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  • European dry spell regimes (1951-2000): Clustering process and time trends

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    Atmospheric research
    Vol. 144, p. 151-174
    DOI: 10.1016/j.atmosres.2013.05.022
    Date of publication: 2014-07-01
    Journal article

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    Aiming to improve the knowledge of droughts in Europe, three indices related to dry spells, DS, regime have been analysed: the number of DS per year, N; the longest annual DS, L-max; and the mean DS length per year, L, for different daily rainfall thresholds (0.1, 1.0, 5.0 and 10.0 mm/day) at annual and seasonal scales. The database consists of daily records from 267 rain gauges, along the years 1951-2000. First, the mean values at annual and seasonal scales of these three indices are represented for the four thresholds. For 0.1 and 1.0 mm/day, spatial patterns suggest a strong N-S gradient for latitudes south of 45 degrees N, especially at annual scale and in summer season. For 5.0 and 10.0 mm/day, the patterns are different, with a strong gradient in the Scandinavian Peninsula and the largest L-max and L at NE Europe, except for summer. Second, a principal component analysis, PCA, is applied to the 60 variables (three indices at five time scales and four thresholds) characterising the DS regime of every gauge. A clustering process leads to a classification of the 267 rain gauges into 20 spatial clusters, on the basis of five selected principal components replacing the original variables. Most of clusters are spatially coherent, with greater spatial variability on DS regimes towards the south and west than to the north and east of Europe. And third, time trends on the three indices are quantified by the Kendall-tau algorithm, and statistical significances at 95% confidence level are assessed by the Mann-Kendall test. For all thresholds and seasons, there is a clear predominance of significant negative trends for N. Specifically, the highest number of rain gauges with significant negative trends corresponds to summer and winter, with average percentages from -2.7 to -8.1% per decade. In summer, significant negative trends are observed in Western Europe at 40 degrees-60 degrees N and between 10 degrees W and 20 degrees E. In annual and winter periods, negative trends are detected also at Western Europe for 0.1 and 1.0 mm/day and at latitudes south of 45 degrees N for the two highest thresholds. Spring, and especially autumn, are characterised by a low number of negative trends, particularly for 1.0, 5.0 and 10.0 mm/day. In summer, L-max depicts remarkable positive trends in Western Europe, at 40 degrees N-60 degrees N and between 0 degrees E and 20 degrees E, with high average values close to +10% per decade. Positive trends on L are dominant at annual scale and winter for 0.1 mm/day, and in summer for 0.1 and 1.0 mm/day, with average trends ranging from +4.8 to +8.1% per decade. Spring and autumn are characterised by numerous negative trends on L for all thresholds. (C) 2013 Elsevier BM. All rights reserved.

    Aiming to improve the knowledge of droughts in Europe, three indices related to dry spells, DS, regime have been analysed: the number of DS per year, N; the longest annual DS, L-max; and the mean DS length per year, L, for different daily rainfall thresholds (0.1, 1.0, 5.0 and 10.0 mm/day) at annual and seasonal scales. The database consists of daily records from 267 rain gauges, along the years 1951-2000. First, the mean values at annual and seasonal scales of these three indices are represented for the four thresholds. For 0.1 and 1.0 mm/day, spatial patterns suggest a strong N-S gradient for latitudes south of 45 degrees N, especially at annual scale and in summer season. For 5.0 and 10.0 mm/day, the patterns are different, with a strong gradient in the Scandinavian Peninsula and the largest L-max and L at NE Europe, except for summer. Second, a principal component analysis, PCA, is applied to the 60 variables (three indices at five time scales and four thresholds) characterising the DS regime of every gauge. A clustering process leads to a classification of the 267 rain gauges into 20 spatial clusters, on the basis of five selected principal components replacing the original variables. Most of clusters are spatially coherent, with greater spatial variability on DS regimes towards the south and west than to the north and east of Europe. And third, time trends on the three indices are quantified by the Kendall-tau algorithm, and statistical significances at 95% confidence level are assessed by the Mann-Kendall test. For all thresholds and seasons, there is a clear predominance of significant negative trends for N. Specifically, the highest number of rain gauges with significant negative trends corresponds to summer and winter, with average percentages from -2.7 to -8.1% per decade. In summer, significant negative trends are observed in Western Europe at 40 degrees-60 degrees N and between 10 degrees W and 20 degrees E. In annual and winter periods, negative trends are detected also at Western Europe for 0.1 and 1.0 mm/day and at latitudes south of 45 degrees N for the two highest thresholds. Spring, and especially autumn, are characterised by a low number of negative trends, particularly for 1.0, 5.0 and 10.0 mm/day. In summer, L-max depicts remarkable positive trends in Western Europe, at 40 degrees N-60 degrees N and between 0 degrees E and 20 degrees E, with high average values close to +10% per decade. Positive trends on L are dominant at annual scale and winter for 0.1 mm/day, and in summer for 0.1 and 1.0 mm/day, with average trends ranging from +4.8 to +8.1% per decade. Spring and autumn are characterised by numerous negative trends on L for all thresholds. (C) 2013 Elsevier BM. All rights reserved.

