Comparing theoretically supported rainfall‐runoff erosivity factors at the Sparacia (South Italy) experimental site          下载免费PDF全文

Vincenzo Bagarello  Costanza Di Stefano  Vito Ferro  Vincenzo Pampalone 《水文研究》2018,32(4):507-515

Interpreting rainfall‐runoff erosivity by a process‐oriented scheme allows to conjugate the physical approach to soil loss estimate with the empirical one. Including the effect of runoff in the model permits to distinguish between detachment and transport in the soil erosion process. In this paper, at first, a general definition of the rainfall‐runoff erosivity factor REF_e including the power of both event runoff coefficient Q_R and event rainfall erosivity index EI₃₀ of the Universal Soil Loss Equation (USLE) is proposed. The REF_e factor is applicable to all USLE‐based models (USLE, Modified USLE [USLE‐M] and Modified USLE‐M [USLE‐MM]) and it allows to distinguish between purely empirical models (e.g., Modified USLE‐M [USLE‐MM]) and those supported by applying theoretical dimensional analysis and self‐similarity to Wischmeier and Smith scheme. This last model category includes USLE, USLE‐M, and a new model, named USLE‐M based (USLE‐MB), that uses a rainfall‐runoff erosivity factor in which a power of runoff coefficient multiplies EI₃₀. Using the database of Sparacia experimental site, the USLE‐MB is parameterized and a comparison with soil loss data is carried out. The developed analysis shows that USLE‐MB (characterized by a Nash–Sutcliffe Efficiency Index NSEI equal to 0.73 and a root mean square error RMSE = 11.7 Mg ha^?1) has very similar soil loss estimate performances as compared with the USLE‐M (NSEI = 0.72 and RMSE = 12.0 Mg ha^?1). However, the USLE‐MB yields a maximum discrepancy factor between predicted and measured soil loss values (176) that is much lower than that of USLE‐M (291). In conclusion, the USLE‐MB should be preferred in the context of theoretically supported USLE type models.  相似文献   

Testing the Universal Soil Loss Equation‐MB equation in plots in Central and South Italy     

Costanza Di Stefano  Vincenzo Pampalone  Francesca Todisco  Lorenzo Vergni  Vito Ferro 《水文研究》2019,33(18):2422-2433

Planning soil conservation strategies requires predictive techniques at event scale because a large percentage of soil loss over a long‐time period is due to relatively few large storms. Considering runoff is expected to improve soil loss predictions and allows relation of the process‐oriented approach with the empirical one, furthermore, the effects of detachment and transport on soil erosion processes can be distinguished by a runoff component. In this paper, the empirical model USLE‐MB (USLE‐M based), including a rainfall‐runoff erosivity factor in which the event rainfall erosivity index EI₃₀ of the Universal Soil Loss Equation (USLE) multiplies the runoff coefficient Q_R raised to an exponent b₁ > 1 is tested by the measurements carried out for the Masse (10 plots) and Sparacia (22 plots) experimental stations in Italy. For the Masse experimental station, an exponent b₁ > 1 was also estimated by tests carried out by a nozzle‐type rainfall simulator. For each experimental site in fallow conditions, the effect of the sample size of the plot soil loss measurements on the estimate of the b₁ coefficient was also studied by the extraction of a fixed number N of randomly obtained pairs of the normalized soil loss and runoff coefficient. The analysis showed that the variability of b₁ with N is low and that 350 pairs are sufficient to obtain a stable estimate of b₁. A total of 1,262 soil loss data were used to parameterize the model both locally and considering the two sites simultaneously. The b₁ exponent varied between the two sites (1.298–1.520), but using a common exponent (1.386) was possible. Using a common b₁ exponent for the two experimental areas increases the practical interest for the model and allows the estimation of a baseline component of the soil erodibility factor, which is representative of the at‐site soil intrinsic and quasi‐static properties. Development of a single USLE‐MB model appears possible, and sampling other sites is advisable to develop a single USLE‐MB model for general use.  相似文献   

Comparing flow resistance law for fixed and mobile bed rills     

Costanza Di Stefano  Alessio Nicosia  Vincenzo Palmeri  Vincenzo Pampalone  Vito Ferro 《水文研究》2019,33(26):3330-3348

