Resolution Improvement of Solar Images

A method for the improvement of resolution in an observed solar image is proposed. A blind deconvolution method is used for restoration of an atmospherically-degraded solar image, and a super-resolution method is applied to its restored image to improve the resolution. It is confirmed that a blind deconvolution process can restore fine structures that are blurred in an observed image, and that the super-resolution process can make a cutoff frequency in a blind-deconvolved image higher. A time series of super-resolved images of a sunspot observed with the 70-cm Vacuum Tower Telescope at Teide Observatory is presented.     

Characterisation of a Campanian deep-sea fan system in the Norwegian Sea by means of ichnofabrics

Ichnofabrics are applied in concert with sedimentological data to discriminate sub-environments within a Campanian deep-sea fan system in the Norwegian Sea. Seven ichnofabric types are recognised in the studied cores, which correspond to specific architectural elements of the fan system, including amalgamated channels, lobate sand sheets, proximal and distal overbank, fan fringe, and hemipelagic basin plain environments. A unique observation is an ultra-deep Chondrites ichnofabric, interpreted to result from the activity of a chemosymbiotic tracemaker, possibly utilising hydrothermal vents or hydrocarbon seeps in the near vicinity of an active rift system. Mapping and inter-well correlation of ichnofabrics allow a better control of lateral and vertical facies changes, which are important to exploration and production strategies. This study demonstrates that ichnofabric analysis is proving to be a valuable tool for the characterisation and prediction of reservoir quality, the recognition of potential flow barriers and prediction of lateral depositional trends in deep-sea fan deposits.     

The global thermohaline circulation in box and spectral low-order models. Part 1: single basin models

Much of the knowledge about ocean circulation stems from rather simple analytical models. The behavior of the meridional overturning and, more specifically, the thermohaline-induced part of the global ocean circulation, under changing surface conditions, is often judged by the bifurcation structure of box models with very low (low-order) resolution. The present study proposes a new low-order model of the thermohaline-driven circulation, which is constructed by severe truncation of a spectral decomposition of the two-dimensional equations of motion (vorticity and heat/salt balances). The physical ingredients of the new model are superior to box models because it has a continuous lateral and vertical representation of the fields and finite diffusion coefficients for heat and salt. The building of the spectral model involves much mathematical labor because the structure functions must be constructed in accordance with the boundary conditions for conservation of momentum, mass, heat, and salt. Furthermore, a number of complicated coupling coefficients must be evaluated. Like the box models, the spectral model is a dynamical system with mathematical complexity, but in most of the versions that we analyze, it still can be handled by standard analytical procedures. These versions are the spectral counterparts of the classical box models of Stommel, Rooth, and Welander, adjusted to the Atlantic overturning. A detailed comparison of the model types reveals a similar bifurcation pattern of box and spectral low-order configurations under symmetric and asymmetric forcing conditions and slight perturbations thereof (we use mixed boundary conditions for heat and salt and the surface freshwater flux as a continuation parameter). Comparison of the spectral low-order models with models towards a higher resolved range, namely, the two-dimensional overturning models for the meridional plane, reveals a close resemblance as well. A major difference of box and spectral models is the appearance of parameter windows in the latter, where only unstable steady states exist. The spectral models then show limit cycles, as well as chaotic trajectories with time scales of thousands of years.     

Field Evaluation of the Effectiveness of Surfactant Modified Zeolite and Iron-Oxide-Coated Sand for Removing Viruses and Bacteria from Ground Water

Field experiments were conducted to evaluate the efficiency of iron-oxide-coated sand (ICS) and surfactant modified zeolite (SMZ) to remove viruses and bacteria from ground water. The reactive media were employed as filter packs of a pumping well that withdrew sewage effluent from a constructed wetland at a rate of 0.72 L/min. The contact time of the pumped water with the filter pack (10 cm thick) was about two minutes. Upgradient of the pumping well, the sewage effluent was spiked with MS-2 bacteriophage and E. coli. While the employed ICS filter pack failed to remove viruses and bacteria to a significant degree, the SMZ filter pack removed more than 99% of the viruses and 100% of E. coli from the ground water while fresh. In an additional field experiment using the same configuration but leaving the filter pack in place for more than five months, the SMZ filter pack was still removing 100% of E. coli , but failed to reduce virus numbers to a significant degree.     

