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As a result of the considerable impacts of hydrological hazard on water resources, on natural environments and human activities, as well as on human health and safety, climate variability and climate change have become key issues for the research community. In fact, a warmer climate, with its heightened climate variability, will increase the risk of hydrological extreme phenomena, such as droughts and floods. The Special Issue "Hydrological Hazard: Analysis and Prevention" presents a collection of scientific contributions that provides a sample of the state-of-the-art and forefront research in this field. In particular, innovative modelling methods for flood hazards, regional flood and drought analysis, and the use of satellite and climate data for drought analysis were the main topics and practice targets that the papers published in this Special Issue aimed to address. [ABSTRACT FROM AUTHOR]

The processes of isotope fractionation in the hydrological cycle naturally occur during vapor formation, vapor condensation, and moisture transportation. These processes are therefore dependent on local and regional surface and atmospheric physical features such as temperature, pressure, wind speed, and land morphology, and hence on the climate. Because of the strong influence of climate on the isotope fractionation, latitudinal and altitudinal effects on the δ18O and δ2H values of precipitation at a global scale are observed. In this study, we present and compare the processes governing precipitation isotope fractionation from two contrasting climatic regions: Virunga in Central-Eastern Africa and the Central Mediterranean (Stromboli and Sicily, Italy). While Virunga is a forested rainy tropical region located between Central and Eastern Africa, the Mediterranean region is characterized by a rainy mild winter and a dry hot summer. The reported δ18O and δ2H dataset are from precipitation collected on rain gauges sampled either on a monthly or an approximately bimonthly basis and published in previous papers. Both regions show clearly defined temporal and altitudinal variations of δ18O and δ2H, depending on precipitation amounts. The Central Mediterranean shows a clear contribution of local vapor forming at the sea–air interface, and Virunga shows a contribution from both local and regional vapor. The vapor of Virunga is from two competing sources: the first is the continental recycled moisture from soil/plant evaporation that dominates during the rainy season, and the second is from the East African Great Lakes evaporation that dominates during the dry season. [ABSTRACT FROM AUTHOR]

In this paper, we study δ15N enrichment as an indicator not only of marine protein diet, but also of climate change. The slope of the variation of δ15N with precipitation was calculated equal to 0.38/100 mm of precipitation for Greek plants, 0.38/100 mm of precipitation for herbivores, and 0.32/100 mm of precipitation for the Greek human population (hair samples). As a case study, the slope was used to re-evaluate the published mean δ15N human bone collagen values from the Early Neolithic to Late Bronze Age for 22 archaeological sites. The results indicate that climate has a significant impact on the final δ15N values of plant and animal tissues. Furthermore, for the same sites, we investigated the intra-site diet patterns, while taking into account the environmental effect on the observed δ15N human bone collagen values. [ABSTRACT FROM AUTHOR]