  • Daily extreme temperature multifractals in Catalonia (NE Spain)

     Burgueño, August; Lana Pons, Francisco Javier; Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors
    Physics letters A
    Vol. 378, num. 11/12, p. 874-885
    Date of publication: 2014-02
    Journal article

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    The multifractal character of the daily extreme temperatures in Catalonia (NE Spain) is analyzed by means of the multifractal detrended fluctuation analysis (MF-DFA) applied to 65 thermometric records covering years 1950¿2004. Although no clear spatial patterns of the multifractal spectrum parameters appear, factor scores deduced from Principal Component analysis indicate some signs of spatial gradients. Additionally, the daily extreme temperature series are classified depending on their complex time behavior, through four multifractal parameters (Hurst exponent, Hölder exponent with maximum spectrum, spectrum asymmetry and spectrum width). As a synthesis of the three last parameters, a basic measure of complexity is proposed through a normalized Complexity Index. Its regional behavior is found to be free of geographical dependences. This index represents a new step towards the description of the daily extreme temperatures complexity.

    The multifractal character of the daily extreme temperatures in Catalonia (NE Spain) is analyzed by means of the multifractal detrended fluctuation analysis (MF-DFA) applied to 65 thermometric records covering years 1950–2004. Although no clear spatial patterns of the multifractal spectrum parameters appear, factor scores deduced from Principal Component analysis indicate some signs of spatial gradients. Additionally, the daily extreme temperature series are classified depending on their complex time behavior, through four multifractal parameters (Hurst exponent, Hölder exponent with maximum spectrum, spectrum asymmetry and spectrum width). As a synthesis of the three last parameters, a basic measure of complexity is proposed through a normalized Complexity Index. Its regional behavior is found to be free of geographical dependences. This index represents a new step towards the description of the daily extreme temperatures complexity.

  • Predictive signs of high-magnitude mainshocks based on the analysis of time behaviour of fractal parameters

     Martínez Santafé, Maria Dolors; Amir Hosseini, Seyed; Lana Pons, Francisco Javier; Serra De Larrocha, Carina
    European Geosciences Union General Assembly
    p. 2779
    Presentation's date: 2014-05-01
    Presentation of work at congresses

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  • European dry spell length distributions, years 1951-2000

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    Theoretical and applied climatology
    Vol. 114, num. 3-4, p. 531-551
    DOI: 10.1007/s00704-013-0857-5
    Date of publication: 2013-11
    Journal article

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  • Análisis estadístico y comportamiento fractal de las réplicas sísmicas del Sur de California  Open access

     Monterrubio Velasco, Marisol
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

