Long memory, seasonality and time trends in the average monthly temperatures in Alaska   总被引：1，自引：0，他引：1  

Luis A. Gil-Alana 《Theoretical and Applied Climatology》2012,108(3-4):385-396

This paper deals with the analysis of monthly temperatures in 19 meteorological stations in Alaska during the last 50?years. For this purpose, we employ a procedure that permits us to examine in a single framework several features observed in climatological time series such as time trends, long-range persistence and seasonality. The results indicate that the highest degrees of persistence are observed in stations located in the southern regions and seasonality appears as a major issue in all cases. Removing the seasonal structure and focussing on the anomalies with respect to the monthly means, the time trend coefficients appear significantly positive in the majority of the cases, implying that temperatures have increased during the last 50?years.  相似文献   

Parametric model for capacity curves     

Luis G. Pujades  Yeudy F. Vargas-Alzate  Alex H. Barbat  José R. González-Drigo 《Bulletin of Earthquake Engineering》2015,13(5):1347-1376

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The local Hubble flow: is it a manifestation of dark energy?     

Yehuda Hoffman  Luis A. Martinez-Vaquero  Gustavo Yepes  Stefan Gottlöber 《Monthly notices of the Royal Astronomical Society》2008,386(1):390-396

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Radar Backscatter from Underdense Meteors and Diffusion Rates     

Werner Singer  Ralph Latteck  Luis Federico Millan  Nick J. Mitchell  Jens Fiedler 《Earth, Moon, and Planets》2008,102(1-4):403-409

Many meteoroids burn up between about 120 km and 70 km, deposit metals and dust and form ionized trails which are detected by radars. Model studies about the influence of neutral or positively charged background dust on the ambipolar diffusion indicate that significant smaller decay times should be observed for weak meteor echoes compared to strong meteor echoes which can affect the estimation of temperatures. The variation of meteor decay times in dependence on echo strength, height, and season was studied using radar observations at 69° N, 22° S, and 67° S. Significantly reduced decay times were found for weak echoes below about 88 km at low latitudes throughout the year, and at high latitudes with the exception of summer. In summer at high latitudes, decreasing decay times of weak and strong meteors are observed at altitudes below about 85 km during the appearance of noctilucent clouds. The impact of reduced decay times on the estimation of neutral temperatures from decay times is discussed.  相似文献   

An approach for estimating the largest probable tsunami from far-field subduction zone earthquakes     

Nikos Kalligeris  Luis Montoya  Aykut Ayca  Patrick Lynett 《Natural Hazards》2017,89(1):233-253

Following the recent unexpected earthquake events of 2004 and 2011, it can be cautiously extrapolated that all major subduction zones bearing the capacity to produce mega-earthquake events will eventually do so given enough time, irrespective of the lack of such in the relatively short historical record. This notion has led to an effort of assigning maximum earthquake magnitudes to all major subduction zones, either based on geological constraints or based on size–frequency relations, or a combination of both. In this study, we utilize the proposed maximum magnitudes to assess tsunami hazard in Central California in the very long return periods. We also assessed tsunami hazard following an alternative methodology to calculate maximum magnitudes, which uses scaling relations for subduction zone earthquakes and maximum fault rupture scenarios found in literature. A sensitivity analysis is performed for Central California that is applicable to any coastal site in the Pacific Rim and can readily provide a strong indication for which subduction zones beam the most energy toward a study area. The maximum earthquake scenarios are then narrowed down to a few candidates, for which the initial conditions are examined in more detail. The chosen worst-case scenarios for Central California stem from the Alaska–Aleutian subduction zone that beams more energy and generates the biggest amplitude waves toward the study area. The largest tsunami scenario produces maximum free surface elevations of 15 m and run-up heights greater than 20 m.  相似文献   

Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method,applied in Risk-UE project     

Seif-eddine Cherif  Mimoun Chourak  Mohamed Abed  Luis Pujades 《Natural Hazards》2017,85(1):329-347

