Componentes Do Balanco de Radiacao Acima DA Copa DA Floresta Amazonica (Terceira Campanha de Coleta de Dados) (Radiation Balance Components Above the Tropical Evergreen Amazon Forests (3rd Campaign of Data Collection))

摘要

Daytime variation of radiation balance components of solar radiation K(incident), reflected radiation K(reflected), net radiation Q(net) and net longwave radiation L(net), from July to August 1984, over the tropical evergreen Amazon forest was investigated. The variation of Q(net) is similar to that of K(incident). During daytime hours the differences in K(incident) and Q(net) are significant due to the presence of convective clouds, and exhibit a systematic pattern. The maximum values of K(incident) and Q(net) were 1301 and 713 W/sq m, respectively. The behavior of Q(net) was explained from the radiant input K(incident) and net longwave radiation L(net). A strong dependence of the albedo on the zenith angle is evident. This dependence is subdued during cloudy days. The daily albedo of solar radiation determined over the forest canopy varied from a maximum value of 0.33 (in the afternoon) to a minimum value of 0.12 (in the middle of the day).