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    Mediante el análisis estadístico y utilizando diversas técnicas fractales en esta tesis se estudia el comportamiento temporal y espacial de tres series de réplicas sísmicas ocurridas en el Sur de California, que tuvieron lugar después de los terremotos de Landers (Mw=7.3, 1992), Northridge (Mw=6.7, 1994) y Hector Mine (Mw=7.1, 1999).Se plantean tres objetivos principales en este trabajo: 1) Caracterizar y analizar el proceso de ocurrencia de las réplicas sísmicas, en particular el comportamiento temporal que presentan. 2) Simular el comportamiento temporal de las tres series de réplicas sísmicas mediante una versión modificada del modelo del Fiber Bundle, el cual describe el proceso de ruptura de un material heterogéneo previamente fracturado, como la corteza terrestre. 3) Analizar y caracterizar el comportamiento fractal de las tres series de réplicas sísmicas mediante dos series temporales, la de distancia, ¿, y la de tiempo, t, entre réplicas consecutivas. De las diversas conclusiones que se obtienen en este estudio, a modo de resumen, se destacan los siguientes: 1) A partir del análisis de la cinemática que presenta la producción de las réplicas sísmicas, se detecta una superposición de dos procesos de relajación del esfuerzo tectónico. El primer proceso describe el decaimiento temporal a largo plazo de las réplicas sísmicas, el cual queda bien descrito por la ley de Omori Modificada, OM. El segundo proceso describe que existen episodios de réplicas que se producen a un ritmo mayor, alejándose del comportamiento descrito por la ley de OM. Las réplicas sísmicas que se producen de forma súbita se les denominan cascades. El gran número de réplicas que tienen las tres series sísmicas (LND, HM y NOR) permite que, a diferencia de los trabajos de CORREIG et al. (1997) y MORENO et al. (2001), se puedan realizar más análisis estadísticos y aplicar más técnicas fractales a las cascades. Por lo tanto, de estos resultados se concluye que las cascades muestran características destacables y comunes a las tres series de réplicas sísmicas. 2) El FBMdp es un modelo adecuado para describir el proceso de producción de las réplicas sísmicas. La comparación que se realiza entre las series de réplicas simuladas y las series reales muestra que las simulaciones permiten reproducir las características principales que se observan en las secuencias empíricas, en particular, el comportamiento temporal que indica un doble proceso de relajación de los esfuerzos tectónicos. Esta similitud entre las series de réplicas simuladas con las reales hace posible relacionar la dinámica intrínseca de este modelo con el proceso físico subyacente a la producción de las réplicas sísmicas. 3) El análisis fractal que se realiza a las series de distancia, ¿, y de tiempo, t, entre réplicas consecutivas proporciona múltiples resultados. A modo de resumen, se destaca que las series de ¿ muestran un comportamiento complejo y caótico con una alta inestabilidad predictiva debido a la aleatoriedad que se observa en el mecanismo dinámico. La distribución estadística de la series de ¿ muestran que, independientemente de la magnitud mínima de análisis que se utilice, todas quedan bien descritas por una única función de distribución acumulada que es la de Pareto Generalizada. El análisis fractal que se realiza a las series de t muestra resultados destacables, en particular, cuando se realiza la comparación entre las series de t y algunas series de tiempo teóricas, tteo, las cuales obedecen estrictamente la ley de OM. Esta comparación pone en evidencia que el comportamiento de las series de t está alterado por la presencia de las cascades. Por lo tanto, se reafirma la hipótesis que indica que, aunque la ley de Omori Modificada describe el proceso general de decaimiento de las réplicas sísmicas, existe otro proceso físico simultáneo que da pie a que ocurran aceleraciones súbitas en la producción de algunas réplicas sísmicas.

