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1.
Field measurement programs in Brazil during the dry seasons in August and September 1979 and 1980 have demonstrated the large importance of the continental tropics in global air chemistry. Many important trace gases are produced in large amounts over the continents. During the dry season, much biomass burning takes place, especially in the cerrado regions, leading to a substantial emission of air pollutants, such as CO, NO x , N2O, CH4 and other hydrocarbons. Ozone concentrations are enhanced due to photochemical reactions. The large biogenic organic emissions from tropical forests play an important role in the photochemistry of the atmosphere and explain why CO is present in such high concentrations in the boundary layer of the tropical forest. Carbon monoxide production may represent more than 3% of the net primary productivity of the tropical forests. Ozone concentrations in the boundary layer of the tropical forests indicate strong removal processes. Due to atmospheric supply of NO x by lightning, there is probably a large production of O3 in the free troposphere over the Amazon tropical forests. This is transported to the marine-free troposphere and to the forest boundary layer.  相似文献   

2.
Agriculture appears to be one of the human activities most vulnerable to climatic changes due to its large dependence on environmental conditions. However, the diversity of Brazilian environmental conditions could be of great advantage to adapting this sector to new climatic conditions, which should be assessed as in this study on shifting Arabica coffee cultivation to the extreme south of the country. The methodology applied is the same the one used to define climatic risks in current productive regions of Brazil and their vulnerability to climatic change predicted by IPCC reports. The basic climatic parameters applied were frost probability and annual average temperature, since annual water deficit did not prove to be a restricting factor for Arabica coffee cultivation in the study area. The climatic conditions suitable for coffee production are: annual average temperature between 18??C and 22??C, annual water deficit less than 100?mm and frost probability (risk of lowest annual temperature less than 1??C) less than 25%. An area is said to have ??low climatic risks?? for coffee production when these three climatic conditions are met. Current climatic conditions were used and simulations of four temperature increases between 1??C and 4??C were also performed. The results indicated a substantial increase in the size of low climatic risks areas for the production of Arabica coffee in the extreme south of Brazil, mainly for mean temperature increases of 3??C in the study area in relation to present conditions. Increases of 2??C and 4??C were also favorable, but not as good as those obtained for 3??C. It should be underscored that areas with low climatic risks will be able to be found mainly in the extreme south of the study region, the border with Uruguay and North of Argentina.  相似文献   

3.
Brazil suffers yearly from extreme weather and climate events, which can be exacerbated in a warmer climate. Although several studies have analyzed the projections of climate change in Brazil, little attention has been paid to defining the locations that can be most affected, and consequently have a more vulnerable population, in a spatially-explicit form. This study presents a spatial analysis of summarized climate change data and a joint investigation combining these possible climate changes and social vulnerability indicators in Brazil. The Regional Climate Change Index (RCCI), which can synthesize a large number of climate model projections, is used for the climate analysis, and the Socio-Climatic Vulnerability Index (SCVI) is proposed to aggregate local population vulnerabilities to the climate change information. The RCCI results show climatic hotspots emerging in Brazil, covering the western portion of the Northeast (NE), northwestern Minas Gerais state and center-western (CW) and northern regions (N), except northeast Pará and Amapá states. The SCVI analysis reveals major socio-climatic hotspots in the NE and several localized hotspots in some of the major Brazilian metropolitan regions, namely Manaus, Belo Horizonte, Brasília, Salvador, Rio de Janeiro and S?o Paulo. The two novelties of this study are a spatially detailed analysis of the RCCI in Brazil and the development of an index that can summarize the large amount of climate model information available today with social vulnerability indicators. Both indices may be important tools for improving the dialogue between climate and social scientists and for communicating climate change to policymakers in a more synthetic and socially relevant form.  相似文献   

4.
Theoretical and Applied Climatology - Air temperature and relative humidity are the main drivers of many fungal diseases, such as moniliasis (Moniliophthora roreri), which affects cocoa production...  相似文献   

