Buchbesprechungen

Ohne Zusammenfassung     

Buchbesprechungen

Ohne Zusammenfassung     

The ARPEGE/IFS atmosphere model: a contribution to the French community climate modelling

A new atmospheric model has been developed jointly by Météo-France, and the European Centre for Medium-range Weather Forecasts (ECMWF) under the acronyms ARPEGE (action de recherche petite echelle grande echelle, which means research project on small and large scales) and IFS (integrated forecast system). This model includes, inter alia, an atmospheric general circulation model (GCM) which is intended by the French climate modelling community to be used for studying the anthropogenic climate impact. A preliminary version of this model has been available since 1992. This paper describes its main characteristics. Three 10-year integrations of this model having spectral horizontal resolutions of T21, T42, and T79 have been performed using prescribed monthly mean sea surface temperatures (SST) observed from 1979 until 1988. The results of these integrations are presented and compared with the observed climatology. The comparison is made for the winter (DJF) and summer (JJA) periods. It is shown that the model is capable of reproducing the observed climatology in a generally successful manner.     

Stochastic Seismic Emission from Acoustic Glories and the Quiet Sun

Helioseismic images of multipolar active regions show enhanced seismic emission in 5-mHz oscillations in a halo surrounding the active region called the `acoustic glory'. The acoustic glories contain elements that sustain an average seismic emission 50% greater than similar elements in the quiet Sun. The most intense seismic emitters tend to form strings in non-magnetic regions, sometimes marking the borders of weak magnetic regions and the separation between weak magnetic regions of opposite polarity. This study compares the temporal character of seismic emission from acoustic glories with that from the quiet Sun. The power distribution of quiet-Sun seismic emission far from solar activity is exponential, as for random Gaussian noise, and therefore not perceivably episodic. The distribution of seismic power emanating from the most intense elements that comprise the acoustic glories is exponential out to approximately 4 times the average power emitted by the quiet Sun. Above this threshold the latter distribution shows significant saturation, suggesting the operation of a hydromechanical non-linearity that sets limits on the acoustic power generated by the convection zone. This could give us considerable insight into the physical mechanism of seismic emission from the near subphotosphere.     

Organochlorine contaminants in endangered Hawaiian monk seals from four subpopulations in the Northwestern Hawaiian Islands

We analyzed blubber and blood samples for organochlorines (OCs) from 158 Hawaiian monk seals (Monachus schauinslandi) at four of their six primary breeding colonies in the Northwestern Hawaiian Islands. Levels of OCs in blubber were lower in adult females compared to juveniles or adult males, evidently owing to the transfer of these lipophilic compounds to pups by pregnant and lactating females. Concentrations of SigmaPCBs and p,p'-DDE in blubber generally increased with age until seals were sexually mature and then continued to increase with age in males after puberty. Average levels of PCBs and PCB toxic equivalents (TEQs) in blubber were significantly higher in adult male and juvenile seals at Midway Atoll than the same age class of seals at the other colonies. Unlike concentrations of OCs in blubber, circulating levels of OCs in blood did not vary consistently among age classes of seals or among breeding colonies. Though the concentrations of OCs measured in Hawaiian monk seals were generally equal to or lower than those reported for other pinniped species in the North Pacific Ocean, they were high enough in a few seals to potentially affect their health.     

Catalogue of Shakhbazian compact groups of galaxies. VI.

The sixth part of the catalogue of Shakhbazian compact groups of galaxies contains the positions and references of all the galaxies of the following 48 groups (north of δ > +2°30''): Shkh 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107. For the estimation of the coordinates the Digitized Sky Survey was used.     

Soil production and hillslope transport in mid‐latitudes during the last glacial–interglacial cycle: a combined data and modelling approach in northern Ardennes

The relative efficiency of various hillslope processes through Quaternary glacial–interglacial cycles in the mid‐latitudes is not yet well constrained. Based on a unique set of topographic and soil thickness data in the Ardennes (Belgium), we combine the new CLICHE model of climate‐dependent hillslope evolution with an inversion algorithm in order to get deeper insight into the ways and timing of hillslope dynamics under one such climatic cycle. We simulate the evolution of a synthetic hill reproducing the slope, curvature, and contributing area distributions of the hillslopes of a ~ 2500 km² real area under a simple two‐stage 120‐kyr‐long climatic scenario with linear transitions between cold and warm stages. The inversion method samples a misfit function in the model parameter space, based on estimates of the fit of topographic derivative distributions in classes of soil thickness and of the relative frequencies of the predicted soil thickness classes. Though the inversion results show remarkable convergence patterns for most parameters, no unique solution emerges. We obtain five clusters of good fits, whose centroids are taken as acceptable model solutions. Based on the predicted time series of average denudation rate and soil thickness, plus snapshots of the soil distribution at characteristic times, we discuss these solutions and, comparing them with independent data not involved in the misfit function, we identify the most realistic scenario. Beyond providing first‐order estimates of several parameters that compare well with published data, our results show that denudation rates increase dramatically for a short time at both warm–cold and cold–warm transitions, when the mean annual temperature passes through the [0, ?5 °C] range. We also point to the overwhelming importance of solifluction in shaping hillslopes and transporting soil, and the role of depth‐dependent creep (including frost creep) throughout the climatic cycle, whereas the contributions of simple creep and overland flow are minor. Copyright © 2016 John Wiley & Sons, Ltd.     

