Evaluating Topological Queries in Linked Data Using DBpedia and GeoNames in Switzerland and Scotland

This article explores the practicability and assesses the quality of searches for Wikipedia pages of topologically related administrative divisions in Switzerland and Scotland via Linked Data. To this end, the quality of searches in the English and German versions of DBpedia is compared, as is that of searches in GeoNames and DBpedia using DBpedia's links to GeoNames or a manually created list of links. In addition, the effects of updates to Swiss municipality borders in the English version of DBpedia on standard quality metrics are studied. It turns out that live searches are practicable with acceptable performance, but that the quality of searches in terms of recall and precision is acceptable only if DBpedia is queried via GeoNames and DBpedia's links to GeoNames are replaced by manually created links. Searches for Scottish unitary authority wards perform poorly for all approaches investigated. Recall and precision are strongly influenced by changes in municipality borders, with a relatively long latency suggesting that, at least in some cases, administrative changes propagate slowly into DBpedia. These results have important implications for those seeking to use location as a means to link data.     

Lagrangian Particle Dispersion Models in the Grey Zone of Turbulence: Adaptations to FLEXPART-COSMO for Simulations at 1 km Grid Resolution

Boundary-Layer Meteorology - Lagrangian particle dispersion models (LPDMs) are frequently used for regional-scale inversions of greenhouse gas emissions. However, the turbulence parameterizations...     

Significance of OH,F and Cl content in biotite during metamorphism of the Western Adamello contact aureole

The hydroxyl (O(4)) site composition of biotite can in principle be used to retrieve information about fluid composition during fluid–rock interaction; however, due to low F and Cl content, as well as difficulties involved with analyzing the H₂O content using in situ techniques, measuring these species in biotite has remained an elusive goal. Here we present high-precision secondary ion mass spectrometry (SIMS) OH–F–Cl measurements from biotite within metapelites from the Western Adamello Tonalite (WAT) contact aureole, Northern Italy. Fluorine, chlorine and hydrogen are analyzed on the SIMS sequentially by peak-hopping at the same biotite spot; H₂O, F and Cl content were measured with a precision (1σ) οφ 0.06 ωτ%, 50 ανδ 5 ππµ, ρεσπεχτι?ελψ. The compositions of isolated biotite crystals in andalusite are compared with that of biotite in the matrix, documenting that halogens and H₂O behave refractory in biotite during the time scale of contact metamorphism. The H₂O and halogen contents of biotite are mostly locked in during the prograde to peak formation of biotite, and are not reset during further heating or cooling, unless significant biotite recrystallization occurs. It also appears that both Ti content and X_Mg of the biotite from the Western Adamello contact aureole were not significantly reset during cooling. The concentration of F and Cl does not vary systematically with metamorphic grade, which indicates that these species reflect initial compositions. No significant Rayleigh fractionation behavior was observed for these elements. H₂O variations in the biotite from samples throughout the Western Adamello contact aureole suggest that Al-oxy substitution partially controls the variations in OH content through charge balance of the type R^2+,VI + OH^? = Al^3+,VI + O^2? + H₂, while the Ti-oxy substitution does not seem to influence the O(4) site occupation. The main titanium substitution appears to be the Ti-vacancy (\({\text{2}}{{\text{R}}^{{\text{2}}+}}~=~{\text{T}}{{\text{i}}^{{\text{4}}+}}~+\,{\square ^{{\text{VI}}}}\)) exchange. Variations in H₂O and halogen concentrations in biotite define sub mm-scale areas of localized equilibration, even for biotite recrystallized during dehydration reactions that produced large amounts of fluid (chlorite or muscovite breakdown). Similar systematics were observed for Ti⁴⁺ and Al³⁺. These findings further support the increasing number of observations that kinetics control much of the mineralogical reactions occurring in contact aureoles, and hence care is advised in using equilibrium thermodynamics in this environment.     

Volcanic eruptions and the forgotten pearls

With this paper we demonstrate, using the example of the Segara Anakan lagoon in south Java, Indonesia, that exploring the environmental history of an area may provide important information for the understanding of present day problems and their possible solutions. The lagoon is seriously affected by sedimentation. Management measures aiming at its preservation were rather ineffective. Until now, most scholars have treated sedimentation of the lagoon as a short-term phenomenon. We found evidence that sedimentation is a long-term driver of ecosystem changes in Segara Anakan. Ecosystem changes are also obvious in the disappearance of species from the lagoon, like pearl oysters.We recommend that preconditions for the development of adequate management decisions regarding the lagoon's sedimentation problem are (1) a distinction between natural and anthropogenic causes of sedimentation and (2) an understanding of changes in species composition.     

Five years’ central pacific sea level from in situ array,satellite altimeter and numerical model: Research note

Abstract

Temporal and spatial features of central equatorial Pacific Ocean sea‐level variation appear similar, in measurements from two very different systems (one in the ocean and one carried on a satellite), and in results from a numerical model of the region. In particular, there is an interannual cycle: during El Nino, Kelvin waves appear at the equator, and the sea‐surface ridge associated with the equatorial current system shifts southward; in non‐El Nino years, instability waves appear at 6°N (strongest around the end of each calendar year), and the ridge shifts to the north. This three‐way comparison gives support to both measurement systems and to the numerical model.     

