The use of the slope–area function to analyse process domains in complex badland landscapes

This paper explores the effectiveness of the widely-used functional relationship between drainage area (A in m²) and slope (S in m/m) to identify local process domains and aid interpretation of process interactions in a complex badland landscape. In order to perform this investigation, a series of sub-basins tributary to the Formone River in the Orcia catchment (central Italy) were selected as a suitable study area within which to explore our questions, given these basins' general representativeness of local terrain, the availability of a high resolution digital terrain model and previous extensive geomorphological research. Eroding basins containing both calanchi and landslides are common in the sub-humid badland landscape of central Italy, where field observation identifies a complex pattern of erosive processes associated with a history of uplift, despite which parts of the local landscape appear disconnected. Results reveal that the shape of all S–A curves (plotted using S data binned on log A) is comparable with that described in the literature, although sub-basins containing calanchi generally plot with higher S values than non-calanchi ones, except in the ‘fluvial’ section of the plots. Second, when viewed on total data (non-binned) S–A plots, landslide source area domains and calanchi domains are entirely coincident in all basins, supporting a cause–effect relationship. Additional plotting of the frequency characteristics of the raw data in a new way supports the interpretation that calanchi frequently initiate in landslide scars. In general though, although the S–A plots can contribute to the disentanglement of geomorphological behaviour in some complex erosional landscapes, it became apparent that in this landscape, process domains do not separate out with clarity along the A axis as suggested by theory. Despite this, an alternative, broader-scale morphoevolutive model can be proposed for the development of within-landslide calanchi, driven by changes to basin connectivity to the base channel. © 2018 John Wiley & Sons, Ltd.     

Seismic risk assessment for developing countries: Pakistan as a case study

Modern Earthquake Risk Assessment (ERA) methods usually require seismo-tectonic information for Probabilistic Seismic Hazard Assessment (PSHA) that may not be readily available in developing countries. To bypass this drawback, this paper presents a practical event-based PSHA method that uses instrumental seismicity, available historical seismicity, as well as limited information on geology and tectonic setting. Historical seismicity is integrated with instrumental seismicity to determine the long-term hazard. The tectonic setting is included by assigning seismic source zones associated with known major faults. Monte Carlo simulations are used to generate earthquake catalogues with randomized key hazard parameters. A case study region in Pakistan is selected to demonstrate the effectiveness of the method. The results indicate that the proposed method produces seismic hazard maps consistent with previous studies, thus being suitable for generating such maps in regions where limited data are available. The PSHA procedure is developed as an integral part of an ERA framework named EQRAM. The framework is also used to determine seismic risk in terms of annual losses for the study region.     

A revisitation of TRIX for trophic status assessment in the light of the European Water Framework Directive: application to Italian coastal waters

The trophic status classification of coastal waters at the European scale requires the availability of harmonised indicators and procedures. The composite trophic status index (TRIX) provides useful metrics for the assessment of the trophic status of coastal waters. It was originally developed for Italian coastal waters and then applied in many European seas (Adriatic, Tyrrhenian, Baltic, Black and Northern seas). The TRIX index does not fulfil the classification procedure suggested by the WFD for two reasons: (a) it is based on an absolute trophic scale without any normalization to type-specific reference conditions; (b) it makes an ex ante aggregation of biological (Chl-a) and physico-chemical (oxygen, nutrients) quality elements, instead of an ex post integration of separate evaluations of biological and subsequent chemical quality elements. A revisitation of the TRIX index in the light of the European Water Framework Directive (WFD, 2000/60/EC) and new TRIX derived tools are presented in this paper. A number of Italian coastal sites were grouped into different types based on a thorough analysis of their hydro-morphological conditions, and type-specific reference sites were selected. Unscaled TRIX values (UNTRIX) for reference and impacted sites have been calculated and two alternative UNTRIX-based classification procedures are discussed. The proposed procedures, to be validated on a broader scale, provide users with simple tools that give an integrated view of nutrient enrichment and its effects on algal biomass (Chl-a) and on oxygen levels. This trophic evaluation along with phytoplankton indicator species and algal blooms contribute to the comprehensive assessment of phytoplankton, one of the biological quality elements in coastal waters.     

An experimental facility for investigating hydromagmatic eruptions at high-pressure and high-temperature with application to the importance of magma porosity for magma-water interaction

An experimental facility has been developed to investigate magma-water interaction (MWI). The facility operates in a high-pressure and high-temperature environment, with temperatures up to 1,200°C and pressures up to 200 MPa. Cylindrical sample-holders (20 by 180 mm in size) are heated conductively to yield a three phase (melt, crystals and gas) system, and then water (or other fluid) is injected into the sample through a capillary tube (diameter 0.5 mm, length ca. 1,000 mm) under controlled conditions. Pressure, volume and temperature changes are continuously recorded during every phase of the experiments. To test this facility, MWI is studied at subliquidus temperatures (800 and 900°C) and pressure (8 MPa), using a leucite tephrite sample with two different initial grain sizes. Because of the grain-size dependence of sintering, the two starting materials produce magmas with different textures at the same temperature: porous magma for large initial grain sizes and dense magma for small initial grain sizes. In these experiments 1.5 g of water at room temperature is injected into 6.0 g of partially molten sample at velocities ranging from 1 to 3 m/s. We find that the extent of fragmentation and transport caused by MWI are mainly controlled by the texture of the interacting sample with explosive interaction occurring only for porous magmas.     

Bombs behaving badly: unexpected trajectories and cooling of volcanic projectiles

We collected thermal infrared video of two explosive eruptions at Stromboli in June 2008 and manually traced the trajectories of 95 particles launched during two eruptions. We found that 10–15?% of the analyzed trajectories deviated from predicted curves due to collisions, causing one particle to travel horizontally more than twice as far as expected. Furthermore, we observed an oscillatory cooling behavior for the airborne pyroclasts, with a median period of 0.46?s. Measured cooling was typically much faster than model-predicted cooling with discrepancies of up to 40?% between measured cooling and theoretical modeling. We interpret the measured cooling curves as resulting from the spinning and twisting and tearing of particles during travel: the periodic re-exposing of the hotter core of the pyroclasts to the atmosphere may cause the observed oscillations, and the spinning may accelerate cooling by enhancing convective heat transfer. Current volcanic trajectory and cooling models do not account for projectile collisions, spinning, or tearing and can thus severely underestimate the maximum landing distance and cooling rates of large pyroclasts.     

Integrating agriculture and energy to assess GHG emissions reduction: a methodological approach

Agriculture is responsible for approximately 25% of anthropogenic global GHG emissions. This significant share highlights the fundamental importance of the agricultural sector in the global GHG emissions reduction challenge. This article develops and tests a methodology for the integration of agricultural and energy systems modelling. The goal of the research is to extend an energy systems modelling approach to agriculture in order to provide richer insights into the dynamics and interactions between the two (e.g. in competition for land-use). We build Agri-TIMES, an agricultural systems module using the TIMES energy systems modelling framework, to model the effect of livestock emissions and explore emissions reduction options. The research focuses on Ireland, which is an interesting test case for two reasons: first, agriculture currently accounts for about 30% of Ireland's GHG emissions, significantly higher than other industrialized countries yet comparable with global levels (here including emissions associated with other land-use change and forestation); second, Ireland is both a complete and reasonably sized agricultural system to act as a test case for this new approach. This article describes the methodology used, the data requirements, and technical assumptions made to facilitate the modelling. It also presents results to illustrate the approach and provide associated initial insights.

Policy relevance

Most of the policy focus with regard to climate mitigation targets has been on reducing energy-related CO₂ emissions, which is understandable as they represent by far the largest source of emissions. Non-energy-related GHG emissions – largely from agriculture, industrial processes, and waste – have received significantly less attention in policy discourse. Going forward, however, if significant cuts are made in energy-related CO₂ emissions, the role of non-energy-related GHG emissions will grow in importance. It is therefore crucial that climate mitigation analyses and strategies are not limited to the energy system. This article shows the value of using integrated energy and agriculture techno-economic modelling techniques to draw evidence for new comprehensive climate policy strategies able to discern between the full range of technical solutions available. It enables the production of economy-wide least-cost climate mitigation pathways.     

Characterization of particulate matter in the Apulia Region (South of Italy): features and critical episodes

The chemical composition of PM₁₀ and PM_2.5 samples collected during two seasonal monitoring campaigns at residential, urban and industrial Apulia Region- sites was investigated. Ionic fraction, carbonaceous compounds and Polycyclic Aromatic Hydrocarbons were determined for all samples. High correlations among PM data collected in the investigated sites suggested the regional character of particulate matter. It was also confirmed by five days back trajectories analysis. Moreover, no significant seasonal trend in PM mass concentration was observed in the investigated sites. These results, relevant for the area under investigations, were not observed in the North of Italy and Europe and allow to conclude that PM₁₀ and PM_2.5 cannot be considered ‘good’ indicators for the evaluation of local anthropic contributions to air quality. On the contrary, the high levels of Polycyclic Aromatic Hydrocarbons found in Taranto sampling sites suggested that PAHs can be a better indicator for this purpose. This result is also relevant in order to weigh the importance of industrial area and to suggest right policy control to decision makers.     

The Sponge Community of a Semi-Submerged Mediterranean Cave

Abstract. The sponge fauna of a semi-submerged cave from the Tremiti Archipelago (Adriatic Sea) was studied, and its distribution was analyzed in relation to abiotic (water-movement and light gradients) and biotic (algae and anthozoan substrate cover) ecological factors. Fifty-five species of sponges were recorded. The number of species and the abundance values of sponges increase in the first part of the cave, then progressively decrease, with a sharp fall at the end of the cave. The quick disappearance of algae along the light gradient allows sponges to thrive in the first portion of the cave. The subsequent, progressive decrement of sponges could be the result of food depletion phenomena due to a long persistence of the water body in this long cavity. A high water-turbulence, due to the peculiar morphology of the cave and indicated by the recorded values of water-movement, occurs at the end of the cavity and probably determines the sharp decrement of sponges in the inner portion of the cave. This turbulence may also explain the absence of typical still-water cave species and probably affects the type of development (shape, overgrowth) of the sponges in the community.     

Is Mimas differentiated?

From the first Voyager pictures, the shape of Mimas appears to be spherical within a few percents. If this result is confirmed, either Mimas's density is higher than 2 g cm^–3, or this small satellite has a core-mantle differentiated structure.