Navegando por Assunto "Climatologia"

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Acesso aberto (Open Access)
Análise dos efeitos térmicos de superfície na cidade de Belém-Pará-Brasil utilizando imagens de satélite
(Universidade Federal do Pará, 2011-08-12) CORRÊA, Leda Vilhena; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401
Using observational data of precipitation and air temperature from1967 to 2008, which drafted the climatology of these variables and analyzed the weather influenced by ENOS, were made an identification, characterization and analysis of spatial thermal effects in Belem (PA), from surface meteorological data and MODIS sensor images (which is prepared on a platform of the Aqua satellite). The average annual precipitation was 2978.6 mm/year, and presented an upward trend over the years, similar behavior has proved to the air temperature. In General, the results show two centers of greater intensity of surface temperatures: a center in Belem and another center in nearby town, Ananindeua. These centers vary spatially and temporally in intensity. During La Niña events, the center of heat island is located in the neighborhoods closest to Guajara Bay, while in the El Niño events, these neighborhoods have milder temperatures than the neighborhoods farther from water sources. The thermal amplitude of surface temperature between urban and rural areas varies greatly, with largest variation of 30,8°C and the lowest of 16,8°C. Thus, the highest surface temperatures were observed in neighborhoods with low NDVI, which is a consequence of a denser urbanization. Urban areas and most vegetated surfaces show cause/effect relationships very close, especially during the dry season, this can be realized by correlation that has value greater than 50%. This study presents results that assist in better understanding of behavior and spatial and temporal thermal effects in Belem, because the use of satellite images is important for the identification and characterization of climatic environmental conditions and urban heat islands.
Acesso aberto (Open Access)
Aspectos regionais da variabilidade de precipitação no estado do Pará: estudo observacional e modelagem climática em alta resolução
(Universidade Federal do Pará, 2009) LOPES, Marcio Nirlando Gomes; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685
The objective of the present work was to join different networks of surface weather stations to build a new integrated database, which it was generated a recent precipitation climatology (1978-2007) for the Pará state in high spatial resolution - 30 km, allowing better to identify the regional climatic variability that is influenced by the physiography aspects as well as large-scale climatic mechanisms of the Pacific and Atlantic Oceans. In addition, it was established an optimized configuration of the regional climatic model RegCM3 using two different cumulus parametrizations: RegCM3/Grell and RegCM3/MIT. 26 simulations (1982/83 to 2007/08) during the rainy season in Eastern Amazon (December to May) for each scheme of convective parametrization, using 30 km of space resolution, were generated. The results showed that the model is able to capture anomaly rainfall signs in the presence of extreme climatic forcing, as the El Niño-Southern Oscillation and the Atlantic dipole phases. RegCM3/MIT obtained better skill in the central region (Altamira) and reasonable performance in the Northeast (Belém), East (Marabá), Southeast (Conceição do Araguaia), and Northwest (Tiriós) sections over Pará state. RegCM3/Grell obtained reasonable skill in the Northeast, East, Southeast and Northwest areas. The North section (Macapá) was the most problematic region, with little or no sensibility presented by the model. Although RegCM3 has obtained reasonable results in most of the domain, systematic errors were detected in the regional simulations, overall those related to dry bias for RegCM3/Grell and wet bias for RegCM3/MIT in the South portion and dry bias in the North portion. These founding‟s denote the need of convection schemes adjustments to the regional conditions in eastern Amazon.
Acesso aberto (Open Access)
Classificação climatológica da energia potencial disponível para a convecção na cidade de Belém-PA
(Universidade Federal do Pará, 2014-12) SANTOS, Josiane Sarmento dos; MOTA, Maria Aurora Santos da; ROCHA, Edson José Paulino da
The climatological classification of the Convection Available Potential Energy (CAPE) was studied in order to verify both the possibility of convection to start and the organizational type, in Belém (Pará - PA, Brazil), associating it to extreme precipitation events (EEPRP). For the CAPE analysis, DTCEA's radiosonde data and precipitation measurements from the INMET's stations, in the period from 1987 to 2011, we used. It was observed that the local atmosphere presented favorable conditions for the development of deep convection, because the most frequent CAPE values were higher than 1000 J/Kg, representing 61% of all radiosonde measurements. According to some authors, a CAPE value of 1000J/Kg is the deep convection limit. The CAPE 2 and 3 classifications presented significant increasing tendencies along the years, whereas CAPE 1 showed a decrease. This is probably due to the air temperature increased at the city, impacting the CAPE value. A low correlation between CAPE and EEPRP, as well as between CAPE and Pacific Ocean Index and the Atlantic Interhemispheric Gradient. was also shown. Therefore CAPE is not sufficient condition for the formation of clouds and precipitation, since meso and large scale dynamical forcing are relevant contributors to the climate modulation on the city.
