Minimum geocoding match rates: an international study of the impact of data and areal unit sizes

ABSTRACT

The analysis of geographically referenced data, specifically point data, is predicated on the accurate geocoding of those data. Geocoding refers to the process in which geographically referenced data (addresses, for example) are placed on a map. This process may lead to issues with positional accuracy or the inability to geocode an address. In this paper, we conduct an international investigation into the impact of the (in)ability to geocode an address on the resulting spatial pattern. We use a variety of point data sets of crime events (varying numbers of events and types of crime), a variety of areal units of analysis (varying the number and size of areal units), from a variety of countries (varying underlying administrative systems), and a locally-based spatial point pattern test to find the levels of geocoding match rates to maintain the spatial patterns of the original data when addresses are missing at random. We find that the level of geocoding success depends on the number of points and the number of areal units under analysis, but generally show that the necessary levels of geocoding success are lower than found in previous research. This finding is consistent across different national contexts.     

Interannual variability of the South Pacific Convergence Zone and implications for tropical cyclone genesis

The interannual variability of the South Pacific Convergence Zone (SPCZ) and its influence on tropical cyclone (TC) genesis in the South Pacific are investigated using observations and ERA40 reanalysis over the 1979?C2002 period. In austral summer, the SPCZ displays four typical structures at interannual timescales. The first three are characterized by a diagonal orientation of the SPCZ and account for 85% of the summer seasons. One is close to climatology and the other two exhibit a 3° northward or southward departure from the SPCZ climatological position. In contrast, the fourth one, that only encompasses three austral summer seasons (the extreme 1982/1983 and 1997/1998 El Ni?o events and the moderate 1991/1992 El Ni?o event), displays very peculiar behaviour where the SPCZ largely departs from its climatological position and is zonally oriented. Variability of the western/central Pacific equatorial sea surface temperature (SST) is shown to modulate moisture transport south of the equator, thereby strongly constraining the location of the SPCZ. The SPCZ location is also shown to strongly modulate the atmospheric circulation variability in the South Pacific with specific patterns for each class. However, independently of its wide year-to-year excursions, the SPCZ is always collocated with the zero relative vorticity at low levels while the maximum vorticity axis lies 6° to the south of the SPCZ position. This coherent atmospheric organisation in the SPCZ region is shown to constrain tropical cyclogenesis to occur preferentially within 10° south of the SPCZ location as this region combines all the large-scale atmospheric conditions that favour the breeding of TCs. This analysis also reveals that cyclogenesis in the central Pacific (in the vicinity of French Polynesia) only occurs when the SPCZ displays a zonal orientation while this observation was previously attributed to El Ni?o years in general. Different characteristics of El Ni?o Southern Oscillation (ENSO)-related Pacific equatorial warming are shown to impact differently on the SPCZ position, suggesting that for regional scales, such as the South Pacific, the SPCZ classification is more appropriate than a simple ENSO index to characterize TC interannual variability. These findings suggest that forecasting the strength of El Ni?o through SST variations in the eastern Pacific may not be sufficient to accurately predict cyclogenesis in the South Pacific, especially east of the dateline.     

A statistical�Cdynamical scheme for reconstructing ocean forcing in the Atlantic. Part I: weather regimes as predictors for ocean surface variables

