Influência do dossel da floresta de Caxiuanã nos fluxos de calor entre o solo e a atmosfera

Air temperatures at 8, 30 and 52 m above ground and vertical fluxes of latent heat and sensible heat at 54 m height, were measured during one month of the dry season (August, 2005) and another month (April, 2005) of the rainy season at Caxiuanã’s forest micrometeorological tower. The average temperature profiles for daylight and night periods, as well as, the sensible and latent heat fluxes estimated and measured, showed significantly different and frequently opposite behavior of these quantities, within two layers defined between 8 and 30 m, below the forest canopy, and 30 to 52 m, above the canopy. The canopy seems to act as a heat source during the daylight hours and a sink of heat at night. Overall, the sum of the sensible and latent heat fluxes may reach 90% of the short wave net radiation, over this site. The results suggest that more attention should be given to the air layer below the canopy, if one seeks to understand the heat and water vapor exchanges between the soils surface and the atmosphere, above the canopy of such type of forest.