Acesso aberto (Open Access)
Climate estimates for Eastern Amazon with OLAM model
(2014-12) SILVA, Renato Ramos da; VITORINO, Maria Isabel; KUHN, Paulo Afonso Fischer; ANANIAS, Daniela dos Santos
The OLAM model has as its characteristics the advantage to represent simultaneously the regional and global meteorological phenomena using a refining grid scheme. During REMAM project OLAM was applied for a few case studies with the goal to evaluate its performance to estimate the regional climate for the eastern Amazon during periods of El Niño and La Niña. Case studies were performed for the rainy periods of the years 2010 and 2011 that were driven by distinct oceanic conditions. Initially, the model results were compared with local observations. The results demonstrated that OLAM was able to represent well the major precipitating regions, the diurnal temperature cycle evolution, and the wind dynamics. After that, analysis of the results demonstrated that if we provide good initial conditions and a good representation of the sea surface temperature evolution, OLAM is able to forecast with two or three months in advance if a rainy season would be wet or dry.
Acesso aberto (Open Access)
Climatologia da estrutura vertical da atmosfera em novembro para Belém-PA
(2010-06) ANANIAS, Daniela dos Santos; SOUZA, Everaldo Barreiros de; SOUZA, Paulo Fernando de Souza; SOUSA, Adriano Marlisom Leão de; VITORINO, Maria Isabel; TEIXEIRA, Gleyciano Mendes; FERREIRA, Douglas Batista da Silva
The present work reports a diagnostic study on the vertical structure of air temperature, dew point temperature and relative humidity over the region of Belém-PA (eastern Amazon), based on monthly dataset for a period of 26 years (1982 to 2007). The focus is on the transition period from dry to wet season in the eastern Amazon, i.e., the month of November. Two contrasting composites in relation to the rainfall regime were considered: the wet and the dry year's composites, which were established objectively by the percentiles method. The results showed that the main difference observed in the temperature and humidity profiles, comparing dry and wet years, occurs in the atmospheric layer between the middle and upper levels of the troposphere (between the patterns level from 700 hPa to 400 hPa). In this layer, the difference between air temperatures and dew point is significantly higher and the contrast of moisture associated with convection also shows the highest values. In general, the compositions showed that the temperature profiles anomalously warmer (cold) and the moisture profiles anomalously wetter (dry) are associate to the years of rainfall above (below) of normal in the region of Belém-PA.
Acesso aberto (Open Access)
Condições oceanográficas, ocupação territorial e problemas ambientais na praia do Atalaia (nordeste do Pará, Brasil)
(Universidade Federal do Pará, 2012-06-28) PINTO, Ketellyn Suellen Teixeira; COSTA, Rauquírio André Albuquerque Marinho da; http://lattes.cnpq.br/4504677939464624; PEREIRA, Luci Cajueiro Carneiro; http://lattes.cnpq.br/9883400404823218
The conservation and management of the coastal zone of the Amazon region demands special attention, given the richness of its natural resources. The aim of the present study was to evaluate the impact of natural events and human activities on Atalaia beach, situated in the NE of the Brazilian state of Pará and to develop guidelines for the implementation of coastal management programs. Data were collected between November, 2008, and November, 2010. Four sets of variables were assessed: (i) physical variables (climatology, hydrodynamics and morfodinâmica), (ii) hydrological variables (water temperature, salinity, pH, turbidity, dissolved oxygen and inorganics nutrients, chlorophyll a and thermotolerant coliform levels), (iii) urban development and (iv) spatial distribution of services and infrastructure. The results indicate that climate and hydrodynamical conditions were the main factors responsible for fluctuations in water salinity, turbidity, dissolved oxygen, inorganic dissolved nutrients, and chlorophyll a concentrations. The discharge of untreated domestic sewage was responsible for bacteriological contamination, although the rapid turnover of the high-energy hydrodynamic environment limited contamination by thermotolerant coliforms. This high hydrodynamic energy, primarily during the equinoctial spring tides, and the lack of urban planning, nevertheless generates other problems, such as coastal erosion. The study area is characterized by high rainfall rates (> 1900 mm during the rainy season), NE winds with mean speeds of up to 4.36 m/s in the dry season and 3.06 m/s in rainy season, macrotidal conditions (tidal range > 4.0 m), moderate tidal current speeds (up to 0.5 m/s), and significant wave heights up to 1.5 m. In March and June (rainiest months), ebb tide currents reached a maximal of 0.4 m/s. Tidal cycle was weakly asymmetric with the ebb tide lasting up to 6 hours 40 minutes. Wave energy was slightly modulated by the low tide due to wave attenuation on sand banks. Water temperature was relatively homogeneous (27.4ºC to 29.3ºC). Salinity varied from 5.7 (June) to 37.4 (November). The water was well oxygenated (up to 9.17 mg/L), turbid (up to 118 nephelometric turbidity units), alkaline (up to 8.68), and eutrophic (maximum of 2.36 μmol/L for nitrite, 24.34 μmol/L for nitrate, 0.6 μmol/L for phosphate, and 329.7 μmol/L for silicate), and it presented high concentrations of chlorophyll a (up to 82 mg/m³). The natural conditions observed in the present study indicate the need for a review of the hydrologic criteria used for the evaluation of beaches by national and international agencies and their adaptation to the reality of the Amazon Coast. The lack of a public sanitation system has led to bacteriologic contamination and the loss of water quality. With respect to morphodynamic state, dissipative conditions were found during high and moderate hydrodynamic energy (equinoctial and nonequinoctial condition), but in November the highest wave heights generated barred dissipative characteristic, whereas during the other months non-barred characteristics dominated. Thus, this study shows that the model proposed by Masselink & Short (1993) seems to be ideal to be applied to beaches with similar characteristics to the studied beach, where wave energy is modulated by the presence of sand banks in some stages of the tide.