Determination of geometrical spreading from traveltimes

Geometrical spreading plays an important role for amplitude preserving migration, which is a very time-consuming process. In order to achieve efficiency in terms of computational time and, particularly, storage space, we propose a method to determine geometrical spreading from coarsely gridded traveltime tables. The method is based on a hyperbolic traveltime expansion and provides also a fast and accurate algorithm for the interpolation of traveltimes, including the interpolation of complete shots. Examples demonstrate the applicability of the method to isotropic and anisotropic media.     

Polychlorinated biphenyls (PCB) and organochlorine pesticides in sediments of the baltic and coastal waters of Mecklenburg-Vorpommern

Summary The distribution of polychlorinated biphenyls (PCB) and organochlorine pesticides, e.g. the isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), p,p’-dichiorodiphenyitrichloroethane (DDT) and its primary metabolites DDE and DDD was investigated in surface sediments (0–2 cm) and sediment cores (0–45 cm) from the western Baltic Sea and the coastal waters of Mecklenburg-Vorpommern. Sediment sampling was carried out in the Belt Sea, the Arkona Basin, the Pomeranian Bight and in almost all Bodden and Haff areas of Mecklenburg-Vorpommern in autumn 1993 and 1994. The highest concentrations of PCB and DDT compounds, measured in the innercoastal waters, reached 214 ng g^-1 dry weight (d. w.). The values of HCH isomers ranged between 0.01 and 2.9 ng g^-1 d.w., the highest levels being those of Β-HCH. Levels of chlorinated hydrocarbons, which varied depending on the sediment properties, indicated increased riverine inputs (Oder, Peene, and Uecker). Elevated levels in the Oderhaff and Peenestrom characterize that area as a sink and, due to remobilization of the upper sediment layer (fluffy layer) into the pelagic, also as a source of organic contaminants. Input from agriculture and industrial point sources (shipyards, shipbuilding) was observed in the coastal waters. The homogeneous PCB and DDT distribution (TOC standardization) observed in the surface sediments of some areas in the western Baltic indicates high sediment dynamics. This is supported by the results of sediment core analyses which showed a constant PCB and DDT distribution down to a depth of 15 to 20 cm.

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Polychlorierte Biphenyle (PCB) und Organochlorpestizide im Sediment der Ostsee und der Küsten-gew?sser Mecklenburg-Vorpommerns

Zusammenfassung Die Verteilungen von polychlorierten Biphenylen (PCB) und Organochlorpestiziden (DDT, HCH und HCB) wurden in Oberfl?chensedimenten (0–2 cm) und in Sedimentkernen (0–45 cm) der westlichen Ostsee und der Küstengew?sser Mecklenburg-Vorpommerns untersucht. Die Sedimentprobenahme erfolgte in der Beltsee, der Arkonasee, der Pommerschen Bucht und in nahezu allen Bodden-und Haffgew?ssern Mecklenburg-Vorpommerns im Herbst 1994 und 1995. Die h?chsten Konzentrationen wurden für die PCB-und DDT-Verbindungen bis 214 ng g^-1 Trockenmasse (TM) in den Küstengew?ssern gemessen. Für die HCH-Isomeren lagen die Werte zwischen 0,01 und 2,9 ng g^-1 TM, mit h?chsten Konzentrationen für das Β-HCH. Die Werte der chlorierten Kohlenwasserstoffe (CKW) variieren nach der Sedimentbeschaffenheit und weisen auf erh?hte Eintr?ge über die Flu\systeme (Oder und Peene) hin. Die h?heren Konzentrationen in den Bodden-und Haffgew?ssern charakterisieren diese Gebiete als Senke und durch erneute Mobilisierung der oberen Sedimentschicht in das Pelagial auch als Quelle für die organischen Schadstoffe. Insbesondere konnten die Eintr?ge aus der Landwirtschaft und aus industriellen Punktquellen (Werftstandorte, Schiffbau) in den Küstengew?ssern festgestellt werden. Die nahezu homogene PCB-und DDT-Verteilung im Oberfl?chensediment der westlichen Ostsee ist ein Hinweis auf die hohe Sedimentdynamik in diesem Gebiet. Dieses wird durch die Ergebnisse der Untersuchungen an Sedimentkernen unterstützt, die eine konstante PCB-und DDT-Verteilung bis zu einer Tiefe von 15 bis 20 cm zeigten.

