Neural network modelling of planform geometry of headland-bay beaches

The shoreline of beaches in the lee of coastal salients or man-made structures, usually known as headland-bay beaches, has a distinctive curvature; wave fronts curve as a result of wave diffraction at the headland and in turn cause the shoreline to bend. The ensuing curved planform is of great interest both as a peculiar landform and in the context of engineering projects in which it is necessary to predict how a coastal structure will affect the sandy shoreline in its lee. A number of empirical models have been put forward, each based on a specific equation. A novel approach, based on the application of artificial neural networks, is presented in this work. Unlike the conventional method, no particular equation of the planform is embedded in the model. Instead, it is the model itself that learns about the problem from a series of examples of headland-bay beaches (the training set) and thereafter applies this self-acquired knowledge to other cases (the test set) for validation. Twenty-three headland-bay beaches from around the world were selected, of which sixteen and seven make up the training and test sets, respectively. As there is no well-developed theory for deciding upon the most convenient neural network architecture to deal with a particular data set, an experimental study was conducted in which ten different architectures with one and two hidden neuron layers and five training algorithms – 50 different options combining network architecture and training algorithm – were compared. Each of these options was implemented, trained and tested in order to find the best-performing approach for modelling the planform of headland-bay beaches. Finally, the selected neural network model was compared with a state-of-the-art planform model and was shown to outperform it.     

The Geology and Petroleum Resources of Kansas: A Review From Alpha to Omega or From the Pleistocene to the Precambrian

The geological story of Kansas is told through the rocks that are present. It is a simple story in generalities but complex in detail. Knowing the story, gives insight into understanding the occurrence and location of possible economic valuable minerals, such as petroleum. This is a brief review of Kansas geology with respect to the known occurrence of oil and gas. Kansas is part of the Midcontinent oil province with oil having been discovered 150 years ago and commercial production commencing in 1873. Although many prospects remain in Kansas, the state has gone from the number 1 producer in the U.S. in 1916 to 8th today. Exploration for new oil and gas production therefore is going to have to be more imaginative and utilize new approaches and techniques to find the elusive petroleum. There are possibilities however for the prospector who can search diligently. Although the big fields probably have been discovered, the prospects today are deeper, in more undetectable traps, and in essentially untested places.     

Einfluß der Gezeitenstromturbulenz auf die hydrographische Schichtung der Nordsee

Zusammenfassung Es wird das kritische vertikale Dichtegefälle ermittelt, das die Gezeitenstromturbulenz, die vom Meeresboden ausgeht, zum Erliegen bringt (Abb. 2). Ihm wird jenes vertikale Dichtegefälle gegenübergestellt, das der tägliche Wärmestrom durch die Turbulenz der winderzeugten Oberflächenströmungen bewirkt (Abb. 3). In derjeningen Tiefe, in der beide Gefällswerte gleich werden, liegt die Obergrenze der bodennahen Mischungsschicht, deren Verteilung in der Nordsee auf zwei ozeanographischen Schnitten verfolgt wird, die mit dem Vermessungs- und Forschungsschiff Gauss im August 1953 ausgeführt wurden (Abb. 1). Der eine Schnitt verläuft vom Nordausgang der Nordsee zu den westfriesischen Inseln, der andere von der schottischen zur norwegischen Küste (Abb. 4). Durch diese Anordnung konnten alle charakteristischen sommerlichen Lagen in der Nordsee erfaßt werden: der Übergang von der unbedeutenden bodennahen Mischungsschicht in der nördlichen Nordsee zur mächtigen Mischungsschicht der mittleren Nordsee, die dort in den Gebieten mit höheren Gezeitenströmen die normale sommerliche Sprungschicht zu einer wenige Dezimeter dicken Schicht zusammendrängt und die in den Gebieten mit starken Gezeitenströmen in die oberflächennahe Mischungsschicht übergreift. Als Folge davon wird in ausgedehnten Gebieten Schichtungslosigkeit während des ganzen Jahres aufrechterhalten. Die weitreichenden, verschiedenartigen Einflüsse dieser Mischungsvorgänge machen sich unter anderem auf den Jahresgang der Oberflächentemperatur der Nordsee deutlich bemerkbar (Abb. 5 und 6).