5.
Providing food and other products to a growing human population while safeguarding natural ecosystems and the provision of their services is a significant scientific, social and political challenge. With food demand likely to double over the next four decades, anthropization is already driving climate change and is the principal force behind species extinction, among other environmental impacts. The sustainable intensification of production on current agricultural lands has been suggested as a key solution to the competition for land between agriculture and natural ecosystems. However, few investigations have shown the extent to which these lands can meet projected demands while considering biophysical constraints. Here we investigate the improved use of existing agricultural lands and present insights into avoiding future competition for land. We focus on Brazil, a country projected to experience the largest increase in agricultural production over the next four decades and the richest nation in terrestrial carbon and biodiversity. Using various models and climatic datasets, we produced the first estimate of the carrying capacity of Brazil's 115 million hectares of cultivated pasturelands. We then investigated if the improved use of cultivated pasturelands would free enough land for the expansion of meat, crops, wood and biofuel, respecting biophysical constraints (i.e., terrain, climate) and including climate change impacts. We found that the current productivity of Brazilian cultivated pasturelands is 32–34% of its potential and that increasing productivity to 49–52% of the potential would suffice to meet demands for meat, crops, wood products and biofuels until at least 2040, without further conversion of natural ecosystems. As a result up to 14.3 Gt CO2 Eq could be mitigated. The fact that the country poised to undergo the largest expansion of agricultural production over the coming decades can do so without further conversion of natural habitats provokes the question whether the same can be true in other regional contexts and, ultimately, at the global scale.  相似文献   

6.
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8.
Montreal Protocol implementation programmes are not as straightforward a task in developing countries as it may seem to the developed world. The market is the driving force in Brazil and the country is under pressure to follow the pace of the developed countries despite the grace period allowed. The lack of a well established national infrastructure to monitor the process closely puts the implementation plan at risk. Leadership and contact points are not well defined for those seeking information and the financial support available from the Multilateral Fund. Regulatory agencies have neither the regulations nor the action programmes to ensure enforcement. The establishment of a National Task Group Office and investment in education and training are also necessary tools to patch some of the ‘holes’.  相似文献   

9.
10.
While the global community is seeking to reduce fossil fuel consumption, a parallel but equally important issue is the environmental impacts of increased world consumption of beef. We provide a comparative analysis and synthesis of the expansion of beef cattle production and its regional and global environmental impacts for Queensland (Australia), Colombia and Brazil. Evidence assembled indicates that rising beef consumption is a major driver of regional and global change, and warrants greater policy attention. We propose four policy imperatives to help mitigate escalating environmental impacts of beef: stop subsidising beef production and promoting beef consumption; control future expansion of soybeans and extensive grazing; protect and restore regrowth forests in grazing lands; and allocate resources to less environmentally damaging alternative land uses.  相似文献   

11.
The study estimated, for the first time, the greenhouse gas emissions associated with cattle raising in Brazil, focusing on the period from 2003 to 2008 and the three principal sources: 1) portion of deforestation resulting in pasture establishment and subsequent burning of felled vegetation; 2) pasture burning; and 3) bovine enteric fermentation. Deforestation for pasture establishment was only considered for the Amazon and Cerrado. Emissions from pasture burning and enteric fermentation were accounted for the entire country. The consolidated emissions estimate lies between approximately 813 Mt CO2eq in 2008 (smallest value) and approximately 1,090 Mt CO2eq in 2003 (greatest value). The total emissions associated with Amazon cattle ranching ranged from 499 to 775 Mt CO2eq, that of the Cerrado from 229 to 231 Mt CO2eq, and that of the rest of the country between 84 and 87 Mt CO2eq. The full set of emissions originating from cattle raising is responsible for approximately half of all Brazilian emissions (estimated to be approximately 1,055 Mt CO2eq in 2005), even without considering cattle related sources not explicitly estimated in this study, such as energy use for transport and refrigeration along the beef and derivatives supply chain. The potential for reduction of greenhouse gas emissions offered by the Brazilian cattle industry is very high and might constitute Brazil’s most important opportunity for emissions mitigation. The study offers a series of policy recommendations for mitigation that can be implemented by public and private administrators at a low cost relative to other greenhouse gas reduction options.  相似文献   

