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Net primary production (NPP) is a key variable for monitoring and understanding the impacts of environmental change on ecosystems and for generating realistic global and regional carbon budgets. In this paper we present a regional algorithm (RATE) for automatically monitoring the rate of carbon fixation (as measured by NPP) of tropical forests in South America. The algorithm is based on a modification of the SITE ecosystem model and uses data obtained from the procedures for aggregation and correction of data from the MOD12Q1 and MOD15A2 products and meteorological data from the National Centers for Environmental Prediction (NCEP). A correction procedure for the MOD15A2 Leaf area index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) used by the RATE algorithm produced satisfactory LAI and FAPAR estimates when compared against observed values. The algorithm was successfully validated in eight field sites from two types of tropical forests in South America (Amazon rainforest and the Atlantic forest), producing an average error of only 4.72%. When applied to Amazonia, RATE indicates that NPP showed little variation in the 2005 and 2010 drought years (NPP = 1.28 kg-C m − 2 year − 1 ) in comparison to non-drought years (NPP = 1.31 kg-C m − 2 year − 1 ). RATE also provides some limited evidence for small decreasing trends in Amazonia carbon assimilation during the period 2001–2010.

It was aimed in this work, through the geospatialization, the identification of the apt, restricted and inapt regions for cultivation of coffee (Coffea arabica L.) in Rio Doce watershed. It was used for such, temperature and water deficit data of 50 meteorological stations installed in the watershed and in bordering watershed. The data of water deficit were determined using the water balance according to Thornthwaite & Mather (1955). They were identified equivalent regions the one third of the watershed, located in the central part and in the northeast of the same, as being inapt to the cultivation of coffee, according to the productivity criterions related with the thermal and hydric demands of culture.

Este trabalho avalia o estado-da-arte de modelos de simulação da taxa de fixação de carbono, ou produção primária liquida (NPP), de ecossistemas tropicais em duas configurações diagnósticas (simulação em sítios micrometeorológicos e simulação forçada por dados climáticos e por produtos de sensoriamento remoto) e uma prognóstica (simulação por um modelo acoplado clima-vegetação). Os resultados indicam que os modelos de estimativa de NPP atingiram capacidade de fazer estimativas não-viesadas de valores médios regionais de NPP, tanto no modo diagnóstico, quanto no modo prognóstico, com erros inferiores a 5%, enquanto o valor esperado do erro em cada sítio é inferior a 10% no modo diagnóstico e inferior a 20% no modo prognóstico. Os modelos estado-da-arte são capazes de monitorar a taxa de fixação de carbono por ecossistemas tropicais de maneira rotineira, sendo esperados baixos erros para essas estimativas. This work evaluates the state-of-the-art of the simulation of carbon fixation rates, or net primary production (NPP) by tropical ecosystems in two diagnostic configurations (simulation at micrometeorological sites and simulation forced by climate datasets and remote sensing products) and one prognostic (simulation by a coupled climate-biosphere model). The results indicate that the NPP simulation models are capable of unbiased estimates of average regional values of NPP, both in diagnostic and in prognostic mode, with errors smaller than 5%, while the expected value of the error in each site is smaller than 10% in the diagnostic mode and smaller than 20% in the prognostic mode. State-of-the-art models are capable of routinely monitoring the net primary production of tropical ecosystems, with low errors expected for these estimates.

Zhao and Running (Reports, 20 August 2010, p. 940) reported a reduction in global terrestrial net primary production (NPP) from 2000 through 2009. We argue that the small trends, regional patterns, and interannual variations that they describe are artifacts of their NPP model. Satellite observations of vegetation activity show no statistically significant changes in more than 85% of the vegetated lands south of 70°N during the same 2000 to 2009 period.