    Mediante el análisis estadístico y utilizando diversas técnicas fractales en esta tesis se estudia el comportamiento temporal y espacial de tres series de réplicas sísmicas ocurridas en el Sur de California, que tuvieron lugar después de los terremotos de Landers (Mw=7.3, 1992), Northridge (Mw=6.7, 1994) y Hector Mine (Mw=7.1, 1999) Se plantean tres objetivos principales en este trabajo: 1) Caracterizar y analizar el proceso de ocurrencia de las réplicas sísmicas, en particular el comportamiento temporal que presentan. De acuerdo con la hipótesis que proponen CORREIG et al. (1997) y MORENO et al. (2001), el análisis de este comportamiento temporal muestra que la producción de las réplicas sísmicas se puede describir como una superposición de dos procesos de relajación de los esfuerzos tectónicos. 2) Simular el comportamiento temporal de las tres series de réplicas sísmicas mediante una versión modificada del modelo del Fiber Bundle, el cual describe el proceso de ruptura de un material heterogéneo previamente fracturado, como la corteza terrestre. El análisis de las réplicas sísmicas simuladas con este modelo modificado, que se introduce en el trabajo de MORENO et al. (2001), (FBMdp), nos permitirá encontrar las similitudes y las diferencias con respecto a las series de réplicas reales. Además, nos proporcionará una interpretación y una posible relación entre la dinámica presente en el modelo y el proceso de ruptura que originan las réplicas sísmicas. 3) Analizar y caracterizar el comportamiento fractal de las tres series de réplicas sísmicas mediante dos series temporales, la de distancia, Δ, y la de tiempo, τ, entre réplicas consecutivas. Para realizar este análisis se aplican diversas técnicas fractales como el análisis de rango reescalado, el posible comportamiento de las series como fractales auto-afines y el análisis de la lacunaridad. Además, se utiliza el teorema de Reconstrucción para caracterizar la predictibilidad del sistema y su posible comportamiento caótico. El análisis fractal que se aplica a estas dos series, Δ y τ, se repite para diferentes valores de magnitud umbral, para poder interpretar la influencia que tiene este parámetro en los resultados. De las diversas conclusiones que se obtienen en este estudio, a modo de resumen, se destacan los siguientes: 1) A partir del análisis de la cinemática que presenta la producción de las réplicas sísmicas, se detecta una superposición de dos procesos de relajación del esfuerzo tectónico. El primer proceso describe el decaimiento temporal a largo plazo de las réplicas sísmicas, el cual queda bien descrito por la ley de Omori Modificada, OM. Las réplicas sísmicas que satisfacen este proceso se les denomina leading aftershocks. El segundo proceso describe que existen episodios de réplicas que se producen a un ritmo mayor, alejándose del comportamiento descrito por la ley de OM. Las réplicas sísmicas que se producen de forma súbita se les denominan cascades. El gran número de réplicas que tienen las tres series sísmicas (LND, HM y NOR) permite que, a diferencia de los trabajos de CORREIG et al. (1997) y MORENO et al. (2001), se puedan realizar más análisis estadísticos y aplicar más técnicas fractales a las cascades. De los resultados que se desprenden de estos análisis se concluye que las cascades muestran características destacables y comunes a las tres series de réplicas sísmicas. 2) El FBMdp es un modelo adecuado para describir el proceso de producción de las réplicas sísmicas. La comparación que se realiza entre las series de réplicas simuladas y las series reales muestra que las simulaciones permiten reproducir las características principales que se observan en las secuencias empíricas, en particular, el comportamiento temporal que indica un doble proceso de relajación de los esfuerzos tectónicos. En base a la similitud de las series de réplicas simuladas con las reales, es posible relacionar la dinámica intrínseca de este modelo con el proceso físico subyacente a la producción de las réplicas sísmicas. Por ejemplo, es posible interpretar el fenómeno de las cascades, que se observan en las secuencias de réplicas sísmicas reales y en las simuladas, en base a las características que presentan los sistemas de auto-organización críticos, SOC (self-organized criticality). Cabe mencionar que algunas características de la sismicidad no se pueden reproducir con este modelo, como por ejemplo, la magnitud de las réplicas sísmicas. Es por esto que algunas leyes clásicas como la ley de Gutenberg-Richter o la ley de Båth no se pueden verificar con este modelo. 3) El análisis fractal que se realiza a las series de distancia, Δ, y de tiempo, τ, entre réplicas consecutivas proporciona múltiples resultados. A modo de resumen, se destaca que las series de Δ presentan una ligera persistencia temporal, ya que el exponente de Hurst es ligeramente superior a 0.5. Esta característica es independiente de la magnitud umbral que se utilice. Además las series de Δ se pueden describir como un fractal auto afín del tipo filtered fractional gaussian noise. El teorema de reconstrucción indica que las series de Δ muestran un comportamiento complejo y caótico con una alta inestabilidad predictiva debido a la aleatoriedad que se observa en el mecanismo dinámico. También es interesante destacar que la distribución estadística de la series de Δ muestran que, independientemente de la magnitud mínima de análisis que se utilice, todas quedan bien descritas por una única función de distribución acumulada que es la de Pareto Generalizada. El análisis fractal que se realiza a las series de τ muestra resultados destacables, en particular, cuando se realiza la comparación entre las series de τ y algunas series de tiempo teóricas, τteo, las cuales obedecen estrictamente la ley de OM. Esta comparación pone en evidencia que el comportamiento de las series de τ está alterado por la presencia de las cascades. Por lo tanto, se reafirma la hipótesis que indica que, aunque la ley de Omori Modificada describe el proceso general de decaimiento de las réplicas sísmicas, existe otro proceso físico simultáneo que da pie a que ocurran aceleraciones súbitas en la producción de algunas réplicas sísmicas.

    In this PhD thesis we are interested in the time and spatial behavior of seismic aftershock sequences. Through statistical analyses and several fractal techniques we intend to analyze three aftershocks sequences occurred at Southern California, after the Landers (Mw = 7.3, 1992), Northridge (Mw = 6.7, 1994) and Hector Mine (Mw = 7.1, 1999) mainshocks. There are three main objectives in this thesis: 1) To characterize and analyze the process of occurrence of aftershocks, particularly the time behavior they exhibit. 2) To simulate the time behavior of the three aftershocks series through a modified version of the Fiber Bundle model, describing the rupture process in heterogeneous and fractured materials, like the Earth crust. 3) To analyze and characterize the fractal behavior of the three aftershock series through two time series, the elapsed distance, ¿, and the elapsed time, t, between consecutive aftershocks. As a summary, the main conclusions are listed below: 1) The kinematic analysis of the aftershock sequences shows a superposition of two different processes of tectonic stress release. The first process describes a long-term time decay of aftershocks, which is well described by the modified Omori law, MO. The aftershocks that satisfy this process are called leading aftershocks. The second process describes the aftershock production at a higher rate, which departs from the behavior described by MO law. These groups of seismic aftershocks are called cascades. Unlike the study by CORREIG et al. (1997) and MORENO et al. (2001), the much larger number of aftershocks belonging to the three sequences (LND, HM and NOR) allows the implementation of additional statistical analyses and fractal techniques to the cascades. The results derived from these analyses lead to conclude that cascades show remarkable features common to the three aftershock series. 2) The FBMdp is a suitable model to describe the process of aftershock generation. The comparison between simulated and real aftershock sequences shows that this model can reproduce features observed in aftershock sequences, in particular, the time behavior suggesting a double process of tectonic stress release. The similarity of simulated and real aftershock sequences make possible to relate the intrinsic model dynamics with the physical process leading the aftershock generation. For example, it is possible to interpret the phenomenon of cascades, which are observed in the simulated and real aftershocks sequences, in the theoretical framework of the self-organized critical (SOC) systems. 3) The fractal analyses applied to the elapsed distances, ¿, and time, t, series show different results. As a summary, it can be noted that the series of ¿ depict slight time persistence as the Hurst exponent is slightly higher than 0.5. This feature is independent of the magnitude threshold. Furthermore, the series of ¿ may be described as a self affine fractal, in particular, as a fractional filtered gaussian noise. The reconstruction theorem states that the ¿ series are complex and show a chaotic behavior with high predictive instability due to randomness in the observed dynamic mechanism. Independently of the minimum magnitude used in the analysis, the statistical distribution of all ¿ series is well described by the Generalized Pareto cumulative distribution function. The fractal analyses were applied to t series and also to some theoretical elapsed time series, tteo, fully satisfying the MO law. Remarkable differences are found between the empirical, t, and theoretical, tteo, series. These differences support that the empirical t series are perturbed by the presence of the cascades. Therefore, the hypothesis that, although Modified Omori law describes the general process of aftershock decay, it is confirmed the existence of another physical process leading to sudden accelerations in the aftershock generation.