Acesso aberto (Open Access)
Dinâmica de transmissão da malária na Amazônia Legal: determinantes ambientais, epidemiológicos e sua distribuição espaço-temporal
(Universidade Federal do Pará, 2016-04-20) PARENTE, Andressa Tavares; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685
Malaria is a worldwide parasite, concentrating mainly in tropical and subtropical locations. In Brazil, in the Legal Amazon region, it is characterized as an endemic disease, and it is responsible for more than 99% of the cases in the Nation. Its presence in the region has a multifactorial character, such as socioeconomic, demographic and environmental influences, and also some variables such as temperature, precipitation and deforestation. All of them influence the dynamics of the disease. The aim of this study was to comprehend the dynamics of malaria transmission in the Legal Amazon and the nine States that comprise of this region (Acre, Amapá, Amazonas, Maranhão, Mato Grosso, Pará, Rondônia, Roraima and Tocantins), establishing relations between the endemic indicators and the regional climate variability and deforestation rates. This study has 5 chapters. The first chapter contains the introduction, where there is the conceptualization of the theme and of the variables that are analyzed in the study, objective and the presentation of the structure of the following chapters. The second chapter talks about the analysis of the Plan of Intensification of Malaria Control Actions (PIACM) in the Legal Amazon, based in secondary data about malaria in the Legal Amazon from 1981 to 2015, and from 1990 to 2012 (by States). It was developed an intervention analysis model in time series with the use of dummy variables that established the Annual Parasite Index (API) average of occurrence before and after the intervention. The average API (after the intervention) had a 48% reduction between the averages from two time periods. Among the States the effect was differentiated, showing the highest impact in the reduction of Malaria in Mato-Grosso, Tocantins, Roraima and Maranhão. The third chapter analyzed the spatial dynamics of the incidence of malaria in the Legal Amazon, from 2003 to 2012, and its association with deforestation and precipitation using the spatial statistic techniques and also the local and global Moran’s index through the GeoDa Program. The global Moran’s index confirmed the spatial dependence for API, precipitation and deforestation among the States. It was identified the States that presented high priority (Acre, Amazonas and Roraima) and low priority (Maranhão, Tocantins and Pará) for the malaria intervention policies. The fourth chapter talked about the modulation of the precipitation and temperature over the incidence of malaria, in both current and in future climate scenarios, focusing on the seasonality, with different results for the States that are part of the Legal Amazon. The fifth chapter was based on the proposal of a model for malaria and quarterly variables involved in the study (precipitation, deforestation, SST of the oceans), and for the final model it was necessary to exclude the variable deforestation, being more significant for the model to utilize the other variables involved. The prevention policies expressed impacts on the series, which showed a decreasing tendency in the number of cases. The States exert influence among themselves on the pattern of Malaria occurrence, being the relations with the environmental variables differentiated in each State. The results indicate that the effects of the borders in the malaria cases in the western portion of the Legal Amazon has contributed to the values of this endemic disease. It is necessary to develop other strategies in order to control the management settings of malaria in the region and the allocation of resources to fight against this disease.