The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to 2002. Daily 500?hPa geopotential height and 1,000?hPa wind anomaly maps are classified following a weather-typing approach to describe the North Atlantic and tropical Atlantic atmospheric dynamics, respectively. The algorithm yields patterns that correspond in the extratropics to the well-known North Atlantic-Europe weather regimes (NAE-WR) accounting for the barotropic dynamics, and in the tropics to wind classes (T-WC) representing the alteration of the trades. 10-m wind and 2-m temperature (T2) anomaly composites derived from regime/wind class occurrence are indicative of strong relationships between daily large-scale atmospheric circulation and ocean surface over the entire Atlantic basin. High temporal correlation values are obtained basin-wide at low frequency between the observed fields and their reconstruction by multiple linear regressions with the frequencies of occurrence of both NAE-WR and T-WC used as sole predictors. Additional multiple linear regressions also emphasize the importance of accounting for the strength of the daily anomalous atmospheric circulation estimated by the combined distances to all regimes centroids in order to reproduce the daily to interannual variability of the Atlantic ocean. We show that for most of the North Atlantic basin the occurrence of NAE-WR generally sets the sign of the ocean surface anomaly for a given day, and that the inter-regime distances are valuable predictors for the magnitude of that anomaly. Finally, we provide evidence that a large fraction of the low-frequency trends in the Atlantic observed at the surface over the last 50?years can be traced back, except for T2, to changes in occurrence of tropical and extratropical weather classes. All together, our findings are encouraging for the prospects of basin-scale ocean dynamical downscaling using a weather-typing approach to reconstruct forcing fields for high resolution ocean models (Part II) from coarse resolution climate models.     

Hydrothermalism in the Tyrrhenian Sea: Inorganic and microbial sulfur cycling as revealed by geochemical and multiple sulfur isotope data

The Palinuro volcanic complex and the Panarea hydrothermal field, both located in the Tyrrhenian Sea (Italy), are associated with island arc magmatism and characterized by polymetallic sulfide mineralization. Dissolved sulfide concentrations, pH, and Eh measured in porewaters at both sites reveal a variable hydrothermal influence on porewater chemistry.Multiple sulfur isotopic measurements for disseminated sulfides (CRS: chromium reducible sulfur) extracted from sediments at Palinuro yielded a broad range in δ³⁴S range between ?29.8 and + 10.2‰ and Δ³³S values between + 0.015 and + 0.134‰. In contrast, sediments at Panarea exhibit a much smaller range in δ³⁴S_CRS with less negative values between ?11.3 and ?1.8‰. The sulfur isotope signatures are interpreted to reflect a mixture between hydrothermal and biogenic sulfide, with a more substantial biogenic contribution at Panarea.Multiple sulfur isotope measurements were performed on sulfides and elemental sulfur from drill core material from the Palinuro massive sulfide complex. δ³⁴S and Δ³³S values for pyrite between ?32.8 and ?1.1‰ and between ?0.012 to + 0.042‰, respectively, as well as for elemental sulfur with δ³⁴S and Δ³³S values between ?26.7 and ?2.1‰ and between + 0.035 and + 0.109‰, respectively, point to a microbial origin for much of the sulfide and elemental sulfur studied. Moreover, data suggest a coupling of bacterial sulfate reduction, sulfide oxidation and sulfur disproportionation. In addition, δ³⁴S values for barite between + 25.0 and + 63.6‰ are also in agreement with high microbial turnover of sulfate at Palinuro.Although a magmatic SO₂ contribution towards the formation of the Palinuro massive sulfide complex is very likely, the activity of different sulfur utilizing microorganisms played a fundamental role during its formation. Thus, porewater and multiple sulfur isotope data reveal differences in the hydrothermal activity at Palinuro and Panarea drill sites and underline the importance of microbial communities for the origin of massive sulfide mineralizations in the hydrothermal subsurface.     

Late Pleistocene climatic change in the French Jura (Gigny) recorded in the δO of phosphate from ungulate tooth enamel

Oxygen isotope compositions of phosphate in tooth enamel from large mammals (i.e. horse and red deer) were measured to quantify past mean annual air temperatures and seasonal variations between 145 ka and 33 ka in eastern France. The method is based on interdependent relationships between the δ¹⁸O of apatite phosphate, environmental waters and air temperatures. Horse (Equus caballus germanicus) and red deer (Cervus elaphus) remains have δ¹⁸O values that range from 14.2‰ to 17.2‰, indicating mean air temperatures between 7°C and 13°C. Oxygen isotope time series obtained from two of the six horse teeth show a sinusoidal-like signal that could have been forced by temperature variations of seasonal origin. Intra-tooth oxygen isotope variations reveal that at 145 ka, winters were colder (? 7 ± 2°C) than at present (3 ± 1°C) while summer temperatures were similar. Winter temperatures mark a well-developed West–East thermal gradient in France of about ? 9°C, much stronger than the ?4°C difference recorded presently. Negative winter temperatures were likely responsible for the extent and duration of the snow cover, thus limiting the food resources available for large ungulates with repercussions for Neanderthal predators.     

