Accurately quantifying forest 3-D structure is of great importance for studies of the Global Carbon Cycle and biodiversity. Recent studies have shown that the combination of landcover maps, radar and lidar data result in more accurate estimates of forest 3-D structure and biomass on large scales. These studies are especially important in Africa, where deforestation rates are high and more background data is needed. Mangrove forests are of great ecological importance and present a good test ecosystem for new methods in vegetation structure estimation because of the flat underlying topography.
In this study we combine and compare ICEsat/GLAS, SRTM C-band data to derive mangrove structure and biomass maps for the African continent. We derived mangrove distribution maps for all of Africa from Landsat images. We used ICEsat/GLAS lidar data to calibrate global coverage SRTM C-band data. We then extracted mangrove forest areas on the SRTM images using the landcover maps and derived height calibration equations, using GLAS measurements. The error estimations showed that C-band data has a RMSE of 30% when accurately calibrated. The resulting maps were published to our website using a Google maps interface through which it is possible to navigate the SRTM height and biomass maps and see the ICEsat/GLAS points and waveforms. Our results showed that the combination of ICEsat/GLAS and SRTM data is well suited for vegetation 3-D mapping on a continental scale and at low cost.
Dr. Lola Fatoyinbo is a NASA Postdoctoral Fellow within the Radar Science and Engineering Section at the Jet Propulsion Laboratory. She received her B.A. in Biology and Ph.D. in Environmental Sciences from the University of Virginia in 2003 and 2008 respectively. Her research focus is on active and passive remote sensing of tropical forest structure and dynamics, with a concentration on mangrove ecosystems. Her particular research interest also includes the use of freely available datasets to develop methodologies that can be implemented in natural resource management in developing nations. Her major study areas are Sub-Saharan Africa and Madagascar.