Rills caused by run‐off concentration on erodible hillslopes have very irregular profiles and cross‐section shapes. Rill erosion directly depends on the hydraulics of flow in the rills, which may differ greatly from hydraulics of flow in larger and regular channels. In this paper, a recently theoretically deduced rill flow resistance equation, based on a power–velocity profile, was tested experimentally on plots of varying slopes (ranging from 9% to 26%) in which mobile and fixed bed rills were incised. Initially, measurements of flow velocity, water depth, cross‐section area, wetted perimeter, and bed slope, carried out in 320 reaches of mobile bed rills and in 165 reaches of fixed rills, were used for calibrating the theoretical flow resistance equation. Then the relationship between the velocity profile parameter Γ, the channel slope, and the flow Froude number was separately calibrated for the mobile bed rills and for the fixed ones. The measurements carried out in both conditions (fixed and mobile bed rills) confirmed that the Darcy–Weisbach friction factor can be accurately estimated using the proposed theoretical approach. For mobile bed rills, the data were supportive of the slope independence hypothesis of velocity, due to the feedback mechanism, stated by Govers. The feedback mechanism was able to produce quasicritical flow conditions. For fixed bed rills, obtained by fixing the rill channel, by a glue, at the end of the experimental run with a mobile bed rill, the slope independence of the flow velocity measurements was also detected. Therefore, an experimental run carried out by a rill bed fixed after modelling flow action is useful to detect the feedback mechanism. Finally, the analysis showed that, for the investigated conditions, the effect of sediment transport on the flow resistance law can be considered negligible respect to the grain roughness effect.  相似文献   

An automatic approach for rill network extraction to measure rill erosion by terrestrial and low‐cost unmanned aerial vehicle photogrammetry     

Costanza Di Stefano  Vincenzo Palmeri  Vincenzo Pampalone 《水文研究》2019,33(13):1883-1895

For an erosion event (October 2016) occurred at the Sparacia experimental area (Southern Italy), both terrestrial and low‐altitude aerial surveys were carried out by consumer grade camera and quadcopter (low‐cost unmanned aerial vehicle [UAV]) to measure rill erosion on two plots with steepness of 22% and 26%. Applying the structure from motion (SfM) technique, the three‐dimensional digital terrain models (3D‐DTMs) and the quasi three‐dimensional models (2.5D‐digital elevation model [DEM]) were obtained by the two surveys. Furthermore, 3D‐DTM and DEM were built using the available aerial photographs (166) and adding 40 terrestrial photographs. For the first time, the convergence index was applied to high‐resolution rill data for extracting the rill network, and a subsequent separation into contributing and non‐contributing rills was carried out. The comparison among the three surveys (terrestrial, UAV, and UAV + terrestrial) was developed using two morphometric parameters of the rill network (drainage density and drainage frequency). Moreover, using as reference the weight of sediment stored on the tanks located downstream of the plots, the reliability of soil loss measurement by 3D models was tested. For both contributing and non‐contributing rills, the morphometric parameters were higher for the terrestrial than for UAV and UAV + terrestrial surveys. For both plots, SfM always provided reliable soil loss measurements, which were affected by errors ranging from ?8% to 13%. Although the applied technique used a low‐cost UAV and a consumer grade camera, the obtained results demonstrated that a reliable estimate of rill erosion can be obtained in an area of interest.  相似文献   

Dispersal of key subplinian–Plinian tephras from Hekla volcano,Iceland: implications for eruption source parameters     

Maria H. Janebo  Thorvaldur Thordarson  Bruce F. Houghton  Costanza Bonadonna  Gudrun Larsen  Rebecca J. Carey 《Bulletin of Volcanology》2016,78(10):66

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Future developments in modelling and monitoring of volcanic ash clouds: outcomes from the first IAVCEI-WMO workshop on Ash Dispersal Forecast and Civil Aviation   总被引：1，自引：1，他引：0  

Costanza Bonadonna  Arnau Folch  Susan Loughlin  Herbert Puempel 《Bulletin of Volcanology》2012,74(1):1-10