气候环境变化研究中影响粘土矿物形成及其丰度因素的讨论

粘土矿物在形成过程中受构造运动、气候、盆地规模、地表母岩、土壤、植被、地貌、介质环境、风以及成岩作用等多种因素的影响,这些因素对地层中粘土矿物的类型和含量的影响程度不一。构造运动和气候是影响粘土矿物形成的两个主要因素,对沉积物中的粘土矿物形成和含量以及影响粘土矿物形成的其他次要影响因素有着控制作用。在构造活动稳定的状态下,气候则成为影响粘土矿物形成和含量的决定性因素,其他因素尽管也有不同程度的影响,但可以看成是相对稳定不变的,粘土矿物携带的主要是气候环境变化的信息。地表水系的复杂程度引起的沉积物的混合程度影响粘土矿物信号的清晰度,沉积埋藏成岩作用对粘土矿物的影响也不容忽视。     

About the effect of relative humidity on the indentation response of Meuse/Haute�CMarne argillite

The unsaturated poromechanical behavior of Callovo-Oxfordian argillite (also referred to as Meuse/Haute–Marne argillite) is analyzed by means of indentation tests at different hygrometries. Numerical simulations carried out with a finite element code are then used to simulate flat punch indentation tests at different controlled hygrometries. The numerical response F(h) is compared to experimental data in order to estimate the drained Young’s modulus E and the internal friction angle \Upphi\Upphi (at high confinement) by means of a back analysis. A linear decrease in the drained Young’s modulus and quasi-constant values of the internal friction angle are observed when the relative humidity ranges. Some predictions of the model are also presented to quantify the activation of hydraulic phenomena. Indeed, the maximal variation of the saturation and porosity relative to the initial state of the specimen are lower than 10% and 8%, respectively.     

Morphology, distribution and origin of recent submarine landslides of the Ligurian Margin (North-western Mediterranean): some insights into geohazard assessment

Based on new multibeam bathymetric data, seismic-reflection profiles and side-scan sonar images, a great number of submarine failures of various types and sizes was identified along the northern margin of the Ligurian Basin and characterized with 3 distinct end-members concerning their location on the margin, sedimentary processes and possible triggering mechanisms. They include superficial landslides mainly located in the vicinity of the main mountain-supplied rivers and on the inner walls of canyons (typically smaller that 10⁸ m³ in volume: Type 1), deep scars 100?C500 m high along the base of the continental slope (Type 2), and large-scale scars and Mass Transport Deposits (MTDs) affecting the upper part of the slope (Type 3 failures). The MTDs are located in different environmental contexts of the margin, including the deep Var Sedimentary Ridge (VSR) and the upper part of the continental slope in the Gulf of Genova (Finale Slide and Portofino Slide), with volumes of missing sediment reaching up to 1.5 × 10⁹ m³. High sedimentation rates related to hyperpycnal flows, faults and earthquake activity, together with sea-level fluctuations are the main factors invoked to explain the distribution and sizes of these different failure types.     

Recent contributions of geotechnical centrifuge modelling to the understanding of jack-up spudcan behaviour

The paper presents an overview of the recent contributions of centrifuge modelling to the understanding of soil-structure interaction and the development of design and predictive methods in the field of mobile jack-up drilling rig foundations. Both advantages and limitations of the centrifuge methods are detailed and key examples are presented. The benefits provided by centrifuge modelling to the development of analysis methods that are now being used within the jack-up industry are highlighted. To conclude, industry trends and research opportunities are discussed, as is the possible role of the geotechnical centrifuge in finding solutions to these new needs.