Linking past flood frequencies in Norway to regional atmospheric circulation anomalies

Analysis of two continuous, high‐resolution palaeo‐flood records from southern Norway reveals that the frequency of extreme flood events has changed significantly during the Holocene. During the early and middle Holocene, flood frequency was low; by contrast, it was high over the last 2300 years when the mean flood frequency was about 2.5–3.0 per century. The present regional discharge regime is dominated by spring/summer snowmelt, and our results indicate that the changing flood frequency cannot be explained by local conditions associated with the respective catchments of the two lakes, but rather long‐term variations of solid winter precipitation and related snowmelt. Applying available instrumental winter precipitation data and associated sea‐level pressure re‐analysis data as a modern analogue, we document that atmospheric circulation anomalies, significantly different from the North Atlantic Oscillation (NAO), have some potential in explaining the variability of the two different palaeo‐flood records. Centennial‐scale patterns in shifting flood frequency might be indicative of shifts in atmospheric circulation and shed light on palaeo‐pressure variations in the North Atlantic region, in areas not influenced by the NAO. Major shifts are found at about 2300, 1200 and 200 years ago (cal. a BP). Copyright © 2011 John Wiley & Sons, Ltd.     

Activity-composition relations in FeTiO3-MnTiO3 ilmenite solid solutions from EMF measurements at 1050–1300 K

The activity of FeTiO₃ in the binary ilmenitepyrophanite (FeTiO₃-MnTiO₃) solid solution has been determined for the temperature range 1050–1300 K by displacement of the reaction: 2 FeTiO₃=2 Fe+2 TiO₂+O₂ in T-O₂ space, using an electrochemical technique with calcia- and yttria-stabilized zirconia solid electrolytes. The activities show small positive deviations from ideality, which, although the data are unusually precise, may be perfectly described by the simple regular solution model, with an interaction parameter, W _Fe-Mn ^ilm , of 2.2±0.3 kJ g-atom^–1, which is independent of temperature. This value, together with the experimental data on the partitioning of Fe and Mn between ilmenite and garnet (Pownceby et al. 1987), gives W _Fe-Mn ^gt =1.2±0.5 kJ g-atom^–1 for the almandine-spessartine (Fe₃Al₂Si₃O₁₂-Mn₃Al₂Si₃O₁₂) solid solution.     

Versuch der Geschlechtsbestimmung beim Wels,Silurus glanis L., mit Hilfe der Diskriminanzanalyse von Brustflossendaten

Width of the first ray of the pectoral fin has been measured in two places for 154 young and 89 adult wels. Statistical relationships between the above characters and fish length as well as its maturity and sex have been proved. Three models of discriminant function for identification of adult fish sex have been derived and verified. The accuracy of sex separation has been 89,5% in a standard sample of wels, and 90,6% in a routine sample, after an adjustment in the procedure.     

Motion of salt water and associated fronts in tideless estuaries

The hydrodynamics of saline water in Polish estuaries are addressed in this paper. The phenomena are described on the basis of field data from several types of estuaries along the Polish Baltic Coast. Field measurements were made to reveal and to characterize the physical processes in these estuaries; this information was then used for analytic testing and verification of mathematical models. The results demonstrate the unsteady and changeable nature of both the flow conditions and the motion of salt water in tideless estuaries. The magnitudes and directions of the barotropic and baroclinic horizontal pressure gradients have a marked influence on the flow characteristics and motion of salt water in these tideless estuaries.     

Uranium and thorium in the Kupferschiefer formation,Lower Zechstein,Poland

The Kupferschiefer in Poland has an increased U content. The facies high in organic matter are significantly enriched in U. The maximum values of U are mostly in the lower part of the Kupferschiefer sequence. The mean (x) U content in the Kupferschiefer from the Lubin-Sieroszowice district is 61.5 ppm and from the rest of the Polish Zechstein basin is about 26 ppm. Thorium occurs only in small quantities (x) = 1.5 and 5 ppm respectively). The high variance of U and Th in the Kupferschiefer is due to multistage diagenetic processes. The main U carrier is thucholite. The investigated thucholite showed a Th-content below 0.36 ppm. Thucholite with uraninite exolutions showed small (up to 1.0 wt.%) admixtures of U and thucholite without microscopically visible exsolutions (up to 37.85 wt.% U). The phosphates showed significant amounts of U (up to 0.24 wt.). The U content in the Kupferschiefer is significantly lower than in black shales from other part of the world. Uranium in the Lubin district is not economic.     

Temperature dependence of the cation distribution in nickel aluminate (NiAl2O4) spinel: a powder XRD study

NiAl₂O₄ is a largely inverse spinel, which in detail shows increasing randomisation with temperature of Ni and Al between the octahedral and tetrahedral cation sites of the spinel structure. We have used powder XRD to determine this cation distribution in various samples of NiAl₂O₄ quenched after annealing between 700 and 1400° C. The inversion parameter (x) can be measured with a precision of ± 0.004 (one standard deviation), and a comparison of different methods of synthesis, X-ray diffraction and refinement techniques, suggests a probable accuracy of better than 0.01. The results are supported by some preliminary single crystal refinements on flux-grown samples.Below 800° C the rate of cation ordering becomes very slow, and, despite reaching an apparently steady state, it is doubtful if our samples attained complete internal equilibrium. Above 1250° C the cation redistribution becomes so fast that the quenching method becomes unreliable. Between 800 and 1250° C inclusive, the degree of inversion changes smoothly from 0.87 at 800° C to 0.79 at 1250° C, and is accompanied by linear changes in u, the oxygen parameter, from 0.2555 to 0.2563 (±0.0002), and a₀, the lattice parameter, from 8.0462 to 8.0522 Å (±0.0002 Å).     

Fast-changing processes in a medium subject to loading as detected by resistivity measurements

Making measurements of electric resistivity at 16 s intervals, the authors noticed fast changes of this parameter prior to the occurrence of the main fracture. The changes are superposed on bay pulsations of increasing amplitude and decreasing period. This finding opens prospects for a wider use of an electric resistivity method and proves the high quality of automatic instruments, in particular their high resolution. It also gives evidence for the occurrence of short-period precursors in the fracture zone while the main fracture is being formed.