Ivan B. T. Lima

Telemetric monitoring system for meteorological and limnological data acquisition

(2006). Telemetric monitoring system for meteorological and limnological data acquisition. SIL Proceedings, 1922-2010: Vol. 29, No. 4, pp. 1747-1750.

Water level dynamics in the Amazon floodplain

Abstract Nonlinear analysis of Amazonian River systems suggests that water level variability is due to Brownian-like motions BH. Dynamical properties of the water level is probably a response of rainfall and runoff smoothing by the stored water in the floodplain; additional inputs of water results in attenuated perturbations of the water level. This implies that noise is a self-affine fractal with scale invariance, and in accordance with surrogate and correlation dimension analysis, which refused the hypothesis of low dimensional chaos for water level dynamics. Opposing to the chaotic approach, we present a fractal model formed by a periodic signal and a BH process that mimics original water level variability. Dynamical exponents are remarkably similar between real and modeled data when BH influence is about 1% the amplitude of the periodic signal. In comparison to natural systems, a hydroelectric reservoir produces different exponents, due to the control of the water level, as demonstrated for the Tucurui dam in the Tocantins River. The Amazon floodplain at Obidos and Curuai exhibits a fortnight cycle most probably due to bore tide influence in the river mouth.

Sunlight effects on diel CO2 and CH4 emissions from a tropical reservoir

eurrent studies show that reservoirs are responsible for emissions of greenhouse gases (ST. Loms et al. 2000, DucHEMIN et al. 2002, SouMIS et al. 2004, ABRIL et al. 2005, LIMA et al. 2008). Surface waters of aquatic ecosystems exhibit supersaturated dissolved e02 (CüLE 1999, RICHEY et al. 2002) because respiration based on both autochthonous and allocthonous organic carbon usually exceeds primary production (DEL GIORGIO et al. 1997, CoLE 1999, JoNssoN et al. 2003). Dissolved organic carbon transported to the aquatic ecosystem from the drainage basin usually remains bio1ogically refractory. Upon exposure to sunlight in a relatively well-lit aquatic environment, however, terrigenous organic carbon might undergo photolytic degradation and become more labile (CoLE 1999). In spite ofphotominemlization, carbon dioxide effiuxes may also result from methanotrophic activities (FRENZEL et al. 1990, ABE et al. 2005, LIMA 2005) associated with diel oxygen production via photosynthesis (KING 1990, LIMA et al. 2005a). Moreover, diel changes in sunlight may also affect dissolved gas solubility and, in particular, surface water density, leading to convection during cooling events (MAclNTYRE et al. 2001). We evaluated possible ro les of sunlight on the daily variability of eH4 and eo2 diffusive fluxes from eorumbá reservoir in Brazíl. Our results support that eo2 and eH4 emissions in eorumbá are substantially influenced by sunlightinduced processes, although we cannot precisely identify the primary variables inducing diel changes.

Localização de áreas de monitoramento telemétrico em ambientes aquáticos da Amazônia

The present work illustrates the application of remote sensing and image processing methods to define appropriate sites for installing buoy moored telemetric systems at the surface of Amazon floodplain lakes for long-term limnologic-micrometeorologic monitoring. The technique consists essentially of Boolean operations over Amazon plume maps and historic inundation of the Curuai Lake at distinct stages of the hydrologic cycle. The precise location for the long-term monitoring is vital to the development of models concerning air-water trace gas exchange in the Amazon floodplains.