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    PMP and Climate Variability and Change: A Review

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    [EN] A state-of-the-art review on the probable maximum precipitation (PMP) as it relates to climate variability and change is presented. The review consists of an examination of the current practice and the various developments published in the literature. The focus is on relevant research where the effect of climate dynamics on the PMP are discussed, as well as statistical methods developed for estimating very large extreme precipitation including the PMP. The review includes interpretation of extreme events arising from the climate system, their physical mechanisms, and statistical properties, together with the effect of the uncertainty of several factors determining them, such as atmospheric moisture, its transport into storms and wind, and their future changes. These issues are examined as well as the underlying historical and proxy data. In addition, the procedures and guidelines established by some countries, states, and organizations for estimating the PMP are summarized. In doing so, attention was paid to whether the current guidelines and research published literature take into consideration the effects of the variability and change of climatic processes and the underlying uncertainties.The authors would like to acknowledge the support of the Global Water Futures Program and the Natural Sciences and Engineering Research Council of Canada (NSERC Discovery Grant RGPIN-2019-06894). The fourth author acknowledges the support of the Spanish Ministry of Science and Innovation, Project TETISCHANGE (RTI2018-093717-B-100). The first author appreciates the continuous support from the Scott College of Engineering of Colorado State University.Salas, JD.; Anderson, ML.; Papalexiou, SM.; FrancĂ©s, F. (2020). PMP and Climate Variability and Change: A Review. Journal of Hydrologic Engineering. 25(12):1-16. https://doi.org/10.1061/(ASCE)HE.1943-5584.0002003S1162512Abbs, D. J. (1999). 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    Quasibrittle fracture scaling and size effect

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    The report attempts a broad review of the problem of size effect or scaling of failure, which has recently come to the forefront of attention because of its importance for concrete and geotechnical engineering, geomechanics, arctic ice engineering, as well as in designing large loadbearing parts made of advanced ceramics and composites, e.g. for aircraft or ships. First the main results of Weibull statistical theory of random strength are briefly summarized and its applicability and limitations described. In this theory as well as plasticity, elasticity with a strength limit, and linear elastic fracture mechanics (LEFM), the size effect is a simple power law because no characteristic size or length is present. Attention is then focused on the deterministic size effect in quasibrittle materials which, because of the existence of a non-negligible material length characterizing the size of the fracture process zone, represents the bridging between the simple powerlaw size effects of plasticity and of LEFM. The energetic theory of quasibrittle size effect in the bridging region is explained and then a host of recent refinements, extensions and ramifications are discussed. Comments on other types of size effect, including that which might be associated with the fractal geometry of fracture, are also made. The historical development of the size effect theories is outlined and the recent trends of research are emphasized

    Extreme rainfall, flood scaling and flood policy options in the United States

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2000.Includes bibliographical references (leaves 220-227).River flood and rainfall have been shown to exhibit scale invariance behavior over a range of space and time scales. Although various approaches have been taken to investigate and model the various scaling aspects of rainfall and floods, little theoretical work has been done on the relation between the scaling of rainfall and flood. If available, such a theory would provide frequency estimate for extreme rainfall and floods outside the range of observations and could also be used to estimate floods at ungaged basins. The relationship between rainfall and flood scaling is the main focus of this thesis. We use a two step approach to investigate the relationship between exponent of peak flows and the scaling of rain. First, we use data analysis to verify existing theories that relate the multi scaling behavior of rainfall to the simple scaling behavior of the IDFs. Second, we use a model to relate the scaling of the IDFs to the scaling of peak flows with basin area. We find that, although temporal rainfall shows multiscaling, the IDFs exhibit simple scaling and peak floods show simple or mild multiscaling. We validate our findings by using U.S. peak annual flow data and rainfall from a few New England stations. Extreme floods damage mitigation requires sound and integrated policy making. We review the flood disaster mitigation situation in the U.S., carry out policy analysis and recommend options for a successful and sustainable flood disaster policy in the U.S.by Babar Mahmood Bhatti.S.M

    Quasibrittle fracture scaling and size effect

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    The report attempts a broad review of the problem of size effect or scaling of failure, which has recently come to the forefront of attention because of its importance for concrete and geotechnical engineering, geomechanics, arctic ice engineering, as well as in designing large loadbearing parts made of advanced ceramics and composites, e.g. for aircraft or ships. First the main results of Weibull statistical theory of random strength are briefly summarized and its applicability and limitations described. In this theory as well as plasticity, elasticity with a strength limit, and linear elastic fracture mechanics (LEFM), the size effect is a simple power law because no characteristic size or length is present. Attention is then focused on the deterministic size effect in quasibrittle materials which, because of the existence of a non-negligible material length characterizing the size of the fracture process zone, represents the bridging between the simple powerlaw size effects of plasticity and of LEFM. The energetic theory of quasibrittle size effect in the bridging region is explained and then a host of recent refinements, extensions and ramifications are discussed. Comments on other types of size effect, including that which might be associated with the fractal geometry of fracture, are also made. The historical development of the size effect theories is outlined and the recent trends of research are emphasized

    ARF : a multifractal analysis

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.Includes bibliographical references (leaves 110-115).The Areal Reduction Factor (ARF) [eta] is a key parameter in the design for hydrologic extremes. For a basin of area A, [eta](A, D, 7) is the ratio between the area-average rainfall intensity over a duration D with return period T and the point rainfall intensity for the same D and T. Besides depending on A, D and possibly T, the ARF is affected by the shape of the basin and by a number of seasonal, climatic and topographic characteristics. Another factor on which ARF depends is the advection velocity, Vad, of the rainfall features. Commonly used formulas and charts for the ARF have been derived by smoothing or curve-fitting empirical ARFs extracted from raingauge network records. Here we derive some properties of the ARF under the assumption that space-time rainfall is exactly or approximately multifractal. We do so for various shapes of the rainfall collecting region and for Vad = 0 and Vad [not equal to] 0. When Vad = 0, a key parameter in the analysis is the ratio Ures = Vres/Ve between the "response velocity" Vres = L/D, where L is the maximum linear dimension of the region, and the "evolution velocity" Ve, = Le/De, where Le and De are the characteristic linear dimension and characteristic duration of organized rainfall features. The effect of Vad [not equal to] 0 depends on the shape of the region. For highly elongated basins, both the direction and magnitude of advection are influential, whereas for regular shaped regions only the magnitude Vad matters. We review ways in which rainfall has been observed to deviate from exact multifractality and models that capture such deviations. We show how the ARF behaves when rainfall is a bounded cascade in space and time.(cont.) We also investigate the effect of estimating areal rainfall from raingauge network measurements. We find that bounded-cascade deviations from multifractality and sparse spatial sampling distort in similar ways the scaling properties of the ARF. Finally we show how one can reproduce various features of empirical ARF charts by using multifractal and bounded cascade models and considering the effects of sparse spatial sampling.by Andreas Langousis.S.M

    Persistence in complex systems

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    Persistence is an important characteristic of many complex systems in nature, related to how long the system remains at a certain state before changing to a different one. The study of complex systems’ persistence involves different definitions and uses different techniques, depending on whether short-term or long-term persistence is considered. In this paper we discuss the most important definitions, concepts, methods, literature and latest results on persistence in complex systems. Firstly, the most used definitions of persistence in short-term and long-term cases are presented. The most relevant methods to characterize persistence are then discussed in both cases. A complete literature review is also carried out. We also present and discuss some relevant results on persistence, and give empirical evidence of performance in different detailed case studies, for both short-term and long-term persistence. A perspective on the future of persistence concludes the work.This research has been partially supported by the project PID2020-115454GB-C21 of the Spanish Ministry of Science and Innovation (MICINN). This research has also been partially supported by Comunidad de Madrid, PROMINT-CM project (grant ref: P2018/EMT-4366). J. Del Ser would like to thank the Basque Government for its funding support through the EMAITEK and ELKARTEK programs (3KIA project, KK-2020/00049), as well as the consolidated research group MATHMODE (ref. T1294-19). GCV work is supported by the European Research Council (ERC) under the ERC-CoG-2014 SEDAL Consolidator grant (grant agreement 647423)

    Persistence in complex systems

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    Persistence is an important characteristic of many complex systems in nature, related to how long the system remains at a certain state before changing to a different one. The study of complex systems' persistence involves different definitions and uses different techniques, depending on whether short-term or long-term persistence is considered. In this paper we discuss the most important definitions, concepts, methods, literature and latest results on persistence in complex systems. Firstly, the most used definitions of persistence in short-term and long-term cases are presented. The most relevant methods to characterize persistence are then discussed in both cases. A complete literature review is also carried out. We also present and discuss some relevant results on persistence, and give empirical evidence of performance in different detailed case studies, for both short-term and long-term persistence. A perspective on the future of persistence concludes the work.This research has been partially supported by the project PID2020-115454GB-C21 of the Spanish Ministry of Science and Innovation (MICINN). This research has also been partially supported by Comunidad de Madrid, PROMINT-CM project (grant ref: P2018/EMT-4366). J. Del Ser would like to thank the Basque Government for its funding support through the EMAITEK and ELKARTEK programs (3KIA project, KK-2020/00049), as well as the consolidated research group MATHMODE (ref. T1294-19). GCV work is supported by the European Research Council (ERC) under the ERC-CoG-2014 SEDAL Consolidator grant (grant agreement 647423)

    Development and evaluation of models for assessing geochemical pollution sources with multiple reactive chemical species for sustainable use of aquifer systems: source characterization and monitoring network design

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    Michael designed a groundwater flow and reactive transport optimization model. He applied this model to characterize contaminant sources in Australia's first large scale uranium mine site in the Northern Territory. He identified the contamination sources to the groundwater system in the area. His findings will assist planning actions and steps needed to implement the mitigation strategy of this contaminated aquifer

    StreamLab Collaboratory: Experiments, Data Sets, and Research Synthesis

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    A series of community-led, large-scale laboratory experiments, termed “StreamLab”, were performed by the National Center for Earth-surface Dynamics (NCED) with the purpose of advancing multidisciplinary research, education, and knowledge transfer at the interface of physical/chemical/biological processes in streams, science-based stream restoration practice, and environmental sensing technologies. Two series of experiments, StreamLab06 and StreamLab08, were conducted in the Main Channel of the St. Anthony Falls Laboratory at the University of Minnesota, a flume 84 m long and 2.75 m wide with water fed by the Mississippi River at a rate of up to 8.5 m3/s. The purpose of this paper is to share with the broader community the data collected with the hope of stimulating further analysis and future experimental campaigns toward advancing our predictive understanding of the physical, chemical, and biological processes in streams. Toward this end, a brief summary of the results to date is included and some ideas for further research are provided
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