  • Fractal structure on inter-event distances: three examples for the aftershock series of Landers, Northridge and Hector Mine mainshocks (Southern California)

     Martínez Santafé, Maria Dolors; Monterrubio Velasco, Marisol; Lana Pons, Francisco Javier; Serra De Larrocha, Carina
    European Geosciences Union General Assembly
    p. 2995
    Presentation's date: 2013-04
    Presentation of work at congresses

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  • Partial duration series and parent distributions of the dry spell lengths in Europe

     Serra De Larrocha, Carina; Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors
    Trobades Científiques de la Mediterrània
    p. 31
    Presentation's date: 2013-10-17
    Presentation of work at congresses

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  • Dry spell length distributions in the Mediterranean

     Serra De Larrocha, Carina; Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors
    International Meeting on Meteorology and Climatology of the Mediterranean
    p. 21
    Presentation's date: 2013-02-27
    Presentation of work at congresses

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  • Some characteristics of a daily rainfall regime based on the Dry Day Last Rain index (DDSLR)

     Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina
    Theoretical and applied climatology
    Vol. 109, num. 1-2, p. 153-174
    DOI: 10.1007/s00704-011-0561-2
    Date of publication: 2012-06
    Journal article

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    The Dry Day Since Last Rain index, DDSLR, quantifies for every recording day the number of consecutive preceding days with daily rainfall below a threshold. In essence, DDSLR may quantify the hydrologic stress generated by consecutive days of rainfall deficit taking into account some daily rainfall thresholds associated with the resolution of the pluviometer, evapotranspiration, runoff and thin layer saturation processes. A detailed analysis of DDSLR at daily and annual scales and for the whole recording period permits a complete description of the daily rainfall deficit regime and induced hydrologic stress. These characteristics have been derived for 0.1, 1.0, 5.0 and 10.0 mm/day thresholds for 93 years (1917–2009) of continuous daily rainfall records at the Fabra Observatory (Barcelona, NE Spain). Time trends on chronological series of DDSLR are determined and statistically tested for every calendar day. Fourier series analysis applied to four calendar day statistics (number of non-null DDSLR, average, standard deviation and maximum of DDSLR) leads to detection of the dominant periodicities, taking as fundamental periodicity the 365 days of the year. The best statistical model reproducing the empirical distribution of DDSLR, year by year, for every calendar day and for the whole recording period, is also investigated. Whatever the time scale considered, the Poisson-gamma model is assumed due to the non-negligible number of null DDSLR. Finally, time trends on extreme series of annual DDSLR, the appropriate statistical model for these series (the generalised logistic distribution, GLO), together with an estimation of DDSLR for several return periods, permit the description of the expected main future patterns of this index. In this way, current and next future hydrologic stress at the Fabra Observatory and neighbouring areas become characterised.

