Study of vertical structure of aerosol optical properties with sun photometers and ceilometer during the MACRON campaign in 2007

This paper presents the measurements of a vertical structure of aerosol optical properties performed during the MACRON (Maritime Aerosol, Clouds and Radiation Observation in Norway) campaign, which took place in July and August 2007 at ALOMAR observatory on Andøya island (69.279°N, 16.009°E, elevation 380 m a.s.l.). The mean value of the aerosol optical thickness (AOT) at 500 nm during campaign was 0.12. Significant increase of the AOT above longtime mean value was observed on 7 and 8 August 2007 when the AOT exceeded 0.4 at 500 nm. Analyses of back trajectories show the aerosol transported from over Africa and Central Europe. The aerosol extinction coefficient obtained from the synergy of ceilometer and sun photometer observations reached 0.05–0.08 km^?1 (at 1064 nm) in the dust layer. The single scattering albedo at the ALOMAR observatory decreased during the dust episode to 0.93–0.94, which indicates some absorptive aerosols in the lower PBL.     

The structure of the crust in TESZ area by kriging interpolation

A precise 3D model of the crust is necessary to start any tectonic or geodynamic interpretation. It is also essential for seismic interpretations of structures lying below as well as for correct analysis of shallow structures using reflection seismics. During the last decades, a number of wide-angle refraction experiments were performed on the territory of central and eastern Europe (POLONAISE’97, CELEBRATION 2000, SUDETES 2003), resulting in many high quality 2D models. It is an interesting and complicated transition zone between Precambrian and Palaeozoic Platforms. This paper presents 3D model of the velocity distribution in the crust and upper mantle interpolated from 2D models of the structure along 33 profiles. The obtained model extends to a depth of 50 km and accurately describes the main features of the crustal structures of Poland and surrounding areas. Different interpolation techniques (Kriging, linear) are compared to assure maximum precision. The final model with estimated uncertainty is an interesting reference of the area for other studies.     

Influence of Elevation Data Source on 2D Hydraulic Modelling

The aim of this paper is to analyse the influence of the source of various elevation data on hydraulic modelling in open channels. In the research, digital terrain models from different datasets were evaluated and used in two-dimensional hydraulic models. The following aerial and satellite elevation data were used to create the representation of terrain–digital terrain model: airborne laser scanning, image matching, elevation data collected in the LPIS, EuroDEM, and ASTER GDEM. From the results of five 2D hydrodynamic models with different input elevation data, the maximum depth and flow velocity of water were derived and compared with the results of the most accurate ALS data. For such an analysis a statistical evaluation and differences between hydraulic modelling results were prepared. The presented research proved the importance of the quality of elevation data in hydraulic modelling and showed that only ALS and photogrammetric data can be the most reliable elevation data source in accurate 2D hydraulic modelling.     

Wavelet Characteristics of Hydrological and Dissolved Oxygen Time Series in a Lowland River

In this study, we investigated the temporal variability of dissolved oxygen and water temperature in conjunction with water level fluctuations and river discharge in the Narew lowland river reach. For this purpose, high resolution hydrologic and water quality time series have been used. Spectral analyses of time series using continuous wavelet transform scheme have been applied in order to identify characteristic scales, its duration, and localisation in time. The results of wavelet analysis have shown a great number of periodicities in time series at the inter-annual time scale when compared to the classical Fourier analysis. Additionally, wavelet coherence revealed the complex nature of the relationship between dissolved oxygen and hydrological variables dependent on the scale and localisation in time. Hence, the results presented in this paper may provide an alternative representation to a frequency analysis of time series.     

The shear-wave velocity structure in the upper mantle beneath Eurasia

We develop an approach that allows us to invert for the mantle velocity structure within a finely parametrized region as a perturbation with respect to a low-resolution, global tomographic model. We implement this technique to investigate the upper-mantle structure beneath Eurasia and present a new model of shear wave velocity, parametrized laterally using spherical splines with ∼2.9° spacing in Eurasia and ∼11.5° spacing elsewhere. The model is obtained from a combined data set of surface wave phase velocities, long-period waveforms and body-wave traveltimes. We identify many features as narrow as few hundred kilometres in diameter, such as subducting slabs in eastern Eurasia and slow-velocity anomalies beneath tectonically active regions. In contrast to regional studies in which these features have been identified, our model encompasses the structure of the entire Eurasian continent. Furthermore, including mantle- and body-wave waveforms helped us constrain structures at depths larger than 250 km, which are poorly resolved in earlier models. We find that up to +9 per cent faster-than-average anomalies within the uppermost ∼200 km of the mantle beneath cratons and some orogenic regions are separated by a sharp gradient zone from deeper, +1 to +2 per cent anomalies. We speculate that this gradient zone may represent a boundary separating the lithosphere from the continental root, which might be compositionally distinct from the overlying lithosphere and remain stable either due to its compositional buoyancy or due to higher viscosity compared with the suboceanic mantle. Our regional model of anisotropy is not significantly different from the global one.     