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Summary The critical vertical density gradient for suppressing the tidal current turbulence which originates from the bottom of the sea is determined (fig. 2). It is compared with the vertical density gradient caused by the daily heat transport in consequence of the turbulence of the wind-produced surface currents (fig. 3). At the depth where the two gradients become equal there lies the upper limit of the mixed ground layer. Its distribution in the North Sea is shown by two oceanographic profiles on the basis of measurements carried out by the survey and research ship Gauss in April 1953 (fig. 1). One profile extends from the northern exit of the North Sea to the West-Frisian islands, the other one from the Scotch to the Norwegian coast (fig. 4). By this arrangement all characteristic summer situations in the North Sea could be included: the change from the small mixed ground layer in the northern North Sea to the mighty mixed ground layer of the central North Sea compressing there, in regions with higher tidal currents, the normal summer discontinuity layer to a few decimeters and, in regions with strong tidal currents, reaching into the mixed surface layer. As a consequence in vast regions a state without stratification is maintained during the whole year. The far-reaching and various influences of these mixing processes, e. g. on the annual variation of the surface temperature of the North Sea, are evident (fig. 5 and 6).

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Résumé On recherche le gradient vertical critique de densité capable d'annuller le remous dû à la marée au fond de la mer (fig. 2) et on le compare au même gradient produit par le réchauffement diurne combiné avec la turbulence des courants de surface dûs au vent (fig. 3). La profondeur à laquelle ces deux gradients sont identiques fixe la limite supérieure de la couche de mélange voisine du fond. La distribution de cette couche dans la Mer du Nord ressort de deux profils relevés par le navire océanographique Gauss en août 1953 (fig. 1). L'un des profils va de l'extrémité septentrionale de cette mer jusqu'aux îles occidentales de la Frise; l'autre s'étend de la côte écossaise à celle de la Norvège (fig. 4). De cette façon une étude de tous les caractères estivaux de la Mer du Nord met en évidence le passage de la faible couche de mélange dans le Nord à la couche très importante dans la région moyenne; cette dernière couche a pour effet de réduire à quelques décimètres la couche de transition estivale normale dans les régions à courants de marée profonds tandis qu'elle pénètre dans la couche de mélange de surface dans les régions à forts courants de marée. En vertu de ces processus, l'absence de stratification se maintient pendant toute l'année dans de vastes régions. Les effets variés et lointains de ces phénomènes de mélange se font nettement sentir, entre autres, sur la variation annuelle de la température de surface dans la Mer du Nord (fig. 5 et 6).

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Mit 6 Textabbildungen.     

Untersuchung über die Wetterabhängigkeit des Todeseintritts

Zusammenfassung Es werden 1257 meist stundengenaue standesamtliche Sterbedaten des Landkreises Sonthofen im Allgäu aus den Jahren 1951 und 1952 mit lückenlosen, stundenmäßigen Aufzeichnungen des Wetterverlaufs nach verschiedenen statistischen Methoden korreliert. In den zeitlichen Teilkollektiven der einzelnen Wettervorgänge (Aufgleiten, labile Vorgänge, Frontdurchgänge, Zyklonalföhn, antizyklonales Absinken) wird eine innerhalb des Zufallsbereichs liegende Erhöhung der Sterbefälle bei hohem Aufgleiten, Kaltfronten und Okklusionen, eine Verringerung der Todesfälle bei Zyklonalföhn gefunden. Nur bei Einbeziehung von Sterbefällen in der unmittelbaren zeitlichen Umgebung der Wettervorgänge ergibt sich eine signifikant überzufällige Erhöhung der Sterbeziffern über die Grundwahrscheinlichkeit für Frontdurchgänge, labile Vorgänge, Aufgleitprozesse und Föhndurchbrüche. Mit einer modifizierten, auf selektivem Zählverfahren beruhendenn-Methode werden Summenkurven der Todesfälle über den Zeitraum von 24 Vor- und 24 Nachstunden für Kaltfrontdurchgänge, labile Vorgänge, Warmfronten und Föhneinbrüche ermittelt. Signifikante Gipfelwerte finden sich bei Kaltfronten und labilen Vorgängen; bei Warmfronten und Föhn fallen Kurvengipfel, die etwas unterhalb der Grenze des Zufallsbereichs bleiben, in das Vorstadium des Vorgangs. Ein Vergleich der mit verschiedenen Methoden gewonnenen Ergebnisse läßt für Kaltfronten, Okklusionen und labile Vorgänge eine Einflußmöglichkeit auf den Todeseintritt besser gesichert erscheinen als für Warmfronten und zyklonale Föhnvorgänge. Schließlich werden Tage mit hoher Sterbeziffer auf Wetterabhängigkeit untersucht. Es zeigt sich, daß Tage mit Beginn von Störvorgängen nach antizyklonalem Stadium mit überzufälliger Häufigkeit hohe Sterbeziffern aufweisen. Auf die Notwendigkeit, die Ergebnisse statistischer Korrelation durch Anwendung verschiedenartiger Methoden sicherzustellen, wird hingewiesen.

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Summary The present paper gives an account of the correlations between 1257 deaths officially and in the majority of cases registered by the hour in 1951 and 1952 for the district of Sonthofen (Germany) on one hand and the weather situation recorded at the same hours on the other hand. An increase in deaths lying within the random limits is found at the following weather situations: upslide motion, cold front, occlusion, a diminution of deaths with cyclonic foehn. There is but an increase in the cases of death beyond the range of hazard at the very temporal surroundings of the weather changes. By using a particular numbering method (n-method) curves are collected which yield the highest values for cold front passages and labile situations; with warm front and irruptions of foehn the maxima precede their entrance. A comparison of the results obtained by different methods shows that the influence to death is better secured for cold fronts, occlusions, and labile processes than for warm fronts and cyclonic foehn. Finally the days with a special great number of cases of deaths are examined for their dependence on weather situations. It is found that days with beginning weather perturbations after an anticyclonic phase show a significant increase of the number of deaths. It will be necessary to verify the results of these statistical correlations by different other methods.

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Résumé L'auteur étudie la corrélation entre 1257 cas de décès officiellement enregistrés et exactement datés (la plupart jusqu'à l'heure du décès) du district de Sonthofen dans l'Allgäu en 1951 et 1952 ainsi que les relevés horaires du temps météorologique. Les ensembles statistiques partiels correspondant à des ascendances frontales, des situations pseudolabiles, des passages frontaux, des cas de foehn et de subsidence révèlent des augmentations infra-aléatoires de décès lors des glissements ascendants frontaux, des fronts froids et des occlusions et une diminution lors du foehn cyclonal. Ce n'est qu'en considérant une marge de temps restreinte autour de ces phénomènes météorologiques que l'on obtient des augmentations supra-aléatoires des décès lors des passages frontaux, de la pseudolabilité, des glissements ascendants et des irruptions du foehn. Une méthode statistique spéciale (méthode den) fait apparaître des maxima de fréquence au voisinage des fronts froids et des processus pseudolabiles; lors des fronts chauds et du foehn, ces maxima infra-aléatoires se placent avant le phénomène. Une comparaison des résultats provenant de différentes méthodes d'investigation fait croire à une influence sur les décès plus probable dans le cas des fronts froids, des occlusions et des processus pseudolabiles que dans celui des fronts chauds et du foehn cyclonal. Enfin on étudie les jours à indice de mortalité élevé en rapport avec le temps; il s'avère que les jours de début de perturbations après un stade anticyclonique coïncident avec des fréquences de décès supra-aléatoires. Il apparaît nécessaire de vérifier les résultats de recherches de ce genre par l'application de plusieurs méthodes d'analyse.