12.
The intracloud to cloud-to-ground lightning flash ratio (Z) has been estimated for the first time in Southeastern Brazil and in the tropical region using the Lightning Imaging Sensor (LIS) and Brazilian lightning detection network (BrasilDat) lightning data obtained from 1999 to 2005. Geographical variations of Z and their relation to elevation, latitude, precipitation, total lightning density and percentage of positive CG lightning will be discussed. Daily variations of Z will also be presented. The results suggest that Z values are similar to studies outside the tropics and that are influenced by orographic features.  相似文献   

13.
Rescaled Range Analysis of Pluviometric Records in Northeast Brazil   总被引:1,自引:0,他引:1  
Summary  We investigate whether the rainfall distribution of a drought prone region is characterized by different scaling properties in comparison to those in temperate regions of the world. We present a Rescaled Range (R/S) analysis of precipitation time series for 21 stations in northeast Brazil. In order to avoid the inclusion of short term variability, the data were smoothed by a moving average procedure. Three different algorithms were applied to the data: the empirical procedure proposed by Hurst; the evaluation of the standard mean deviation around the average profile; the evaluation ofthe mean deviation around the best fit line. The latter two methods have also been used for the evaluation of the nature of surface irregularities (rugosity) in surface profiles. The results obtained by the R/S method point to an average value H=0.709 > 0.5. This value indicates that the records show a degree of persistence quite close to that found for 10 stations in Spain. It also shows that drought occurrence does not alter the persistence of the rainfall distribution. Received July 13, 1998 Revised January 11, 1999  相似文献   

14.
Among several urban design parameters, the height-to-width ratio (H/W) and orientation are important parameters strongly affecting thermal conditions in cities. This paper quantifies changes in thermal comfort due to typical urban canyon configurations in Campinas, Brazil, and presents urban guidelines concerning H/W ratios and green spaces to adapt urban climate change. The study focuses on thermal comfort issues of humans in urban areas and performs evaluation in terms of physiologically equivalent temperature (PET), based on long-term data. Meteorological data of air temperature, relative humidity, wind speed and solar radiation over a 7-year period (2003–2010) were used. A 3D street canyon model was designed with RayMan Pro software to simulate the influence of urban configuration on urban thermal climate. The following configurations and setups were used. The model canyon was 500 m in length, with widths 9, 21, and 44 m. Its height varied in steps of 2.5 m, from 5 to 40 m. The canyon could be rotated in steps of 15°. The results show that urban design parameters such as width, height, and orientation modify thermal conditions within street canyons. A northeast–southwest orientation can reduce PET during daytime more than other scenarios. Forestry management and green areas are recommended to promote shade on pedestrian areas and on façades, and to improve bioclimate thermal stress, in particular for H/W ratio less than 0.5. The method and results can be applied by architects and urban planners interested in developing responsive guidelines for urban climate issues.  相似文献   

15.
This study evaluated the effects of climate change on sugarcane yield, water use efficiency, and irrigation needs in southern Brazil, based on downscaled outputs of two general circulation models (PRECIS and CSIRO) and a sugarcane growth model. For three harvest cycles every year, the DSSAT/CANEGRO model was used to simulate the baseline and four future climate scenarios for stalk yield for the 2050s. The model was calibrated for the main cultivar currently grown in Brazil based on five field experiments under several soil and climate conditions. The sensitivity of simulated stalk fresh mass (SFM) to air temperature, CO2 concentration [CO2] and rainfall was also analyzed. Simulated SFM responses to [CO2], air temperature and rainfall variations were consistent with the literature. There were increases in simulated SFM and water usage efficiency (WUE) for all scenarios. On average, for the current sugarcane area in the State of São Paulo, SFM would increase 24 % and WUE 34 % for rainfed sugarcane. The WUE rise is relevant because of the current concern about water supply in southern Brazil. Considering the current technological improvement rate, projected yields for 2050 ranged from 96 to 129 t?ha?1, which are respectively 15 and 59 % higher than the current state average yield.  相似文献   

16.
Modeling monthly mean air temperature for Brazil   总被引:1,自引:1,他引:0  
Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant (α?≤?0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67?×?108?pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.  相似文献   

