Comparison of two bias correction methods for precipitation simulated with a regional climate model     

Tschöke  Gabriele Vanessa  Kruk  Nadiane Smaha  de Queiroz  Paulo Ivo Braga  Chou  Sin Chan  de Sousa Junior  Wilson Cabral 《Theoretical and Applied Climatology》2017,127(3-4):841-852

This study evaluates the performance of two bias correction techniques—power transformation and gamma distribution adjustment—for Eta regional climate model (RCM) precipitation simulations. For the gamma distribution adjustment, the number of dry days is not taken as a fixed parameter; rather, we propose a new methodology for handling dry days. We consider two cases: the first case is defined as having a greater number of simulated dry days than the observed number, and the second case is defined as the opposite. The present climate period was divided into calibration and validation sets. We evaluate the results of the two bias correction techniques using the Kolmogorov-Smirnov nonparametric test and the sum of the differences between the cumulative distribution curves. These tests show that both correction techniques were effective in reducing errors and consequently improving the reliability of the simulations. However, the gamma distribution correction method proved to be more efficient, particularly in reducing the error in the number of dry days.

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Observations on the Spatio-Temporal Distribution of Crustacean Amphipods in the Fusaro Coastal Lagoon (Central Tyrrhenian Sea, Italy) and Some Notes on Their Presence in Mediterranean Lagoons     

Gabriele  Procaccini Maria Beatrice  Scipione 《Marine Ecology》1992,13(3):203-224

Abstract. The amphipod population of the Fusaro coastal lagoon (Tyrrhenian Sea, Italy) was studied on a spatial-temporal scale. During a one-year period, samples were collected on hard and soft bottoms along a transect from the inland to the seaward side of the lagoon. Thirteen species were identified. The dominant taxa included species typical of lagoon environments, such as Corophium insidiosum and Microdeutopus gryllotalpa , and species typical of marine environments yet also inhabiting sheltered or semi-closed areas, such as Corophium acutum, Ericthonius brasiliensis , and Elasmopus rapax.
An inner-outer gradient was not evident, while a seasonal pattern was recognizable. At the community level, clear differences between the two substrata were not evident because of high algal growth and organogenic detritus on the soft bottoms. The importance of hydrodynamic forces in a euhaline lagoon in selecting amphipod communities - characterized by a typical trophic behaviour and way of life – is discussed. Information on the ecology of the collected species and a list of Mediterranean lagoons where they are present are also provided.  相似文献   

Size-dependent, Spatial, and Temporal Variability of Juvenile Walleye Pollock (Theragra chalcogramma) Feeding at a Structural Front in the Southeast Bering Sea     

Robert Schabetsberger  Marc Sztatecsny  Gabriele Drozdowski  Richard D. Brodeur  Gordon L. Swartzman  Matthew T. Wilson  reas G. Winter  & Jeffrey M. Napp 《Marine Ecology》2003,24(2):141-164

Abstract. The waters surrounding the Pribilof Islands are an important nursery ground for juvenile walleye pollock (Theragra chalcogramma), an important forage fish in the pelagic food web of the productive Bering Sea shelf region. The diet of juvenile pollock was studied in two consecutive years along a transect line crossing from a well‐mixed coastal domain, through a frontal region to stratified water farther offshore. Variability in stomach fullness was high and evidence for increased feeding intensity in the front was weak. Prey diversity and prey size generally increased with increasing fish size, shifting from predominantly small copepods to larger, more evasive prey items such as euphausiids, crab megalopae and fish. The diet of the fish reflected changes in the relative abundance of copepods and euphausiids in the prey fields between years. Juvenile pollock showed increased feeding rates at dusk, and stomach fullness as well as prey condition were generally lowest just before sunrise; however, the proportion of euphausiids increased in the diet of pollock caught at night, suggesting that some food was also ingested during darkness. Juvenile pollock and their euphausiid prey both vertically migrated above the thermocline at night, although each had a different daytime depth.  相似文献   

Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East   总被引：5，自引：5，他引：0  

John Douglas  Sinan Akkar  Gabriele Ameri  Pierre-Yves Bard  Dino Bindi  Julian J. Bommer  Sanjay Singh Bora  Fabrice Cotton  Boumédiène Derras  Marcel Hermkes  Nicolas Martin Kuehn  Lucia Luzi  Marco Massa  Francesca Pacor  Carsten Riggelsen  M. Abdullah Sandıkkaya  Frank Scherbaum  Peter J. Stafford  Paola Traversa 《Bulletin of Earthquake Engineering》2014,12(1):341-358

This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan.  相似文献   

Benthic control upon the morphology of transported fine sediments in a low‐gradient stream          下载免费PDF全文

James Fox  William Ford  Kyle Strom  Gabriele Villarini  Michelle Meehan 《水文研究》2014,28(11):3776-3788

The structure of fluvial sediments in streams has environmental implications to contaminant fate, nutrient budgeting and the carbon flux associated with fine particulate organic matter (FPOM). However, the influence of sediment structure is lacking in environmental predictive models. To this end, the present study links field‐based results of sediment aggregate structure to seasonal biological functions in the surface fine‐grained laminae (SFGL) of a low‐gradient stream. Fluvial sediment collection, microscopy and image analysis are used to show that aggregates collected over a 20 month time period support the concept that aggregate structure can vary seasonally in low‐gradient streams where temporarily stored sediment is prominent. Results show that the structure of the transported aggregates is more irregular in the summer with the structure being elongated about the long axes. In the winter, the aggregate structure is compacted and more spherical. Statistical analysis and results suggest that heterotrophic and autotrophic biological activity within the SFGL exhibits seasonal control upon the morphology of transported sediments. Implications of this research are highlighted through calculations of the reactive surface area of the transported suspended sediment load. The surface area of transported sediment is estimated to be 40% greater in the summer as compared to the winter time period, which implies that (i) the affinity of sediments to sorb contaminants is higher in summer months and (ii) the downstream reactivity of FPOM in large rivers, lakes and estuaries is not just a function of microbial drivers but also the seasonally dependent structure of transported FPOM derived from low‐order streams. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Variability of the health effects of crystalline silica: Fe speciation in industrial quartz reagents and suspended dusts—insights from XAS spectroscopy     

Francesco Di Benedetto  Francesco D’Acapito  Fabio Capacci  Gabriele Fornaciai  Massimo Innocenti  Giordano Montegrossi  Werner Oberhauser  Luca A. Pardi  Maurizio Romanelli 《Physics and Chemistry of Minerals》2014,41(3):215-225

We investigated the speciation of Fe in bulk and in suspended respirable quartz dusts coming from ceramic and iron-casting industrial processes via X-ray absorption spectroscopy, with the aim of contributing to a better understanding of the variability of crystalline silica toxicity. Four different bulk industrial quartz powders, nominally pure quartz samples with Fe contents below 200 ppm, and three respirable dusts filters were selected. Fe speciation was determined in all samples through a coupled study of the X-ray absorption near-edge structure and extended X-ray absorption fine structure regions, operating at the Fe–K edge. Fe speciation revealed common features at the beginning of the different production processes, whereas significant differences were observed on both respirable dusts and bulk dusts exiting from the production process. Namely, a common pollution of the raw quartz dusts by elemental Fe was evidenced and attributed to residuals of the industrial production of quartz materials. Moreover, the respirable samples indicated that reactivity occurs after the suspension of the powders in air. The gravitational selection during the particle suspension consistently allowed us to clearly discriminate between suspended and bulk dusts. On the basis of the obtained results, we provide an apparent spectroscopic discrimination between the raw materials used in the considered industrial processes, and those that are effectively inhaled by workers. In particular, an amorphous Fe^III oxide, with an unsaturated coordination sphere, can be related to silica reactivity (and health consequences).  相似文献   