Numerical simulations of type III planetary migration – III. Outward migration of massive planets

We present a numerical study of rapid, so-called type III migration for Jupiter-sized planets embedded in a protoplanetary disc. We limit ourselves to the case of outward migration, and study in detail its evolution and physics, concentrating on the structure of the corotation and circumplanetary regions, and processes for stopping migration. We also consider the dependence of the migration behaviour on several key parameters. We perform this study using global, two-dimensional hydrodynamical simulations with adaptive mesh refinement. We find that the outward-directed type III migration can be started if the initial conditions support the initial average non-dimensional migration rate bigger than one. Unlike the inward-directed migration, in the outward migration the migration rate increases due to the growing of the volume of the co-orbital region. We find the migration to be strongly dependent on the rate of the mass accumulation in the circumplanetary disc, leading to two possible regimes of migration, fast and slow. The structure of the co-orbital region and the stopping mechanism differs between these two regimes.     

Sublimation-driven evolution of the local radius and the moment of inertia of a long-period comet

In this paper we intend to analyze how the sublimation of ice from cometary nuclei affects changes of the moments of inertia. Our aim is to show general trends for different orientations of cometary nucleus’ rotation axis. Thus we apply numerical model of a hypothetical homogeneous and initially spherical nucleus composed of water ice and dust. As an example we present simulations for a model comet of the orbital elements and the nucleus size the same as determined for C/1995 O1 Hale-Bopp, a widely analyzed long-period comet. We calculated water production from the nucleus and changes of the shape (initially spherical) and of the moment of inertia versus time. Simulations are performed for the full range (0–90°) of inclinations I of the rotation axis. The second paramater related to the orientation of the rotation axis is the argument Φ (0–360°). The heat conductivity of the nucleus spans over the vast range, 0.04–4 W m⁻¹ K⁻1.     

Geostatistical evaluation of magnetic indicators of forest soil contamination with heavy metals

The goal of the study was the geostatistical evaluation of quantitative magnetic measures, which can be used for effective delineation of the extent of the area polluted with heavy metals. Several parameters of magnetic susceptibility, measured in the soil profile, were proposed as magnetic indicators of soil pollution and analyzed in detail. The following parameters were calculated: maximum magnetic susceptibility, magnetic susceptibility at the depth of 3 cm and 5 cm, and the area under the curve of magnetic susceptibility. Measurements were performed at two forested study areas, located in Upper Silesian Industrial Area (Poland). Analyses were performed using geostatistical methods, and the results were verified using dense chemical measurements. The results showed that the area under curve of magnetic susceptibility was the most effective magnetic indicator of soil contamination with heavy metals. It was possible to detect the entire polluted area, and only about 16% of the study area was assumed to be contaminated while being unpolluted. The results obtained with maximum magnetic susceptibility and magnetic susceptibility at the depth of 3 cm and 5 cm were less effective in comparison with the area under curve of magnetic susceptibility.     

Searching for Regional Crustal Velocity-Density Relations with the Use of 2-D Gravity Modelling – Central Europe Case

In this paper we search for a reference relation between seismic P-wave velocity V and density ρ _ref for the continental crust. Based on the results of modern seismic experiments, we compiled 2-D seismic models into a network of four, each about 1100–1400 km long, continental-scale seismic transects cutting all main tectonic units in Central Europe. The Moho depth (about 52 km beneath the TESZ in SE Poland, to about 25 km beneath the Pannonian Basin) and the crustal structure of this area are characterised by a large variation. This structural variation provides an interesting basis for gravity studies and especially for analysing the difference of the density structure between two major tectonic provinces of distinctive age difference: Precambrian and Phanerozoic. The 2-D gravity modelling applied for crustal cross-sections representing the regional structure, based on a unified gravity anomaly map of the area, allows for a stable determination of some general features of the regional reference velocity-density relation for the continental crust. In general three major seismo-petrological types of rocks can be distinguished: sediments, crystalline crust and mantle. In compacted sediments the reference velocity-density relation is well described by the Gardner or Nafe-Drake model. Calculated gravity anomalies, using unified velocity-density relation for the whole crystalline crust, well describe observed anomalies, with an average difference of 14 mGal. However, calculated gravity anomalies, using separated velocity-density relations for the crystalline crust of Precambrian and Phanerozoic Europe, describe observed anomalies better than for the entire crust, with an average difference 12 mGal. The most important feature of these relations is the large differentiation of the derivative dρ _ref /dV in the crystalline crust, being about 0.3 g s/m⁴ for Precambrian, and about 0.1 g s/m⁴ for the Phanerozoic crystalline crust. The modelling suggests a very small density value in the uppermost mantle ρ = 3.11 g/cm³ below the younger area, while for the older area it is ρ = 3.3 g/cm³.