As a result of the serious consequences of the 2010 Eyjafjallajökull eruption (Iceland) on civil aviation, 52 volcanologists, meteorologists, atmospheric dispersion modellers and space and ground-based monitoring specialists from 12 different countries (including representatives from 6 Volcanic Ash Advisory Centres and related institutions) gathered to discuss the needs of the ash dispersal modelling community, investigate new data-acquisition strategies (i.e. quantitative measurements and observations) and discuss how to improve communication between the research community and institutions with an operational mandate. Based on a dedicated benchmark exercise and on 3 days of in-depth discussion, recommendations have been made for future model improvements, new strategies of ash cloud forecasting, multidisciplinary data acquisition and more efficient communication between different communities. Issues addressed in the workshop include ash dispersal modelling, uncertainty, ensemble forecasting, combining dispersal models and observations, sensitivity analysis, model variability, data acquisition, pre-eruption forecasting, first simulation and data assimilation, research priorities and new communication strategies to improve information flow and operational routines. As a main conclusion, model developers, meteorologists, volcanologists and stakeholders need to work closely together to develop new and improved strategies for ash dispersal forecasting and, in particular, to: (1) improve the definition of the source term, (2) design models and forecasting strategies that can better characterize uncertainties, (3) explore and identify the best ensemble strategies that can be adapted to ash dispersal forecasting, (4) identify optimized strategies for the combination of models and observations and (5) implement new critical operational strategies.  相似文献   

Insights into eruption dynamics from textural analysis: the case of the May, 2008, Chaitén eruption     

Fabrizio Alfano  Costanza Bonadonna  Lucia Gurioli 《Bulletin of Volcanology》2012,74(9):2095-2108

The May, 2008, Chaitén (southern Chile) eruption was characterized by several explosive events, each associated with plumes which reached up to about 19?km above sea level on May 6. A study of the textural and physical features of the juvenile clasts erupted during the climactic phase of the 2008 eruption of Chaitén is presented. Pumice clasts show unimodal density distribution (main mode at 600?kg/m³), average vesicularity of about 69?%, a glassy groundmass with no microcrystals, and vesicles with dimension between ～1?μm and ～2?mm. They also show a unimodal vesicle size distribution with most frequent vesicle size in the range 0.05–0.08?mm and an estimated vesicle number density of 1.3?±?0.5?×?10⁵?mm^?3 related to a rapid nucleation event produced during the late phases of magma rise. This is confirmed by the absence of microcrystals that could otherwise have delayed vesicle formation and allowed the magma to maintain a low viscosity and a supersaturation in volatiles. Vesiculation and fragmentation were triggered by a sudden decompression of the melt associated with the opening of the volcanic conduit (～10?MPa?s^?1).  相似文献   

A conceptual framework for multi-regional climate change assessments for international market systems with long-term investments     

Julie A. Winkler  Suzanne Thornsbury  Marco Artavia  Frank-M. Chmielewski  Dieter Kirschke  Sangjun Lee  Malgorzata Liszewska  Scott Loveridge  Pang-Ning Tan  Sharon Zhong  Jeffrey A. Andresen  J. Roy Black  Robert Kurlus  Denys Nizalov  Nicole Olynk  Zbigniew Ustrnul  Costanza Zavalloni  Jeanne M. Bisanz  Géza Bujdosó  Lesley Fusina  Yvonne Henniges  Peter Hilsendegen  Katarzyna Lar  Lukasz Malarzewski  Thordis Moeller  Roman Murmylo  Tadeusz Niedzwiedz  Olena Nizalova  Haryono Prawiranata  Nikki Rothwell  Jenni van Ravensway  Harald von Witzke  Mollie Woods 《Climatic change》2010,103(3-4):445-470

A conceptual framework for climate change assessments of international market systems that involve long-term investments is proposed. The framework is a hybrid of dynamic and static modeling. Dynamic modeling is used for those system components for which temporally continuous modeling is possible, while fixed time slices are used for other system components where it can be assumed that underlying assumptions are held constant within the time slices but allowed to vary between slices. An important component of the framework is the assessment of the “metauncertainty” arising from the structural uncertainties of a linked sequence of climate, production, trade and decision-making models. The impetus for proposing the framework is the paucity of industry-wide assessments for market systems with multiple production regions and long-term capital investments that are vulnerable to climate variations and change, especially climate extremes. The proposed framework is pragmatic, eschewing the ideal for the tractable. Even so, numerous implementation challenges are expected, which are illustrated using an example industry. The conceptual framework is offered as a starting point for further discussions of strategies and approaches for climate change impact, vulnerability and adaptation assessments for international market systems.  相似文献   