  • Normalised monthly shortage curves: a contribution for a better understanding of monthly rain deficit in Western Europe

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    Theoretical and applied climatology
    Vol. 108, num. 3-4, p. 535-552
    DOI: 10.1007/s00704-011-0547-0
    Date of publication: 2012-05
    Journal article

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  • Nuevas Avances de la Geofísica y la Ingeniería aplicados a la evaluación del riesgo sísmico

     Lana Pons, Francisco Javier; Caselles Magallon, Jose Oriol; Perez Gracia, Maria de La Vega; Gonzalez Drigo, Jose Ramon; Martínez Santafé, Maria Dolors; Lopez Almansa, Francisco; Serra De Larrocha, Carina; Canas Torres, Jose Antonio; Pujades Beneit, Luis Gonzaga
    Competitive project

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  • Time behaviour of aftershock series simulated by using a modified version of the Dynamic Fiber Bundle (FBM) model

     Martínez Santafé, Maria Dolors; Monterrubio Velasco, Marisol; Lana Pons, Francisco Javier
    European Geosciences Union General Assembly
    Presentation's date: 2012-04
    Presentation of work at congresses

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  • Access to the full text
    Response to the comments on ¿Time trends of daily maximum and minimum temperatures in Catalonia (NE Spain) for the period 1975-2004¿  Open access

     Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Burgueño, August; Lana Pons, Francisco Javier
    International journal of climatology
    Vol. 31, num. 1, p. 153-157
    DOI: 10.1002/joc.2073
    Date of publication: 2011-01
    Journal article

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  • CLIVAR-SPAIN contributions: trends in dry spells across Catalonia (NE Spain) during the second half of the 20th century

     Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Burgueño, August; Lana Pons, Francisco Javier
    World Climate Research Programme
    p. 210
    Presentation's date: 2011-10-27
    Presentation of work at congresses

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  • Nonlinear analysis of the north atlantic (NAO), atlantic mutidecadal (AMO) and western mediterranean (WeMO) oscillations for the cammon period 1856-2009

     Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina
    European Geosciences Union General Assembly
    p. 2149
    Presentation's date: 2011-04
    Presentation of work at congresses

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  • Trends of dry spells in Europe (1951-2000)

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    European Geosciences Union General Assembly
    p. 2746
    Presentation's date: 2011-04
    Presentation of work at congresses

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  • Patterns of the seismic generation rate detected by the Southern California seismic network (SCSN)

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier
    European Geosciences Union General Assembly
    p. 2154
    Presentation's date: 2011-04
    Presentation of work at congresses

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  • Extreme normalised residuals of daily temperatures in Catalonia (NE Spain): sampling strategies, return periods and clustering process

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    Theoretical and applied climatology
    Vol. 101, p. 1-17
    DOI: 10.1007/s00704-009-0172-3
    Date of publication: 2010-06
    Journal article

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    Extreme normalised residuals, defined as departures from the average values, of 65 daily maximum, T max, and minimum, T min, temperature series recorded in Catalonia (NE Spain) during 1950–2004 are analysed. Similarly to the sampling strategies applied to long dry spells, the partial duration series (PDS) offer some advantages in comparison with the annual extreme series. Instead of using a common percentile threshold for all temperature series, PDS are chosen according to the mean excess plot procedure. Series of extreme residuals are modelled, in terms of the L-moments formulation, by the generalised Pareto distribution. Extreme residuals of T max and T min are estimated for return periods ranging from 2 to 50 years and their spatial distribution is represented for selected return periods of 2, 5, 10, 25 and 50 years. Two daily extreme temperatures events, a hot episode (in August) and a cold episode (in February), are simulated taking into account the average T max (T min) for a day in August (February), their standard deviations and the extremes for a 50-year return period. Both simulations are compared with outstanding real episodes recorded on August 13th 2003 and February 11th 1956. Additionally, a spatial regionalisation of Catalonia in several clusters, in terms of the extreme residuals for return periods from 2 to 50 years, is done. A principal component analysis is applied to the extreme residual curves characterising every temperature series and, using as variables the principal components, the regionalisation is obtained by applying the average linkage clustering algorithm. Finally, each cluster is characterised by its average extreme residual curve for return periods ranging from 2 to 50 years at 1-year interval.

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    Complex behaviour and predictability of the European dry spell regimes  Open access

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Burgueño, August
    Nonlinear processes in geophysics
    Vol. 17, num. 5, p. 499-512
    DOI: 10.5194/npg-17-499-2010
    Date of publication: 2010-09
    Journal article

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    The complex spatial and temporal characteristics of European dry spell lengths, DSL, (sequences of consecutive days with rainfall amount below a certain threshold) and their randomness and predictive instability are analysed from daily pluviometric series recorded at 267 rain gauges along the second half of the 20th century. DSL are obtained by considering four thresholds, R0, of 0.1, 1.0, 5.0 and 10.0 mm/day. A proper quantification of the complexity, randomness and predictive instability of the different DSL regimes in Europe is achieved on the basis of fractal analyses and dynamic system theory, including the reconstruction theorem. First, the concept of lacunarity is applied to the series of daily rainfall, and the lacunarity curves are well fitted to Cantor and random Cantor sets. Second, the rescaled analysis reveals that randomness, persistence and anti-persistence are present on the European DSL series. Third, the complexity of the physical process governing the DSL series is quantified by the minimum number of nonlinear equations determined by the correlation dimension. And fourth, the loss of memory of the physical process, which is one of the reasons for the complex predictability, is characterized by the values of the Kolmogorov entropy, and the predictive instability is directly associated with positive Lyapunov exponents. In this way, new bases for a better prediction of DSLs in Europe, sometimes leading to drought episodes, are established. Concretely, three predictive strategies are proposed in Sect. 5. It is worth mentioning that the spatial distribution of all fractal parameters does not solely depend on latitude and longitude but also reflects the effects of orography, continental climate or vicinity to the Atlantic and Arctic Oceans and Mediterranean Sea.

