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Brasília, Brazil

Bielenki Junior C.,University of Sao Paulo | de Souza F.A.O.,Agencia Nacional de Aguas ANA | Mauad F.F.,University of Sao Paulo
Anuario do Instituto de Geociencias | Year: 2015

The application of regionalization methods is one of the most important procedures for the estimation of the streamflow discharge in ungauged rivers catchments and its automation can reduce both processing time and susceptibility to errors. The Environmental Systems Research Institute (ESRI), in cooperation with the Center for Research in Water Resources at University of Texas (CRWR), has developed the ArcHydro toolset, a geospatial data model designed for hydrological models and used to accumulate attributes in the hydrographical net, among other functionalities. The present paper addresses the automation of the low flow index Q95 accumulation in the Doce River Basin by ArcHydro and the application of the regionalization method based on the proportionality of the ratio discharge per unit of drainage area. The effects of the reservoirs operation on water availability were computed automatically in this process and reliable results time savings were achieves. © 2015, Universidade Federal do Rio de Janeiro. All rights reserved.

Vasconcellos R.M.,Federal Rural University of Rio de Janeiro | Araujo F.G.,Federal Rural University of Rio de Janeiro | De Sousa Santos J.N.,Federal Rural University of Rio de Janeiro | De Araujo Silva M.,Agencia Nacional de Aguas ANA
Marine Ecology | Year: 2010

Short-term dynamics in juvenile fish assemblage structure were studied to test whether the most abundant species show temporal segregation, in order to assess whether selected environmental variables could predict species groupings, and to examine the stability of sunset-day-sunrise-night differences. Samplings were collected at 3-h intervals over 48 h on a seasonal basis between spring 2005 and winter 2006. Fish species richness and abundance were higher in spring, and the lowest values occurred in winter. Harengula clupeola occurred mainly in spring, whereas Atherinella brasiliensis peaked in summer and autumn. On the other hand, Trachinotus carolinus, Umbrina coroides and Mugil liza were abundant in winter. Although temperature, salinity and dissolved oxygen were not found to have a strong effect on the abundance patterns of most species, they did appear to have a significant influence on assemblage groupings, according to canonical correspondence analysis and Spearman rank correlation. There is no consistency of diel usage patterns by a given species across seasons. The relative abundance differed between the time of day, which differed among the seasons; this further complicates an understanding of the dynamics of an assemblage. Studies of diel changes that pooled the sampling period as day or night can miss important changes that occur in a short time scale, such as a 3-h period. © 2010 Blackwell Verlag GmbH.

Filizola N.,Federal University of Amazonas | Latrubesse E.M.,University of Texas at Austin | Fraizy P.,French National Center for Scientific Research | Souza R.,University of the State of Amazonas | And 2 more authors.
Geomorphology | Year: 2014

Floods are fundamental components of Amazon nature and culture. The large flood of 2009, however, opened a new perspective on hazards and disasters in the Amazon basin. More than 238,000 residents from 38 municipalities were affected by floods along the Amazon River and lower reaches of its tributaries. Never before has a flood in the Amazon produced such a dramatic effect on the local population. The magnitude of the disaster suggested it was the largest recorded Amazon flood since the beginning of measurements in 1928 at Óbidos and that it could represent the largest recorded flood on Earth. A complex combination of atmospheric and hydrologic factors made the 2009 Amazon flood the most hazardous. It was the result of large scale and regional climatic events, non-typical mechanisms of flood transmission generating complex inter-relations in time and space between the main system and the tributaries, and recent urban growth of riverine cities without adequate planning. Our measurements at Óbidos, however, indicate that the 2009 flood was the highest recorded Amazon stage, but most likely not the largest water discharge. We propose as well that the magnitude of the Amazon floods at Óbidos has been overestimated for decades and that the available values of flood discharge have been a source of error for a multidisciplinary set of scientists developing climate and environmental modeling. © 2013 Elsevier B.V.

Remotely sensed evapotranspiration estimations have been used for the calculation of the water balance in hydrographical basins, the definition of aquifer recharge, and the monitoring of drought events. However, there are limitations on local scale applications, such as agricultural management and hydrological modeling that arise from the lack of spatial resolution or the low frequency of image acquisition of current polar satellite constellations. The present article puts forward a procedure to improve the spatial resolution of evapotranspiration estimations obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS), from 1 km to 500 meters resolution. The procedure is based on the disaggregation of the thermal band before estimating of evapotranspiration. Comparison with the ASTER sensor, at 500 meters resolution, indicates a mean error of 25 W m-2 and a correlation coefficient of 0.95.

The objective was to evaluate the influence of particle size of the solid ground corncob and sugarcane bagasse, used as filter materials, the efficiency of removing pollutants from swine wastewater (SWW). It was used columns containing the filtering material in three particle sizes (0.84 to 1.19; 1.19 to 2.00 and 2.00 to 2.83 mm). To evaluate the efficiency of the system, the influent and effluent were characterized in relation to the following parameters: biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total solids (TS), total nitrogen (total-N) total phosphorus (total-P), potassium (K), sodium (Na), total copper (total-Cu) and total zinc (total-Zn). Curves were generated by relating the relative concentrations of the variables and the depth of the filtered SWW. The lowest concentrations of BOD in the effluent were obtained, in general, filters made of materials in its largest size; the removals of COD, TS, total-N, total-P were not significantly influenced by the size of the filter materials; the Na and the K had not been retained in the filter materials, in none of the grain sizes studied, however the removal of total-Zn and total-Cu were generally higher in filters consist of filter materials of smaller particle size.

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