Tectonics,sea-level changes and palaeoenvironments in the early Pleistocene of Rome (Italy)     

Domenico Cosentino  Paola Cipollari  Letizia Di Bella  Alessandra Esposito  Costanza Faranda  Guido Giordano  Elsa Gliozzi  Massimo Mattei  Ilaria Mazzini  Massimiliano Porreca  Renato Funiciello 《Quaternary Research》2009,72(1):143-155

The historical site of the Monte Mario lower Pleistocene succession (Rome, Italy) is an important marker of the Pliocene/Pleistocene boundary. Recently, the Monte Mario site was excavated and restudied. A spectacular angular unconformity characterizes the contact between the Monte Vaticano and the Monte Mario formations, which marks the Pliocene/Pleistocene boundary. Biostratigraphical analyses carried out on ostracod, foraminifer, and calcareous nannofossil assemblages indicate an Early Pliocene age (topmost Zanclean, 3.81–3.70 Ma) for the underlying Monte Vaticano Formation, whereas the Monte Mario Formation has been dated as early Pleistocene (Santernian, 1.66–1.59 Ma). Palaeomagnetic analyses point to C2Ar and C1r2r polarity chrons for the Monte Vaticano and the Monte Mario formations, respectively. The Monte Mario Formation consists of two obliquity-forced depositional sequences (MM1 and MM2) characterized by transgressive systems tracts of littoral marine environments at depths, respectively, of 40–80 m and 15–20 m. The data obtained from foraminifer and ostracod assemblages allow us to reconstruct early Pleistocene relative sea-level changes near Rome. At the Plio/Pleistocene transition, a relative sea-level drop of at least 260 m occurred, as a result of both tectonic uplift of the central Tyrrhenian margin and glacio-eustatic changes linked to early Pleistocene glaciation (Marine Isotope Stage 58).  相似文献   

Intrusion of shoshonitic magmas at shallow crustal depth: <Emphasis Type="Italic">T</Emphasis>–<Emphasis Type="Italic">P</Emphasis> path,H<Subscript>2</Subscript>O estimates,and AFC modeling of the Middle Triassic Predazzo Intrusive Complex (Southern Alps,Italy)     

Federico?CasettaEmail author  Massimo?Coltorti  Ryan?B.?Ickert  Costanza?Bonadiman  Pier?Paolo?Giacomoni  Theodoros?Ntaflos 《Contributions to Mineralogy and Petrology》2018,173(7):57

The multi-pulse shoshonitic Predazzo intrusive complex represents an ideal igneous laboratory for investigating the chemical and physical conditions of magma emplacement in a crustal context, since numerical models can be constrained by field evidence. It constitutes the most intriguing remnant of the Middle Triassic magmatic systems of the Dolomitic Area (Southern Alps), preserved by the Alpine tectonics. Predazzo Intrusive Complex comprises silica saturated (pyroxenites/gabbros to syenites), silica undersaturated (gabbros to syenites), and silica oversaturated (granites and syenogranites) rock suites. In this paper, we modeled its emplacement and evolution with a multiple thermo-/oxy-barometric, hygrometric, and EC-AFC approach. At odds with what proposed in literature but according to the field evidence, the emplacement of the Predazzo Intrusive Complex occurred at shallow depth (<?6 km). In this context, the different pulses differed slightly in bulk water content, but shared a common thermal regime, with temperatures between 1000 and 1100 °C and ~?600 °C at low-to-moderate oxidizing conditions (? 0.1 to +?0.7 ΔFMQ). The interaction between the intrusion and the shallow crustal rocks was minimal, with Sr and Nd isotopic compositions indicating an average of 5–6% assimilation of crust. A thermo- and oxy-barometric comparison with the nearby Mt. Monzoni also enabled to speculate about the solidification time of the intrusion, which we infer took place over about 700 ka.  相似文献