Rates of energy storage and stem heat fluxes in a terra firme forest in central Amazonia. / Taxas de arnazenamento de energia e fluxos de calor nos troncos em floresta de terra firme na Amazônia central

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The parts of the Rate of Energy Storage (RES) in a one hectare site of a Terra Firme forest in Central Amazonia was determined for a set of typical days during the dry season. Thus, to obtain the RES in part of the above ground biomass fraction of the forest (stem, branches, and litter), the temperatures of four stems of the dominating tree species were measured in three height levels and several radial depths. To compute the RES in the other part of the above ground biomass fraction (twigs, leaves and other components such as palm trees and lianas) and the RES atmospheric fraction due the variations of the air temperature, the temperature of the air was measured at several heights inside the forest, including the ones mentioned. To compute the RES in the air due the changes in the moisture content, the relative humidity of the air was also measured at the same levels. The site (02°3645 S, 60°1240 W) is part of the Estação de Manejo Florestal ZF-2, located at NW of Manaus, AM. To obtain the RES of the stems, three methods were used. The first one depends on all stem temperature measurements. The other two methods, which are based on an analytical solution of the heat conduction equation, depend only on the temperature measurements in one radial depth of a tree with the average characteristics of the complete set of 670 trees of the site. The results of the first method remain systematically between the ones of the other two methods. One third of the RES of the forest is due to the stems, while other third is due to the air; finally, the last one is divided among the other parts: litter, other components such as palm trees and lianas, branches, twigs and leaves. Considering the hourly terms during the daylight cycle, the RES of the forest (S) presents values usually between 30 and 40 W m-2, but with maxima up to 90 W m-2; however, during rain events, S presents minima of up to -225 W m-2. During the night and the transition periods S may constitute a sizable fraction of the net radiation (Rn), or even exceed it. On a daily basis, the values of S were observed between 1 and 10% of Rn, depending on the weather conditions along the day.

ASSUNTO(S)

transferência de calor micrometeorologia floresta tropical rain forests heat transfer meteorologia energy storage camadas limite micrometeorology stems troncos boundary layer armazenamento de energia amazônia central amazon region (south america) meteorology caules trunks

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