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Relação do padrão sazonal da vegetação com a precipitação na região de Cerrado da Amazônia Legal, usando índices espectrais de vegetação

A precipitação é um dos principais fatores que determina a dinâmica sazonal da vegetação na região de savanas tropicais, como é o caso do cerrado brasileiro. Neste trabalho foram analisadas as relações da precipitação sazonal, com o comportamento sazonal das classes de uso e cobertura da...
  • por Portal Padrão
  • publicado
  • 26/08/2009
  • 1:01 PM

Precipitation and water vapor transport in the Suthern Hemisphere with emphasis on the South American region

December to March climatologies of precipitation and vertically integrated water vapor transport were analyzed and compared in order to find the main paths by which moisture is fed to high rainfall regions in the southern hemisphere in this season. The southern tropics (20°S to 0°) exhibit high ra...
  • por Portal Padrão
  • publicado
  • 26/08/2009
  • 1:00 PM

Games on cellular spaces: an evolutionary approach

By using differential equations, evolutionary game theory shows that most of the games of competition for resources have equilibrium strategies named Evolutionary Stable. Although this approach can deduce these points, it is not possible to say how or whether a population will reach such equilibrium...
  • por Portal Padrão
  • publicado
  • 26/08/2009
  • 12:59 PM

Games on cellular spaces: an evolutionary approach.

By using differential equations, evolutionary game theory shows that most of the games of competition for resources have equilibrium strategies named Evolutionary Stable. Although this approach can deduce these points, it is not possible to say how or whether a population will reach such equilibrium...
  • por Portal Padrão
  • publicado
  • 21/08/2009
  • 1:41 PM

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

Current studies show that reservoirs are responsible for emissions of greenhouse gases (St. Louis 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 CO2 (Cole 1999, Richey et al. 2002) bec...
  • por Portal Padrão
  • publicado
  • 26/04/2009
  • 1:06 PM

Land change modeling and institutional factors: heterogeneous rules of territory use in the Brazilian Amazonia

Land changes are determined by a complex web of biophysical and socio-economic factors that interact in time and space, in different historical and geographical contexts, creating different trajectories of change. It is peopleís response to economic opportunities mediated by institutional factors t...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:46 PM

Spatial relations across scales in land change models

Land changes are the result of a complex web of interaction between human and biophysical factors, which act over a wide range of temporal and spatial scales. In this paper we conceptualize spatial relations among geographic objects at different scales. We analyze two types of spatial relations: hie...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:45 PM

Improving downscaling: South America Rainfall

However the spatial resolution of GCMs remains quite coarse , in the order of 300 x 300 km, and at scale , the regional and local details of the climate which are influenced by spatial heterogeneities in the regional physiography are lost. Therefore, there is the need to convert the GCM outputs into...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:44 PM

Measuring projections of climate change skill: South America precipitation using IPCC models

As Histoty embraces the beginning of a new millennium, old problem still constitute enormous challenges to the popoulation in general, and to the academic world in particular. It is now widely accepted that General Circulation Models (CCMs) represent the most satisfactory technique to answer these c...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:44 PM

Positive leader characteristics from high-speed video observations

Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be reso...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:43 PM

On the sensitivity of cloud-to-ground lightning activity to surface air temperature changes at different time scales in São Paulo, Brazil

This paper presents a study about the sensitivity of cloud-to-ground (CG) lightning activity to changes in surface air temperature at daily, monthly, yearly, and decadal timescales in the city of São Paulo (Brazil). Lightning data collected in the city by the Brazilian Lightning Detection Network (...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:42 PM

First versus subsequent return-stroke current and field peaks in negative cloud-to-ground lightning discharges

We examine relative magnitudes of electric field peaks of first and subsequent return strokes in negative cloud-to-ground lightning flashes recorded in Florida, Austria, Brazil, and Sweden. On average, the electric field peak of the first stroke is appreciably, 1.7 to 2.4 times, larger than the fiel...
  • por Portal Padrão
  • publicado
  • 23/08/2008
  • 3:41 PM