HR: 0830h
AN: B51E-1011    [PDF]
TI: Spatiotemporal Variability of Global and Diffuse PAR in the Amazon Region and its Significance for Tropical Forest Photosynthesis
AU: * Dye, D G
EM: dye@jamstec.go.jp
AF: Ecosystem Change Research Program, Frontier Research System for Global Change, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa,, 236-0001 Japan
AB: This study examines seasonal and inter-annual variation in surface fluxes of global and diffuse photosynthetically active radiation (PAR, 400-700 nm) in the tropical forest of the Amazon region. Spatial and temporal patterns of global and diffuse PAR are determined from reanalysis data from the National Center for Environmental Prediction (NCEP), and from the SeaWIFS Solar Surface Irradiance (SSI) data set. The PAR data and satellite-derived estimates of leaf area index (LAI) are applied to an existing sun-shade model of forest canopy photosynthesis. The seasonality of atmospheric scattering (quantified as the diffuse fraction of global PAR) as a determining factor for the relative influence of variation and trends in incident PAR on tropical forest photosynthesis is quantitatively evaluated. The results provide insight into the role of the surface PAR regime in the dynamics of ecosystem-atmosphere carbon exchange in the Amazon and other tropical forest regions.
DE: 0315 Biosphere/atmosphere interactions
DE: 1615 Biogeochemical processes (4805)
DE: 1620 Climate dynamics (3309)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting