bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Evaluation of the Modern and Future Origins of Atmospheric River Moisture Over the West Coast of the United States
Authors: Nusbaumer Jesse , Noone David 
Published: June 2018

AbstractAtmospheric rivers (ARs) are one of the major causes of extreme precipitation and flooding in many regions around the world and have been found to contribute substantially to global poleward moisture transport. However, the evaporative origin of the moisture in ARs remains unclear, at least on climatological timescales. Here we use the water tracer and water isotope‐enabled Community Atmosphere Model version 5 (CAM5) model to examine the moisture sources of ARs that impact the West Coast of the United States. The climatological distribution of moisture sources is determined for both the modern era and for 2100 under a Representative Concentration Pathway (RCP) 8.5 scenario. It is found that 33 to 53% of the precipitable water over the West Coast of the United States originates from the Northeast Pacific, in particular the midlatitudes and subtropics, although in June‐July‐August more moisture is recycled from continental regions. It is also found that although ARs are at least 70% Northeast Pacific moisture, a significant amount of the moisture is derived from tropical latitudes (>15% from south of 20°N). It is found that in the warmer 2100 climate there is a 39% increase in the magnitude of ARs. In this future epoch, moisture is transported from more remote regions for all seasons and for both ARs and the average climatology. To provide future observational evidence that this model result is robust, it is shown that water isotopes provide an observational constraint on the moisture transport pathways, and thus the possibility to observe changes in moisture source.
Antenna Array Simulation and Detection Performance Analysis of Sanya Prototype Incoherent Scatter Radar
Authors: Zhao Hailong , Yao Ming , Deng Xiaohua , Yuan Kai , Ding Feng , Zeng Lingqi , Li Chen 
Published: June 2018

AbstractIncoherent scatter radars have become an important means of ionospheric detection, which is the only ground instrument that can detect important plasma parameters over the entire ionosphere (60–2,000 km). In Sanya of China, the advanced high‐power phased array incoherent scatter radar is under construction. The radar has the advantages of continuous observation, full space coverage, and rapid scanning. Usually, since the plasma‐scattered signal is weak, the estimation of signal‐to‐noise ratio (SNR) and relative error is significant for radar detection performance analysis. Major factors affecting the detection performance, such as power aperture product, pulse width, daytime and nighttime, and different antenna gains (zenith angles), are investigated in the present study. Details of the impacts of these factors on the radar performance are analyzed. According to analysis, the SNR and the detection range could be enhanced significantly by increasing the power aperture product. The integration significantly reduces the relative error; for instance, the relative error could reach 5% in the range of 80–700 km by a few seconds' integration. The SNR decreases with the range resolution improving. The detection performance during nighttime is worse than that of daytime. Furthermore, the SNR decreases with the increasing zenith angle. However, the detection performance can be compensated by the integration. Once the radar becomes operational practically, the numerical simulation results will help to choose the appropriate operation parameters to achieve the best operational performance with given budget of operation cost.
Development of Probabilistic Dam Breach Model Using Bayesian Inference
Authors: Peter S. J. , Siviglia A. , Nagel J. , Marelli S. , Boes R. M. , Vetsch D. , Sudret B. 
Published: June 2018

AbstractDam breach models are commonly used to predict outflow hydrographs of potentially failing dams and are key ingredients for evaluating flood risk. In this paper a new dam breach modeling framework is introduced that shall improve the reliability of hydrograph predictions of homogeneous earthen embankment dams. Striving for a small number of parameters, the simplified physics‐based model describes the processes of failing embankment dams by breach enlargement, driven by progressive surface erosion. Therein the erosion rate of dam material is modeled by empirical sediment transport formulations. Embedding the model into a Bayesian multilevel framework allows for quantitative analysis of different categories of uncertainties. To this end, data available in literature of observed peak discharge and final breach width of historical dam failures were used to perform model inversion by applying Markov chain Monte Carlo simulation. Prior knowledge is mainly based on noninformative distribution functions. The resulting posterior distribution shows that the main source of uncertainty is a correlated subset of parameters, consisting of the residual error term and the epistemic term quantifying the breach erosion rate. The prediction intervals of peak discharge and final breach width are congruent with values known from literature. To finally predict the outflow hydrograph for real case applications, an alternative residual model was formulated that assumes perfect data and a perfect model. The fully probabilistic fashion of hydrograph prediction has the potential to improve the adequate risk management of downstream flooding.
New Hypothesis for the Final Equilibrium Stage of a River Levee Breach due to Overflow
Authors: Michelazzo Giovanni , Oumeraci Hocine , Paris Enio 
Published: June 2018

AbstractBreaching of earthen embankments is a complex process that often results in disastrous inundations of the hinterland. The process has been studied during the last decades by means of physical and numerical modeling with particular reference to the dam case, while for river levees only few specific studies have been conducted. Moreover, the understanding and prediction of the breach final configuration are still scarce and not yet deeply addressed, despite their importance for mitigating flood risk in the protected areas. The paper attempts to examine the existence of a final equilibrium stage in the river‐breach system under specified conditions based on a significant data set from new laboratory experiments. Using these data, together with those of previous studies, a new hypothesis for the final equilibrium of the river‐breach system is proposed which is supported by new flow formulae and field data.
Saving Energy From Urban Water Demand Management
Authors: Escriva‐Bou A. , Lund J. R. , Pulido‐Velazquez M. 
Published: June 2018

AbstractWater use directly causes a significant amount of energy use in cities. In this paper we assessed energy and carbon dioxide emissions related to each part of the urban water cycle and the consequences of some water demand management policies in terms of water, energy, and CO2 emissions in urban water users, water and energy utilities, and the environment. First, we developed an hourly model of urban water uses by customer category, including water‐related energy consumption. Next, using real data from the East Bay Municipal Utility District in California, we calibrated a model of the energy used in water supply, treatment, pumping, and wastewater treatment by the utility, obtaining also energy costs. Then, using data from the California Independent System Operator, we obtained hourly costs of energy generation and transport to the point of use for the energy utility. Finally, using average emission factors reported by energy utilities, we estimated greenhouse gas emissions for the entire urban water cycle. Results for East Bay Municipal Utility District show that water end uses account for almost 95% of all water‐related energy use; however, the remaining 5% of energy used by the utility still costs over USD12 million annually. The carbon footprint of the urban water cycle is 372 kg CO2/person/year, representing approximately 4% of the total per capita emissions in California. Several simulations analyze the consequences of different water demand management policies, resulting in significant economic impacts for water and energy utilities and environmental benefits by reducing CO2 emissions.
Direct Channel Precipitation and Storm Characteristics Influence Short‐Term Fallout Radionuclide Assessment of Sediment Source
Authors: Karwan D. L. , Pizzuto J. E. , Aalto R. , Marquard J. , Harpold A. , Skalak K. , Benthem A. , Levia D. F. , Siegert C. M. , Aufdenkampe A. K. 
Published: June 2018

AbstractFallout radionuclides (FRNs) and their ratios, such as Beryllium‐7 (7Be) and excess Lead‐210 (210Pbxs), have been used to determine suspended sediment source and age in catchments. These models are based on numerous assumptions, for example, that channel deposition of FRNs from precipitation is negligible in comparison to their delivery to the channel from land surface erosion during individual storm events. We test this assumption using a mass balance approach during eight storms from summer 2011 to fall 2012 in a mid‐Atlantic United States piedmont region watershed with mixed land use. Event peak discharge and storm type corresponded to the importance of direct channel FRN deposition from precipitation. During relatively low discharge summer thunderstorms, with minimal overland flow, less than 1% of7Be and210Pbxsflux deposited on the watershed exits the watershed associated with suspended sediment. The majority but not all deposited on the stream channel exits the watershed associated with suspended sediment (60% of7Be and 80% of210Pbxs). Here precipitation and throughfall onto the wetted channel area can be responsible for any FRN newly associated with suspended sediment, as opposed to landscape surface erosion. Furthermore, FRNs can be stored with sediments in the channel between events. Events with higher discharges, including hurricanes, show the opposite pattern—FRN flux associated with suspended sediment exported from the reach is greater than channel FRN wet deposition, suggesting net erosion from the watershed landscape and/or stored material during these types of storms.
Metamodeling for Groundwater Age Forecasting in the Lake Michigan Basin
Authors: Fienen Michael N. , Nolan B. Thomas , Kauffman Leon J. , Feinstein Daniel T. 
Published: June 2018

AbstractGroundwater age is an important indicator of groundwater susceptibility to anthropogenic contamination and a key input to statistical models for forecasting water quality. Numerical models can provide estimates of groundwater age, enabling interpretation of measured age tracers. However, to extend to national‐scale groundwater systems where numerical models are not routinely available, a more efficient metamodeling approach can provide a less precise but widely applicable estimate of groundwater age, trained to make forecasts based on predictor variables that can be measured independent of numerical models. We trained gradient‐boosted regression tree statistical metamodels to MODFLOW/MODPATH‐derived groundwater age estimates in five inset models in the Lake Michigan Basin, USA. Using high‐throughput computing, we explored an exhaustive range of tuning parameters and tested metamodels through cross validation, a 20% holdout, and a round robin approach among the five inset models withholding each inset model from training and testing on the held‐out inset model. Forecast skill—measured by Nash Sutcliffe efficiency—was high for age‐related responses in the 20% hold‐out case (ranging from 0.73 to 0.84). The round robin analysis provided the opportunity to explore extending to unmodeled areas and a greater range of skill indicated the need to evaluate when it is appropriate to apply a metamodel from one region to another. We further explored the ramifications of metamodel simplification achieved through removing predictor variables based on their estimated importance. We found that similar metamodel performance was achievable with a fraction of the candidate set of predictor variables with well construction variables being most important.
Full‐Wave Seismic Tomography in the Northeastern United States: New Insights Into the Uplift Mechanism of the Adirondack Mountains
Authors: Yang Xiaotao , Gao Haiying 
Published: June 2018

AbstractStudying the driving force of intracratonic uplifts is important in understanding the deformation mechanism of continental lithosphere and the role of mantle dynamics. The Adirondack Mountains are located at the eastern Laurentian margin in the northeastern United States forming a distinct domal uplift. Subsurface structural constraints on their uplift mechanism are limited. Here we construct a high‐resolution velocity model for the crust and mantle lithosphere using full‐wave ambient noise tomography. A distinct low shear velocity anomaly with a diameter of ~70–100 km is imaged beneath the Moho at the Adirondack Mountains. This anomaly is connected with the large‐scale low‐velocity volume beneath southern New England and eastern New York at greater depths. The observed low‐velocity anomalies may reflect asthenosphere upwelling induced by a combined effect of the Great Meteor hot spot and edge‐driven mantle convections. The buoyancy of upwelling asthenosphere, together with possible thermal expansion, may have uplifted the Adirondack Mountains.
Agricultural Fire Impacts on Ozone Photochemistry Over the Yangtze River Delta Region, East China
Authors: Li Mengmeng , Wang Tijian , Xie Min , Li Shu , Zhuang Bingliang , Chen Pulong , Huang Xin , Han Yong 
Published: June 2018

AbstractAgricultural fires could affect tropospheric photochemistry by emitting trace gases, interacting with solar radiation or providing reactive surfaces for heterogeneous reactions. This study examines the effects of a typical agricultural fire event (8–13 June 2012) on ozone photochemistry over the Yangtze River Delta region, East China. The online coupled Weather Research and Forecasting‐Chemistry model is used, with the inclusion of a detailed agricultural fire emission inventory and seven heterogeneous reactions on soot surfaces. Comparisons with satellite and ground observational data indicate that the model is capable of reproducing the transport and evolution of this crop fire event. The precursor emissions from agricultural fires play a major role in modifying ozone photochemistry, with a maximal increase in ozone mixing ratio reaching 20 ppb (40%) near the fire zones in northern Anhui. The radiation feedback generates a small increase of surface NO2 levels by 2% and a decrease in surface O3 levels by 1% in the smoke plume. The effects due to heterogeneous uptake on soot are rather small, on average, changing the average O3, NO2, ˙OH, and HO2˙ concentrations by +0.8%, −0.5%, −0.7%, and +0.8%, respectively. This study highlights the complicated interactions between agricultural fire emissions and photochemistry.
North Pacific Paleotemperature and Paleoproductivity Reconstructions Based on Diatom Species
Authors: Lopes C. , Mix A. C. 
Published: June 2018

AbstractRegionally developed diatom‐based transfer functions reconstruct both summer sea surface temperature and primary productivity (PP) in the North Pacific based on a calibration data set including the eastern subtropical gyre (California and Oregon), the Gulf of Alaska, the western Pacific, and Bering Sea. Factors of the floral assemblage and environment data sets, and canonical correspondence, support estimation of two essentially orthogonal variables. Validation of the summer sea surface temperature transfer function resulted in r2jack of 0.9 and a root‐mean‐square error of prediction of 1.0°C over a range of 7–17°C. The summer PP transfer function yielded r2jack of 0.7 and a root‐mean‐square error of prediction of 219 g C·m2·year over a range of 200–2,000 g C·m2·year. Application in downcore locations within the modern nearshore upwelling regime and within the California Current offshore Oregon reveals that during Holocene time higher PP (>800 g C·m2·year) was associated with cooler temperatures (<16°C) forced by upwelling. In contrast, during the Last Glacial Maximum, when subpolar conditions are present off Oregon, higher PP (>1,000 g C·m2·year) was associated with warmer SSTs (>10°C; significant in the nearshore site). This finding supports previous hypotheses that in cold regimes warming may augment biological production, perhaps by relieving metabolic constraints. This is of particular interest because of projected amplification of future warming in high latitudes and the potential for greening of the subpolar and polar oceans.
Tectonic Evolution of the Chos Malal Fold‐and‐Thrust Belt (Neuquén Basin, Argentina) From (U‐Th)/He and Fission Track Thermochronometry
Authors: Sánchez N. P. , Coutand I. , Turienzo M. , Lebinson F. , Araujo V. , Dimieri L. 
Published: June 2018

AbstractIn the southern central Andes at 37–38°S latitude, the Chos Malal fold‐and‐thrust belt (FTB), which results from the Late Cretaceous closure of the Neuquén Basin, has generated increasing interest because of its potential for hydrocarbon exploration. Using detailed field mapping, seismic reflection, and well data analysis, we have produced balanced cross sections, which combined with apatite and zircon (U‐Th)/He, and fission track thermochronology from samples distributed along the FTB, bring new constraints on the chronology of the structural development of the Chos Malal FTB. Fully reset samples obtained from the Early Jurassic rocks at the bottom of the sedimentary sequence exposed in the Cordillera del Viento, a major basement‐involved hinterland structure, permit to quantify its cooling rate from 5.4 ± 4.1 and 3.8 ± 3.2 °C/Ma between 70 and 55 Ma down to between 2.0 ± 1.3 and 1.3 ± 0.9 °C/Ma after 55 Ma until the present. Detrital apatite fission track ages from Late Jurassic and Early Cretaceous sandstones reveal that tectonically driven exhumation through basement‐involved thrusting has occurred at ~15–7 Ma in both the inner and outer sectors of the FTB. Finally, the cooling and exhumation of the Las Yeseras‐Pampa Tril basement‐involved anticlines at the mountain front at ~9–7 Ma, slightly younger than previously assumed, suggests a normal sequence of faulting propagation. Our proposed thermostructural model of the Chos Malal FTB contributes to a better understanding of the tectonic evolution of this segment of the Andes.
Mesozoic Development of Nonmarine Basins in the Northern Yidun Terrane: Deposition and Deformation in the Eastern Tibetan Plateau Prior to the India‐Asia Collision
Authors: Jackson W. T. , Robinson D. M. , Weislogel A. L. , Shang F. , Jian X. 
Published: June 2018

AbstractTo determine the timing and spatial patterns of syntectonic nonmarine deposition and deformation in the eastern Tibetan Plateau, we present field data, thin section petrology, and detrital U‐Pb zircon geochronology from the west Ganzi basin (WGB) and east Ganzi basin (EGB) in the northern Yidun terrane. The WGB and EGB contain ~800 and ~1,300–1,600 m of nonmarine strata, respectively, deposited in alluvial environments. Along the southern margins of both the WGB and EGB and the northwestern margin of the WGB, reverse faults place Triassic Ganzi Pluton and Triassic Yidun Grouprocks on top of nonmarine strata. Growth strata in the footwalls of basin‐bounding faults indicate that deposition was synchronous with fault development. The western and eastern margins of the WGB, as well as the northern margin of the EGB, exhibit uncomformable contacts with the underlying Triassic Ganzi Pluton and Triassic Yidun Grouprocks. Provenance results suggest a regionally mixed sediment source from the Yidun and Songpan‐Ganzi terranes. Maximum deposition ages from detrital U‐Pb zircon geochronology, as well as previously reported thermochronology and palynology results, indicate a Late Mesozoic depositional age for WGB and EGB strata. We interpret the spatial and temporal developments of the WGB and EGB to be associated with the Lhasa‐Qiangtang collision.
Exploring How Changing Monsoonal Dynamics and Human Pressures Challenge Multireservoir Management for Flood Protection, Hydropower Production, and Agricultural Water Supply
Authors: Quinn J. D. , Reed P. M. , Giuliani M. , Castelletti A. , Oyler J. W. , Nicholas R. E. 
Published: June 2018

AbstractMultireservoir systems require robust and adaptive control policies capable of managing hydroclimatic variability and human demands across a range of time scales. This is especially true for river basins with high intraannual and interannual variability, such as monsoonal systems that need to buffer against seasonal droughts while also managing extreme floods. Moreover, the timing, intensity, duration, and frequency of these hydrologic extremes may evolve with deeply uncertain changes in socioeconomic and climatic pressures. This study contributes an innovative method for exploring how possible changes in the timing and magnitude of the monsoonal cycle impact the robustness of reservoir operating policies designed assuming stationary hydrologic and socioeconomic conditions. We illustrate this analysis on the Red River basin in Vietnam, where reservoirs and dams serve as important sources of hydropower production, multisectoral water supply, and flood protection for the capital city of Hanoi. Applying our scenario discovery approach, we find that reservoir operations designed assuming stationarity provide robust hydropower performance in the Red River but that increased mean streamflow, amplification of the within‐year monsoonal cycle, and increased interannual variability all threaten their ability to manage flood risk. Additionally, increased agricultural water demands can only be tolerated if they are accompanied by greater mean flow, exacerbating food‐flood trade‐offs in the basin. These findings highlight the importance of exploring the impacts of a wide range of deeply uncertain socioeconomic and hydrologic factors when evaluating system robustness in monsoonal river basins, considering in particular both lower‐order moments of annual streamflow and intraannual monsoonal behavior.
Phage-inducible chromosomal islands are ubiquitous within the bacterial universe
Authors: Fillol-Salom Alfred , Martínez-Rubio Roser , Abdulrahman Rezheen F , Chen John , Davies Robert , Penadés José R 
Published: June 2018

Abstract
Phage-inducible chromosomal islands (PICIs) are a recently discovered family of pathogenicity islands that contribute substantively to horizontal gene transfer, host adaptation and virulence in Gram-positive cocci. Here we report that similar elements also occur widely in Gram-negative bacteria. As with the PICIs from Gram-positive cocci, their uniqueness is defined by a constellation of features: unique and specific attachment sites, exclusive PICI genes, a phage-dependent mechanism of induction, conserved replication origin organization, convergent mechanisms of phage interference, and specific packaging of PICI DNA into phage-like infectious particles, resulting in very high transfer frequencies. We suggest that the PICIs represent two or more distinct lineages, have spread widely throughout the bacterial world, and have diverged much more slowly than their host organisms or their prophage cousins. Overall, these findings represent the discovery of a universal class of mobile genetic elements.