The contribution of the intercepted rain water by the vegetation covering, and its variations have been shown as an important component of the Amazon hydrologic cycle, with outstanding influence in the evapotranspiration rate. During the foliage wetting period, soon after a rain event, it is observed a tendency for a greater evapotranspiration rate since the process of water transfer is dependent only by atmospheric conditions, not by stomatal regulation.
The morphology of the Amazon Forest is not homogeneous, presenting differences in the architecture and leaf area index, leading to differences in the capacity of water storage by the canopy among different places. Moreover, the pluviometric regime also differs inside the basin generating differences in the rate of water loss by the process of intercepted water evaporation.
The objective of this study is to deepen the knowledge about the seasonal and spatial variation of the evaporation of the water intercepted by the Amazon Forest. It is investigated the individualized contribution of the rain events, intensity and recurring period, in the transfer of water vapor to the atmosphere.
It was used the rainfall patterns observed in the course of the two-years in the places of Ji-Paraná-RO, Manaus-AM and Marabá.
In general, during the most humid months there is a larger contribution of the intercepted water evaporation in the total amount evapotranspired. During the driest months, although the intercepted totals are smaller, larger occurrence of low intensity rains exists, favoring a relative increase in the contribution of this component in the total transfer of water to the atmosphere.
Porto Velho and Manaus present very close annual totals of rain, however, Porto Velho presents a larger frequency of low intensity rains and is subject of greater losses of water by the interception process.