Comparison of the orientation of small-scale electron density irregularities and F region plasma flow direction

Results are shown from an experimental campaign where satellite scintillation was observed at three sites at high latitudes and, simultaneously, the F region plasma flow was measured by the nearby EISCAT incoherent scatter radar. The anisotropy parameters of field-aligned irregularities are determined from amplitude scintillation using a method based on the variance of the relative logarithmic amplitude. The orientation of the anisotropy in a plane perpendicular to the geomagnetic field is compared with the direction of F region plasma flow. The results indicate that in most cases a good agreement between the two directions is obtained.     

CORRELATION METHODS OF TRANSFORMATION AND INTERPRETATION OF GEOPHYSICAL ANOMALIES*

The methods of anomaly transformations considered are based on a system of combined analysis of the geophysical field and a priori) information on the structure of a geological object. The methods involve calculation of a transformative polynomial (describing geophysical noise) which makes it possible to separate the residual field component related to the geological characteristic under study in a correlatively optimal way. The structure of the transformative polynomial is determined by the nature of the geophysical noise that is eliminated by the field transformation. Various correlation methods of anomaly transformations arise, depending on the structure of the transformative polynomial chosen. By way of example, the correlation method employed for separating the geophysical anomalies is shown to be highly effective in investigating the local geological structure.     

Large to intermediate-scale aquifer heterogeneity in fine-grain dominated alluvial fans (Cenozoic As Pontes Basin,northwestern Spain): insight based on three-dimensional geostatistical reconstruction

Facies reconstructions are used in hydrogeology to improve the interpretation of aquifer permeability distribution. In the absence of sufficient data to define the heterogeneity due to geological processes, uncertainties in the distribution of aquifer hydrofacies and characteristics may appear. Geometric and geostatistical methods are used to understand and model aquifer hydrofacies distribution, providing models to improve comprehension and development of aquifers. However, these models require some input statistical parameters that can be difficult to infer from the study site. A three-dimensional reconstruction of a kilometer scale fine-grain dominated Cenozoic alluvial fan derived from more than 200 continuously cored, closely spaced, and regularly distributed wells is presented. The facies distributions were reconstructed using a genetic stratigraphic subdivision and a deterministic geostatistical algorithm. The reconstruction is only slightly affected by variations in the geostatistical input parameters because of the high-density data set. Analysis of the reconstruction allowed identification in the proximal to medial alluvial fan zones of several laterally extensive sand bodies with relatively higher permeability; these sand bodies were quantified in terms of volume, mean thickness, maximum area, and maximum equivalent diameter. These quantifications provide trends and geological scenarios for input statistical parameters to model aquifer systems in similar alluvial fan depositional settings.     

Ultramafic–Mafic Assemblage of Plutonic Rocks and Hornblende Schists of Shirshov Rise,Bering Sea,and Stalemate Ridge,Northwest Pacific: Geodynamic Interpretations of Geochemical Data

The paper presents data on plutonic and metamorphic rocks dredged during Cruise 249 of the German R/V Sonne to the Stalemate Ridge, Northwest Pacific Ocean and the Shirshov Rise, western Bering Sea. Dredges in the northwestern sector of the Stalemate Ridge and central portion of the Shirshov Rise show that the plutonic and metamorphic rocks obtained here are amazingly similar. Our petrologic and geochemical data led us to view the rocks as members of a mafic–ultramafic assemblage typical of cumulate portions of ophiolite complexes and backarc spreading centers. The plutonic complexes of the Shirshov Rise and Stalemate Ridge show similarities not only in the petrography and mineralogy of their protoliths but also in the character of their metamorphic transformations. Plutonic rocks from both areas display mineralogical evidence of metamorphism within a broad temperature range: from the high-temperature amphibolite facies to the greenschist facies. Relations between the index mineral assemblages indicate that the metamorphic history of plutonic complexes in the Stalemate Ridge and Shirshov Rise proceeded along a retrograde path. Hornblende schists accompanying the plutonic rocks of the Stalemate Ridge and Shirshov Rise are petrographically close to foliated amphibolites in subophiolitic metamorphic aureoles. Within the framework of geodynamic interpretations of our results, it is realistic to suggest that the examined plutonic complexes were exhumed from subduction zones of various age.     

Wind tunnel modeling of small-scale meteorological processes

After introductory remarks on similarity laws to be satisfied in wind tunnel experiments simulating small-scale meteorological processes, mean and turbulence characteristics of wind tunnel boundary layers are presented and compared with the characteristics of the atmospheric boundary layer. The results are used to evaluate the possibilities and limitations of physical modeling of pollutant dispersion in general. In the second part of the paper, the potential of wind tunnels to solve micro-meteorological problems of real practical interest will be demonstrated. The example involves the investigation of the effects of building downwash on ground-level concentrations for flue gases discharged from natural draft wet cooling towers.     

Reconstruction of Holocene Environmental Changes in North-Western Pacific in Relation to Paleorecord from Shikotan Island

Doklady Earth Sciences - Results of a paleolimnological investigation of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP a warm...     

Parameters of the dust envelope of the symbiotic star CH Cygni

The brightness and color variations of the symbiotic star CH Cygni are studied, and its stationary, spherically symmetric, extended dust envelope is modeled based on long-term UBVRJHKLM photometry, the mid-IR spectral energy distribution (7–23 µm), and far-IR fluxes measured by IRAS and ISO. The existence of a hot dust envelope, detected earlier in the near IR, is confirmed; the optical depth of the envelope has probably increased with time. Model fits to the IRAS and ISO data indicate that the V-band optical depth increased from 0.22 to 0.41 due to dust density enhancement during the 14 years between the observations by the two spacecraft. The mass-loss rate, gas-expansion velocity at the outer boundary of the envelope, and upper limit of the mass of the central source of emission are estimated assuming that the stellar wind of the system is driven by the pressure of the red giant's radiation on the dust, with subsequent momentum transfer to the gaseous medium.     

Facies architecture of an isolated carbonate platform: tracing the cycles of the Latemàr (Middle Triassic, northern Italy)

The 720-m-thick succession of the Middle Triassic Latemàr Massif (Dolomites, Italy) was used to reconstruct the lagoonal facies architecture of a small atoll-like carbonate platform. Facies analysis of the lagoonal sediments yields a bathymetric interpretation of the lateral facies variations, which reflect a syndepositional palaeorelief. Based on tracing of lagoonal flooding surfaces, the metre-scale shallowing-upward cycles are interpreted to be of allocyclic origin. Short-term sea-level changes led to subaerial exposure of wide parts of the marginal zone, resulting in the development of a tepee belt of varying width. Occasional emergence of the entire lagoon produced lagoon-wide decimetre-thick red exposure horizons. The supratidal tepee belt in the backreef area represented the zone of maximum elevation, which circumscribed the sub- to peritidal lagoonal interior during most of the platform's development. This tepee rim, the subtidal reef and a sub- to peritidal transition zone in between stabilized the platform margin. The asymmetric width of facies belts within individual metre-scale cycles was caused by redistribution processes that reflect palaeowinds and storm paths from the present-day south and west. The overall succession shows stratigraphic changes on a scale of tens of metres from a basal subtidal unit, overlain by three tepee-rich intervals, separated by tepee-poor units composed of subtidal to peritidal facies. This stacking pattern reflects two third-order sequences during the late Anisian to early middle Ladinian.