987 resultados para climatic data


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O presente trabalho analisou o ritmo climático da cidade de Descalvado - SP, por meio de dois episódios representativos do fato climático (de inverno e de primavera), bem como o comportamento térmico no interior de duas casas populares ocupadas, situadas na área urbana do município. Utilizou-se estação automática (CR10X - Campbell Scientific Inc.) que possibilitou a aquisição e o armazenamento dos dados meteorológicos, vinculando estes dados climáticos ao sistema de circulação atmosférica secundária. Dentro da abordagem Dinâmica do Clima, utilizou-se os conceitos de tipos de tempo afeito ao comportamento térmico das casas ocupadas. Os limites da zona de conforto propostos por GIVONI (1992) foram utilizados como referencial na análise do comportamento térmico das casas ocupadas. Os resultados demonstraram que as duas residências apresentaram comportamento térmico semelhante durante as possíveis situações de estresse de calor e frio. Conclui-se que, apesar de se tratar, do ponto de vista econômico, de moradias de baixo custo de construção, são casas que apresentaram adequado desempenho térmico.

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The geothermal regime of the western margin of the Great Bahama Bank was examined using the bottom hole temperature and thermal conductivity measurements obtained during and after Ocean Drilling Program (ODP) Leg 166. This study focuses on the data from the drilling transect of Sites 1003 through 1007. These data reveal two important observational characteristics. First, temperature vs. cumulative thermal resistance profiles from all the drill sites show significant curvature in the depth range of 40 to 100 mbsf. They tend to be of concave-upward shape. Second, the conductive background heat-flow values for these five drill sites, determined from deep, linear parts of the geothermal profiles, show a systematic variation along the drilling transect. Heat flow is 43-45 mW/m**2 on the seafloor away from the bank and decreases upslope to ~35 mW/m**2. We examine three mechanisms as potential causes for the curved geothermal profiles. They are: (1) a recent increase in sedimentation rate, (2) influx of seawater into shallow sediments, and (3) temporal fluctuation of the bottom water temperature (BWT). Our analysis shows that the first mechanism is negligible. The second mechanism may explain the data from Sites 1004 and 1005. The temperature profile of Site 1006 is most easily explained by the third mechanism. We reconstruct the history of BWT at this site by solving the inverse heat conduction problem. The inversion result indicates gradual warming throughout this century by ~1°C and is agreeable to other hydrographic and climatic data from the western subtropic Atlantic. However, data from Sites 1003 and 1007 do not seem to show such trends. Therefore, none of the three mechanisms tested here explain the observations from all the drill sites. As for the lateral variation of the background heat flow along the drill transect, we believe that much of it is caused by the thermal effect of the topographic variation. We model this effect by obtaining a two-dimensional analytical solution. The model suggests that the background heat flow of this area is ~43 mW/m**2, a value similar to the background heat flow determined for the Gulf of Mexico in the opposite side of the Florida carbonate platform.

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Combined seasonal to monthly resolution coral skeletal delta(18)O, Sr/Ca, and Mg/Ca records are reported for one modem and two late Holocene Porites lutea corals from a fringing reef at Leizhou Peninsula, the northern coast of the South China Sea (SCS). All the profiles for the period 1989-2000 reveal annual cycles well correlated with instrumental sea surface temperatures (SST), and display broad peaks in summer and narrow troughs in winter, reflecting seasonal growth rate variations. Calibration against instrumental SST yields the following equations: delta(18)O=-0.174(+/- 0.010)xSST(degrees C)-1.02(+/- 0.27) (MSWD=5.8), Sr/Ca-(mmol/mol)=-0.0424(+/- 0.0031)xSST(degrees C)+9.836(+/- 0.082) (MSWD=8.6), and Mg/Ca-(mmol/mol)=0.110(+/- 0.009)XSST(degrees C)+ 1.32(+/- 0.23) (MSWD=55). The scatter in the Mg/Ca-SST relationship is much larger than analytical uncertainties can account for, suggesting the presence of SST-unrelated components in the Mg/Ca variation. Calculated Sr/Ca-SST values for two later Holocene Porites lutea samples (U-series ages similar to 541 BC and similar to 487 AD, respectively) from the same reef suggest that SST in the SCS at similar to 541 BC was nearly as warm as in the 1990s (the warmest decade of the last century), but at similar to 487 AD, it was significantly cooler. This observation is consistent with climatic data reported in Chinese historic documents, confirming that the Sr/Ca-SST relationship is a reliable thermometer. Removing the SST component in the delta(18)O variation based on calculated Sr/Ca-SST values, the residual delta(18)O reflects the deviation of the Holocene seawater delta(18)O from the modem value, which is also a measure of the Holocene sea surface salinity (SSS) or the summer monsoon moisture level in mainland China. Such residual delta(18)O was close to zero at similar to 541 BC and -0.3 parts per thousand at similar to 487 AD, suggesting that it was as wet as in the 1990s at similar to 541 BC but significantly drier at similar to 487 AD in mainland China, which are also consistent with independent historic records. Calculated Mg/Ca-SST values for the two late Holocene corals are significantly lower than the Sr/Ca-SST values and are also in conflict with Chinese historic records, suggesting that coral Mg/Ca is not reliable proxy for SST. At comparable Sr/Ca ranges, fossil corals always display negative Mg/Ca offsets if compared with the modem coral of the same site. We interpret this observation as due to preferential loss of Mg during meteoric dissolution of cryptic Mg-calcite-bearing microbialites in the exposed fossil corals. Microbialites (MgO up to 17%, Sr only 100-300 ppm) are ubiquitous during reef-building processes and their presence in only a trace amount will have a significant impact on coral Mg/Ca ratios without detectable influence on coral Sr/Ca ratios. (c) 2004 Elsevier B.V. All rights reserved.

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Broccoli is a vegetable crop of increasing importance in Australia, particularly in south-east Queensland and farmers need to maintain a regular supply of good quality broccoli to meet the expanding market. A predictive model of ontogeny, incorporating climatic data including frost risk, would enable farmers to predict harvest maturity date and select appropriate cultivar – sowing date combinations. To develop procedures for predicting ontogeny, yield and quality, field studies using three cultivars, ‘Fiesta’, ‘Greenbelt’ and ‘Marathon’, were sown on eight dates from 11 March to 22 May 1997, and grown under natural and extended (16 h) photoperiods at the University of Queensland, Gatton Campus. Cultivar, rather than the environment, mainly determined head quality attributes of head shape and branching angle. Yield and quality were not influenced by photoperiod. A better understanding of genotype and environmental interactions will help farmers optimise yield and quality, by matching cultivars with time of sowing. The estimated base and optimum temperature for broccoli development were 0°C and 20 °C, respectively, and were consistent across cultivars, but thermal time requirements for phenological intervals were cultivar specific. Differences in thermal time requirement from floral initiation to harvest maturity between cultivars were small and of little importance, but differences in thermal time requirement from emergence to floral initiation were large. Sensitivity to photoperiod and solar radiation was low in the three cultivars used. This research has produced models to assist broccoli farmers in crop scheduling and cultivar selection in south-east Queensland.

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The impact of climate change on the potential distribution of four Mediterranean pine species – Pinus brutia Ten., Pinus halepensis Mill., Pinus pinaster Aiton, and Pinus pinea L. – was studied by the Climate Envelope Model (CEM) to examine whether these species are suitable for the use as ornamental plants without frost protection in the Carpathian Basin. The model was supported by EUFORGEN digital area database (distribution maps), ESRI ArcGIS 10 software’s Spatial Analyst module (modeling environment), PAST (calibration of the model with statistical method), and REMO regional climate model (climatic data). The climate data were available in a 25 km resolution grid for the reference period (1961–1990) and two future periods (2011–2040, 2041–2070). The regional climate model was based on the IPCC SRES A1B scenario. While the potential distribution of P. brutia was not predicted to expand remarkably, an explicit shift of the distribution of the other three species was shown. Northwestern African distribution segments seem to become abandoned in the future. Current distribution of P. brutia may be highly endangered by the climate change. P. halepensis in the southern part and P. pinaster in the western part of the Carpathian Basin may find suitable climatic conditions in the period of 2041–2070.

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The potential future distribution of four Mediterranean pines was aimed to be modeled supported by EUFORGEN digital area database (distribution maps), ESRI ArcGIS 10 software’s Spatial Analyst module (modeling environment), PAST (calibration of the model with statistical method), and REMO regional climate model (climatic data). The studied species were Pinus brutia, Pinus halepensis, Pinus pinaster, and Pinus pinea. The climate data were available in a 25 km resolution grid for the reference period (1961-90) and two future periods (2011-40, 2041-70). The climate model was based on the IPCC SRES A1B scenario. The model results show explicit shift of the distributions to the north in case of three of the four studied species. The future (2041-70) climate of Western Hungary seems to be suitable for Pinus pinaster.

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Background & Objective: The most northern populations of two sand fly species (Phlebotomus mascittii and Phlebotomus neclectus) in the Carpathian Basin are known from Central Hungary. The most important limiting factor of the distribution of Phlebotomus species in the region is the annual minimum temperature which may be positively affected by the urban heat island and the climate change in the future. Method: Based on the latest case reports of the species, Climate Envelope Model was done for the period 1961-1990 and 2025-2050 to project the potential urban distribution of the species. The climatic data were obtained from RegCM regional climate model and MODIS satellite images. Results: The recent occurrence of the species in Central Hungary indicates that Phlebotomus species can overwinter in non-heated shelters in the built environment. Interpretation & Conclusion: Jointly heat island and future climate change seem to be able to provide suitable environment for the studied species in urban areas in a great extent.

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The stabilization of energy supply in Brazil has been a challenge for the operation of the National Interconnected System in face of hydrological and climatic variations. Thermoelectric plants have been used as an emergency source for periods of water scarcity. The utilization of fossil fuels, however, has elevated the cost of electricity. On the other hand, offshore wind energy has gained importance in the international context and is competitive enough to become a possibility for future generation in Brazil. In this scenario, the main goal of this thesis was to investigate the magnitude and distribution of offshore wind resources, and also verify the possibilities of complementing hydropower. A data series of precipitation from the Climatic Research Unit (CRU) Blended Sea Winds from the National Climatic Data Center (NCDC/NOAA) were used. According to statistical criteria, three types of complementarity were found in the Brazilian territory: hydro × hydro, wind × wind and hydro × wind. It was noted a significant complementarity between wind and hydro resources (r = -0.65), mainly for the hydrographical basins of the southeast and central regions with Northeastern Brazil winds. To refine the extrapolation of winds over the ocean, a method based on the Monin-Obukhov theory was used to model the stability of the atmospheric boundary layer. Objectively Analyzed Air-Sea Flux (OAFLUX) datasets for heat flux, temperature and humidity, and also sea level pressure data from NCEP/NCAR were used. The ETOPO1 from the National Geophysical Data Center (NGDC/NOAA) provided bathymetric data. It was found that shallow waters, between 0-20 meters, have a resource estimated at 559 GW. The contribution of wind resources to hydroelectric reservoir operation was investigated with a simplified hybrid wind-hydraulic model, and reservoir level, inflow, outflow and turbine production data. It was found that the hybrid system avoids drought periods, continuously saving water from reservoirs through wind production. Therefore, from the results obtained, it is possible to state that the good winds from the Brazilian coast can, besides diversifying the electric matrix, stabilize the hydrological fluctuations avoiding rationing and blackouts, reducing the use of thermal power plants, increasing the production cost and emission of greenhouse gases. Public policies targeted to offshore wind energy will be necessary for its full development.

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Archaeological fish otoliths have the potential to serve as proxies for both season of site occupation and palaeoclimate conditions. By sampling along the distinctive sub-annual seasonal bands of the otolith and completing a stable isotope (δ¹⁸O, δ¹³C) analysis, variations within the fish’s environment can be identified. Through the analysis of cod otoliths from two archaeological sites on Kiska Island, Gertrude Cove (KIS-010) and Witchcraft Point (KIS-005), this research evaluates a micromilling methodological approach to extracting climatic data from archaeological cod otoliths. In addition, δ¹⁸Ootolith data and radiocarbon dates frame a discussion of Pacific cod harvesting, site occupation, and changing climatic conditions on Kiska Island. To aid in the interpretation of the archaeological Pacific cod results, archaeological and modern Atlantic cod otoliths were also analyzed as a component of this study to develop. The Atlantic cod otoliths provided the methodological and interpretative framework for the study, and also served to assess the efficacy of this sampling strategy for archaeological materials and to add time-depth to existing datasets. The δ¹⁸Ootolith values successfully illustrate relative variation in ambient water temperature. The Pacific cod δ¹⁸O values demonstrate a weak seasonal signal identifiable up to year 3, followed by relatively stable values until year 6/7 when values continuously increase. Based on the δ¹⁸O values, the Pacific cod were exposed to the coldest water temperatures immediately prior to capture. The lack of a clear cycle of seasonal variation and the continued increase in values towards the otolith edge obscures the season of capture, and indicates that other behavioural, environmental, or methodological factors influenced the otolith δ¹⁸O values. It is suggested that Pacific cod would have been harvested throughout the year, and the presence of cod remains in Aleutian archaeological sites cannot be used as a reliable indicator of summer occupation. In addition, when the δ¹⁸O otolith values are integrated with radiocarbon dates and known climatic regimes, it is demonstrated that climatic conditions play an integral role in the pattern of occupation at Gertrude Cove. Initial site occupation coincides with the end of a neoglacial cooling period, and the most recent and continuous occupation coincides with the end of a localized warming period and the onset of the Little Ice Age (LIA).

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Acknowledgements The authors would like to thank Jonathan Dick, Maria Blumstock, Claire Tunaley and Jason Lessels for assistance with the field work and Audrey Innes for lab sample preparation. Climatic data were provided by Iain Malcolm and Marine Scotland Fisheries at the Freshwater Lab, Pitlochry. Additional precipitation and temperature data were provided by the UK Meteorological Office and the British Atmospheric Data Centre (BADC). We are grateful for the careful and constructive comments of two anonymous reviewers that helped to improve an earlier version of this manuscript. The European Research Council ERC (project GA 335910) is thanked for funding.

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Acknowledgements The authors would like to thank Jonathan Dick, Maria Blumstock, Claire Tunaley and Jason Lessels for assistance with the field work and Audrey Innes for lab sample preparation. Climatic data were provided by Iain Malcolm and Marine Scotland Fisheries at the Freshwater Lab, Pitlochry. Additional precipitation and temperature data were provided by the UK Meteorological Office and the British Atmospheric Data Centre (BADC). We are grateful for the careful and constructive comments of two anonymous reviewers that helped to improve an earlier version of this manuscript. The European Research Council ERC (project GA 335910) is thanked for funding.

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A 245-year coral oxygen isotope record from the northern Red Sea (Ras Umm Sidd/Egypt, ~28°N) in bimonthly resolution is presented. The mean annual coral delta18O signal apparently reflects varying proportions of both sea surface temperature and delta18Oseawater variability. In conjunction with instrumental observations of climate the coral record suggests for interannual and longer timescales that colder periods are accompanied by more arid conditions in the northern Red Sea but increased rainfall in the southeastern Mediterranean, whereas warmer periods are accompanied by decreased rainfall in the latter and less arid conditions in the northern Red Sea. A ~70-year oscillation of probably North Atlantic origin dominates the coral time series. Interannual to interdecadal variability is correlated with instrumental indices of the North Atlantic Oscillation (NAO), the El Niño-Southern Oscillation (ENSO), and North Pacific climate variability. The results suggest that these modes contributed consistently to Middle East climate variability since at least 1750, preferentially at a period of ~5.7 years.

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La gestion intégrée de la ressource en eau implique de distinguer les parcours de l’eau qui sont accessibles aux sociétés de ceux qui ne le sont pas. Les cheminements de l’eau sont nombreux et fortement variables d’un lieu à l’autre. Il est possible de simplifier cette question en s’attardant plutôt aux deux destinations de l’eau. L’eau bleue forme les réserves et les flux dans l’hydrosystème : cours d’eau, nappes et écoulements souterrains. L’eau verte est le flux invisible de vapeur d’eau qui rejoint l’atmosphère. Elle inclut l’eau consommée par les plantes et l’eau dans les sols. Or, un grand nombre d’études ne portent que sur un seul type d’eau bleue, en ne s’intéressant généralement qu’au devenir des débits ou, plus rarement, à la recharge des nappes. Le portrait global est alors manquant. Dans un même temps, les changements climatiques viennent impacter ce cheminement de l’eau en faisant varier de manière distincte les différents composants de cycle hydrologique. L’étude réalisée ici utilise l’outil de modélisation SWAT afin de réaliser le suivi de toutes les composantes du cycle hydrologique et de quantifier l’impact des changements climatiques sur l’hydrosystème du bassin versant de la Garonne. Une première partie du travail a permis d’affiner la mise en place du modèle pour répondre au mieux à la problématique posée. Un soin particulier a été apporté à l’utilisation de données météorologiques sur grille (SAFRAN) ainsi qu’à la prise en compte de la neige sur les reliefs. Le calage des paramètres du modèle a été testé dans un contexte differential split sampling, en calant puis validant sur des années contrastées en terme climatique afin d’appréhender la robustesse de la simulation dans un contexte de changements climatiques. Cette étape a permis une amélioration substantielle des performances sur la période de calage (2000-2010) ainsi que la mise en évidence de la stabilité du modèle face aux changements climatiques. Par suite, des simulations sur une période d’un siècle (1960-2050) ont été produites puis analysées en deux phases : i) La période passée (1960-2000), basée sur les observations climatiques, a servi de période de validation à long terme du modèle sur la simulation des débits, avec de très bonnes performances. L’analyse des différents composants hydrologiques met en évidence un impact fort sur les flux et stocks d’eau verte, avec une diminution de la teneur en eau des sols et une augmentation importante de l’évapotranspiration. Les composantes de l’eau bleue sont principalement perturbées au niveau du stock de neige et des débits qui présentent tous les deux une baisse substantielle. ii) Des projections hydrologiques ont été réalisées (2010-2050) en sélectionnant une gamme de scénarios et de modèles climatiques issus d’une mise à l’échelle dynamique. L’analyse de simulation vient en bonne part confirmer les conclusions tirées de la période passée : un impact important sur l’eau verte, avec toujours une baisse de la teneur en eau des sols et une augmentation de l’évapotranspiration potentielle. Les simulations montrent que la teneur en eau des sols pendant la période estivale est telle qu’elle en vient à réduire les flux d’évapotranspiration réelle, mettant en évidence le possible déficit futur des stocks d’eau verte. En outre, si l’analyse des composantes de l’eau bleue montre toujours une diminution significative du stock de neige, les débits semblent cette fois en hausse pendant l’automne et l’hiver. Ces résultats sont un signe de l’«accélération» des composantes d’eau bleue de surface, probablement en relation avec l’augmentation des évènements extrêmes de précipitation. Ce travail a permis de réaliser une analyse des variations de la plupart des composantes du cycle hydrologique à l’échelle d’un bassin versant, confirmant l’importance de prendre en compte toutes ces composantes pour évaluer l’impact des changements climatiques et plus largement des changements environnementaux sur la ressource en eau.

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Knowledge of the marine soils properties, together with hydrodynamic and climatic data, plays an important role for a better understanding of the dynamic behavior of sandy and muddy coasts. This paper deals with reporting and basic interpretation of two campaigns of exploration and characterization of the mud of Cassino Beach, southern Brazil, carried out during the years of 2004 and 2005. Samples were obtained by means of cores collected at some locations offshore, and were submitted to various laboratory geotechnical tests, including determination of the physical index, grain size distribution, Atterberg limits, and shear resistance by both triaxial and shear vane tests. Results confirm the existence of a very soft soil deposit offshore Cassino Beach, highly plastic, compressible, and viscous, forming an important database for further studies.

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Coffee is predicted to be severely affected by climate change. We determined the thermal tolerance of the coffee berry borer, Hypothenemus hampei, the most devastating pest of coffee worldwide, and make inferences on the possible effects of climate change using climatic data from Colombia, Kenya, Tanzania, and Ethiopia. For this, the effect of eight temperature regimes (15, 20, 23, 25, 27, 30, 33 and 35 degrees C) on the bionomics of H. hampei was studied. Successful egg to adult development occurred between 20-30 degrees C. Using linear regression and a modified Logan model, the lower and upper thresholds for development were estimated at 14.9 and 32 degrees C, respectively. In Kenya and Colombia, the number of pest generations per year was considerably and positively correlated with the warming tolerance. Analysing 32 years of climatic data from Jimma (Ethiopia) revealed that before 1984 it was too cold for H. hampei to complete even one generation per year, but thereafter, because of rising temperatures in the area, 1-2 generations per year/coffee season could be completed. Calculated data on warming tolerance and thermal safety margins of H. hampei for the three East African locations showed considerably high variability compared to the Colombian site. The model indicates that for every 1 degrees C rise in thermal optimum (T(opt)), the maximum intrinsic rate of increase (r(max)) will increase by an average of 8.5%. The effects of climate change on the further range of H. hampei distribution and possible adaption strategies are discussed. Abstracts in Spanish and French are provided as supplementary material Abstract S1 and Abstract S2.