Present-day sediment dynamics of the Sanaga catchment (Cameroon): from the total suspended sediment (TSS) to erosion balance

ABSTRACT

Total suspended sediment (TSS) data for 1960–1970 and from recent investigations (1990–2000) are used to evaluate the variability in sediment yield of the Sanaga catchment (Cameroon) and the equivalent rates of erosion. At the annual and seasonal time scales, total suspended sediment concentrations for the Mbam sub-catchment are three to four times higher than for the Sanaga basin, reflecting the higher sensitivity of the former to erosion. Classical clockwise hysteresis loops are observed in both sub-catchments, despite a significant increase in human-induced catchment changes. At the multi-year time frame (over a 40-year period), it appears that the second half of the 1990s is marked by a downward trend in TSS. This shift is due to the control infrastructures (river impoundments and ponds) installed in certain parts of the whole catchment, combined with a drop in annual rainfall and river discharge.

Editor Z.W. Kundzewicz; Associate editor not assigned     

Computerdarstellung von Achsenverteilunganalysen

Zusammenfassung Ein wichtiges Verfahren der Gefügeanalyse ist die Achsenverteilungsanalyse. Dieses zeitaufwendige Verfahren wird besser und schneller mit Hilfe eines Computers durchgeführt. Ein selbstentwickeltes Programmsystem in ALGOL, das besonders im Hinblick auf die Durchführung von Achsenverteilungsanalysen entworfen wurde, beherrscht sowohl die traditionellen Verfahren zur Auswertung des Makro- und Mikrogefüges als auch neuere Methoden zur Darstellung von Achsenverteilungsanalysen.Nach einer schematischen Darstellung des angewendeten Verfahrens wird als Beispiel ein 9×9 mm großer Bereich eines Chlorit-Biotit-Gneises analysiert und abschließend die Anwendung des Verfahrens im Makrobereich diskutiert.

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The axial-distribution analysis is an important method for the investigation of petrofabrics. The analytical procedure is very time-consuming and can be more exactly and rapidly performed by means of a computer. The program system which was developed by the author is written in ALGOL language and has been worked out with special respect to the performance of axial-distribution analyses. The program masters the traditional procedures of treating the macro-, meso-, and microscopic fabrics as well as new representation methods of axial-distribution analysis.The method is described by a sequence of graphs illustrating the proceeding of the analytical process. It is applied to the analysis of a 9×9 mm area of a chlorite-biotitegneiss. Finally, the application of the method to the investigation of macroscopic areas is discussed.

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Résumé L'analyse de la distribution des axes est une méthode très importante de l'analyse structurelle. Cette méthode, qui consomme beaucoup de temps, est mieux et plus vite réalisée à l'aide d'une calculatrice électronique. Un système de programmes en langue ALGOL, qui a été développé par l'auteur spécialement pour l'exécution des analyses de distribution des axes, traite aussi bien les méthodes traditionnelles de l'évaluation des macroet microstructures que les méthodes nouvelles pour la représentation des analyses de distribution d'axes. La méthode employée est appliquée à l'analyse d'une surface de 9×9 mm d'un gneiss à chlorite et biotite et est finalement discutée aux échelles supérieures.

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Die Diagramme wurden mit der aus Mitteln der DFG betriebenen Rechenanlage Electrologica X8/X1 berechnet.Mein besonderer Dank gilt Herrn Prof. Dr. F.Karl für das Verständnis, das er den langwierigen Programmierarbeiten entgegenbrachte, sowie die hilfreichen Diskussionen der gefügekundlichen Probleme. Dank schulde ich ferner Herrn F.Pina Mendes für einige Diskussionen sowie das Einmessen des untersuchten Dünnschliffes.     

Lithologic control of bedrock meander dimensions in the appalachian valley and ridge province: A comment on a comment

Abrahams' comment relates meander length to channel cross-section shape and recurrence interval so that meander length can be both directly and inversely proportional to rock resistance. This reply notes that either meander length is directly proportional to rock resistance or it is not; one cannot have it both ways. Many Appalachian Valley and Ridge bedrock meanders are shown to be the same size as alluvial meanders, and appear to be somewhat underfit. A hypothesis is proposed where modest discharge increases may have accelerated bedrock meander cutting although present streams remain capable of slowly cutting the meanders.