Acesso aberto (Open Access)
Os efeitos da subida do nível do mar sobre os manguezais do litoral sul da Bahia durante o Holoceno
(Universidade Federal do Pará, 2015-03-25) FONTES, Neuza Araújo; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
This work integrates the palinological, sedimentological and geomorphological data with radiocarbon dating, as well as δ13C and C/N from the sedimentary organic matter to identify the impact of changes in sea level and climate during the Holocene in Jucuruçu River’s mangroves, near the city of Prado, South Bahia. A sediment core with 4.5 m depth was sampled from a fluvial valley, 23 km away from the modern coastline. The base of sediment core presents age of 7450 cal yrs BP. The data reveal two important phases characterized by 1) an estuarine system with tidal flats colonized by mangroves. Its sedimentary organic matter is mainly sourced from estuarine algae during the early and middle Holocene; and 2) in the second phase, the mangroves shrank and herbaceous vegetation expanded. The δ13C and C/N values show an increase in contribution of terrestrial C3 plants. These phases identified in this study are in agreement with the relative sea-level (RSL) rise during the early and middle Holocene, and its subsequent fall during the late Holocene. In addition, the influence of weather patterns proposed for Holocene may be identified throughout the studied sediment core. Probably, changes in depositional environment and dominant vegetation at the study site were caused by the combined action of changes in RSL and fluvial discharge. According to the model proposed in this work, during the early and middle Holocene occurred a RSL rise that caused a marine incursion along the studied fluvial valley. The dry period occurred during the early and middle Holocene produced a decrease in the fluvial discharge and contributed to this marine transgression. However, during the late Holocene occurred a RSL fall and a wet period. It favored the marine regression and consequently, the mangroves migrated to tidal flats attached to the edge of lagoons near the modern coastline. The geomorphologic and vegetation evolution is in agreement with the mid-Holocene RSL maximum above present RSL and subsequent fall to the present time. Keywords: climate; Holocene; relative sea-level; South of Bahia; vegetation.
Acesso aberto (Open Access)
Eventos extremos da zona de convergência intertropical sobre o Atlântico durante o período chuvoso da Amazônia oriental
(Universidade Federal do Pará, 2008) FERREIRA, Douglas Batista da Silva; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685
This work reports an observational analysis of the climatological characteristics (period of 1985-2007) associated with the ITCZ extreme events, observed over the equatorial Atlantic Ocean, establishing its influences on the pluviometric variability over eastern Amazon, during the months of February, March and April. These events were selected objectively through Empirical Orthogonal Functions analysis, and the ocean-atmosphere patterns associated with ITCZ events, as well as, its impacts on eastern Amazon rainfall, were investigated through monthly composites. The results showed some monthly differences in the dynamical pattern related to the 200 hPa atmospheric circulation and configuration of vertical tropospheric motion, associated with the equatorial Hadley cell. Basically, the dynamic structure of the ocean-atmosphere patterns observed in February, March and April, showed that the ITCZ is formed over the equatorial Atlantic Ocean in a region of confluence between northeasterly and southerly winds that is coincident with areas of abnormally hotter SST, upward vertical air motion associated with the Hadley cell, and divergent outflow at high levels. The impacts of such events in the precipitation variability over the eastern Amazon, showed that the states affected by ITCZ are mainly Amapá, Pará and Maranhão. Additionally, it were reported some socio-environmental impacts (floods, falling trees, proliferation of diseases, among others) that occurred in the metropolitan area of Belém, associated with the occurrence of extreme weather events ITCZ selected in this work, associated to the presence of ITCZ over the region.
Acesso aberto (Open Access)
A Influência da Circulação de Revolvimento Meridional do Atlântico na Definição da Posição Média da ZCIT ao Norte do Equador. Uma Revisão
(Universidade Federal do Pará, 2016-12) AIMOLA, Luis Antônio Lacerda; MOURA, Mauricio do Nascimento
The Intertropical Convergence Zone (ITCZ) is considered the most important atmospheric system in the generation of precipitation in the tropics. Although in the present climate the annual average insolation is symmetrical around the equator, the ITCZ is positioned north of the equator, also having the maximum of precipitation there. In this review article we describe the vision developed in recent studies of the influence of the Atlantic Meridional Overturning Circulation on the Hadley cell in determining of the ZCIT's position asymmetry. We indicate the importance of strengthening this research topic in face of possible future displacements of the ITCZ with global warming and the consequent tropical rain regime changes.
Acesso aberto (Open Access)
Linhas de instabilidade e trocas turbulentas na interface floresta amazônica-atmosfera
(Universidade Federal do Pará, 2023-05-05) GONÇALVES, Marcos Barradas; COHEN, Júlia Clarinda Paiva; http://lattes.cnpq.br/0293299378753887; https://orcid.org/0000-0003-2048-8915; DIAS JÚNIOR, Cleo Quaresma; http://lattes.cnpq.br/9857237626091379; https://orcid.org/0000-0003-4783-4689
Squall lines (SLs) are convective phenomena that frequently occur in the tropical atmosphere and have been widely investigated by the scientific community. In this work, high-frequency experimental data were collected at the Amazon Tall Tower Observatory (ATTO) site during two years, one of which was considered “normal” (2014) and the other was a year of strong El Niño (2015), and the satellite images of the central region of the Amazonia. The objective was to investigate whether there is influence in El Niño years on the number of occurrence of SLs and consequently on the impact that these phenomena exert on precipitation, temperature, relative humidity, radiation and turbulent fluxes calculated by the turbulent eddies correlation method. For this, the average daily cycles of these magnitudes were used for different seasons and years. The results showed an increase in the occurrence of SLs in El Niño years. It was noted that during the presence of SLs, the following occurred: 1) high precipitation rates (on average 11.5 mm per event) being higher in El Niño years; 2) temperature decay of 2 and 2.5°C in 2014 and 2015, respectively; 2) temperature decay of 2 and 2.5 °C in 2014 and 2015, respectively; 3) increase in wind speed by 1.5 and 2 m s⁻², in 2014 and 2015; 4) decrease in shortwave radiation by more than 50% in 2014 and more than 70% in 2015, caused by cloud cover that reduced the passage of radiation; and 5) increase in relative humidity, being higher in the El Niño year. Regarding turbulent fluxes, there was a decrease of 35 W m⁻² in 2014 and 25 W m⁻² in 2015 in the sensible heat flux, and 90 W m⁻² in latent heat in the two years at the time of the SLs occurrence and the momentum flux presented values 3 times greater than the values registered hours before the occurrence of SL. The CO2 flux, on the other hand, had a increase of 13 and 22 μmol m⁻² s⁻¹ in 2014 and 2015, respectively, at the time of the occurrence of SLs due to the decrease in incident radiation, which impacted on the photosynthetic rates of plants. It is believed that these results are important, since the transport of water vapor and CO2 and consequently the hydrological and CO2 cycles can be altered by the presence of SLs and the occurrence of the El Niño. Consequently, in a scenario of climate change, where El Niños and SLs are expected to be more frequent, people's quality of life can be compromised.
