Detecting thermal anomalies within the Molasse Basin, southern Germany

The groundwater flow regime at great depth within the Molasse Basin (SW Germany) was studied. Data relevant for a flow model at 600–1,600 m depth are sparse in the western part of the basin. However, temperature measurements are available covering much of the area at a wide range of depths. Therefore, a thermal 3D steady-state model was set up with the aim of comparing modeled with observed subsurface temperatures. Stratigraphic information from many boreholes was also available, but only a few values of rock thermal conductivity and heat-production rate could be obtained. Some strong thermal residual anomalies were identified with respect to the purely conductive model, especially along fault zones, and within stratigraphic layers with high hydraulic conductivity. These anomalies can be explained by various advective heat-transport mechanisms, yet most explanations can be eliminated. The most plausible constellation explaining the major positive thermal anomalies of 10 Kelvin and more is a fault zone of E–W strike, intersected by an aquifer with flow parallel to the fault zone. This concept was investigated by using a simplified type model. In spite of some shortcomings, the method presented here can be used to identify temperature anomalies, and to identify possible explanations.     

Expanding envelopes of binary stars

In this paper which is a continuation of Neutsch and Schmidt (1985a) (later on referred to as part I) we shall investigate the structure of binary envelopes under the hypothesis that at least one of the companions produces a very intense radiation field. The limiting case in which the forces due to the system's rotation (i.e., Coriolis and centrifugal forces) as well as gas pressure can be neglected is solved analytically using a classical result of Euler. Beyond this the velocity and density distributions in the envelope are determined.Under the assumptions mentioned above, the results are exact and are, therefore, of value as a reference model for later more advanced considerations (see, e.g., Neutsch and Schmidt, 1985b). Although the present approach is quite simple, it nevertheless shows some typical features of the general case. Furthermore, it serves as a helpful guide in guessing the system parameters to be initially adopted in physically sounder. calculations (for example: the Monte-Carlo approximation which will be described in Part III).     

Area-preserving Poincaré mappings of the unit disk

The best way to investigate the long-time behaviour of dynamical systems is to introduce an appropriate Poincaré mapping P and study its iterates.Two cases of physical interest arise: Conservative and dissipative systems. While the latter has been considered by a great many authors, much less is known for the first one (according to Liouville's theorem, here the mapping leaves a certain measure in phase space invariant). In this paper, we concentrate our attention on compact phase spaces (or, rather, surfaces of section). This assumption is mathematically useful and physically reasonable.We consider the simplest possible (2-dimensional) systems whehre the phase space is the compact unit disk D in ². A family of simple area-preserving mappings from D onto itselves will be given and discussed in detail.It is shown that general characteristics of the dynamics are quite similar to those of e.g. the Hénon-Heiles system, while other features, as the structure of invariant curves, are different.     

Bias in the estimation of wave-induced fatigue damage of offshore structures

The most widely adopted approach for estimating the wave-induced fatigue damage of the tubular joints of offshore structures relies on a wave scatter diagram to characterise the wave environment. This paper shows that the commonly adopted approach to compiling the wave scatter diagram and the subsequent selection of characteristic individual wave height and period pairs for analysis purposes will almost invariably lead to bias in the estimation of fatigue lives. A statistical argument is developed to show the sources and nature of this bias. This is supported by fatigue calculations based on individual wave data collected in the northern North Sea. It is found that the current practice in most cases introduces a substantial conservative bias into estimated fatigue lives. An alternative procedure for producing wave scatter diagrams and selecting wave heights and periods for subsequent finite-element analysis is presented which should lead to unbiased (or at least much less biased) estimates of fatigue lives.     

Effect of sampling rate on wave height statistics

This paper examines the effects of digital processing, and therefore discretisation or sampling, of sea surface elevations that are, in reality, continuous. Using random linear wave theory, probability distributions for the measured (as opposed to actual) wave amplitudes and heights have been obtained which are conditional on the sampling rate. It is shown that with low sampling rates there are significant departures from the usual Rayleigh distribution. Rates of 1 Hz or less may lead to significant underestimation of the probability of very large waves. An analysis of full-scale measurements obtained from a platform in the North Sea supports these results.     

Deriving and Applying Response Surface Diagrams for Evaluating Climate Change Impacts on Crop Production

This paper presents the method to develop response surface diagrams (RSD) suitable to evaluate the impacts of climate change on potential crop production and crop area. The diagrams depict the response of different agricultural crops to average long-term changes in ambient temperature and precipitation on a country basis. They take into account the spatial and seasonal variability of climate, and differences in the climate response of important crops. RSDs for Germany and the Democratic Republic of Congo illustrate that countries and crop types differ greatly in their sensitivity to unit changes in long-term average climate. In comparing the area-weighted RSDs for Germany and Democratic Republic of Congo, it was found that the potential production in Germany of a weighted aggregation of crops is mainly sensitive to changes in temperature, whereas the potential crop production in the Democratic Republic of Congo mainly responds to changes in precipitation (over the specified ranges of climate variables). The RSDs can provide a visual overview of these varying sensitivities, and are a convenient and simple-to-understand method to summarize crop responses to climate change in a particular country.     

