Large wood clogging during floods in a gravel‐bed river: the Długopole bridge in the Czarny Dunajec River,Poland

During floods, large quantities of wood can be mobilized and transported downstream. At critical sections, such as bridges, the transported wood might be entrapped and a quick succession of backwater effects can occur as a result of the reduction of the cross‐sectional area. The aim of this work is to explore large wood‐related hazards during floods in the gravel‐bed river Czarny Dunajec (Polish Carpathians), where the river flows through the village of D?ugopole. This work is based on the numerical modelling of large wood transport together with flow dynamics in which inlet and boundary conditions were designed based on field observations. The exploratory approach developed in this study uses multiple scenarios (193) to analyse the factors controlling bridge clogging: wood size, wood supply, flow conditions, morphology and obstacles in the riverbed. Results highlighted the strong control of log length (stronger than that of log diameter) on potential blockage probability; however, according to our results the main factor controlling bridge clogging was the flood discharge. River morphology and wood supply play an important role as well. The river morphology may reduce bridge blockage, as it influences flow velocity and depth, and creates natural retention zones for wood. In addition, the impacts of bridge blockage were analysed in terms of afflux depth and length, and flooded area. Results showed that bridge blockage may result in a significant increase in water depth (up to 0.7 m) and flooded area (up to 33% more), therefore increasing flood risk in the village. Copyright © 2016 John Wiley & Sons, Ltd.     

High-resolution computed microtomography for the characterization of a diffusion tensor imaging phantom

This paper addresses the issue of the quantitative characterization of the structure of the calibration model (phantom) for b-matrix spatial distribution diffusion tensor imaging (BSD-DTI) scanners. The aim of this study was to verify manufacturing assumptions of the structure of materials, since phantoms are used for BSD-DTI calibration directly after manufacturing. Visualization of the phantoms’ structure was achieved through optical microscopy and high-resolution computed microtomography (µCT). Using µCT images, a numerical model of the materials structure was developed for further quantitative analysis. 3D image characterization was performed to determine crucial structural parameters of the phantom: porosity, uniformity and distribution of equivalent diameter of capillary bundles. Additionally calculations of hypothetical flow streamlines were also performed based on the numerical model that was developed. The results obtained in this study can be used in the calibration of DTI-BST measurements. However, it was found that the structure of the phantom exhibits flaws and discrepancies from the assumed geometry which might affect BSD-DTI calibration.     

Application of the Unified Stream Assessment Method to Determine the Direction of Revitalization of Heavily Transformed Urban Rivers

Water Resources - The issues related to the assessment of the hydro morphological status of urban rivers in order to identify the revitalisation actions possible to be carried out, has been...     

Precambrian crustal contribution to the Variscan accretionary prism of the Kaczawa Mountains (Sudetes,SW Poland): evidence from SHRIMP dating of detrital zircons

SHRIMP dating of detrital zircons from sandstones of the Gackowa Formation (Kaczawa Complex, Sudetes, SW Poland) indicates input from late (550–750 Ma) and early Proterozoic to Archaean sources (∼2.0–3.4 Ga, the latter being the oldest recorded age from the Sudetic region). These dates preclude within-terrane derivation from seemingly correlatory acid volcanic rocks of early Palaeozoic age. Rather, they indicate provenance from Cadomian and older rocks that currently form part of other, geographically distant terranes; the most likely source identified to date is the Lusatian Block in the Saxothuringian Zone. Hence, the Gackowa Formation may be late Proterozoic rather than early Palaeozoic in depositional age, possibly coeval with the late Proterozoic (pre-Cadomian) greywackes of Lusatia, being subsequently tectonically interleaved with early Palaeozoic volcanic rocks into the Kaczawa accretionary prism during the Variscan orogeny. However, correlation with the lithologically similar early Ordovician Dubrau Quartzite of Saxothuringia, and so assignation to the early Paleozoic (post-Cadomian) rift succession deposited at the northern margin of Gondwana, cannot yet be precluded.     