  • Statistical distributions of daily rainfall regime in Europe for the period 1951-2000

     Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Lana Pons, Francisco Javier
    Theoretical and applied climatology
    Vol. 102, num. 1-2, p. 213-226
    DOI: 10.1007/s00704-010-0251-5
    Date of publication: 2010-09
    Journal article

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    Long-term rainfall monthly shortage in Spain: spatial patterns, statistical models and time trends  Open access

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    International journal of climatology
    Vol. 30, p. 1668-1688
    DOI: 10.1002/joc.2017
    Date of publication: 2010-09
    Journal article

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    Predictability of the monthly North Atlantic Oscillation index based on fractal analyses and dynamic system theory  Open access

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    Nonlinear processes in geophysics
    Vol. 17, num. 2, p. 93-101
    DOI: 10.5194/npg-17-93-2010
    Date of publication: 2010-03
    Journal article

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    Time trends of daily maximum and minimum temperatures in Catalonia (ne Spain) for the period 1975-2004  Open access

     Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Burgueño, August; Lana Pons, Francisco Javier
    International journal of climatology
    Vol. 30, p. 267-290
    DOI: 10.1002/joc.1884
    Date of publication: 2010-02
    Journal article

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  • Shear-wave attenuation tomography of the lithosphere-asthenosphere system beneath the Mediterranean region

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Guinto, E.R.
    Tectonophysics
    Vol. 481, num. 1-4, p. 51-67
    DOI: 10.1016/j.tecto.2008.11.008
    Date of publication: 2010
    Journal article

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  • Statistical distributions of daily rainfall regime in Europe for the period 1951-2000

     Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Lana Pons, Francisco Javier
    European Geosciences Union General Assembly
    p. 3249
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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  • Leading aftershocks and cascades: two possible stress release processes

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier
    European Geosciences Union General Assembly
    p. 8640
    Presentation's date: 2010-05-04
    Presentation of work at congresses

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  • Modelling European dry spell length distributions, years 1951-2000

     Serra De Larrocha, Carina; Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors
    European Geosciences Union General Assembly
    p. 3242
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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    Una revisión de los análisis estadísticos de las precipitaciones diarias y mensuales en Catalunya  Open access

     Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina
    Tethys: revista del temps i el clima de la Mediterrània occidental
    num. 6, p. 15-30
    DOI: 10.3369/tethys.2009.6.02
    Date of publication: 2009
    Journal article

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  • CONTRIBUCIONES SISMOLÓGICAS, GEOFISICAS Y DE INGENIERIA A LA PREDICCION Y PREVENCION DEL RIESGO SISMICO

     Perez Gracia, Maria de La Vega; Caselles Magallon, Jose Oriol; Lantada Zarzosa, Nieves; Clapes Boixader, Jaime; Gonzalez Drigo, Jose Ramon; Osorio Gomez, Raul; Lopez Almansa, Francisco; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Canas Torres, Jose Antonio; Lana Pons, Francisco Javier; Pujades Beneit, Luis Gonzaga
    Competitive project

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  • GEOFÍSICAI ENGINYERIA SÍSMICA

     Perez Gracia, Maria de La Vega; Caselles Magallon, Jose Oriol; Clapes Boixader, Jaime; Gonzalez Drigo, Jose Ramon; Osorio Gomez, Raul; Lopez Almansa, Francisco; Pujades Beneit, Luis Gonzaga; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Lana Pons, Francisco Javier; Canas Torres, Jose Antonio
    Competitive project

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  • Monthly shortage trends for Central and Western Europe

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    Annual Meeting European Meteorological Society organised with European Conference on Aplications of Meteorology
    p. 106
    Presentation's date: 2009-09-28
    Presentation of work at congresses

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  • Distribucions estadístiques de la precipitació diària a Catalunya, anys 1950-2000

     Burgueño, August; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Serra De Larrocha, Carina
    Jornades de Meteorologia Eduard Fontserè
    p. 131-140
    Presentation's date: 2009-11-29
    Presentation of work at congresses

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  • Predictability of the monthly NAO index: fractal analyses and comparisons with daily rainfall regimes and seismic activity

