Über die Bearbeitung von Strombeobachtungen von mehr als fünfzehn Tagen Dauer     

Heinrich Neumann 《Ocean Dynamics》1960,13(5):209-225

  相似文献   

Measures taken by the authorities of the vulcanological survey to safeguard the population from the consequences of volcanic outbursts     

M. Neumann Van Padang 《Bulletin of Volcanology》1960,23(1):181-192

  相似文献   

Geology and mineralogy of the Cu−Ni−Co−U ore deposits at Talmessi and Meeskani,central Iran     

Prof. Dr. M. Tarkian  Dipl.-Geol. W. D. Bock  Dipl.-Geol. M. Neumann 《Mineralogy and Petrology》1983,32(2-3):111-133

  相似文献   

Petrology and geochemistry of Jurassic basalt dykes from Vestfjella, Dronning Maud Land, Antarctica     

Herald Furnes  Else-Ragnhild Neumann  Bjrn Sundvoll 《Lithos》1982,15(4):295-304

Mineral and whole rocks analyses of 12 Jurassic basalt dykes from Vestfjella, Dronning Maud Land, Antarctica, are presented, and their genesis discussed. On the basis of major oxides and norms the basalts may be classified as olivine and quartz tholeiites. Plotted in the Plag---Cpx---(Opx + 4Q) and Ol---Plag---Q projections, the compositions are most compatible with fractional crystallization of olivine, clinopyroxene and plagioclase from a basalt liquid at very low pressure. The ratios between strongly incompatible elements such as Rb, Cs, Zr, Hf, Ta and Th vary considerably, and petrographic mixing calculations give poor fits with respect to Rb, Cs, Ta, Th and light REE. Initial ⁸⁷Sr/⁸⁶ Sr ratios range between 0.70347 and 0.70687, and show no correlation with Rb/Sr or any other SIE ratios. The trace element and Sr isotope data thus do not suggest any simple cogenetic petrogenetic model. It is concluded that the basalt melts most plausibly have been contaminated by, or mixed with anatectic melts of crustal material, rather than reflecting mantle heterogeneity.  相似文献   

The Validity of Similarity Theory in the Roughness Sublayer Above Forests   总被引：1，自引：0，他引：1  

I. J. Simpson  G. W. Thurtell  H. H. Neumann  G. Den Hartog  G. C. Edwards 《Boundary-Layer Meteorology》1998,87(1):69-99

Flux-gradient relationships based upon similarity theory have been reported to severely underestimate scalar fluxes in the roughness sublayer above forests, as compared to independent flux estimates (for example, eddy covariance or energy balance measurements). This paper presents the results of a unique three-month investigation into the validity of similarity theory in the roughness sublayer above forests. Eddy covariance and flux-gradient measurements of carbon dioxide (CO²) exchange were compared above a mixed deciduous forest at Camp Borden, Ontario, both before and after leaf senescence. The eddy covariance measurements used a Li-Cor infrared gas analyzer, and the flux-gradient (similarity theory) measurements featured a tunable diode laser Trace Gas Analysis System (TGAS). The TGAS resolved the CO² concentration difference to 300 parts per trillion by volume (ppt) based upon a half-hour sampling period. The measured enhancement factor (the ratio of independent flux estimates, in this case eddy covariance, to similarity theory fluxes) was smaller and occurred closer to the canopy than in most previous investigations of similarity theory. Very good agreement between the eddy covariance and similarity theory fluxes was found between 1.9 and 2.2 canopy heights (h^c), and the mean enhancement factors measured before and after leaf senescence were 1.10 plusmn; 0.06 and 1.24 ± 0.07, respectively. Larger discrepancies were measured closer to the canopy (1.2 to 1.4 h^c), and mean enhancement factors of 1.60 ± 0.10 and 1.82 ± 0.11 were measured before and after leaf senescence, respectively. Overall, the Borden results suggest that similarity theory can be used within the roughness sublayer with a greater confidence than previously has been believed.  相似文献   

The Algoma-type iron-formations of the Nigerian metavolcano-sedimentary schist belts     

A. Mücke  A. Annor  U. Neumann 《Mineralium Deposita》1996,31(1-2):113-122

Field relationships as well as petrographical and geochemical considerations form the basis of a model for the origin of the protoliths of the iron-formations and the associated phyllitic host rock of the Palaeoproterozoic schist belts of northern Nigeria. The iron-formations which consist of both the magnetite-subfacies and silicatefacies occur as relatively small, sporadic tabular bodies throughout the belts. They are concordantly interbanded with metasedimentary phyllites with which they share common metamorphic and deformational imprints. The iron-formations have high contents of Mn, Ca, Fe and P₂O₅ and low concentrations of alkalis (Na,K, Rb) Ba and Sr, Ti, Al and Si, whereas the phyllite exhibits exactly the opposite character. These results and other features (e.g. the composition of tourmaline in the phyllite and the occurrence of hydroclastic Cr-Mn-spinel and sulphides in the iron-formation) indicate a supply of materials from two different sources to the marine basin of Nigeria probably during Birimian time: slow but continuous deposition of continentally derived material of pelitic to psammitic composition; and rapid, sometimes intermittent, sporadic pulses of submarine-volcanic exhalations. During regional metamorphism (probably of Eburnian age) at greenschist to lower amphibolite fades conditions, the continental materials were transformed into phyllites and the mudstone-like sediments derived from volcanic exhalations into iron-formations. In the northern Nigerian schist belts two types of metamorphic parageneses in the iron-formations are recognized, both with various subtypes and without transitions between these two facies: (1) silicate-rich parageneses without magnetite (silicatefacies) and (2) magnetite-rich parageneses (magnetite-subfacies). In contrast to these parageneses, the iron-formations in the higher-grade metamorphic terrains of central Nigeria turn out to be hematitic (hematite-subfacies), and are derived from magnetite-bearing iron-formations by a second tectono-metamorphic event of Pan-African age (Mücke and Annor 1993). Whole-rock analyses of the Nigerian iron-formations explain the abundance of garnet (mainly spessartine) and clearly show that the formation of metamorphic minerals depended not only on temperature and pressure but also on the existing redox conditions. These environmental conditions controlled the formation of either magnetite parageneses (low redox conditions) or silicate parageneses without magnetite (high redox conditions). The environmental conditions are also an indication that magnetite (and hematite) could not have been constituents of the original sedimentary protolith of the Nigerian schist belts, but are exclusively of metamorphic origin.  相似文献   