Identification of seismic anomalies caused by gas saturation on the basis of theoretical P and PS wavefield in the Carpathian Foredeep,SE Poland

The thin-layer build of the Carpathian Foredeep Miocene formations and large petrophysical parameter variation cause seismic images of gas-saturated zones to be ambiguous, and the location of prospection wells on the basis of anomalous seismic record is risky. A method that assists reservoir interpretation of standard recorded seismic profiles (P waves) can be a converted wave recording (PS waves). This paper presents the results of application of a multicomponent seismic survey for the reservoir interpretation over the Chałupki Dębniańskie gas deposit, carried out for the first time in Poland by Geofizyka Kraków Ltd. for the Polish Oil and Gas Company. Seismic modeling was applied as the basic research tool, using the SeisMod program based on the finite-difference solution of the acoustic wave equation and equations of motion. Seismogeological models for P waves were developed using Acoustic Logs; S-wave model (records only from part of the well) was developed on the basis of theoretical curves calculated by means of the Estymacja program calibrated with average S-velocities, calculated by correlation of recorded P and PS wavefields with 1D modeling. The conformity between theoretical and recorded wavefields makes it possible to apply the criteria established on the basis of modeling for reservoir interpretation. Direct hydrocarbon indicators (bright spots, phase change, time sag) unambiguously identify gas-prone layers within the ChD-2 prospect. A partial range of the indicators observed in the SW part of the studied profile (bright spot that covers a single, anticlinally bent seismic horizon) points to saturation of the horizon. The proposed location is confirmed by criteria determined for converted waves (continuous seismic horizons with constant, high amplitude) despite poorer agreement between theoretical and recorded wavefields.     

Impact of the surface temperature and vertical shear of zonal wind on the dynamics of a simple two-layer model of the atmosphere

The paper presents and analyzes, from the point of view of smooth dynamic systems theory, a two-layer baroclinic model of the troposphere in geostrophic approximation. The model describes airflow in β-channel within the tropospheric part of the main Hadley circulation cell. It enables to obtain, after application of the Galerkin method, a fairly simple low-parametric dynamic system describing the phenomena of non-linear interactions, bifurcations and blocking in the atmosphere. This enables to take into consideration such basic factors influencing the atmospheric dynamics like the heat exchange within the surface, orography, vertical variability of zonal wind and hydrostatic stability. Impact of zonal thermal variability of the surface and vertical shear of zonal wind in the troposphere on the orographic bifurcation was investigated and the oscillation character in the dynamic system after Hopf bifurcation of the second kind was analyzed. Additionally, the model dynamics was investigated in conditions including momentum forcing in the upper and lower parts of the troposphere and excluding orographic interaction, as well as in the conditions of thermal interaction between the troposphere and the surface for the vertical shear of zonal wind in both tropospheric layers. Impact of the mean zonal wind in the troposphere on the properties of model dynamics was assessed. It was proved that zonally varied surface temperature and layered mean zonal wind in the atmosphere are the parameters that have basic influence on the model dynamics. They cause numerous bifurcations and strongly influence the periods of oscillations of the model variables. They are often Hopf bifurcations of the second kind during which tropospheric states fairly distant from the ones before the bifurcations are generated. This significantly influences the model predictability.     

Random cascade driven rainfall disaggregation for urban hydrology: An evaluation of six models and a new generator

Six variations of multiplicative random cascade models for generating fine-resolution (i.e., 5-minute interval) rainfall time series were evaluated for rainfall in Wroclaw, Poland. Of these variations, one included a new beta-normal generator for a microcanonical cascade. This newly proposed model successfully reproduces the statistical behavior of local 5-minute rainfalls, in terms of intermittency as well as variability. In contrast, both the canonical cascade models with either constant or time-scaled parameters and a microcanonical cascade model with a beta generator substantially underestimate 5-minute maximum rainfall intensities. The canonical models also fail to properly reproduce the intermittency of the rainfall process across a range of timescales. New observations are also made concerning the histograms of the breakdown coefficients (BDC). The tendency of the BDC histograms to have values exactly equal to 0.5 is identified and explained by the quality of pluviograph records. Moreover, the hierarchical evolution of BDC histograms from beta-like for long time steps to beta-normal histograms for short time steps is observed for the first time. The potential advantage is shown of synthetic high resolution rainfall time series generated by the revised microcanonical model for use in hydrology, especially hydrodynamic modelling of urban drainage networks.     