Acesso aberto (Open Access)
Linhas de instabilidade e trocas turbulentas na interface floresta amazônica-atmosfera
(Universidade Federal do Pará, 2023-05-05) GONCALVES, Marcos Barradas; COHEN, Júlia Clarinda Paiva; http://lattes.cnpq.br/0293299378753887; https://orcid.org/0000-0003-2048-8915; DIAS JÚNIOR, Cleo Quaresma; http://lattes.cnpq.br/9857237626091379; https://orcid.org/0000-0003-4783-4689
Squall lines (SLs) are convective phenomena that frequently occur in the tropical atmosphere and have been widely investigated by the scientific community. In this work, high-frequency experimental data were collected at the Amazon Tall Tower Observatory (ATTO) site during two years, one of which was considered “normal” (2014) and the other was a year of strong El Niño (2015), and the satellite images of the central region of the Amazonia. The objective was to investigate whether there is influence in El Niño years on the number of occurrence of SLs and consequently on the impact that these phenomena exert on precipitation, temperature, relative humidity, radiation and turbulent fluxes calculated by the turbulent eddies correlation method. For this, the average daily cycles of these magnitudes were used for different seasons and years. The results showed an increase in the occurrence of SLs in El Niño years. It was noted that during the presence of SLs, the following occurred: 1) high precipitation rates (on average 11.5 mm per event) being higher in El Niño years; 2) temperature decay of 2 and 2.5°C in 2014 and 2015, respectively; 2) temperature decay of 2 and 2.5 °C in 2014 and 2015, respectively; 3) increase in wind speed by 1.5 and 2 m s⁻², in 2014 and 2015; 4) decrease in shortwave radiation by more than 50% in 2014 and more than 70% in 2015, caused by cloud cover that reduced the passage of radiation; and 5) increase in relative humidity, being higher in the El Niño year. Regarding turbulent fluxes, there was a decrease of 35 W m⁻² in 2014 and 25 W m⁻² in 2015 in the sensible heat flux, and 90 W m⁻² in latent heat in the two years at the time of the SLs occurrence and the momentum flux presented values 3 times greater than the values registered hours before the occurrence of SL. The CO2 flux, on the other hand, had a increase of 13 and 22 μmol m⁻² s⁻¹ in 2014 and 2015, respectively, at the time of the occurrence of SLs due to the decrease in incident radiation, which impacted on the photosynthetic rates of plants. It is believed that these results are important, since the transport of water vapor and CO2 and consequently the hydrological and CO2 cycles can be altered by the presence of SLs and the occurrence of the El Niño. Consequently, in a scenario of climate change, where El Niños and SLs are expected to be more frequent, people's quality of life can be compromised.