Image Processing Techniques and Feature Recognition in Solar Physics

This review presents a comprehensive and systematic overview of image-processing techniques that are used in automated feature-detection algorithms applied to solar data: i) image pre-processing procedures, ii) automated detection of spatial features, iii) automated detection and tracking of temporal features (events), and iv) post-processing tasks, such as visualization of solar imagery, cataloguing, statistics, theoretical modeling, prediction, and forecasting. For each aspect the most recent developments and science results are highlighted. We conclude with an outlook on future trends.     

Aspects of CO2 advection measurements

Observations of vegetation–atmosphere exchange of carbon dioxide (CO₂) by the eddy covariance (EC) technique are limited by difficult conditions such as nighttime and heterogeneous terrain. Thus, advective flux components are included into the net ecosystem exchange (NEE) budget. However, advection measurements are experimentally challenging and do not always help to solve the night flux problem of the EC technique. This study investigates alternative methods for the observation of horizontal advection, in particular horizontal concentration gradients, as well as different approaches to coordinate rotation and vertical advection. Continuous high-frequency measurements of the horizontal CO₂ concentration field are employed and compared to the often used discontinuous sequential sampling. Significant differences were found in the case of 30-min mean concentration values between the conventional discontinuous sampling approach and the complete observation of the time series by continuous sampling. Estimates of vertical advection rely on accurate estimates of vertical wind velocity ( $\emph{w}$ ). Therefore, different approaches to the planar fit coordinate rotation have been investigated. Sector-wise rotation was able to eliminate directional dependencies of mean $\emph{w}$ . Furthermore, the effect of the data set length used for rotation (window length) was investigated and was found to have significant impact on estimates of vertical advection, with larger window lengths yielding about 50% larger vertical advection. A sequential planar fit with controlled window length is proposed to give reproducible results. The different approaches to the measurement and calculation of horizontal and vertical advection presented are applied to data obtained during the exchange processes in mountainous region experiment at the FLUXNET site Waldstein–Weidenbrunnen (DE-Bay). Estimates of NEE including advection are compared to NEE from turbulent and storage flux alone without advection. NEE including vertical advection with sector-wise planar fit rotation and controlled window length and including horizontal advection from continuous gradient measurements, which were comprehensively bias corrected by a new approach, did compare well with the expected night flux error, with meteorological drivers of the fluxes and with soil chamber measurements. Unrealistically large and noisy values of horizontal advection from the conventional discontinuous sampling approach, which lead to unrealistic values of NEE, could be eliminated by the alternative approaches presented. We therefore suggest the further testing of those approaches at other sites in order to improve the accuracy of advection measurements and, subsequently, estimates of NEE.     

Effects of Bubbles and Sea Spray on Air–Sea Exchange in Hurricane Conditions

The lower limit on the drag coefficient under hurricane force winds is determined by the break-up of the air–sea interface due to Kelvin–Helmholtz instability and formation of the two-phase transition layer consisting of sea spray and air bubbles. As a consequence, a regime of marginal stability develops. In this regime, the air–sea drag coefficient is determined by the turbulence characteristics of the two-phase transition layer. The upper limit on the drag coefficient is determined by the Charnock-type wave resistance. Most of the observational estimates of the drag coefficient obtained in hurricane conditions and in laboratory experiments appear to lie between the two extreme regimes: wave resistance and marginal stability.     

Large calcite and bulk-rock volume loss in metacarbonate xenoliths from the Quérigut massif (French Pyrenees)

Chemical mass transfer was quantified in a metacarbonate xenolith enclosed within the granodiorite of the Quérigut massif (Pyrenees, France). Mass balance calculations suggest a strong decrease of CaO, SrO and CO₂ contents (up to −90%), correlated with a decrease of modal calcite content as the contact is approached. Most other chemical elements behave immobile during metasomatism. They are therefore passively enriched. Only a small increase of SiO₂, Al₂O₃ and Fe₂O₃ contents occurs in the immediate vicinity of the contact. Hence, in this study, skarn formation is characterized by the lack of large chemical element influx from the granitoid protolith. A large decrease of the initial carbonate volume (up to −86%) resulted from a combination of decarbonation reactions and loss of CaO and CO₂. The resulting volume change has potentially important consequences for the interpretation of stable isotope profiles: the isotope alteration could have occured over greater distances than those observed today.     

Comparison of STEREO/EUVI Loops with Potential Magnetic Field Models

The Solar Terrestrial Relations Observatory (STEREO) provides the first opportunity to triangulate the three-dimensional coordinates of active region loops simultaneously from two different vantage points in space. Three-dimensional coordinates of the coronal magnetic field have been calculated with theoretical magnetic field models for decades, but it is only with the recent availability of STEREO data that a rigorous, quantitative comparison between observed loop geometries and theoretical magnetic field models can be performed. Such a comparison provides a valuable opportunity to assess the validity of theoretical magnetic field models. Here we measure the misalignment angles between model magnetic fields and observed coronal loops in three active regions, as observed with the Extreme Ultraviolet Imager (EUVI) on STEREO on 30 April, 9 May, and 19 May 2007. We perform stereoscopic triangulation of some 100?–?200 EUVI loops in each active region and compute extrapolated magnetic field lines using magnetogram information from the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO). We examine two different magnetic extrapolation methods: (1) a potential field and (2) a radially stretched potential field that conserves the magnetic divergence. We find considerable disagreement between each theoretical model and the observed loop geometries, with an average misalignment angle on the order of 20°?–?40°. We conclude that there is a need for either more suitable (coronal rather than photospheric) magnetic field measurements or more realistic field extrapolation models.