AFORS autonomous fibre-optic rotational seismograph: Design and application

We outline the research leading to development of the Autonomous Fibre-Optic Rotational Seismograph (AFORS) and describe the final version of the instrument. The instrument with linear changes of sensitivity keeps accuracy from 5.1 × 10⁻⁹ to 5.5 × 10⁻⁸ rad/s in the detection bandpass 1.66–212.30 Hz; it is designed for a direct measurement of rotational components emitted during seismic events. The presented system is based on the optical part of the fibre optic gyro construction where a special autonomous signal processing unit (ASPU) optimizes its operation for the measurement of rotation motions instead of the angular changes. The application of a newly designed telemetric system based on the Internet allows for a remote system control, as shown in an example of the system’s operation in Książ (Poland) seismological observatory.     

Protomylonite evolution potentially revealed by the 3D depiction and fractal analysis of chemical data from a feldspar

Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (δ¹⁸O, δD, δ¹¹B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl–oxyschorl tourmalines from granitic rocks have variable foititic component (^X□ = 17–57 %) and Mg/(Mg + Fe) ratios (0.19–0.50 in two-mica granitic rocks, and 0.05–0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant δ¹⁸O values (12.1 ± 0.1 ‰), with wider-ranging δD (?78.2 ± 4.7 ‰) and δ¹¹B (?10.7 to ?9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31–0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by δ¹⁸O = 12.4 ‰, δD = ?29.5 ‰, and δ¹¹B = ?9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26–0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant δ¹⁸O values (13.1–13.3 ‰), though wider-ranging δD (?58.5 to ?36.5 ‰) and δ¹¹B (?10.2 to ?8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35–0.78] and oxydravite [Mg/(Mg + Fe) = 0.51–0.58], respectively. Boron contents of the granitic rocks are low (<650 ppm) compared to the minimum B contents normally required for tourmaline saturation in granitic melts, implying loss of B and other volatiles to the surrounding host-rocks during the late-magmatic stages. This process was responsible for tourmalinization at the exocontact of the Penamacor-Monsanto pluton, either as direct tourmaline precipitation in cavities and fractures crossing the pluton margin (vein/breccia tourmalinites), or as replacement of mafic minerals (chlorite or biotite) in the host-rocks (replacement tourmalinites) along the exocontact of the granite. Thermometry based on ¹⁸O equilibrium fractionation between tourmaline and fluid indicates that a late, B-enriched magmatic aqueous fluid (av. δ¹⁸O ~12.1 ‰, at ~600 °C) precipitated the vein/breccia tourmaline (δ¹⁸O ~12.4 ‰) at ~500–550 °C, and later interacted with the cooler surrounding host-rocks to produce tourmaline at lower temperatures (400–450 °C), and an average δ¹⁸O ~13.2 ‰, closer to the values for the host-rock. Although B-metasomatism associated with some granitic plutons in the Iberian Peninsula seems to be relatively confined in space, extending integrated studies such as this to a larger number of granitic plutons may afford us a better understanding of Variscan magmatism and related mineralizations.     

Periglacial structures within fluvio‐aeolian successions of the end of the Last Glaciation – examples from SE Poland and NW Ukraine

The nature of permafrost and related environmental conditions in the Weichselian Late Pleniglacial and Lateglacial are reconstructed based on the assessment of frost structures that are best documented in the Loess Belt and in plateau areas composed of glacial till. Investigations were conducted in the central‐eastern part of the European Sand Belt (SE Poland and NW Ukraine) on a fluvio‐aeolian sedimentary succession and took into account its chronological context given by luminescence dating. Various generations of periglacial structures found in these deposits indicate not only the development of permafrost (ice‐wedge pseudomorphs) and decreased humidity (composite wedge casts) but also the degradation of permafrost (large‐scale involutions) and, finally, the establishment of deep seasonal frost (frost cracks). The diversity of structures in the study region appears to result from local conditions rather than increasing continentality of climate towards the east.