The capacity and mechanism of the adsorption of aqueous barium (Ba), cobalt (Co), strontium (Sr), and zinc (Zn) by Ecuadorian (NatAllo) and synthetic (SynAllo-1 and SynAllo-2) allophanes were studied as a function of contact time, pH, and metal ion concentration using kinetic and equilibrium experiments. The mineralogy, nano-structure, and chemical composition of the allophanes were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and specific surface area analyses. The evolution of adsorption fitted to a pseudo-first-order reaction kinetics, where equilibrium between aqueous metal ions and allophane was reached within <10 min. The metal ion removal efficiencies varied from 0.7 to 99.7% at pH 4.0 to 8.5. At equilibrium, the adsorption behavior is better described by the Langmuir model than by the Dubinin--Radushkevich model, yielding sorption capacities of 10.6, 17.2, and 38.6 mg/g for Ba2+, 12.4, 19.3, and 29.0 mg/g for HCoO2-; 7.2, 15.9, and 34.4 mg/g for Sr2+; and 20.9, 26.9, and 36.9 mg/g for Zn2+, by NatAllo, SynAllo-2, and SynAllo-1, respectively. The uptake mechanism is based on a physical adsorption process rather than chemical ion exchange. Allophane holds great potential to effectively remove aqueous metal ions over a wide pH range and could be used instead of other commercially available sorbent materials such as zeolites, montmorillonite, carbonates, and phosphates for special wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Ian Carmichael wrote of an "andesite aqueduct" that conveys vast amounts of water from the magma source region of a subduction zone to the Earth's surface. Diverse observations indicate that subduction zone magmas contain 5 wt % or more H2O. Most of the water is released from crystallizing intrusions to play a central role in contact metamorphism and the genesis of ore deposits, but it also has important effects on the plutonic rocks themselves. Many plutons were constructed incrementally from the top down over million-year time scales. Early-formed increments are wall rocks to later increments; heat and water released as each increment crystallizes pass through older increments before exiting the pluton. The water ascends via multiple pathways. Hydrothermal veins record ascent via fracture conduits. Pipe-like conduits in Yosemite National Park, California, are located in or near aplite–pegmatite dikes, which themselves are products of hydrous late-stage magmatic liquids. Pervasive grain-boundary infiltration is recorded by fluid-mediated subsolidus modification of mineral compositions and textures. The flood of magmatic water carries a large fraction of the total thermal energy of the magma and transmits that energy much more rapidly than conduction, thus enhancing the fluctuating postemplacement thermal histories that result from incremental pluton growth. The effects of water released by subduction zone magmas are central not only to metamorphism and mineralization of surrounding rocks, but also to the petrology and the thermal history of the plutons themselves. [ABSTRACT FROM AUTHOR]

Canopy throughfall comprises the largest portion of net precipitation that is delivered to the forest floor. This water flux is highly variable across space and time and is influenced by species composition, canopy foliage, stand structure, and storm meteorological characteristics. In upland forests throughout the central hardwoods region of the Eastern United States, a compositional shift is occurring from oak-hickory to more mesic, shade-tolerant species such as red maple, sweetgum, and winged elm. To better understand the impacts of this shift on throughfall flux and the hydrologic budget, we monitored throughfall for one year in Northern Mississippi under the crowns of midstory and overstory oak (post oak and southern red oak) and non-oak species (hickory, red maple, and winged elm). In general, oak had more throughfall than co-occurring non-oak species in both canopy levels. In the overstory during the leaf-off canopy phase, white oak had relatively higher throughfall partitioning (standardized z-score = 0.54) compared to all other species (z-score = −0.02) (p = 0.004), while in the leaf-on canopy phase, red maple had relatively lower throughfall (z-score = −0.36) partitioning compared to all other species (z-score = 0.11). In the midstory, red maple was the only species to exhibit a difference in throughfall between canopy phases, with much lower throughfall in the leaf-off compared to the leaf-on canopy phase (z-score = −0.30 vs. 0.202, p = 0.039). Additionally, throughfall under oak crowns was less variable than under non-oak crowns. These results provide evidence that the spatial and temporal distribution of throughfall inputs under oak crowns are different than non-oak species, likely due to differences in crown architecture (i.e., depth and density). As oak dominance diminishes in these forests, it is possible that the portion of rainfall diverted to throughfall may decrease as well. The net impacts to watershed hydrology are still unknown, but these results provide one mechanism by which the distribution of water resources may be affected. [ABSTRACT FROM AUTHOR]

This study provides a unique procedure for validating and reconstructing temperature and precipitation data. Although developed from data in Middle Italy, the validation method is intended to be universal, subject to appropriate calibration according to the climate zones analysed. This research is an attempt to create shared applicative procedures that are most of the time only theorized or included in some software without a clear definition of the methods. The purpose is to detect most types of errors according to the procedures for data validation prescribed by the World Meteorological Organization, defining practical operations for each of the five types of data controls: gross error checking, internal consistency check, tolerance test, temporal consistency, and spatial consistency. Temperature and precipitation data over the period 1931–2014 were investigated. The outcomes of this process have led to the removal of 375 records (0.02%) of temperature data from 40 weather stations and 1286 records (1.67%) of precipitation data from 118 weather stations, and 171 data points reconstructed. In conclusion, this work contributes to the development of standardized methodologies to validate climate data and provides an innovative procedure to reconstruct missing data in the absence of reliable reference time series. [ABSTRACT FROM AUTHOR]