17.
Heavy rainfall events in austral summer are responsible for almost all the natural disasters in Southeast Brazil. They are mostly associated with two types of atmospheric perturbations: Cold Front (53%) and the South Atlantic Convergence Zone (47%). The important question of what synoptic characteristics distinguish a heavy rainfall event (HRE) from a normal rainfall event (NRE) is addressed in this study. Here, the evolutions of such characteristics are identified through the anomalies with respect to climatology of the composite fields of atmospheric variables. The anomalies associated with HRE are significantly more intense than those associated with NRE in all fundamental atmospheric variables such as outgoing long-wave radiation, sea-level pressure, 500-hPa geopotential, lower and upper tropospheric winds. The moisture flux convergence over Southeast Brazil in the HRE composites is 60% larger than in the NRE composites. The energetics calculations for the HRE that occurred in the beginning of February 1988 strongly suggest that the barotropic instability played an important role in the intensification of the perturbation. These results, especially the intensities of the wind, pressure anomalies, and the moisture convergence are useful for the meteorologists of the Southeast Brazil for forecasting heavy precipitation.  相似文献   

18.
The impacts of global warming on farmers in Brazil and India   总被引:1,自引:0,他引:1  
How big a threat is global warming to climate-sensitive and economically important sectors such as agriculture in developing countries? How well will farmers be able to adapt to the threats of global warming? This paper attempts to shed light on these two important questions. A cross-sectional analysis is employed to estimate the climate sensitivity of agriculture in Brazil and India. Using panel data from both countries, the study measures how net farm income or property values vary with climate, and consequently, how farmers in India and Brazil react and adapt to climate. The estimated relationships are then used to predict the consequence of alternative climate scenarios. Global warming by the end of the next century could cause annual damages in Brazil between 1% and 39% and between 4% and 26% in India, although some of this effect may be potentially offset by carbon fertilization. These estimates do not factor into account climate-induced extreme weather events.  相似文献   

19.
One of the most significant impacts of the United Nations Framework Convention on Climate Change (UNFCCC) has been the establishment of a participatory process for Reducing Emissions from Deforestation and Forest Degradation (REDD+). We analyse the case of Brazil, the country whose land-use emissions from deforestation and forest degradation have declined the most. Through semi-structured interviews with 29 country policy experts – analysed in full text around 7 categories of activities that existing literature identifies as central elements of an effective governance system – we find weak links between the international REDD+ system and what actually happens on the ground inside Brazil. The greatest weaknesses are rooted in the absence of any formal learning system, which prevents higher-level efforts from obtaining useful feedback from lower-level entities responsible for implementation. Analytically our approach is rooted in the idea of ‘experimentalist governance’ in which local policy experiments map the space of what is possible and effective with transformative land policy. These experiments provide information to broader international initiatives on how local implementation shapes the ability and strategy to reach global goals. The Brazilian experience suggests that even when international funding is substantial, local implementation remains a weak link. REDD+ reforms should focus less on the total amount of money being spent and much more on how those funds are used to generate useful local policy experiments and learning.

Key policy insights

  • A nascent system of experimentalist governance to implement REDD+ is taking shape in Brazil. However, the potential for experimentalism to improve policy reforms within Brazil is far from realized;

  • Experimentalist problem-solving approaches could have a big impact on REDD+ with stronger incentives to promote experimentation and learning from experience;

  • Reforms to REDD+ incentive schemes should focus less on the total amount of money being spent and more on whether those funds are actually generating experimental learning and policy improvement – in Brazil and in other countries struggling with similar challenges.

  相似文献   

20.
The present paper aims of computing climatology and trend analysis of occurrence and intensity of extreme events of precipitation in subregions of Northeast Brazil (NEB). We used daily rainfall data of 148 rain gauges collected from the hydrometeorological network managed by the National Water Agency during 1972 to 2002 and used quantiles technique in order to select rainfall events. Defining heavy rainfall events as those when at least one rain gauge recorded rainfall above the 95th percentile, normal rainfall was between the 45th and 55th percentiles, and weak rainfall events were under the 5th percentile. The Mann-Kendall nonparametric test was used to calculate the linear trend of the quantity and intensity of rainfall events. The NEB was divided in five subregions using the cluster analysis based on Euclidean distance and Ward’s method: Northern coast, Northern semiarid, Northwest, Southern semiarid, and Southern coast. The results suggest that the subregions are less influenced by El Niño and La Niña, and dry areas have higher variability, with the greatest number of intense events.  相似文献   

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