Acesso aberto (Open Access)
Pecuária e sustentabilidade: uma análise da produção de gado de corte em propriedades rurais no município de Paragominas, Estado do Pará
(Universidade Federal do Pará, 2016-09-29) AGUIAR, Andrea Farias do Nascimento; REBELLO, Fabrício Khoury; lattes.cnpq.br/8656930211054464; ADAMI, Marcos; lattes.cnpq.br/7484071887086439
Regulatory guidelines have in their policies the planning tool and transmutation of productive realities in man-environment relationship, making the market of the agricultural sector increasingly competitive and demanding as to reduce the impacts on climate, environment and society. The multiplicity of aspects involved delineate the transition to more sustainable production systems and dictate the pace of these changes. They also expose deep-rooted cultural traditions, technical and administrative deficiencies where individuals become synonymous with potentiation of economic matrix at the expense of social and environmental. Even before these contrasts the meaning of sustainability has been trivialized and used the favorable adjectives of agricultural production, whose practical realities in a broader context, not justify the positivism of marketing strategies. This case study aimed to evaluate the sustainability of beef cattle developed in properties located Paragominas, one of the Green Counties of Pará state. To this end, visits were undertaken in 17 properties taken as a reference in the region, of which collected productive, economic, social and environmental data with the help of special forms to characterize the producer profiles and landenvironmental production and properties. From the set of data indicators have been calculated, and established conformity in relation to the new sustainable guidelines based on Sustainable Livestock Working Group Criteria, chosen for its specificity and breadth policy. Both of them have been tabulated according to the categorized production systems. Emissions in GHGs and impacts on water resources were also estimated and perceptions of the main actors of the local livestock value chain recorded. The Barometer of Sustainability was the method of assessment used in both production level systems as the governing context. GHG emissions and impacts on water resources were calculated based on the methodology of the IPCC and Pereira (2012), respectively. The results showed that for the specific context of the production systems there was a concentration of properties ranging from the intermediate levels and potentially unsustainable. Increased the accuracy analysis for SFWG criteria, there was a downward migration to potentially unsustainable, and unsustainable levels, demonstrating the transience of any favorable status. Indicators of low productivity, profitability, costs efficiency, support of pasture capacity, recovery and job satisfaction were presented as recurring vulnerabilities in all systems analyzed. The environmental impacts demonstrate is proportional to the scale of production, coupled with the paradox that certain properties are fulfilling their social functions. The weak cohesion between the local livestock value chain agents is compounded by deficiencies of administration preventing the spread and consolidation of successful examples, as well as open space for practices focused on small groups of interests. Supported strategies for public-private partnerships, quality technical assistance and investments in Science, Technology and Innovation were recommended to overcome the specific disadvantages.
Acesso aberto (Open Access)
Processos autocíclicos e alocíclicos afetando os registros da paleoflora da foz do rio Jucuruçu, litoral sul da Bahia, durante os últimos 1000 anos
(Universidade Federal do Pará, 2016-06-07) MORAES, Caio Alves de; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
The vegetation holocenic history along the southern Bahia littoral is characterized by establishment, expansion and contraction phases of mangroves. This vegetation dynamics is mainly associated to climate change and to relative sea level oscillations. However, punctually and in a smaller time scales, for example, during the last 1000 years, other processes inherent to the sedimentary dynamics of depositional environment, termed autocyclic processes, are controlling the pollen assembly along stratigraphic profiles formed by active channels followed by its abandonment. Based on sedimentary features, pollen grains, isotopes (δ13C, δ15N C/N) and radiocarbon dating of sedimentary organic matter from two cores (PR-11 and PR-12) sampled from an abandoned meander and a tidal flat in the mouth of the Jucuruçu river, is proposed a model for evolution of a tidal channel surrounded by wetlands. The core PR-11, with 1.48 meters depth, was sampled from a mangrove zone, with a maximum age of 678 cal yr BP. The PR-12 was collected from a várzea vegetation, approximately 2.7 km from the current shoreline with 1.92 meters depth and, maximum age of 680 cal yr BP. The data present two facies associations: (A) Tidal channel, represented by massive sand deposits (facies Sm); cross-stratified sand (Scs) and facies flaser heterolithic bedding (Hf) and (B) Tidal plain, represented by facies wavy heterolithic bedding (Hw), lenticular heterolithic bedding (Hl), massive mud (Mm) and massive sand (Sm). The pollen data reveals that the facies association (A) presents absence of pollen grains of mangroves. It may have been caused be an intense activity of sediments reworking of channel margins and sediment deposition with pollen grains sourced from vegetation units not necessarily from the study site. In the top of the studied succession, in association facies (B), is possible to identify the establishment and expansion of mangroves in the newly formed tidal flat (PR-11) or lake (PR-12). Regarding the core PR-12, it is marked by channel abandonment. The reduced interaction between fluvial discharge and tidal waves have caused the infilling of mud sediments, and a highest potential for organic matter preservation. It provided conditions for the mangrove development and pollen preservation. In the case of PR-11, the tidal channel migration have caused the development of a tidal flat, which have favored the mangrove expansion. These depositional environments, favorable to the formation of mangroves, can be partially or completely modified by the natural dynamics of tidal channels and estuarine channels, which are under the influence of changes of sedimentary fluvial contribution on the shore and littoral drift processes along the coast associated with tides, waves and currents. These results were compared with some data from one core sampled 23 km upstream of Jucuruçu River that also indicated the presence of mangroves on tidal flat with estuarine organic matter during the early and middle Holocene, followed by herbaceous vegetation on a fluvial plain with organic matter sourced from freshwater during the late Holocene (Fontes, 2015). In this case, the sea level fluctuations and climate change were the main driving forces controlling the wetlands dynamics at the mouth of this river during the Holocene, characterizing an allocyclic process. However, considering the stratigraphic sequences of the analyzed cores in this master's work (PR-11 and PR-12), such sedimentary sequences associated with changes in vegetation and sources of organic matter are related to the infilling processes of coastal depressions, mainly marked by active channels, abandoned channels and tidal flats. Therefore, in a small time scale of coastal vegetation changes are not necessarily directly associated with sea-level and climate change (allocyclic processes). On the other hand, processes associated to the sedimentary dynamics of the depositional environment (autocyclic processes) must have controlled pollen assembly along the studied stratigraphic profiles.