Use of NTv2 transformation grids in engineering applications     

Gabriele Garnero 《Earth Science Informatics》2014,7(2):139-145

This paper describes a technique to transform coordinates between map references based on NTv2 format grids. Using the grids rather than carrying out a transformation allows to avoid map archives doubling, thereby easing “on the fly” transformation between different map representations. The paper also includes a case-study on a highway stretch currently under construction, the ‘Pedemontana Lombarda’ highway.  相似文献   

Earth walls as repositories of background levels of soil metal contaminants     

Valter Boero  Gabriele Fabietti  Franco Ajmone-Marsan 《Environmental Earth Sciences》2014,72(2):491-498

Data about the background concentration of potentially toxic elements in soils are indispensable for establishing legislative limits, risk thresholds and, in general, assess the intensity of the pollution. Crude earth buildings are diffuse in the Mediterranean area and may be used as archives for original concentration of various metals. The building technique uses local soil which is mixed with water, let dry in formworks and covered with plaster. This has protected the soil material from external additions. The aim of this work was to evaluate the crude earth walls as repositories of the original concentration of some metals. Six crude earth walls were investigated in a location in northwestern Italy. Their concentration in Cd, Cu, Cr, Ni, Pb and Zn were measured and compared with those of surrounding soil profiles. Also, the results were compared with those of the Province. Organic carbon and pH seem to confirm the different evolution of the soils in the field with respect to that in the wall while iron oxides were not useful in discriminating the samples. Cadmium and Pb appeared to be the most reliable for the evaluation of the accumulated contamination evaluated while Cr and Ni are influenced by the lithogenic substratum.  相似文献   

Research and development of advanced technologies for landslide hazard analysis in Italy   总被引：2，自引：0，他引：2  

Francesca Bozzano  Paolo Mazzanti  Alberto Prestininzi  Gabriele Scarascia Mugnozza 《Landslides》2010,7(3):381-385

The Research Centre on Prediction, Prevention and Control of Georisks, "Sapienza Università di Roma" (CERI) was selected as one of the World Centres of Excellence on Landslide Risk Reduction (WCoE) under the title of “Research and development of advanced technologies for landslide hazard analysis in Italy” in the period 2008–2011. The present paper provides background information on the activities carried out by the CERI, in the frame of the WCoE network. Pre-defined purposes have been achieved by the implementation of integrated monitoring systems and early warning systems for landslides movements. The application of GBInSAR technique for monitoring landslides interacting with infrastructures is discussed, and two case histories are presented. It is shown that this technique is particularly suitable for the displacements monitoring of landslides interacting with infrastructures, thanks to its peculiar features (i.e. areal mapping, operability under every weather and lighting conditions and continuous and completely remote monitoring). Hence, it can be considered a very important tool for the reduction of risks connected to the realisation and activity of large infrastructures.  相似文献   

Coastal deformation between the Versilia and the Garigliano plains (Italy) since the last interglacial stage     

Marco F. Nisi  Fabrizio Antonioli  Giuseppe Dai Pra  Gabriele Leoni  Sergio Silenzi 《第四纪科学杂志》2003,18(8):709-721

The opening of the north‐central Tyrrhenian Sea is the result of the Cretaceous–Paleogene alpine collision, which triggered a series of regional uplift, subsidence and transcurrent tectonic mechanisms along the coastal Tyrrhenian sectors of peninsular Italy. These tectonic processes, in conjunction with the effects of glacio‐ and hydro‐isostasy during the Quaternary, produced substantial crustal responses that, in some cases, reached metres in extent. In the study of coastal neotectonics, geomorphological markers of the last interglacial maximum, corresponding to marine isotope stage 5.5, are generally used to quantify the magnitude of the vertical crustal displacements that have occurred since 125 kyr. Through altimetrical, palaeoenvironmental and chronological reinterpretation of the most significant works published since 1913, combined with an additional set of data reported here, a detailed reconstruction of the shoreline displacements evident along 500 km of coast between northern Tuscany and southern Latium is presented. The reconstruction was carried out by quantifying the vertical movement since the last interglacial period and by identifying the tectonic behaviour of different coastal sectors. This has been done by carefully choosing the eustatic marker, among those available at each study site, in order to minimize the margin of error associated with the measurements. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献