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21.
Barthel Roland Haaf Ezra Giese Markus Nygren Michelle Heudorfer Benedikt Stahl Kerstin 《Hydrogeology Journal》2021,29(5):1693-1709
Hydrogeology Journal - A new concept is proposed for describing, analysing and predicting the dynamic behaviour of groundwater resources based on classification and similarity. The concept makes... 相似文献
22.
Roland Schmidt Kaarina Weckström Stefan Lauterbach Richard Tessadri Kerstin Huber 《第四纪科学杂志》2012,27(1):40-50
High‐resolution multi‐proxy analyses of a sediment core section from Lake Jeserzersee (Saissersee) in the piedmont lobe of the Würmian Drau glacier (Carinthia, Austria) reveal pronounced climatic oscillations during the early late glacial (ca. 18.5–16.0k cal a BP). Diatom‐inferred epilimnetic summer water temperatures show a close correspondence with temperature reconstructions from the adjacent Lake Längsee record and, on a hemispheric scale, with fluctuations of ice‐rafted debris in the North Atlantic. This suggests that North Atlantic climate triggered summer climate variability in the Alps during the early late glacial. The expansion of pine (mainly dwarf pine) between ca. 18.5 and 18.1k cal a BP indicates warming during the so‐called ‘Längsee oscillation’. The subsequent stepwise climate deterioration between ca. 18.1 and 17.6k cal a BP culminated in a tripartite cold period between ca. 17.6 and 16.9k cal a BP with diatom‐inferred summer water temperatures 8.5–10 °C below modern values and a shift from wet to dry conditions. This period probably coincides with a major Alpine glacier advance termed the Gschnitz stadial. A warmer interval between ca. 16.9 and 16.4k cal a BP separates this cold phase from a second, shorter and less pronounced cold phase between ca. 16.4 and 16.0k cal a BP, which is thought to correlate with the Clavadel/Senders glacier advance in the Alps. The following temperature increase, coupled with wet (probably snow‐rich) conditions, caused the expansion of birch during the transition period to the late glacial interstadial. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
23.
Nitric oxide profiles obtained from three flights of chemiluminescent instruments during the Globus '85 campaign held in France in the autumn of 1985 are reported. When the profile obtained in the early morning of 20 September is compared with the flight made the previous afternoon, an average morning to midday NO ratio of 0.7 for the region between 26 and 33 km is obtained. This value is in good agreement with theoretical studies involving the photolysis of N2O5 and the establishment of the NO2–NO equilibrium. 相似文献
24.
We report single grain and grain-domain U–Pb zircon ages for the Tojottamanselkä tonalitic gneiss previously investigated by the whole-rock Rb–Sr, Pb–Pb and Sm–Nd methods, by conventional U–Pb zircon density/size fraction analysis and by Hf-isotopes (Kröner et al. 1981; Patchett et al. 1981; Jahn et al. 1984) and established as one of the oldest known rocks of the Baltic shield. Our data confirm the intrusive age as 3115±29 Ma (standard error), but we also found slightly older xenocrystic zircon cores with 207Pb/206Pb ages between 3161±19 and 3248±10 Ma that may either be derived from earlier phases of the tonalite melt or from pre-tonalite sialic crust. New magmatic zircon growth, probably during a metamorphic event that led to migmatization, is recorded by an age of 2836±30 Ma and may be coeval with widespread tonalite emplacement elsewhere in the northern Baltic shield at about this time. 相似文献
25.
Sh. B. Akhmedov G. B. Gelfreikh F. Fürstenberg J. Hildebrandt A. Krüger 《Solar physics》1983,88(1-2):103-108
Model calculations of the S-component are compared with observations of the RATAN-600 telescope at five discrete microwave frequencies referring to active region McMath No. 15974 on May 1, 1979. The spectral variations of source diameter, flux density, and degree of polarization are used to derive the height scale of the magnetic field in accordance with a magnetic dipole distribution under the assumption of advanced temperature and electron density distributions according to most recent EUV observations. 相似文献
26.
Polarization measurements of type III bursts at 23.5 and 29.5 MHz have been compared for several years with indicators of magnetic fields in different height levels such as sunspot data, S-component characteristics, and noise storm data. By applying the Mount-Wilson and Brunner types of the related spot groups there results a positive relationship between the average degree of type III burst polarization and the magnitude or complexity of photospheric magnetic fields. For other parameters (leading spot area, peak intensity of the S-component at 9.1 cm wavelength) such a clear monotonic relation has not been found. Possibly the degree of polarization is influenced by height variations of the emitting level of the type III bursts at a fixed frequency due to variable electron densities. No connection has been detected between the type III burst polarization and noise storm fluxes which may be due to the local distance of the origin of both emissions. 相似文献
27.
