Volunteered geographic information systems: Technological design patterns

Volunteered geographic information (VGI) has been studied extensively within various contexts, however, generally focusing on isolated aspects of data. Therefore, we still need to advance the structured knowledge of the mechanisms that affect and support its creation. This article aims to contribute to the integrated study of VGI systems (VGIS) in order to enhance design processes that lead to a more systematic and efficient VGI management. We define VGIS, their main components, and general architectures. Then, we use the service blueprinting technique to conduct the case study of several systems, identifying system actions to find the processes and technologies forming the different functional components of VGIS: elements of the technological infrastructure that implement diverse processes to facilitate participation and data management. Integrated in the data collection component, we also propose a typology of crowdsourcing tasks that—coupled with the functional components—establishes a foundation for VGIS research and design. We characterize these components, arguing that they are necessary in the development of VGIS, however, there is still a need for a more detailed study of the flow of processes and subprocesses and how they work under the criteria of different types of projects to continue facilitating their design.     

Regional scenarios of sea level rise and impacts on Basque (Bay of Biscay) coastal habitats,throughout the 21st century

Global climate models have predicted a rise on mean sea level of between 0.18 m and 0.59 m by the end of the 21st Century, with high regional variability. The objectives of this study are to estimate sea level changes in the Bay of Biscay during this century, and to assess the impacts of any change on Basque coastal habitats and infrastructures. Hence, ocean temperature projections for three climate scenarios, provided by several atmosphere–ocean coupled general climate models, have been extracted for the Bay of Biscay; these are used to estimate thermosteric sea level variations. The results show that, from 2001 to 2099, sea level within the Bay of Biscay will increase by between 28.5 and 48.7 cm, as a result of regional thermal expansion and global ice-melting, under scenarios A1B and A2 of the Intergovernmental Panel on Climate Change. A high-resolution digital terrain model, extracted from LiDAR, data was used to evaluate the potential impact of the estimated sea level rise to 9 coastal and estuarine habitats: sandy beaches and muds, vegetated dunes, shingle beaches, sea cliffs and supralittoral rock, wetlands and saltmarshes, terrestrial habitats, artificial land, piers, and water surfaces. The projected sea level rise of 48.7 cm was added to the high tide level of the coast studied, to generate a flood risk map of the coastal and estuarine areas. The results indicate that 110.8 ha of the supralittoral area will be affected by the end of the 21st Century; these are concentrated within the estuaries, with terrestrial and artificial habitats being the most affected. Sandy beaches are expected to undergo mean shoreline retreats of between 25% and 40%, of their width. The risk assessment of the areas and habitats that will be affected, as a consequence of the sea level rise, is potentially useful for local management to adopt adaptation measures to global climate change.     

Hydrodynamics of a headland-bay beach—Nearshore current circulation

This paper is devoted to the analysis of the hydrodynamic equilibrium of a headland or semi-elliptic shaped beach. It is shown that the state of equilibrium depends not only on the in- and outgoing sediment but also on the accommodation of the sediment within the embayment. The shape and relative depth of shoals, or settling zones, also directly affect the wave and current patterns inside the bay, within which the resultant breaker line almost stops wave-induced currents at some locations, whereas the magnitude of current increases at other locations. Several numerical tests are analytically conducted in a semi-elliptic beach with two symmetrical shoals of varying relative depth where circulatory current systems are detected and analyzed. Numerical modelling for wave climate and wave-induced current estimation is also presented in order to corroborate results and provide a tool for complicated and/or physical domains. The results lead to a redefinition of the concept of equilibrium for headland-bay beaches taking into account not only the net sediment transport but also the role of the formation and disappearance of settling zones, as well as sediment interchanges between the beach and shoals.     

Towards an Integrated Model of Interoperability for Spatial Data Infrastructures

Although there is a vast literature available on interoperability models, and their respective interoperability levels, limited research has been carried out on the development of interoperability models for the implementation of Spatial Data Infrastructures. This article demonstrates the important role of metadata elements in the formalisation of interoperability models for the implementation of Spatial Data Infrastructures. It describes an approach for designing an integrated interoperability model based on the definition of a common template that integrates seven interoperability levels. They are: technical, syntactic, semantic, pragmatic, dynamic, conceptual and organisational levels. A non-hierarchical structure is proposed to ensure the relationship among these interoperability levels.     

