Scaling Up Above Ground Live Biomass from Plot Data to Landscape in Amazon Basin
Sassan
S.
Saatchi, JPL/CALTECH, saatchi@congo.jpl.nasa.gov
(Presenting)
The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use changes. Direct measurements of above ground biomass are limited to small areas of forest inventory plots, and site-specific allometric regression equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we introduce a methodology based on a combination of land cover map, remote sensing derived metrics, and more than 500 forest plots distributed over the basin. A model has been developed to extrapolate the plot data through remote sensing metrics to the entire Amazon region. Several landscape and forest structural attributes such as digital elevation, slope, canopy roughness, percent tree cover are incorporated in the model to augment the remote sensing metrics. The plot data are included in a bootstrapping approach to derive a multivariate parametric expression to extrapolate the forest above ground live biomass over the entire basin at 1 km spatial resolution. The bootstrapping methodology provided a performance accuracy of estimation that increased with forest biomass to a maximum of 70 tons/ha for undisturbed forests of approximately 400 tons/ha.
The resulting biomass map was used to determine the total carbon stored in live forest biomass of the basin and its partition in land cover types. It has also been used to compare with two other estimates derived from spatial interpolation of plot data and an ecosystem models. By examining the uncertainties of biomass measurements, an error analysis was performed to quantify the uncertainties in basin-wide biomass in amplitude and spatial variations.
Submetido por Sassan Sepehri Saatchi em 18-MAR-2004
Tema Cient�fico do LBA: CD (Armazenamento e Trocas de Carbono)