Particulate air pollution from wildfires in the Western US under climate change     

Jia Coco Liu  Loretta J. Mickley  Melissa P. Sulprizio  Francesca Dominici  Xu Yue  Keita Ebisu  Georgiana Brooke Anderson  Rafi F. A. Khan  Mercedes A. Bravo  Michelle L. Bell 《Climatic change》2016,135(3-4):655-668

  相似文献   

A new method for specular and diffuse pseudorange multipath error extraction using wavelet analysis     

Giovanni?Pugliano  Umberto?RobustelliEmail authorView author&#;s OrcID profile  Fabio?Rossi  Raffaele?Santamaria 《GPS Solutions》2016,20(3):499-508

Multipath remains one of the major challenges in Global Navigation Satellite System (GNSS) positioning because it is considered the dominant source of ranging errors, which can be classified into specular and diffuse types. We present a new method using wavelets to extract the pseudorange multipath in the time domain and breaking it down into the two components. The main idea is an analysis-reconstruction approach based on application of both continuous wavelet transform (CWT) and discrete wavelet transform (DWT). The proposed procedure involves the use of L1 code-minus-carrier (CMC) observable where higher-frequency terms are isolated as residuals. CMC residuals are analyzed by applying the CWT, and we propose the scalogram as a technique for discerning time–frequency variations of the multipath signal. Unlike Fourier transform, the potential of the CWT scalogram for examining the non-stationary and multifrequency nature of the multipath is confirmed as it simultaneously allows fine detection and time localization of the most representative frequencies of the signal. This interpretation of the CWT scalogram is relevant when choosing the levels of reconstruction with DWT, allowing accurate time domain extraction of both the specular and diffuse multipath. The performance and robustness of the method and its boundary applicability are assessed. The experiment was carried out using a receiver of Campania GNSS Network. The results are given in which specular multipath error is achieved using DWT level 7 approximation component and diffuse multipath error is achieved using DWT level 6 denoised detail component.  相似文献   

Hierarchical simulation of aquifer heterogeneity: implications of different simulation settings on solute-transport modeling     

Alessandro Comunian  Leonardo De Micheli  Claudio Lazzati  Fabrizio Felletti  Francesca Giacobbo  Mauro Giudici  Riccardo Bersezio 《Hydrogeology Journal》2016,24(2):319-334

The fine-scale heterogeneity of porous media affects the large-scale transport of solutes and contaminants in groundwater and it can be reproduced by means of several geostatistical simulation tools. However, including the available geological information in these tools is often cumbersome. A hierarchical simulation procedure based on a binary tree is proposed and tested on two real-world blocks of alluvial sediments, of a few cubic meters volume, that represent small-scale aquifer analogs. The procedure is implemented using the sequential indicator simulation, but it is so general that it can be adapted to various geostatistical simulation tools, improving their capability to incorporate geological information, i.e., the sedimentological and architectural characterization of heterogeneity. When compared with a standard sequential indicator approach on bi-dimensional simulations, in terms of proportions and connectivity indicators, the proposed procedure yields reliable results, closer to the reference observations. Different ensembles of three-dimensional simulations based on different hierarchical sequences are used to perform numerical experiments of conservative solute transport and to obtain ensembles of equivalent pore velocity and dispersion coefficient at the scale length of the blocks (meter). Their statistics are used to estimate the impact of the variability of the transport properties of the simulated blocks on contaminant transport modeled on bigger domains (hectometer). This is investigated with a one-dimensional transport modeling based on the Kolmogorov-Dmitriev theory of branching stochastic processes. Applying the proposed approach with diverse binary trees and different simulation settings provides a great flexibility, which is revealed by the differences in the breakthrough curves.  相似文献   

Reply to Comment on “Impact of groundwater withdrawals on the interaction of multi-layered aquifers in the Viterbo geothermal area (central Italy)”: report published in Hydrogeology Journal (2013) 21:1339–1353, by Antonella Baiocchi,Francesca Lotti and Vincenzo Piscopo     

Baiocchi  Antonella  Lotti  Francesca  Piscopo  Vincenzo 《Hydrogeology Journal》2016,24(2):541-545

Hydrogeology Journal -  相似文献   

DNA and fluorescein tracer tests to study the recharge,groundwater flowpath and hydraulic contact of aquifers in the Umbria-Marche limestone ridge (central Apennines,Italy)     

Lucia Aquilanti  Francesca Clementi  Torquato Nanni  Stefano Palpacelli  Alberto Tazioli  Paola Maria Vivalda 《Environmental Earth Sciences》2016,75(7):626

  相似文献   

Implementing landslide path dependency in landslide susceptibility modelling     

Jalal Samia  Arnaud Temme  Arnold K. Bregt  Jakob Wallinga  John Stuiver  Fausto Guzzetti  Francesca Ardizzone  Mauro Rossi 《Landslides》2018,15(11):2129-2144