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    European Geosciences Union General Assembly
    p. 2410
    Presentation's date: 2009-04-23
    Presentation of work at congresses

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  • Elastic-anelastic regional structures of the crust and upper mantle beneath the Mediterranean basin derived from uncoupled causal inversion of Rayleigh wave attenuation coefficients and group velocities

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Guinto, E R
    European Geosciences Union General Assembly
    p. 2420
    Presentation's date: 2009-04-23
    Presentation of work at congresses

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  • Statistics of hot and cold events in Catalonia (NE Spain) for the recording period 1950-2004

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Burgueño, August; Serra De Larrocha, Carina
    Theoretical and applied climatology
    Vol. 97, num. 1-2, p. 135-150
    Date of publication: 2009-06
    Journal article

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  • A review on dry spells statistics in Catalonia (NE Spain)

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina; Burgueño, August
    Date of publication: 2008-11
    Book chapter

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  • Estadístiques d'episodis secs en Catalunya durant la segona meitat del segle XX

     Lana Pons, Francisco Javier
    XIV Jornades de Meteorologia Eduard Fontserè
    Presentation's date: 2008-11-26
    Presentation of work at congresses

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  • Spatial and statistical features of extreme residuals of daily minimum and maximum temperatures in Catalonia (NE Spain), years 1950-2004

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    European Geosciences Union General Assembly
    p. 1
    Presentation of work at congresses

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  • Estadístiques d'episodis secs en Catalunya durant la segona meitat del segle XX

     Lana Pons, Francisco Javier; Burgueño, August; Martínez Santafé, Maria Dolors; Serra De Larrocha, Carina
    XIV Jornades de Meteorologia Eduard Fontserè
    p. 43-56
    Presentation of work at congresses

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  • Spatial and statistical features of extreme residuals of daily maximum and minimum temperatures in Catalonia (NE Spain), years 1950-2004

     Serra De Larrocha, Carina; Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August
    Primeres Jornades de Meteorologia i Climatologia de la Mediterrània Occidental
    p. 13
    Presentation of work at congresses

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  • Exàmens d'electromagnetisme amb solucions (2001-2008)

     Bohigas Janoher, Xavier; Fernandez Mills, Gonzalo; Jaen Herbera, Javier; Lana Pons, Francisco Javier; Periago Oliver, M. Cristina; Serra De Larrocha, Carina
    Date of publication: 2008-12-31
    Book

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  • Return period maps of dry spells for Catalonia (northeastern Spain) based on the Weibull distribution

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Burgueño, August; Serra De Larrocha, Carina
    Hydrological sciences journal - Journal des sciences hydrologiques
    Vol. 53, num. 1, p. 48-64
    Date of publication: 2008-02
    Journal article

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  • Spatial and temporal patterns of dry spell lengths in the Iberian Peninsula for the second half of the twentieth century

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Burgueño, August; Serra De Larrocha, Carina; Martín-Vide, J; Gómez, L
    Theoretical and applied climatology
    Vol. 91, num. 1-4, p. 99-116
    Date of publication: 2008-02
    Journal article

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  • 1r Premi Internacional de Meteorologia Eduard Fontserè

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Serra De Larrocha, Carina; Burgueño, August
    Award or recognition

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  • STATISTICAL PATTERNS OF HOT AND COLD EVENTS IN NE SPAIN, YEARS 1950-2004

     Lana Pons, Francisco Javier
    7th EMS Annual Meeting /8th ECAM
    Presentation's date: 2007-10-01
    Presentation of work at congresses

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  • Statistical patterns of hot and cold events in NE Spain, years 1950-2004

     Lana Pons, Francisco Javier; Martínez Santafé, Maria Dolors; Burgueño, August; Serra De Larrocha, Carina
    7th EMS Annual Meeting /8th ECAM
    p. 1
    Presentation of work at congresses

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  • Trends in daily minimum and maximum temperatures in Catalonia (NE Spain) along the 1950-2004 recording period

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Serra De Larrocha, Carina; Burgueño, August
    European Geosciences Union General Assembly
    p. 3527
    Presentation of work at congresses

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  • Spatial and temporal daily rainfall regime in Catalonia (NE Spain) derived from four precipitation indices, years 1950-2000

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    International journal of climatology
    Vol. 27, num. 1, p. 123-138
    Date of publication: 2007-01
    Journal article

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  • Lacunarity, predictability and predictive instability of the daily pluviometric regime in the Iberian Peninsula

     Martínez Santafé, Maria Dolors; Lana Pons, Francisco Javier; Burgueño, August; Serra De Larrocha, Carina
    Nonlinear processes in geophysics
    Vol. 14, num. 2, p. 109-121
    Date of publication: 2007-03
    Journal article

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