Decision bias in marine spatial planning of offshore wind farms: Problems of singular versus cumulative assessments of economic impacts on fisheries     

Jörg Berkenhagen  Ralf Döring  Heino O. Fock  Matthias H.F. Kloppmann  Søren A. Pedersen  Torsten Schulze 《Marine Policy》2010

The current approval procedure for wind farm proposals in the German EEZ only considers site specific conflict analysis between the wind farm and fisheries. Due to the relatively small spatial coverage of the sites potential opportunity losses to the fisheries are always considered as low or negligible. Cumulative effects on fisheries that will occur once all proposed wind farms are in place are not yet considered adequately. However, those cumulative effects will be quite substantial because, in particular, opportunities to catch such valuable species as flatfish will be considerably reduced.  相似文献   

Chemical and isotopic (B, Sr) composition of alluvial sediments as archive of a past hydrothermal outflow     

M. Pennisi  G. Bianchini  W. Kloppmann  A. Muti 《Chemical Geology》2009,266(3-4):123-134

The geochemical and isotopic signature of Quaternary alluvial sediments filling a post-orogenic basin along the Tyrrhenian coasts of Italy (Cornia Plain, Tuscany) was investigated to unravel possible interactions with geothermal fluids from the Larderello geothermal field. Two cores located in the upper (UCP) and lower (LCP) sector of the plain were sampled to depths of up to 80 m. A third core in a neighbouring area not affected by geothermal activity was also sampled (Arno plain at Pisa), and its sediment composition was used as reference. The Cornia sediments (fraction < 65 μm) show high B, Cs and Sb concentrations related to a peculiar chemical enrichment of the clay fraction. They also show remarkable enrichments in As (up to 1000 μg g^− 1) reflecting a contribution from local ore deposits.⁸⁷Sr/⁸⁶Sr ratios, ranging from 0.71022 to 0.71698, reveal the nature of the weathered mother rocks of the alluvial sediments, whereas the boron isotopic composition, varying from − 20‰ to − 10‰, suggests an interaction between the clay fraction and boron-rich fluids at temperatures greater than 50 °C. This implies that hydrothermal fluids widely circulated within the Cornia basin in the past, ultimately leading to the geochemical anomalies currently recorded in local sediments.Although natural (geogenic) in origin, these anomalies cause severe problems to the regional water management (groundwater exploitation) through leaching of trace elements into circulating groundwater, a phenomenon which has to be carefully studied and monitored.  相似文献   

Description of the larval stage of Drusus mixtus (Pictet, 1834) (Trichoptera: Limnephilidae: Drusinae) with notes on its ecology and zoogeography     

Johann Waringer  Wolfram Graf  Thomas Pitsch  Steffen U. Pauls  Ana Previši?  Mladen Ku?ini? 《Limnologica》2011,41(3):249-255

In the Swiss Jura adults of Drusus mixtus and unknown Drusinae larvae which could not be identified with existing keys were sampled. Based on ripe pupae, the unknown larvae were identified as D. mixtus. The association was confirmed by specimen rearing in aquaria.Based on morphology, larvae of D. mixtus key out together with Drusus croaticus in existing keys. D. mixtus is separated from the latter species by the shape of the anteromedian metanotal sclerites which are broadly triangular, whereas in D. croaticus the sclerites are almost parallel-sided, resembling a stretched rectangle. In addition, the two species are geographically well separated: D. croaticus is restricted to the confines of Croatia and Slovenia, whereas D. mixtus is only present in Switzerland and eastern France. With this present paper, all Central European Drusinae species except Drusus chapmani McL, 1901, (France, Switzerland) and D. noricus Malicky, 1981, an endemic from the Saualpe (Carinthia, Austria), are known in the larval stage.  相似文献   

Coronal holes and icosahedral symmetry     

Herbert Kalisch  Wolfram Neutsch  Horst Fichtner  S. Ranga Sreenivasan  Maurice Shevalier 《Astrophysics and Space Science》2003,288(4):445-469

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

Jelle G. Van Minnen  Joseph Alcamo  Wolfram Haupt 《Climatic change》2000,46(3):317-338

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.  相似文献   

Expanding envelopes of binary stars     

Wolfram Neutsch  Hans Schmidt 《Astrophysics and Space Science》1985,109(2):249-257

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).  相似文献   

Neue Betrachtungen über Zementationsfaktoren und ihre Bedeutung für geoelektrische Untersuchungen     

Univ.-Doz. Dr. Wolfram Bitterlich  Dr. Hans Wöbking 《Meteorology and Atmospheric Physics》1970,19(2):211-225

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Area-preserving Poincaré mappings of the unit disk     

Wolfram Neutsch  Josef Kallrath 《Celestial Mechanics and Dynamical Astronomy》1987,43(1-4):185-191

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.  相似文献   

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

Julian Wolfram  Graham Feld 《Applied Ocean Research》1995,17(6):363-378

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.  相似文献   

Effect of sampling rate on wave height statistics     

Paul Stansell  Julian Wolfram  Brian Linfoot 《Ocean Engineering》2002,29(9):1023-1047

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.  相似文献