J. Hildebrandt A. Krüger I.M. Chertok V.V. Fomichev R.V. Gorgutsa 《Solar physics》1998,181(2):337-349
Usually the gyrosynchrotron emission of microwave bursts from electron populations with a power-law (PL) energy distribution has been considered under the assumption that the spectral index of the distribution is constant over a wide range of energies. Meanwhile, there is strong evidence, in particular from hard X-ray and -ray, but also from cm/mm wavelength radio observations, that in many solar flare events the spectrum of the emitting electrons is characterized by a significant hardening at energies above 100–500 keV. We present some examples of calculated microwave burst spectra at cm/mm wavelengths taking into account the above evidence. It is shown that a break in the energy spectrum of the PL electrons can indeed result in a spectral hardening sometimes observed in microwave bursts at frequencies above 10–30 GHz. 相似文献
28.
Niranjan D. Chatterjee Ralf Krüger Gerd Haller Walter Olbricht 《Contributions to Mineralogy and Petrology》1998,133(1-2):149-168
An internally consistent thermodynamic dataset has been derived for 148 endmember phases (145 solids and 3 fluids) comprising
the elements Li, Na, K, Be, Mg, Ca, Ti, Cr, Mn, Fe, Zn, Al, Si, C, H, and O. This has been achieved by simultaneous treatment
of phase property (like standard enthalpy of formation, standard entropy, molar heat capacity, molar volume, thermal expansivity,
bulk modulus etc.) and reaction reversal data by the Bayesian method. The theory underlying the approach, and the computational
methods involved, are briefly outlined. (For the benefit of readers unfamiliar with inference statistics, the basic concepts
of the Bayes method are also presented in such a way that they can be grasped intuitively.) Although not yet addressed, this
method can be extended to refine the thermodynamic mixing properties of crystalline solutions. The sources of the input data,
culled from the literature, are summarized in the Appendix. The resulting database is succinctly documented in this paper.
It includes the enthalpies of formation and entropies, their uncertainties, and the correlation among them. The database allows
calculation of P-T, T-X
CO2, P-X
CO2, and T-f
O2 sections, with error propagation into the computed phase diagrams on a routine basis. A user-friendly computer program has
been written to generate such phase diagrams. It is public domain software. The software and the thermodynamic database (which
includes a complete documentation of the thermodynamic data above and beyond those listed (Table 2, here) may be downloaded from the web site
http://homepage.ruhr-uni-bochum.de/niranjan.chatterjee/Index.htm. Examples of computed phase diagrams are given to illustrate
the quality of the data and the capabilities of the software.
Received: 11 March 1998 / Accepted: 11 June 1998 相似文献
29.
Fred W. Krüger 《GeoJournal》1998,46(2):79-87
Namibia and Botswana differ from other sub-Saharan nations in their record of stable political performance. However, both
countries have to face increasing social problems. In the case of Namibia these are still mainly related to the process of
post-apartheid national reconciliation and identity building, in the case of Botswana they refer to issues of growing tribal
tensions and of a gradual interior restructuring of society. This paper analyzes the various patterns of social transformation
in the two countries and examines in what ways state-society relations are different from other African nations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
30.
We report on dust measurements obtained during the seventh orbit of the Galileo spacecraft about Jupiter. The most prominent
features observed are highly time variable dust streams recorded throughout the Jovian system. The impact rate varied by more
than an order of magnitude with a 5 and 10 hour periodicity, which shows a correlation with Galileo's position relative to
the Jovian magnetic field. This behavior can be qualitatively explained by strong coupling of nanometer-sized dust to the
Jovian magnetic field. In addition to the 5 and 10 h periodicities, a longer period which is compatible with Io's orbital
period is evident in the dust impact rate. This feature indicates that Io most likely is the source of the dust streams. During
a close (3,095 km altitude) flyby at Ganymede on 5 April 1997 an enhanced rate of dust impacts has been observed, which suggests
that Ganymede is a source of ejecta particles. Within a distance of about 25 RJ(Jupiter radius, RJ= 71,492 km) from Jupiter impacts of micrometer-sized particles have been recorded which could be particles on bound orbits
about Jupiter.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献