Similarity of rivers and their systems

Similarity criteria of rivers and river systems are studied. Zonal and azonal indicators of their similarity are established. The role of river system patterns in the changes of hydrographic and hydrologic characteristic of rivers in the passage from river heads to mouths is considered. The efficiency of applying fractal and indication analyses to river systems is examined. The extent and the scale effect of changes in various characteristics of the flow-channel systems are shown to depend on changes in river orders. The fractal dimension and the scale effects of their changes are correlated. A universal relationship between river orders, on the one hand, and river drainage area and river network density, on the other hand, was established. The root-mean-square error of the obtained formula, evaluated based on data on 274 watersheds, was 0.27, enabling it to be used in hydrological calculations under various landscape conditions.     

Capillary End Effects in Reservoirs with Heterogeneous Wettability

Doklady Earth Sciences - A new type of capillary end effect in oil and gas reservoirs due to heterogeneous wettability has been justified. This type of capillary end effect is not related to the...     

Zur linearen Anordnung nicht frontal gebundener Niederschlagszellen

Zusammenfassung Die möglichen Ursachen der linienhaften Anordnung von Schauern in einer homogenen Luftmasse werden erörtert.

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Summary Possible causes of linear arrangement of showers in a homogeneous air mass are discussed.

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Résumé L'auteur discute les causes possibles de la disposition linéaire d'averses dans une masse d'air homogène.

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Mit 7 Textabbildungen     

Age and structure of the southern Rockall Trough new evidence

The Rockall Trough separates the Rockall Plateau microcontinent from the shelf and slope west of the British Isles. The structure and age of the trough has been the source of considerable discussion. Although widely considered to be of oceanic origin, postulated ages for the spreading range from Permian to Cretaceous. New seismic profiles linked to the IPOD sites in the Bay of Biscay and to oceanic anomalies of known age are used to present a new assessment of the age and structure of the southern Rockall Trough. It is concluded that about 120 km of ocean crust is present in the trough and that spreading took place in the Albian-Maastrichtian interval.     

Behandlung eines einfachen hydromagnetischen Dynamos mittels Linearisierung

The non-linear equations of the spherical α = const-dynamo are solved by a linearisation with respect to the deviation of α from the critical value. The magnitude of the induced magnetic field is derived. Representations of the toroidal and the poloidal component of the magnetic field are given.     

The upper Bathonian ammonite zonation of East Siberia

Modifications to the upper Bathonian zonal scale for northern East Siberia provided by the newly available paleontological record on Middle Jurassic reference sections in the Arctic regions of Yakutia and by the revised earlier collections, are justified. The oldest East Siberian members of Cadoceras are found to be characteristic not of the initial Callovian age as believed by Russian paleontologists, but of the terminal Bathonian age as was previously shown in the biostratigraphic scheme of East Greenland. The succession of zones and index species analogous to that of the latter is revealed in the studied region and the zonal boundaries in Siberia and East Greenland are inferred to be synchronous. Finds of Cadoceras calyx in the upper Bathonian scale permitted, for the first time, the recognition of a corresponding zone. The Bathonian-Callovian boundary is placed between the calyx and anabarense zones. The upper Bathonian zonal scale of northern East Siberia is now in total agreement with the East Greenland zonal scale.     

Bidirectional Type III Solar Radio Bursts

Bidirectional coronal type III bursts are modeled by combining a model of coronal electron heating and beam generation via time-of-flight effects with semiquantitative estimates of quasilinear relaxation. Electromagnetic emissivities are estimated by extending the recently developed theory of interplanetary type III bursts to coronal emissions, including its features of stochastic Langmuir-wave growth and three-wave interactions. The results are investigated for heating on open and closed coronal field lines and are compared with observations of normal, reverse-slope, bidirectional, and inverted-J and -U coronal type III radio bursts. Harmonic emission is predicted to dominate at plasma frequencies above roughly 100 MHz where the efficiency of fundamental emission falls off steeply, while its free-free reabsorption rises. The model also explains the observed trends in the likelihood of occurrence of normal, reverse-slope, and bidirectional coronal type III bursts.