Kranke Meere? Verschmutzung und ihre Folgen     

Joachim W. Dippner 《Ocean Dynamics》1993,45(4):279-280

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Cusps in cold dark matter haloes     

Jürg Diemand  Marcel Zemp  Ben Moore  Joachim Stadel  Marcella Carollo 《Monthly notices of the Royal Astronomical Society》2005,364(2):665-673

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The Institute of Geography and Geoecology of the Academy of Sciences     

Prof.Dr. Joachim Heinzmann 《GeoJournal》1990,22(2):205-207

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Leptonic jets from young stellar objects?     

Hans Joachim Blome  Wolfgang Kundt 《Astrophysics and Space Science》1988,148(2):343-361

Various explanations of the bipolar-flow phenomenon in star-forming regions are compared and confronted with the observed facts. It is concluded that stellar-wind interpretations are inconsistent with the constraints. The exotic property of young stellar objects may be their extreme spin which implies strong magnetic fields and vacuum discharges above thee ^± pair-formation threshold (of 10¹² eV). Pair-plasma jets are thought to be centrifugally driven by young stars during their first 10^4±1 years of rapid rotation.  相似文献   

SST anomalies in the north sea in relation to the North Atlantic Oscillation and the influence on the theoretical spawning time of fish     

Joachim W. Dippner 《Ocean Dynamics》1997,49(2-3):267-275

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Sediment-chemistry response to land-use change and pollutant loading in a hypertrophic lake, southern Sweden   总被引：3，自引：0，他引：3  

Siv Olsson  Joachim Regnéll  Anders Persson  Per Sandgren 《Journal of Paleolimnology》1997,17(3):275-294

Responses to recent land-use changes and pollutant loading in the sediment of a hypertrophic lake in southern Sweden were studied by comparison of geochemical, pollen and magnetic records with historical land-use data. A chronology was constructed for the last two centuries by correlating changes in the pollen diagram to major events in the land-use history. Sediment accumulation was low (mean c. 0.2 g cm^-2 yr^-1) prior to 1800 AD, when less than 25% of the catchment was arable land. Reorganization of the agrarian system during the 19th century increased the annually tilled area by 300%, which accelerated soil erosion and substantially increased the accumulation of allochtonous matter in the lake. Since the turn of the century 90% of the catchment has been ploughed every year. The deposition of clastic matter in the lake has, however, decreased due to a gradual rerouting of the drainage system, which has reduced the effective catchment area by c. 85%.Authigenic vivianite (Fe3(PO4)2.8H2O) is a major P phase in the preindustrial non-sulphidic sediments, which suggests that the sediments at that time served as a fairly efficient sink for P. The arable expansion, increased manuring and, eventually, the introduction of artificial fertilizers during the 19th century led to a massive influx of nutrients, which elevated primary production in the lake. Subsequent development of bottom water anoxia around 1900, in combination with an additional pollutant burden of sulphate within the lake basin, led to major alterations of the biogeochemical cycles. The most critical change in the post-1900 sediments involved the cycling of Fe and P. The linkage between the lacustrine P and Fe cycles can explain that FeS formation was paralleled by a release of P from the sedimentary pool. This supply of P to the lake basin must have supplemented the nutrient supply by modern agriculture and contributed to recent hypertrophication. The bacterial sulphate reduction also affected the generation of alkalinity which supported a significant calcite precipitation in the post-1900 sediments.S is enriched 10-fold in the post-1900 sediments compared to preindustrial values. Along with the rise in S, soot particles derived from fossil fuel combustion appear in the sediments for the first time. Therefore, Bussj¨osj¨on is thought to be a good example of how a well-buffered, highly productive lake may respond to the pollution by sulphur from acid rain.  相似文献   

Heterogeneously nucleated calcite precipitation in Lake Constance. A short time resolution study     

Jonna Küchler-Krischun  Joachim Kleiner 《Aquatic Sciences - Research Across Boundaries》1990,52(2):176-197