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Mit 1 Textabbildung.     

The ethnocultural component of tourism development in the Altai Republic

A characterization is provided for the recreation resources of the Altai Republic. The diversity of the national-ethnical composition of the population of the Altai Republic is determined as well as analyzing the spatial distribution of the ethnoses on its territory. The coefficients of ethnical diversity are calculated for all administrative districts. The territories with a different level of ethnical diversity and a different combination of ethnical groups are determined. The study revealed a connection of ethnical diversity and natural conditions of the territory and the concentration of separate ethnoses in definite landscapes. A characterization is provided for the ethnocultural tourism and recreation resources of the Altai Republic within the context of administrative districts. Information is provided concerning the territorial distribution of separate ethnical groups, traditional kinds of their nature management, religion, main national dishes, elements of national costume, national festivities and rites, etc. An analysis of the spatial distribution of the ethnocultural recreation resources identified promising clusters (nodes) or destinations for the arrangement of special ethnocultural tourist routes. Schematic maps are provided, which display the ethnical diversity in the districts of the region, and promising districts for the organization of ethnocultural tourist routes.     

Linking Tarim Basin sea retreat (west China) and Asian aridification in the late Eocene

The Tarim Basin in western China formed the easternmost margin of a shallow epicontinental sea that extended across Eurasia and was well connected to the western Tethys during the Paleogene. Climate modelling studies suggest that the westward retreat of this sea from Central Asia may have been as important as the Tibetan Plateau uplift in forcing aridification and monsoon intensification in the Asian continental interior due to the redistribution of the land‐sea thermal contrast. However, testing of this hypothesis is hindered by poor constraints on the timing and precise palaeogeographic dynamics of the retreat. Here, we present an improved integrated bio‐ and magnetostratigraphic chronological framework of the previously studied marine to continental transition in the southwest Tarim Basin along the Pamir and West Kunlun Shan, allowing us to better constrain its timing, cause and palaeoenvironmental impact. The sea retreat is assigned a latest Lutetian–earliest Bartonian age (ca. 41 Ma; correlation of the last marine sediments to calcareous nannofossil Zone CP14 and correlation of the first continental red beds to the base of magnetochron C18r). Higher up in the continental deposits, a major hiatus includes the Eocene–Oligocene transition (ca. 34 Ma). This suggests the Tarim Basin was hydrologically connected to the Tethyan marine Realm until at least the earliest Oligocene and had not yet been closed by uplift of the Pamir–Kunlun orogenic system. The westward sea retreat at ca. 41 Ma and the disconformity at the Eocene–Oligocene transition are both time‐equivalent with reported Asian aridification steps, suggesting that, consistent with climate modelling results, the sea acted as an important moisture source for the Asian continental interior.     

Electric sector investments under technological and policy-related uncertainties: a stochastic programming approach

Although emerging technologies like carbon capture and storage and advanced nuclear are expected to play leading roles in greenhouse gas mitigation efforts, many engineering and policy-related uncertainties will influence their deployment. Capital-intensive infrastructure decisions depend on understanding the likelihoods and impacts of uncertainties such as the timing and stringency of climate policy as well as the technological availability of carbon capture systems. This paper demonstrates the utility of stochastic programming approaches to uncertainty analysis within a practical policy setting, using uncertainties in the US electric sector as motivating examples. We describe the potential utility of this framework for energy-environmental decision making and use a modeling example to reinforce these points and to stress the need for new tools to better exploit the full range of benefits the stochastic programming approach can provide. Model results illustrate how this framework can give important insights about hedging strategies to reduce risks associated with high compliance costs for tight CO₂ caps and low CCS availability. Metrics for evaluating uncertainties like the expected value of perfect information and the value of the stochastic solution quantify the importance of including uncertainties in capacity planning, of making precautionary low-carbon investments, and of conducting research and gathering information to reduce risk.