Acesso aberto (Open Access)
Radar-observed spatial and temporal rainfall variability near the Tapajós-Amazon confluence
(Universidade Federal do Pará, 2014-12) COHEN, Júlia Clarinda Paiva; FIZJARRALD, David Roy; D'OLIVEIRA, Flávio Augusto Farias; SARAIVA, Ivan; BARBOSA, Illelson Rafael da Silva; GANDU, Adilson Wagner; KUHN, Paulo Afonso Fischer
Standard Amazonian rainfall climatologies rely on stations preferentially located near river margins. River breeze circulations that tend to suppress afternoon rainfall near the river and enhance it inland are not typically considered when reporting results. Previous studies found surprising nocturnal rainfall maxima near the rivers in some locations. We examine spatial and temporal rainfall variability in the Santarém region of the Tapajós-Amazon confluence, seeking to describe the importance of breeze effects on afternoon precipitation and defining the areal extent of nocturnal rainfall maxima.We used three years of mean S band radar reflectivity from Santarém airport with a Z-R relationship appropriate for tropical convective conditions. These data were complemented by TRMM satellite rainfall estimates. Nocturnal rainfall was enhanced along the Amazon River, consistent with the hypothesis that these are associated with the passage of instability lines, perhaps enhanced by local channeling and by land breeze convergence. In the daytime, two rainfall bands appear in mean results, along the east bank of the Tapajós River and to the south of the Amazon River, respectively.
Acesso aberto (Open Access)
Regimes térmico e hídrico em solos sob ecossistemas naturais e área agrícola no Leste da Amazônia
(Universidade Federal do Pará, 2007-12-14) CARVALHO, Saulo Prado; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
Soils temperature and moisture are variables whose knowledge is required to Determine the energy and water budgets in the biosphere. The thermal and hydric regimes of soils beneath each ecosystem, present considerable variations, according to their mineralogy, the local climate and vegetation. In this context, soil temperatures and moistures were measured under three ecosystems existing over the eastern portion of the Amazon Region, namely: native forest (Caxiuana's National Forest, 01° 42' 30" S and 51° 31' 45" W), pasture area (Soure, 00° 43' 25" S and 48° 30' 29" W) and cultivated area (Igarape-Acu, 01° 07' 59" S and 47° 36' 55" W). Field data at the forest and pasture sites were collected between December, 2001 and February, 2005; while at the cultivated area, the monitoring was limited to the August, 2003 to February, 2005, period. These observations of soil physical variables were analyzed taken into consideration the simultaneously measured meteorological variables such as the incoming solar radiation flux and pluviometric precipitation, which directly impacted the soil variables at each site selected for study. The soil temperatures were monitored by means of thermal sondes at 0.05, 0.2 and 0.5 m depths. Heat fluximeters, measured heat flux at 0.05 and 0.2 m depth levels. The upper 0.3 m soil layer bulk moisture was measured by double probe Time Domain Reflectometer (TDR) sondes at each site. Analyses were made, considering the soil responses during the local dry and rainy seasons at these three representative ecosystems of eastern Amazonia. Apparent thermal diffusivity estimates were made by the amplitude and phase methods, using the daily heating pulse propagation data in these soils. The results showed quite different values. However, the first approach seemed to be more reliable and suitable to numerical modeling. As expected, considering their small vegetation cover, the soil temperatures at the upper levels, presented larger variations at the pasture and cultivated sites. Unexpectedly, the temperatures at 0.5 m depth beneath the forest showed larger amplitude variations than at 0.2 and 0.05 m depths. The numerical modeling of time variations of temperature, as function of depth, for each soil was made through the harmonic method. The results showed that the first harmonic represented over 90% of the total variation of the observed daily pulse of temperature for the pasture and cultivated areas at 0.2 and 0.05 m depths. Similar performance of the modeling was observed for the forest at 0.05 and 0.20 m levels. The magnitude of heat fluxes beneath the pasture and cultivated sites reached values six times larger than those observed beneath the soil of the forest. The results also show that, for the upper 0.30 m layer of soils, the bulk moisture beneath the forest is larger than under the other ecosystems studied in this work. This result apparently is due to the forest's protection against the soils surface evaporation. An analysis of the seasonal and daily behavior of the soils temperature and moisture in response to the incoming solar radiation and precipitation are presented. Case studies of the rate of soil moisture losses after significant water recharge by precipitation events were also analyzed. Some estimates of daily water depletion and even, night recharge of moisture by rising water from lower layers to the 0.30 m layer were made. This work analyzed the largest time series of soil temperature and moisture data taken at high sampling rates, available so far, for eastern Amazonia. It was possible to characterize the differences of these physical variables regimes, beneath three important ecosystems in this Region. Further studies of the minerals and organic materials in these soils, as well as the foliar area and biomass indexes of their vegetation covers, would improve the comprehension of the regimes described in this work.