Calcite precipitation in spring 1988 in Lake Constance was studied by measuring physical, chemical and biological parameters in daily intervals. Algae triggering calcite precipitation in spring after an induction period of 1 day wereStephanodiscus hantzschii andChlorella spp. whereas no time lag concerning maximum saturation index was observed. Number and size distribution of crystals were determined by microscopical methods. Simple equations were given for estimation of the precipitated mass of calcite by approximating the volume of calcite crystals by simple geometric bodies and multiplying by crystal numbers. Particulate calcium was analysed after dissolving suspended matter and amounted to 90% of inorganic dry weight. Crystals were observed for the first time after dissolved phosphorus was no more detectable.  相似文献   

Comparison of ground temperature response of energy pile and borehole heat exchanger during thermal response tests     

Jin Luo  Haifeng Zhao  Shuqiqang Gui  Wei Xiang  Joachim Rohn 《Environmental Earth Sciences》2016,75(22):1463

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Big Data Analytics for Earth Sciences: the EarthServer approach   总被引：1，自引：0，他引：1  

Peter Baumann  Paolo Mazzetti  Joachim Ungar  Roberto Barbera  Damiano Barboni  Alan Beccati 《International Journal of Digital Earth》2016,9(1):3-29

Big Data Analytics is an emerging field since massive storage and computing capabilities have been made available by advanced e-infrastructures. Earth and Environmental sciences are likely to benefit from Big Data Analytics techniques supporting the processing of the large number of Earth Observation datasets currently acquired and generated through observations and simulations. However, Earth Science data and applications present specificities in terms of relevance of the geospatial information, wide heterogeneity of data models and formats, and complexity of processing. Therefore, Big Earth Data Analytics requires specifically tailored techniques and tools. The EarthServer Big Earth Data Analytics engine offers a solution for coverage-type datasets, built around a high performance array database technology, and the adoption and enhancement of standards for service interaction (OGC WCS and WCPS). The EarthServer solution, led by the collection of requirements from scientific communities and international initiatives, provides a holistic approach that ranges from query languages and scalability up to mobile access and visualization. The result is demonstrated and validated through the development of lighthouse applications in the Marine, Geology, Atmospheric, Planetary and Cryospheric science domains.  相似文献   

Quantitative Durchsichtigkeitsmessungen im Meere     

Joachim Joseph 《Ocean Dynamics》1950,3(3-4):214-219

Zusammenfassung Mit Durchsichtigkeitsmessungen wird die durch Absorption und Streuung verursachte Gesamtextinktion eines Lichtstrahls im Meerwasser erfat. Als Mazahl der Extinktion eignet sich der physikalische Extinktionskoeffizient. Dem Ziel, geräteunabhängige absolute Mewerte zu erhalten, kann man im sichtbaren Teil des Spektrums durch Eichung der. Durchsichtigkeitsmegeräte mit einem Pulfrich-Photometer näher kommen. Doch bleibt die Genauigkeit der Mewerte besonders durch die Schwerpunktsverschiebungen, die für verschiedene mittlere Durchlässigkeiten des Meerwassers berechnet und tabellarisch zusammengestellt werden, und durch die technischen Eigenschaften der Megeräte und Photoelemente beschränkt. Es wird ein Meprinzip angegeben, das diese Nachteile weitgehend vermeidet und gestattet, auch im UV absolute Extinktionswerte in exakt definierten Punkten des Spektrums zu messen.

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Quantitative measurements of transparency in the sea

Summary The total extinction of a ray of light in sea water caused by absorption and scattering is ascertained by measuring the transparency. The physical extinction coefficient is suitable to act as an indicator of extinction. In the visible part of the spectrum, it is possible to obtain approximately absolute measurements not influenced by the instruments used, by standardizing the transparency-meters with the aid of a Pulfrich-Photometer. The accuracy of the measurements continues, however, to be limited in particular by the shifting of the centres which are calculated and tabulated for various mean values of transparency of sea water, as well as by the technical properties of the instruments and the rectifier photocell. A principle for measuring transparency free of these deficiencies to a large extent and allowing the measurement of absolute extinction values at exactly defined points of the spectrum, including the ultra-violet, is described.

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Herrn Prof. Dr. G. Wüst gewidmet zum 60. Geburtstag.  相似文献