HR: 14:40h
AN: B43D-05    [Abstracts]
TI: Sources of Variation of Albedo of Amazonian Tropical Vegetation
AU: Yanagi, S M
EM: smonteiro@vicosa.ufv.br
AF: Federal University of Vi‡osa, Av. P. H. Rolfs, s/n, Vi‡osa, MG 36570-000 Brazil
AU: * Costa, M H
EM: mhcosta@ufv.br
AF: Federal University of Vi‡osa, Av. P. H. Rolfs, s/n, Vi‡osa, MG 36570-000 Brazil
AU: Ferreira, D F
EM: danielff@ufla.br
AF: Federal University of Lavras, Caixa Postal 37, Lavras, MG 37200-000 Brazil
AB: We investigate the main sources of variation of surface albedo of Amazonian tropical vegetation, at both the hourly and seasonal time scales. In particular, we investigate the role of canopy wetness and cloud cover, in addition to the traditional sources of variation (land cover and zenithal angle), as well as the interactions among the sources of variation. Field data used in this analysis were collected at eight micrometeorological sites during ABRACOS (Anglo Brazilian Amazonian Climate Observation Study) and LBA projects (Large-Scale Biosphere-Atmosphere Experiment in Amazonia). At the hourly-scale, land cover variation (forest x pasture), atmospheric transmissivity, canopy wetness (wet x dry) and zenithal angle explains 43.99, 6.77, 3.42 and 0.06 percent of the variance observed in the data, respectively. We also find out that, when calculating the land surface albedo, neither the role of atmospheric transmissivity nor the role of canopy wetness is well represented in land surface models today. Future work will incorporate the results of this study in land surface models to improve the accuracy of land surface albedo simulations.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting