193 research outputs found

    Spatio-temporal variability of surface air temperature in northeastern Spain

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    The present thesis examined changes in the annual and seasonal distribution of daily maximum and minimum temperatures for northeastern Spain. A better understanding of the ongoing changes in the temperature means and extremes was the primary objective. Further aims involved the analysis of large-scale atmospheric circulation patterns at different geopotential levels as well as the Mean Sea Level (MSL) pressure based on climate composites analysis and canonical variates in order to quantify the driving forces beyond the observed variability. Finally, this work aimed to assess future climate projections of seasonal temperature and their spatial variations to improve the understanding and prediction of the long-term trends of temperature means and extremes simulations. To achieve all these goals, it was necessary to develop a homogenous dataset with high spatial and temporal resolution. The next few paragraphs answer the main research questions raised during this work

    An assessment of the role of homogenization protocols in the performance of daily temperature series and trends: application to northeastern Spain

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    Ponencia presentada en: VII Congreso de la Asociación Española de Climatología: clima, ciudad y ecosistemas, celebrado en Madrid entre el 24 y 26 de noviembre de 2010.This paper details a full protocol applied to develop high resolution daily temperature dataset. Our methodology has been tested from a dataset of 1583 temperature observatories over the NE Spain. The raw dataset was initially tested for internal and external consistency and an algorithm was utilized to reconstruct the daily temperature series for selected candidate observatories. Discontinuities in the reconstructed series were determined by combining the results obtained by three homogeneity tests: the Standard Normal Homogeneity Test (SNHT), the Easterling and Peterson two-phased regression method and the Vincent test. To assess the role of data homogenization, a set of selected tests was applied to the temperature trends and the spatial and frequency properties of the series. Results show significant improvement in the spatial dependence of temperature trends at seasonal and annual scales after application of homogeneity correction. However, frequency statistics of the series evidenced no significant impact of the homogenization procedure. From the temporal and spatial perspectives, the new compiled dataset seems to be outstanding in a variety of meteorological, ecological, hydrological and agricultural research applications at local, regional and continental scales.This work has been supported by the research projects CGL2008-01189/BTE, CGL2006-11619/HID and CGL2008-1083/CLI financed by the Spanish Commission of Science and Technology and FEDER, EUROGEOSS (FP7-ENV-2008-1-226487) and ACQWA (FP7-ENV-2007-1- 212250) financed by the VII Framework Programme of the European Commissio

    An assessment of the role of homogenization protocol in the performance of daily temperature series and trends: Application to northeastern Spain

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    [EN] This paper gives the complete details of the protocols applied for developing a spatially and temporarily high-resolution dataset of temperature for northeastern Spain. Our methodologies used data from a large number of observatories (1583) spanning some portions of the period between 1900 and 2006. The raw dataset was first tested for internal and external consistency to check data quality. To improve data completeness, a linear regression model was then utilized to infill gaps in the daily temperature series using the best correlated data from nearby sites. Discontinuities in the reconstructed series were determined by combining the results of three homogeneity-relative tests: the Standard Normal Homogeneity Test (SNHT), the Eastrerling and Peterson two-phased regression method and the Vincent test. To assess the possible impact of data homogenisation on trends and statistical properties of the final series, a set of tests (e.g. semivariance models and L-moment statistics) was applied to the series before and after correction. Semivariance models suggest a significant improvement in the spatial dependence of the corrected dataset on both seasonal and annual timescales. Also, L-moments gave no evidence of significant changes in the probability distribution of daily temperature series after correction. Taken together, the newly compiled dataset seems to be more robust and reveals more coherent spatial and temporal patterns of temperature compared with the original dataset. From the temporal and spatial perspectives, the new dataset comprises the most complete register of temperature in northeast Spain (1900-2006), with a reasonably spatial coverage. Accordingly, this database can provide a more reliable base for studying temperature changes and variability in the region. This dataset can also be of particular relevance to a number of meteorological, ecological, hydrological and agricultural applications on local, regional and continental scales. © 2011 Royal Meteorological Society.We are indebted to the anonymous reviewers for their constructive comments which were most helpful in improving this paper. We would like to thank the Agencia Estatal de Meteorologia for providing the temperature data used in this study. This work has been supported by the research projects CGL2006-11619/HID, CGL2008- 01189/BTE, CGL2011-27574-CO2-02, CGL2011-27753- CO2-01 and CGL2011-27536 financed by the Spanish Commission of Science and Technology; and also FEDER, EUROGEOSS (FP7-ENV-2008-1-226487) and ACQWA (FP7-ENV-2007-1- 212250) financed by the VII Framework Programme of the European Commission, La nieve en el Pirineo Aragones y su respuesta a ´ la variabilidad climatica, and Efecto de los escenarios ´ de cambio climatico sobre la hidrolog ´ ´ıa superficial y la gestion de embalses del Pirineo Aragon ´ es, financed by ´ Obra Social La Caixa and the Aragon Government and ´ Influencia del cambio climatico en el turismo de nieve, ´ CTTP01/10, financed by the Comision de Trabajo de los ´ Pirineos.Peer Reviewe

    Toxicity Assessment of Buprofezin, Lufenuron, and Triflumuron to the Earthworm Aporrectodea caliginosa

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    Earthworms are particularly important soil macroinvertebrates and are often used in assessing the general impact of pesticide pollution in soil. The present study was conducted in order to investigate the toxicity of three insect growth regulators (IGRs) buprofezin, lufenuron, and triflumuron, at different application rates and exposure times toward mature earthworms Aporrectodea caliginosa. The effects of these pesticides on the growth rate in relation to the activities of acetylcholinesterase (AChE) and glutathione S-transferase (GST) as biochemical indicators were evaluated to elucidate the mechanisms of action. Toxicity studies indicated that lufenuron was the most harmful pesticide to mature earthworms, followed in descending order by buprofezin and triflumuron. A reduction in growth rate in all pesticide-treated worms was dose-dependent over the 28-day exposure period, which was accompanied by a decrease in AChE and GST activities. Relationships between growth rate, AChE, and GST provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides

    The Aleurocanthus spiniferus (OSW) in Europe: a becoming invasive threat to citrus also.

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    The orange spiny whitefly (OSW), Aleurocanthus spiniferus, is a worldwide known citrus pest native to tropical Asia. Since the beginning of the 20th century, OSW spread throughout Asia, the Pacific, central and Southern Africa and from 2008 it was intercepted many times in EPPO area (Italy, Croatia and Montenegro). OSW polyphagy is well known, being able to infest more than 90 host plants belonging to unrelated botanical families, although Citrus spp. are considered the primary hosts. Accurate samplings highlighted OSW new host associations extending the range of plant families potentially exploitable and confirming the existence of host-shift phenomena. Analyses of the mitochondrial COI gene revealed that OSW Apulian population belongs solely to one of the two haplogroups present in China. Furthermore, the study of microbiota allowed us to identify the principal endosymbiotic bacteria in OSW. So far, field samplings confirmed the presence of predators belonging to Coccinellidae family able to prey on different evelopmental stages of A. spiniferus. These findings could be considered as an opportunity for biological control of OSW. Results laid solid foundations in the knowledge of European OSW populations now invading Italy and neighbouring countries to counteract a pan-Mediterranean invasion of this harmful whitefly. Further studies are essential for the assessment of an effective IPM strategy tailored either for organic or intensive agricultural context

    Nanospider Technology for the Production of Nylon-6 Nanofibers for Biomedical Applications

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    Nylon-6 nanofiber mat incorporated with 5,5-dimethyl hydantoin (DMH) as an antimicrobial drug was electrospun from formic acid. The morphology of the nanofiber mat using scanning electron microscope (SEM) showed that the obtained fiber had an average diameter of around 15–328 nm. The nanofiber was characterized by FTIR spectra, TGA, and DSC. The nanofiber containing drug showed initial fast release. It released about 55% of its drug content within the first two hours. Moreover, the antimicrobial activity of the electrospun nylon-6 nanofiber containing drug was examined against Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger, and Aspergillus flavus. The nylon-6 nanofiber exhibited high inhibitory effects against the microbes. The results clearly indicate that the antimicrobial activity of the electrospun nylon-6 nanofiber containing drug varies with the species of the organisms used. Thus, the study ascertains the value of the use of electrospun nanofiber, which could be of considerable interest to the development of new antimicrobial materials. The microbes, examined by SEM, were totally deformed and exhibited severe destruction. Abnormal cell division was observed at high frequencies among cells that tried to divide in the presence of the nanofiber. Many cells were enlarged, elongated, empty ghosts, or fragmented, consistent with the extremely low viability

    Riesgo de precipitación extrema asociado a eventos de circulación atmosférica en el noroeste español

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    Ponencia presentada en: VI Congreso Internacional de la Asociación Española de Climatología celebrado en Tarragona del 8 al 11 de octubre de 2008.[ES]En este trabajo se analiza, en el noreste español, el riesgo de ocurrencia de precipitaciones extremas asociado a tres patrones de circulación atmosférica: la Oscilación del Atlántico Norte, la Oscilación Mediterránea y la Oscilación del Mediterráneo Occidental. El análisis se ha realizado a una escala de eventos atmosféricos obtenidos de índices de circulación diarios. A partir de las series pluviométricas diarias en 174 observatorios entre 1950 y 2006 se obtuvo la máxima precipitación diaria y la magnitud total registrada durante el evento de circulación. Las series de eventos siguen una distribución General de Pareto, independientemente del signo y el patrón de circulación atmosférica. Mediante la aplicación de análisis probabilísticos y modelización espacial asistida con Sistemas de Información Geográfica se obtuvieron mapas continuos de los parámetros de la distribución General de Pareto, determinándose la probabilidad y el periodo de retorno de precipitaciones de gran intensidad asociada a los eventos de circulación atmosférica.[EN]This paper analyses the extreme precipitation risk in North east Spain associated to three atmospheric circulation configurations: the North Atlantic Oscillation, the Mediterranean Oscillation and the Western Mediterranean Oscillation. The analysis has been performed considering an event-based scale, obtained from daily atmospheric circulation indices. Using daily precipitation records in 174 precipitation observatories between 1950 and 2006, we obtained the maximum precipitation intensity and the total precipitation magnitude recorded during the positive and negative circulation events. These precipitation records clearly follow a Generalised Pareto (GP) distribution, both for maximum intensity of precipitation and magnitude but also for positive and negative phases of the three atmospheric circulation indices. We applied a novel method that combined probabilistic analysis and spatial modelling assisted by GIS to determine the magnitude and maximum intensity precipitation probability and the quantile precipitation for any period of years associated to the positive and the negative phases of the three atmospheric circulation patterns.Este trabajo ha contado con la ayuda del proyecto CGL2005-04508/BOS, financiado por la Comisión Nacional de Ciencia y Tecnología y FEDER, y por el Programa de grupos de investigación consolidados, financiado por el Gobierno de Aragón
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