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P. Brigode E. Paquet P. Bernardara J. Gailhard F. Garavaglia P. Ribstein 《水文科学杂志》2015,60(7-8):1424-1437
AbstractThe Kamp River is a particularly interesting case study for testing flood frequency estimation methods, since it experienced a major flood in August 2002. Here, the Kamp catchment is studied in order to quantify the influence of such a remarkable flood event on the calibration of a rainfall–runoff model, in particular when it is used in a stochastic simulation method for flood estimation, by performing numerous rainfall–runoff model calibrations (based on split-sample and bootstrap tests). The results confirmed the usefulness of the multi-period and bootstrap testing schemes for identifying the dependence of model performance and flood estimates on the information contained in the calibration period. The August 2002 event appears to play a dominating role for the Kamp River, since the presence or absence of the event within the calibration sub-periods strongly influences the rainfall–runoff model calibration and the extreme flood estimations that are based on the calibrated model. 相似文献
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The new Database of Italy’s Seismogenic Sources (Basili et al. 2008) identifies areas with a degree of homogeneity in earthquake generation mechanism judged sufficiently high. Nevertheless, their seismic sequences show rather long and regular interoccurrence times mixed with irregularly distributed short interoccurrence times. Accordingly, the following question could naturally arise: do sequences consist of nearly periodic events perturbed by a kind of noise; are they Poissonian; or short interoccurrence times predominate like in a cluster model? The relative reliability of these hypotheses is at present a matter of discussion (Faenza et al., Geophys J Int 155:521–531, 2003; Corral, Proc Geoph 12:89–100, 2005, Tectonophysics 424:177–193, 2006). In our regions, a statistical validation is not feasible because of the paucity of data. Moreover, the classical tests do not clearly suggest which one among different proposed models must be favoured. In this paper, we adopt a model of interoccurrence times able to interpret the three different hypotheses, ranging from exponential to Weibull distributions, in a scenario of increasing degree of predictability. In order to judge which one of these hypotheses is favoured, we adopt, instead of the classical tests, a more selective indicator measuring the error in respect to the chosen panorama of possible truths. The earthquake prediction is here simply defined and calculated through the conditional probability of occurrence depending on the elapsed time t0 since the last earthquake. Short-term and medium-term predictions are performed for all the Italian seismic zones on the basis of datasets built in the context of the National Projects INGV-DPC 2004–2006, in the frame of which this research was developed. The mathematical model of interoccurrence times (mixture of exponential and Weibull distributions) is justified in its analytical structure. A dimensionless procedure is used in order to reduce the number of parameters and to make comparisons easier. Three different procedures are taken into consideration for the estimation of the parameter values; in most of the cases, they give comparable results. The degree of credibility of the proposed methods is evaluated. Their robustness as well as their sensitivity are discussed. The comparison of the probability of occurrence of a Maw >5.3 event in the next 5 and 30 years from January 1, 2003, conditional to the time elapsed since the last event, shows that the relative ranking of impending rupture in 5 years is roughly maintained in a 30-year perspective with higher probabilities and large fluctuations between sources belonging to the same macro region. 相似文献
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A.G. Borrego L. Garavaglia W.D. Kalkreuth 《International Journal of Coal Geology》2009,77(3-4):409-415
Partial substitution of coal by biomass in combustion systems in conjunction with advanced technologies for CO2 capture and storage may result in a significant reduction of greenhouse gases emissions. This study investigates three biomass chars produced from rice husk, forest residuals and wood chips under N2 and CO2 atmospheres using a drop tube furnace (DTF) heated at 950 °C. The char constitutes an unburned residue which has been devolatilized under conditions resembling in thermal history those in full scale boilers. Higher weight losses were achieved under N2 than under CO2 for each type of biomass, and the highest weight loss was that of wood chips biomass, followed by forest residuals and then rice husk. The results indicate significant morphological differences between the biomass chars produced. The wood chips yielded thick-walled chars with a cenospheric shape very similar to those of low-rank vitrinite. The forest residual chars were angular in shape and often had a tenuinetwork structure, while the rice husk chars retained their vegetal structure. Overall, the studied biomass chars can be described as microporous solids. However, in the case of the rice husk, the silica associated to the char walls was essentially mesoporous, increasing the adsorption capacity of the rice husk chars. The atmosphere in the DTF affects the development of porosity in the chars. The pore volumes of the rice husk and forest residual chars prepared under a CO2 atmosphere were higher than those of chars prepared under a N2 atmosphere, whereas the opposite was the case with the wood chip chars. The chars that experienced the most drastic devolatilization were those with the lowest intrinsic reactivity. This indicates a more efficient reorganization of the chemical structure that reduces the number of active sites available for oxygen attack. Overall a similar morphology, optical texture, specific surface area and reactivity were found for the biomass chars generated under N2 and CO2, which is a similar result to that obtained for coal chars. 相似文献
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O. D’arcangelo S. Garavaglia A. Simonetto C. Sozzi M. Bersanelli A. Mennella F. Villa 《Experimental Astronomy》2003,16(3):165-187
An experimental study on the perturbation of the angular response of a W-band corrugated horn produced by nearby feeds, reproducing a typical situation of multi-feed arrays commonly used in high sensitivity Cosmic Microwave Background instruments, is reported in this paper. The effects for different positions of the scattering horn in the two principal polarisation planes were measured. We analyze the effects on both the side-lobe level and on the main beam. In particular, these results allowed us to validate design criterion for the multi-frequency focal array of the ESA PLANCK mission.This revised version was published online in July 2005. The first author’s e-mail address was removed. 相似文献
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Statistical Analysis of the Completeness of a Seismic Catalogue 总被引：1，自引：0，他引：1
Among the numerous issues that the study of seismic events presents, theincompleteness of catalogues is certainly one of the most important. It is also one that only the contribution of many and different skills canprovide with a valid solution. In this paper the search for the complete part of a catalogue is expressed in terms of identification of the changepoint in a hierarchical Bayesian model. Stochastic simulation methods, recently presented in the literature, have enabled us to overcome the computational issues that previously made this approach prohibitive. We have applied the method on data, drawn from the Italian NT4.1.1 catalogue,related to some seismogenetic zones of ZS.4 zonation within which we assumespatial incompleteness to be homogeneous. The results obtained are given inthe concluding sections of the paper. 相似文献
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