A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Development of new Instrumentation for Accurate Measurement of Throughfalland Stemflow, and the Coupling of this in the study of Water Interception for anUndisturbed Rainforest in Central Amazonia.Luz Adriana Cuartas-Pineda 1 , Antonio D. Nobre 1 , Martin Hodnett 2 ,Alessandro C. Araújo 1 , Ari O.Marques 1 , Javier Tomasella 31 Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Brazil2 Centre for Ecology and Hydrology, Grã-Bretanha3Instituto Nacional de Pesquisas Espaciais – INPE, Cachoeira Paulista, BrazilAv. André Araújo, 2936, INPA, CEP:69083-000, Tel: 00 55 92 643 3153.E-mail: lacuarta@inpa.gov.brAbstractThis work is part of a project that aims at quantifying the C fluxes associated to thewater cycle, in a 5 km 2 catchment in the INPA Manaus-Cuieiras reservation. The shorttermwater balance (daily, weekly, monthly time scales) requires some variables, likeinterception, that for the long-term estimations (like the ones to feed climate models)could be negligible in the volumetric sense, once canopy storage of water is near to nil.However, interception is closely related to the energy balance through its effects onevaporation. Thus, interception is a crucial component of the energy budget that hasbeen very poorly quantified due to difficulties associated to inherent complexities of therainforest environment. Therefore, we have designed and developed a new permanentand tiping-bucket gauged collector system for througfall and stemflow that is muchsuperior to the traditional array of collectors used in past studies. The unique feature ofthis system is the associated measurement of water vapor exchange at the interfaceforest-atmosphere using a tower and eddyflux covariance. Previous studies had to relyon estimations or empirical measurements of evapotranspiration. Throughfall is gaugedthrough two sets of specially designed and built 5cm X 36 m V shaped troughs,connected each to a large volume tiping-bucket. Stemflow is collected fromaproximately 60 trees, that cover roughly the area of the throughfall study, usingencircling aluminum/asfalt tape shaped to divert the flow to a pipe system that join allthe flows into two tiping-bucket gauges. The measurement system is completed by avertical profile of surface wetness logging sensors and a free rainfall improved gaugingsystem.