Amazon forest biomass density maps: tackling the uncertainty in carbon emission estimates     

Jean Pierre Ometto  Ana Paula Aguiar  Talita Assis  Luciana Soler  Pedro Valle  Graciela Tejada  David M. Lapola  Patrick Meir 《Climatic change》2014,124(3):545-560

As land use change (LUC), including deforestation, is a patchy process, estimating the impact of LUC on carbon emissions requires spatially accurate underlying data on biomass distribution and change. The methods currently adopted to estimate the spatial variation of above- and below-ground biomass in tropical forests, in particular the Brazilian Amazon, are usually based on remote sensing analyses coupled with field datasets, which tend to be relatively scarce and often limited in their spatial distribution. There are notable differences among the resulting biomass maps found in the literature. These differences subsequently result in relatively high uncertainties in the carbon emissions calculated from land use change, and have a larger impact when biomass maps are coded into biomass classes referring to specific ranges of biomass values. In this paper we analyze the differences among recently-published biomass maps of the Amazon region, including the official information used by the Brazilian government for its communication to the United Nation Framework on Climate Change Convention of the United Nations. The estimated average pre-deforestation biomass in the four maps, for the areas of the Amazon region that had been deforested during the 1990–2009 period, varied from 205?±?32 Mg ha^?1 during 1990–1999, to 216?±?31 Mg ha^?1 during 2000–2009. The biomass values of the deforested areas in 2011 were between 7 and 24 % higher than for the average deforested areas during 1990–1999, suggesting that although there was variation in the mean value, deforestation was tending to occur in increasingly carbon-dense areas, with consequences for carbon emissions. To summarize, our key findings were: (i) the current maps of Amazonian biomass show substantial variation in both total biomass and its spatial distribution; (ii) carbon emissions estimates from deforestation are highly dependent on the spatial distribution of biomass as determined by any single biomass map, and on the deforestation process itself; (iii) future deforestation in the Brazilian Amazon is likely to affect forests with higher biomass than those deforested in the past, resulting in smaller reductions in carbon dioxide emissions than expected purely from the recent reductions in deforestation rates; and (iv) the current official estimate of carbon emissions from Amazonian deforestation is probably overestimated, because the recent loss of higher-biomass forests has not been taken into account.  相似文献   

Use of radon isotopes,gamma radiation and dye tracers to study water interactions in a small stream in Brazil   总被引：1，自引：0，他引：1  

Vinícius V. M. Ferreira  Rubens M. Moreira  Zildete Rocha  Cláudio J. Chagas  Raquel L. M. Fonseca  Talita O. Santos  Paulo C. H. Rodrigues  Maria Angela B. C. Menezes 《Environmental Earth Sciences》2018,77(19):699

In this study, natural (²²²Rn) and fluorescent (uranin) tracers were used to investigate the interactions between surface and subsurface waters in a small hydrographical basin located in the southeast region of Brazil. Levels of ²²²Rn were measured in 117 water samples with the use of an alpha solid-state detector. After the identification of the probable discharge sections along the stream, a measurement of the natural flows, upstream and downstream of these sections, was done with the use of a fluorimeter and fluorescent tracers. Also, scanning was done to verify a correlation between the natural gamma radiation and the ²²²Rn in the areas where its activity was higher. The results showed some sections where the ²²²Rn activity is more significant and contributed to the growth of the flows along the stream. It was possible to confirm a correlation between the discharge sections and the natural gamma radiation, what can be used as a preliminary approach to finding these sections in scenarios similar to the one studied here.  相似文献   

Pilocarpus microphyllus seedling growth threatened by climate change: an ecophysiological approach     

Amaral  Genilda Canuto  Pezzopane  José Eduardo Macedo  de Souza Nóia Júnior  Rogério  Martínez  Manuel Fernández  Fonseca  Mariana Duarte Silva  Gibson  Elbya Leão  Toledo  João Vitor  Pezzopane  José Ricardo Macedo  Klippel  Valéria Hollunder  Xavier  Talita Miranda Teixeira 《Theoretical and Applied Climatology》2022,147(1-2):347-361

Theoretical and Applied Climatology - The climate change endangers many species of the Amazon Forest. An example, in the endangered medicinal species Pilocarpus microphyllus (popularly known as...  相似文献   

Unraveling Hydrocarbon Microseepages in Onshore Basins Using Spectral–Spatial Processing of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Data     

Talita Lammoglia  Carlos Roberto de Souza Filho 《Surveys in Geophysics》2013,34(3):349-373

This study focuses on the spectral characterization of superficial effects caused by natural gaseous hydrocarbon (HC) escapes (microseepages) on onshore basins and means to detect the phenomena using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery. The Northern Tucano basin (NTB) (Brazil) displays archetypal onshore microseepages, and it is used here as a case study area. Regional HC geochemical data yielded from NTB soil samples helped to outline the strategies for imagery processing and assessment of results. We firstly devised a generic detection model for onshore basins in which microseepages indicated by HC geochemistry should spatially match a number of surface expressions with key remote sensing signatures, such as bleached soil and rocks (i.e., reduction in Fe³⁺ to Fe²⁺), concentration of specific clays (kaolinite), and carbonates (siderite) and geobotanical markers. These evidences guided the use of remote sensing data and information extraction techniques to find more sites favorable to host HC microseepages in the NTB. ASTER data processed through spectral mixing analysis and supervised and unsupervised neural network systems highlighted sites where features predicted in the detection model concurred seamlessly with geochemical anomalies. The approach also revealed other sites with similar characteristics, but for which no geochemical data exist. These sites are taken as new potential targets for the presence of microseepages and possibly HC reservoirs. The research demonstrated the potential of remote sensing data and spectral–spatial methodologies for economical, onshore detection of HCs for exploration purposes. Potential ramifications of the study include indirect detection of gaseous HC reservoirs in terrestrial planets (fostering the search for signs of life) and depiction of non-negligible, replenishable continental sources of HC emissions on Earth that may contribute to global warming.  相似文献