Landslide susceptibility modelling—a crucial step towards the assessment of landslide hazard and risk—has hitherto not included the local, transient effects of previous landslides on susceptibility. In this contribution, we implement such transient effects, which we term “landslide path dependency”, for the first time. Two landslide path dependency variables are used to characterise transient effects: a variable reflecting how likely it is that an earlier landslide will have a follow-up landslide and a variable reflecting the decay of transient effects over time. These two landslide path dependency variables are considered in addition to a large set of conditioning attributes conventionally used in landslide susceptibility. Three logistic regression models were trained and tested fitted to landslide occurrence data from a multi-temporal landslide inventory: (1) a model with only conventional variables, (2) a model with conventional plus landslide path dependency variables, and (3) a model with only landslide path dependency variables. We compare the model performances, differences in the number, coefficient and significance of the selected variables, and the differences in the resulting susceptibility maps. Although the landslide path dependency variables are highly significant and have impacts on the importance of other variables, the performance of the models and the susceptibility maps do not substantially differ between conventional and conventional plus path dependent models. The path dependent landslide susceptibility model, with only two explanatory variables, has lower model performance, and differently patterned susceptibility map than the two other models. A simple landslide susceptibility model using only DEM-derived variables and landslide path dependency variables performs better than the path dependent landslide susceptibility model, and almost as well as the model with conventional plus landslide path dependency variables—while avoiding the need for hard-to-measure variables such as land use or lithology. Although the predictive power of landslide path dependency variables is lower than those of the most important conventional variables, our findings provide a clear incentive to further explore landslide path dependency effects and their potential role in landslide susceptibility modelling.  相似文献   

Chronology of the Mediterranean sea-level highstand during the Last Interglacial: a critical review of the U/Th-dated deposits     

Francesca Pasquetti  Monica Bini  Biagio Giaccio  Andrea Ratti  Matteo Vacchi  Giovanni Zanchetta 《第四纪科学杂志》2021,36(7):1174-1189

Relative sea-level (RSL) evolution during Marine Isotopic Stage (MIS) 5 in the Mediterranean basin is still not fully understood despite a plethora of morphological, stratigraphic and geochronological studies carried out on highstand deposits of this area. In this review we assembled a database of 323 U/Th-dated samples (e.g. corals, molluscs, speleothems) which were used to chronologically constrain RSL evolution within MIS 5. The application of strict geochemical criteria to the U/Th samples indicates that only ~33% of data available for the Mediterranean Sea can be considered ‘reliable’. Most of these data (~65%) refer to the MIS 5e highstand, while only ~17% could be related to the MIS 5a. No attribution to MIS 5c can be unequivocally supported. Nevertheless, the resulting framework does not allow us to define a satisfactory RSL trend during the MIS 5e highstand and subsequent MIS 5 substages. Overall, the proposed selection of reliable/unreliable data would be useful for detecting areas where MIS 5 substage attributions are not supported by confident U/Th chronological data and thus the related reconstructions need to be revised. In this regard, the resulting framework calls for a reappraisal and re-examination of the Mediterranean records with advanced geochronological methodologies.  相似文献   

Evaluating soil erosion by water in a small alpine catchment in Northern Italy: comparison of empirical models     

Berteni  Francesca  Barontini  Stefano  Grossi  Giovanna 《中国地球化学学报》2021,40(4):507-524

Acta Geochimica - To quantify water erosion rates and annual soil loss in mountainous areas, two different empirical models were used to estimate the effects of soil erosion in a small mountain...  相似文献   

Seismic image quality beneath strongly scattering structures and implications for lower crustal imaging: numerical simulations     

Francesca Martini  Christopher J. Bean  Sean Dolan  David Marsan† 《Geophysical Journal International》2001,145(2):423-435

  相似文献   

Geodynamic significance of ophiolites within the Calabrian Arc     

Francesca  Liberi  Lauro  Morten  Eugenio  Piluso 《Island Arc》2006,15(1):26-43

Abstract Slices of oceanic lithosphere belonging to the neo‐Tethys realm crop out discontinuously in the northern Calabrian Arc, Southern Apennines. They consist of high‐pressure–low‐temperature metamorphic ophiolitic sequences formed from metaultramafics, metabasites and alternating metapelites, metarenites, marbles and calcschist. Ophiolites occupy an intermediate position in the northern Calabrian Arc nappe pile, situated between overlying Hercynian continental crust and the underlying Apenninic limestone units. In the literature, these ophiolitic sequences are subdivided into several tectonometamorphic units. Geochemical characteristics indicate that metabasites were derived from subalkaline basalts with tholeiitic affinity (transitional mid‐oceanic ridge basalt type), and a harzburgitic‐lherzolitic protolith is suggested for the serpentinites. The pressure–temperature‐deformation paths of the metabasites from different outcrops display similar features: (i) the prograde segment follows a typical Alpine geothermal gradient up to a metamorphic climax at 350°C and 0.9 GPa and crystallization of the high‐pressure mineral assemblage occurs along a pervasive foliation developed during a compressive tectonic event; and (ii) the retrogression path can be subdivided in two segments, the first is characterized by nearly isothermal decompression to approximately 400°C and 0.3 GPa and the second follows a cooling trajectory. During low‐pressure conditions, a second deformation event produces millimetric to decametric scale asymmetric folds that describe west‐verging major structures. The third deformation event is characterized by brittle extensional structures. The tectonometamorphic evolution of the ophiolitic sequences from the different outcrops is similar. Both thermobarometric modeling and tectonic history indicate that the studied rocks underwent Alpine subduction and exhumation processes as tectonic slices inside a west‐verging accretionary wedge. The subduction of oceanic lithosphere was towards the present east; therefore, the Hercynian continental crust, overthrusted on the ophiolitic accretionary wedge after the neo‐Tethys closure, was part of the African paleomargin or a continental microplate between Africa and Europe.  相似文献