Acesso aberto (Open Access)
Variabilidade da precipitação em tempo e espaço associada à Zona de Convergência Intertropical
(2012-12) MOURA, Mauricio do Nascimento; VITORINO, Maria Isabel
This study aims to present an atmospheric analysis of spatial and temporal variability of the Intertropical Convergence Zone (ITCZ) in Belem, Jakarta and Nairobi, which are located on the continents of South America, Asia and Africa, respectively. For this, daily precipitation and observed long wave radiation data for the period 1999 to 2008 were used, and mathematical and statistical techniques, such as the arithmetic mean and the Morlet wavelet transform were applied. In general, the results indicate that spatially, the month rainfall varies considerably, since that the three studied cities are located far apart in different continents in the tropical zone. This occurs mainly during the months from January to May, period of greatest activity of the ITCZ in the southern hemisphere. The atmospheric variations observed from the phase wavelet scalograms indicate that the interdecadal scales, annual, interannual and intraseasonal scales are rainfall modulators. Such scales can be represented by the ocean-atmosphere phenomenon mechanisms of El Niño Southern Oscillation and intraseasonal oscillation of Madden and Julian. The contribution of these phenomena to the rainfall distribution over these regions is evident during the study period, and Nairobi, in spite of being located at latitude similar to that of Belem, shows low evidence of the annual cycle and high at interdecadal scale. In the case of Belem and Jakarta oscillations at multiscale rainfall concentrated in the mechanisms scales that modulate the rain associated with the annual cycle and intraseasonal cycle during the period.
Acesso aberto (Open Access)
Variabilidade interanual dos eventos extremos e a sua percepção pela comunidade de Santa Maria de Sirituba - PA
(Universidade Federal do Pará, 2017-12-13) CÂMARA, Renata Kelen Cardoso; PIMENTEL, Marcia Aparecida da Silva; http://lattes.cnpq.br/3994635795557609; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
The perception of extreme events by man interferes in the process of adaptation to the influence of extreme climatic variability. The perception approach constitutes an important tool for the understanding of the forms of relationship between individuals or societies with the environment in which they live. Considering the interference of extreme precipitation in socioeconomic and environmental activities and the relationship in the adaptation process, this study aimed to analyze the perception of riparian communities regarding the impacts of extreme events on their social, economic and environmental activities. The research contemplates the approach of extreme precipitating events in the Santa Maria Rio Sirituba -PA community, located in the eastern region of the Amazon. The study utilized time series of monthly precipitation, surface temperature anomaly of the Niño 3.4 region and the National Oceanic Atmospheric Administration (NOAA) North and South Atlantic basin from 01/01/1979 to 12/31/2015; and local subjective aspects through semi-structured questionnaires formulated according to the classification of Marconi and Lakatos (2003) and the proposal by Whyte (1977). The classification of extreme events was categorized by the Quantis technique and related to the El Niño Southern Oscillation (ENSO) phenomena both in its positive phase (El Niño) and in the negative phase (La Niña) and the Atlantic Dipole (ADP); the degree of perception was obtained through the method of the hierarchical analysis process. The results of the study indicated that extreme precipitation may be associated with years of ENSO events and ADP patterns, with ENSO events being characterized by the reduction and increase of rainfall in the study area; it was observed that the ADP pattern may favor or disfavor the accumulated rainfall, but its influences are related to the intensity of the ENSO phenomena. In the use of the Analytic Hierarchy Process (AHP), three levels of hierarchy were defined as level 1: Perception, that is, the objective of the hierarchy; level 2 are the decision criteria: leisure (C1), work (C2) and health (C3) and level 3 the determining factors: air temperature (A1), wind (A2), tide (A3) and rain (A4). Through the standard matrix of criteria and local average priorities it was observed that criterion C2 has the highest degree of importance with relative weight (WR) of 48.99%, then the criterion C3 with WR of 45.07% and lastly the criterion C1 with a lower degree of importance with WR of 5.94%. The Global Priority (GP) obtained indicated the alternative A4 with the highest noticeable degree of weather and climate for the rivers with GP of 37.94%, then the alternatives A3, A2 and A1, with GP of 31.41%, 22.86% and 7.79%, respectively. Finally, the results showed that the rivers have a high perception of the impacts of the extreme precipitating events on the socioeconomic and environmental activities, confirmed in the AHP technique the order of importance obtained in the GP. Thus the study is relevant in the process of elaborating adaptation strategies to extreme precipitating events.