     

Controllability and observability in two-phase porous media flow

Reservoir simulation models are frequently used to make decisions on well locations, recovery optimization strategies, etc. The success of these applications is, among other aspects, determined by the controllability and observability properties of the reservoir model. In this paper, it is shown how the controllability and observability of two-phase flow reservoir models can be analyzed and quantified with aid of generalized empirical Gramians. The empirical controllability Gramian can be interpreted as a spatial covariance of the states (pressures or saturations) in the reservoir resulting from input perturbations in the wells. The empirical observability Gramian can be interpreted as a spatial covariance of the measured bottom-hole pressures or well bore flow rates resulting from state perturbations. Based on examples in the form of simple homogeneous and heterogeneous reservoir models, we conclude that the position of the wells and of the front between reservoir fluids, and to a lesser extent the position and shape of permeability heterogeneities that impact the front, are the most important factors that determine the local controllability and observability properties of the reservoir.     

Variscan orogeny in Corsica: new structural and geochronological insights,and its place in the Variscan geodynamic framework

In Western Corsica, remnants of pre-batholitic lithological and metamorphic assemblages are preserved as km-scale septa enclosed within Lower Carboniferous to Early Permian plutons. Two groups of septa were recognized: (1) the Argentella and Agriates-Tenda fragments correspond to Neoproterozoic rocks deformed and metamorphosed during the Cadomian–Panafrican orogeny, and (2) the Zicavo, Porto-Vecchio, Solenzara–Fautea, Belgodère, Topiti, and Vignola fragments consist of Variscan metamorphic rocks. The lithological content and the main ductile deformation events for each septum are presented. In the Zicavo, Porto-Vecchio, and Topiti septa, a top-to-the-SW ductile shearing (D1 event) coeval with an amphibolite facies metamorphism is responsible for crustal thickening at ca 360 Ma. This main event was preceded by eclogite and granulite facies metamorphic events preserved as restites within migmatites dated at ca 345–330 Ma. A top-to-the-SE ductile shearing (D2 event) coeval with the crustal melting accommodated the exhumation of the D1 event. In contrast, the Belgodère segment is peculiar as it exhibits a top-to-the-E vergence, although retrogressed high-pressure rocks are also recognized. The pre-Permian fragments are arranged in four NW–SE-striking stripes that define a SW–NE zoning with (1) a Western domain in Topiti, Vignola, Zicavo, Porto-Vecchio, and Solenzara–Fautea; (2) a Neoproterozoic basement with its unconformable Early Paleozoic sedimentary cover in Argentella; (3) an Eastern metamorphic domain in Belgodère; (4) another Neoproterozoic basement with its Upper Paleozoic sedimentary cover in Agriates-Tenda. The Argentella basement is separated from the Western and Eastern domains by two sutures: S1 and S2. The Variscan Corsica represents the Eastern part of the Sardinia–Corsica–Maures segment. The comparison of this segment with other Variscan domains allows us to propose some possible correlations. We argue that the Western domain, Argentella, Belgodère, and Agriates-Tenda domains can be compared with the Southern Variscan belt exposed in French Massif Central–Southern Massif Armoricain, Armorica microblock, Léon block, respectively.     

The year-long unprecedented European heat and drought of 1540 – a worst case

The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring–summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km², we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.