13e SESSION DU COMITÉ CONSULTATIF KARACHI 4–15 NOVEMBRE 1957

Abstract

Event-based methods are used in flood estimation to obtain the entire flood hydrograph. Previously, such methods adopted in the UK have relied on pre-determined values of the input variables (e.g. rainfall and antecedent conditions) to a rainfall–runoff model, which is expected to result in an output flood of a particular return period. In contrast, this paper presents a method that allows all the input variables to take on values across the full range of their individual distributions. These values are then brought together in all possible combinations as input to an event-based rainfall–runoff model in a Monte Carlo simulation approach. Further, this simulation strategy produces a long string of events (on average 10 per year), where dependencies from one event to the next, as well as between different variables within a single event, are accounted for. Frequency analysis is then applied to the annual maximum peak flows and flow volumes.

Citation Svensson, C., Kjeldsen, T.R., and Jones, D.A., 2013. Flood frequency estimation using a joint probability approach within a Monte Carlo framework. Hydrological Sciences Journal, 58 (1), 1–20.     

In two waters: contemporary evolution of lagoonal and marine white seabream (Diplodus sargus) populations

Brackish water ecosystems are often exposed to wide variations in environmental variables, including temperature and salinity, which may cause strong selective pressures on organisms modifying the genetic patterns of species. The aim of this work was to test whether there is a ‘divergence-with-gene flow’ in coastal lagoon populations of white seabream (Diplodus sargus) (Ria Formosa, S Portugal and Mar Menor, SE Spain) respect to four marine populations, by using partial sequences of cyt b mitochondrial gene and information from nine microsatellite loci. Genetic diversity was highest in both coastal lagoons (Mar Menor and Ria Formosa) considering mitochondrial and nuclear markers. Although some of F_ST population pairwise comparisons were not significant, analyses of molecular variance (AMOVAs) detected differences between groups (coastal lagoon and marine) close to significance. Also, only two haplotypes (Cytb-17 and Cytb-18) were detected in both coastal lagoon sampling sites and these localities (Mar Menor and Ria Formosa) showed the highest number of singletons, some of them with a high number of mutations, as has been already described for other Mar Menor populations (Pomatochistus marmoratus and Holothuria polii). Also, several tests detected significant positive and balancing selection considering mtDNA and microsatellite data. These data support the hypothesis of selection as one of the drivers of the genetic differences found between coastal lagoon and marine populations. The life strategy adopted by Diplodus sargus in coastal lagoons allows it to decrease its mortality rate and improve the heritability of its genes. Also, the increase time spent in coastal lagoons with different temperatures and salinities favours the fitness selection and the maintenance of exclusive haplotypes and genotypes in coastal lagoon inhabitants favouring the ‘divergence-with-gene-flow’.     

Chronicle of a forecast flood: exposure and vulnerability on the south-east coast of Spain

Natural Hazards - In recent years, floods have become one of the natural hazards that generate the greatest economic and human losses on the planet. As is well known, torrential rainfall events are...     

The influence of land use/land cover variability and rainfall intensity in triggering landslides: a back-analysis study via physically based models

Natural Hazards - The objective of this study was to use physically based models to carry out a back-analysis of the set of factors that may have influenced slope instability and the consequent...     

The role of massive AGB stars in the early solar system composition

Abstract— We demonstrate that a massive asymptotic giant branch (AGB) star is a good candidate as the main source of short‐lived radionuclides in the early solar system. Recent identification of massive (4–8 M⊙) AGB stars in the galaxy, which are both lithium‐ and rubidium‐rich, demonstrates that these stars experience proton captures at the base of the convective envelope (hot bottom burning), together with high‐neutron density nucleosynthesis with ²²Ne as a neutron source in the He shell and efficient dredge‐up of the processed material. A model of a 6.5 M⊙ star of solar metallicity can simultaneously match the abundances of ²⁶Al, ⁴¹Ca, ⁶⁰Fe, and ¹⁰⁷Pd inferred to have been present in the solar nebula by using a dilution factor of 1 part of AGB material per 300 parts of original solar nebula material, and taking into account a time interval between injection of the short‐lived nuclides and consolidation of the first meteorites equal to 0.53 Myr. Such a polluting source does not overproduce ⁵³Mn, as supernova models do, and only marginally affects isotopic ratios of stable elements. It is usually argued that it is unlikely that the short‐lived radionuclides in the early solar system came from an AGB star because these stars are rarely found in star forming regions, however, we think that further interdisciplinary studies are needed to address the fundamental problem of the birth of our solar system.