Al Hoceima is one of the most seismic active regions in north of Morocco. It is demonstrated by the large seismic episodes reported in seismic catalogs and research studies. However, seismic risk is relatively high due to vulnerable buildings that are either old or don’t respect seismic standards. Our aim is to present a study about seismic risk and seismic scenarios for the city of Al Hoceima. The seismic vulnerability of the existing residential buildings was evaluated using the vulnerability index method (Risk-UE). It was chosen to be adapted and applied to the Moroccan constructions for its practicality and simple methodology. A visual inspection of 1102 buildings was carried out to assess the vulnerability factors. As for seismic hazard, it was evaluated in terms of macroseismic intensity for two scenarios (a deterministic and probabilistic scenario). The maps of seismic risk are represented by direct damage on buildings, damage to population and economic cost. According to the results, the main vulnerability index of the city is equal to 0.49 and the seismic risk is estimated as Slight (main damage grade equal to 0.9 for the deterministic scenario and 0.7 for the probabilistic scenario). However, Moderate to heavy damage is expected in areas located in the newer extensions, in both the east and west of the city. Important economic losses and damage to the population are expected in these areas as well. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategies in Al Hoceima.  相似文献   

Modelling of rupture propagation using high-order mimetic finite differences   总被引：1，自引：0，他引：1  

Otilio Rojas  Steven Day  Jose Castillo  Luis A. Dalguer 《Geophysical Journal International》2008,172(2):631-650

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Coastal vulnerability assessment based on video wave run-up observations at a mesotidal,steep-sloped beach     

Michalis Ioannis Vousdoukas  Dagmara Wziatek  Luis Pedro Almeida 《Ocean Dynamics》2012,62(1):123-137

Coastal imagery obtained from a coastal video monitoring station installed at Faro Beach, S. Portugal, was combined with topographic data from 40 surveys to generate a total of 456 timestack images. The timestack images were processed in an open-access, freely available graphical user interface (GUI) software, developed to extract and process time series of the cross-shore position of the swash extrema. The generated dataset of 2% wave run-up exceedence values R ₂ was used to form empirical formulas, using as input typical hydrodynamic and coastal morphological parameters, generating a best-fit case RMS error of 0.39 m. The R ₂ prediction capacity was improved when the shore-normal wind speed component and/or the tidal elevation η _tide were included in the parameterizations, further reducing the RMS errors to 0.364 m. Introducing the tidal level appeared to allow a more accurate representation of the increased wave energy dissipation during low tides, while the negative trend between R ₂ and the shore-normal wind speed component is probably related to the wind effect on wave breaking. The ratio of the infragravity-to-incident frequency energy contributions to the total swash spectra was in general lower than the ones reported in the literature E _infra/E _inci > 0.8, since low-frequency contributions at the steep, reflective Faro Beach become more significant mainly during storm conditions. An additional parameterization for the total run-up elevation was derived considering only 222 measurements for which η _total,2 exceeded 2 m above MSL and the best-fit case resulted in RMS error of 0.41 m. The equation was applied to predict overwash along Faro Beach for four extreme storm scenarios and the predicted overwash beach sections, corresponded to a percentage of the total length ranging from 36% to 75%.  相似文献   

Kinematic interaction factors of deep foundations with inclined piles          下载免费PDF全文

Cristina Medina  Luis A. Padrón  Juan J. Aznárez  Ariel Santana  Orlando Maeso 《地震工程与结构动力学》2014,43(13):2035-2050

The beneficial or detrimental role of battered piles on the dynamic response of piled foundations has not been yet fully elucidated. In order to shed more light on this aspect, kinematic interaction factors of deep foundations with inclined piles, are provided for single‐battered piles, as well as for 2 × 2 and 3 × 3 groups of piles subjected to vertically incident plane shear S waves. Piles are modelled as linear‐elastic Bernoulli beams, whereas soil is assumed to be a linear, isotropic, homogeneous viscoelastic half‐space. Different pile group configurations, pile‐soil stiffness ratios, and rake angles are considered. The relevance and main trends observed in the influence of the rake angle on the kinematic interaction factors of the analysed foundations are inferred from the presented results. An important dependence of the kinematic interaction factors on the rake angle is observed together with the existence of an inclination angle at which cap rotation and excitation become out of phase in the low‐to‐mid frequency range. The existence of a small batter angle that provides minimum cap rotation is also shown. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Characterizing hydroclimatic variability in tributaries of the Upper Colorado River Basin—WY1911-2001     

Margaret A. Matter  Luis A. Garcia  Darrell G. Fontane  Brian Bledsoe 《Journal of Hydrology》2010,380(3-4):260-276

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