl measurement requirements

Saatchi, Sassan: Jet Propulsion Laboratory / Caltech (Project Lead)

Project Funding: 2009 - 2012

NRA: 2008 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
Vegetation biomass, the quantity of living matter, is a fundamental parameter characterising the biosphere. Despite its crucial nature, biomass is poorly quantified across most parts of the planet due to the great difficulties in measuring it on the ground and consistently aggregating available measurements across scales. Obtaining spatially explicit measurement of biomass and its changes due to human and climate perturbations is important for understanding and quantifying the global carbon cycle and its dynamics. In a recent study, the National Research Council (NRC) Decadal Survey recommended the active remote sensing sensors (radar and lidar) as NASA's DESDynl mission concept to provide these measurements. Distribution of vegetation biomass stock and the annual changes from disturbance and recovery are recommended as two important variables to quantify global terrestrial carbon sinks and sources.

The overall goal of this project is to assess the capability of these active sensors to detect changes in aboveground vegetation biomass in temperate and tropical forests, without necessarily estimating the biomass stock. Our study will focus on three study areas covering a range of ecosystem structure and stages of disturbance and biomass accumulation. We propose to develop a data fusion methodology and change detection algorithm by combining radar measurements from ALOS PALSAR and airborne lidar (LVIS) with extensive field measurements, and ecosystem modeling techniques to address two questions:

  1. Can changes of biomass be detected from fusion of L-band radar and multi-beam lidar from space?
  2. What are the spatial and temporal resolutions and specific measurement requirements for DESDynl?
Intellectual Merit: The results of this study will address one of the major challenges in understanding the global carbon cycle by quantifying the magnitude and spatial distribution of carbon sinks and sources in terrestrial ecosystems. It will do so by developing a data fusion methodology to estimate changes of aboveground vegetation biomass in different ecosystems for the first time using L-band radar and lidar measurements. The focus of the proposal is on processes of disturbance and recovery including limiting cases where forests are in mature post-disturbance state. The data fusion and change detection algorithm will be developed and tested for the ability to quantify changes of biomass globally at various spatial and temporal scales.

NRA and NASA Relevance: This proposal is a direct response to ROSES' Terrestrial Ecology announcement that calls for urgent research to develop and evaluate data analysis methodologies for the DESDynl's measurements. The proposed research in the data fusion of L-band radar and lidar is directed towards quantifying changes of biomass from the disturbance/recovery process that is widely recognized as DESDynl's major science objective. The project also extends into the area of integration of vegetation 3D- structure with advanced ecological models to improve predictions of ecological and biogeochemical processes. Our study will contribute to improving the science and measurement requirements of NASA's next generation spaceborne missions.

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

  • Forest Disturbance Spectrum of the Amazon Forest   --   (Fernando Espírito-Santo, Michael Keller, Manuel Gloor, Yadvinder Malhi, Sassan Saatchi, Michael Palace, Steve Frolking, Oliver Phillips)   [abstract]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

  • Spatio-Temporal Tropical Forest Dynamics from Small-Footprint Lidar Remote Sensing   --   (Maxim Neumann, Sassan Saatchi, David B. Clark)   [abstract]
  • Detection of Changes of Tropical Forest Biomass from Fusion of Multi-temporal Radar and Lidar Data   --   (Sassan Saatchi, David B. Clark, Robin Lee Chazdon, Maxim Neumann)   [abstract]

2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)

  • Field and Aircraft Observations in Support of DESDynI   --   (Ralph Dubayah, Kathleen Bergen, Bryan Blair, Bruce Cook, Peter Griffith, Forrest Hall, Megan McGroddy, Paul Montesano, Amy Morrell, Ross Nelson, Wenge Ni-Meister, Michael O'Connell, Jon Ranson, Chelsea Robinson, Jeremy Rubio, Sassan Saatchi, Marc Simard, Paul Siqueira, Alan Strahler, Guoqing Sue, Anuradha Swatantran)   [abstract]   [poster]
  • Constraining Forest Ecosystem Dynamics by integrating Remote Sensing data with a State-of-the-Art Terrestrial Biosphere Model   --   (Alexander S Antonarakis, Paul R Moorcroft)   [abstract]

More details may be found in the following project profile(s):