Review of Understanding of Earth’s Hydrological Cycle: Observations,Theory and Modelling

Water is our most precious and arguably most undervalued natural resource. It is essential for life on our planet, for food production and economic development. Moreover, water plays a fundamental role in shaping weather and climate. However, with the growing global population, the planet’s water resources are constantly under threat from overuse and pollution. In addition, the effects of a changing climate are thought to be leading to an increased frequency of extreme weather causing floods, landslides and drought. The need to understand and monitor our environment and its resources, including advancing our knowledge of the hydrological cycle, has never been more important and apparent. The best approach to do so on a global scale is from space. This paper provides an overview of the major components of the hydrological cycle, the status of their observations from space and related data products and models for hydrological variable retrievals. It also lists the current and planned satellite missions contributing to advancing our understanding of the hydrological cycle on a global scale. Further details of the hydrological cycle are substantiated in several of the other papers in this Special Issue.     

Kohlendioxid-Messungen in einem Durchfluß-Meßsystem mit einem neu entwickelten CO2-Sensor am Beispiel eines Hartwassersees (Willersinnweiher, Ludwigshafen am Rhein)

The concentrations of free dissolved carbon dioxide in lake water were measured with a newly developed CO₂ sensor, which was installed in a through-flow measurement system. The results of measurements demonstrate the CO₂ dynamics in lake Willersinnweiher. The CO₂ concentrations showed a correlation with the oxidation of CH₄ in the metalimnion and caused shifts in the carbonate system, thus affecting the autochthonous precipitation and dissolution of calcite.

From the results of measurement appears that the CO₂ sensor is capable of very exact measurements of dissolved free CO₂ in lake water. At the same time, the parameter is easily determined in the field without large expenditures.     

Petrologische Untersuchungen am Mauthausner Granit im österreichischen Moldanubikum

Zusammenfassung Der Mauthausner Granit bildet im österreichischen Moldanubikum eine Anzahl von gang- und stockförmigen Durchbrüchen. Er wurde an Hand von vier Vorkommen—Mauthausen selbst, Gloxwald (bei Sarmingstein), Plöcking und Schrems—einer detaillierten chemischen und mineralogischen Untersuchung unterzogen.Das Gestein ist ein Biotitgranit mit geringen Mengen primären Muskovits. Der Plagioklas (bis 38 Vol. %) besitzt einen progressiven und oszillatorischen Zonarbau, primäre und sekundäre Verzwillingung und einen durchschnittlichen An-Gehalt von An=20% (Plöckinger Granit An=25%). Der Alkalifeldspat (durchschnittlich 28 Vol. %) ist ein scharf gegitterter perthitischer Mikroklin (entmischte Phase Or=89%, >90) mit durchschnittlich Ab+15%. Der Biotit (ca. 10 Vol.%) bildet 2M₁ Polymorphe, ebenso der Muskovit (<1 Vol.%). Der Zirkon bildet zwei Typen verschiedener Herkunft; das Gestein ist hybrid. Aus den Komponentenanalysen ergeben sich als Bildungsbedingungen: relativ rasche Kristallisation bei steigendem pH₂O im Bereich von ca. 5000 bar, fallende Temperatur und fallender Belastungsdruck, was auf große Bildungstiefen hinweist. Die Intrusion erfolgte während der Plagioklaskristallisation und während des Abklingens der variskischen Regionalmetamorphose in eine relativ kühle Umgebung.

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Summary The Mauthausen granite belongs to the Moldanubian zone of Austria, and is represented by a number of dike-and plug-like minor intrusions. Four representative localities were chosen for a detailed chemical and mineralogical investigation (Mauthausen, Gloxwald near Sarmingstein, Plöcking and Schrems).The rock is a biotite granite with subordinated amounts of primary muscovite. The rock contains up to 38 vol.-% plagioclase which shows progressive and oscillatory zoning, primary and secondary twinning and an average An-content of 20% (Plöcking 25%). The alkali feldspar forms about 28 vol.-% of the rock. It is strongly cross-hatched microcline-perthite with average Ab 15%. Its unmixed potassium phase contains Or=89%, >90. Biotite (ca. 10 vol.-%) and muscovite (<1 vol.-%) are 2M₁ polymorphs. Investigations on zircons show types of different origin expressing a remarkable hybridity of the rock in question. From the analyses of the components the following conclusions elucidate: Relatively rapid crystallisation under increasing pH₂O around 5000 bar, falling temperature and load pressure. This indicates great depth of formation. The intrusion took place during the crystallisation of the plagioclase into a relatively cool surrounding. The time of intrusion can be fixed near the end of the variscian regional metamorphism.

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Mit 8 Textabbildungen

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Herrn Professor Dr.F. Machatschki zum 70. Geburtstag gewidmet.