Olivine clinopyroxenite xenoliths in the Oslo Rift,SE Norway   总被引：1，自引：0，他引：1  

E. -R. Neumann  T. Andersen  E. W. Mearns 《Contributions to Mineralogy and Petrology》1988,98(2):184-193

Olivine clinopyroxenite xenoliths in a basalt flow at Krokskogen in the Oslo rift consist mainly of Al-Ti-rich clinopyroxene and alteration products after olivine (possibly also orthopyroxene). The clinopyroxene contains primary inclusions of Cr-Al-bearing titanomagnetite, pyrite and devitrified glass, and secondary fluid inclusions rich in CO₂. On the basis of petrography, mineral compositions and bulk major and trace element chemistry, it is concluded that the xenoliths represent cumulates with about 5% trapped liquid, formed from a mildly alkaline basaltic magma. Microthermometrical analysis of secondary or pseudosecondary fluid inclusions give a minimum pressure of formation of 5.5 to 6 kbars, that is a depth greater than 16–17 km. The host lava has initial _Nd=+4.16±0.17 and _Sr=–5.50±0.26, which is believed to reflect the isotopic composition of the lithospheric mantle source region under south Norway in early Permian time. The isotopic character of the magma which gave rise to the xenoliths is preserved in clinopyroxenes which have _Nd ^t =+1.9 to +2.6 and _Sr ^t = –1.1 to –1.8. The isotopic differences between the host magma and the xenoliths reflect some degree of crustal contamination of the xenolith's parent magma.The xenoliths of this study represent an important source of information about the large masses of dense cumulates found at depth in the crust under the Oslo rift.  相似文献   

Influence of foliar density and thermal stability on profiles of Reynolds stress and turbulence intensity in a deciduous forest   总被引：4，自引：7，他引：4  

R. H. Shaw  G. Den Hartog  H. H. Neumann 《Boundary-Layer Meteorology》1988,45(4):391-409

Observations were made of turbulence in an extensive deciduous forest on level terrain using a vertical array of seven three-dimensional sonic anemometer/thermometers within and above the canopy. Data were collected through the period of leaf fall and over a range of thermal stabilities. A bulk canopy drag coefficient was nearly independent of the density of the forest but decreased greatly with the onset of nocturnal stability. The depth of penetration of momentum into the forest increased with leaf fall but, again, was greatly curtailed by stable conditions. Turbulent velocities decreased with increasing depth in the forest but relative turbulence intensities increased to mid-canopy levels. Leaf density influenced turbulence levels but not as strongly as did thermal stability. Thermal effects were adequately described by the single parameter h/L, where h is the canopy height and L is the Monin-Obukhov length. The longitudinal and vertical velocity correlation coefficient was larger in magnitude than expected in the upper layers of the forest but decreased to a small value in the lowest layers where the Reynolds stress was small. The ratio _w /u ^*, where u ^* is the local friction velocity, reflected changes in the uw correlation, becoming smaller than usual in the upper canopy layers. It is believed that these effects result from the intermittent, spatially coherent structures that are responsible for a large fraction of the momentum flux to the forest.  相似文献   

不同初值对台风路径预报的影响          下载免费PDF全文

徐一鸣  C.J.Neumann  A.C.Pike 《气象学报》1988,46(1):97-101

统计及数值模式客观预报已作为当今发布要素预报的重要参考依据,而制作客观预报的基础是初始资料及初始场的分析。气象场的客观分析方法有很多种,主要的有多项式插值法、遂次订正法、变分技术法、特征函数展开法,和统计插值法等。对于客观分析结果的一些特征近年来曾有过不少的研究。例如,对于美国国家气象中心的Hough函数业务客观分析(特征函数展开法的一种)的研究发  相似文献   

Climatic change as a topic in the classical Greek and Roman literature     

J. Neumann 《Climatic change》1985,7(4):441-454

A search was made of the classical Greek and Roman literature for references to climatic change, irrespective whether facts of observation or views. It was found that several scholars/scientists of the classical antiquity made pronouncements on the subject and their statements are either summarized or quoted verbatim in this paper. From the Greek literature we quote Plato, Aristotle and Theophrastus; Herodotus is also quoted for an indirect reference to the topic. From the Roman literature we cite the agricultural writer Columella and the scientist Pliny the Elder; actually, Columella quotes the distinguished writers on husbandry, the Sasernas, father and son.Aristotle's statement is relevant to a degree to the Mycenaean drought (~ 1200 B.C.) problem. The Columella-Saserna pronouncement relates to the astronomical theory of climatic change, while Theophrastus discusses man-made climatic changes.Appendix I gives a statistics of storms, as gleaned from the classical literature, covering approximately the months April–October. Further, it lists some pointers to the relative coolness of the era 850/800–400/300 B.C. in some areas of the Mediterranean. Appendix II offers a few examples for the usefulness of the ancient literature from the point of view of environmental data or events.Now visiting with the Department of Meteorology, The University of Helsinki, Helsinki, Finland.  相似文献