European forest cover mapping with high resolution satellite data: The Carpathians case study

The aim of the study was to elaborate a methodology for forest mapping based on high resolution satellite data, relevant for reporting on forest cover and spatial pattern changes in Europe. The Carpathians were selected as a case study area and mapped using 24 Landsat scenes, processed independently with a supervised approach combining image segmentation, knowledge-based rules to extract a training set and the maximum likelihood decision rule. Validation was done with available very high resolution imagery. Overall accuracies per scene ranged from 93 to 96%. The labelling disagreement in overlapping areas of adjacent scenes was 6.8% on average.     

Characterization of polysomatism in biopyriboles: Double-/triple-chain lamellar intergrowths

As a first step towards accurate quantification of the polysomatic states of biopyriboles, we have studied the polysomatic transformation between amphibole and hydrous triple-chain silicate (TCS) in the synthetic system Na₂O-MgO-SiO₂-H₂O (NMSH). The reaction is: 4Na₂Mg₄Si₆O₁₆(OH)₂ TCS 3Na_2.67Mg_5.33Si₈O_21.33(OH)_2.67. Amphibole We have characterised a polysomatic intergrowth of amphibole and TCS (synthesized at 2 kbar/(653° C) by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), infrared spectroscopy and ²⁹Si magic-angle-spinning (MAS) NMR spectroscopy. The sample is a fine-scale lamellar intergrowth of double- and triple-chain structures; lamellae are 27 Å to hundreds of Ångströms wide. The ²⁹Si MAS NMR spectrum of the intergrowth is explicitly a superposition of the individual amphibole and TCS spectra. By ensuring that the recycle delay time used considers the longest spin-lattice relaxation time (ca. 900 s), the relative amounts of double- and triple-chain structures can be quantified by simple deconvolution of the spectrum. The relative amounts of double- and triple-chain structures are 42 ± 5 and 58 ± 5 mol%, respectively. With regard to quantifying populations of chain multiplicities in biopyriboles, we believe that ²⁹Si NMR is more accurate than the conventional HRTEM fringe-counting method (Maresch and Czank 1983, 1988), and is far superior to XRD and infrared spectroscopy, which suffer from high sensitivity to particle size and calibration problems. ²⁹Si MAS NMR can provide an accurate means of monitoring the progress of polysomatic reactions in biopyriboles. It is likely to be most effective for samples containing only a few different chain multiplicities (e.g. m = 1, 2, 3 and perhaps 4), such as occur in natural pyroxenes and amphiboles.     

Differential biomagnification of PCB, PBDE, Hg and Radiocesium in the food web of the European hake from the NW Mediterranean

Consumption of marine organisms represents one of the main exposure sources of contaminants for human populations. To obtain a global view of the contamination in commercial fish in the NW Mediterranean Sea, we analysed four types of priority contaminants (PCBs, PBDEs, Hg and (137)Cs) in the European hake, Merluccius merluccius, from the Gulf of Lions in relation with organism's trophic level (δ(15)N). All contaminants presented a significant increase in concentration in hake muscle with trophic level. However, obvious differences between contaminants were evidenced. Biomagnification factors (BMF and FWMF) along the hake food web were higher for Hg and CB-153 than for BDE-47 and (137)Cs, and increase in contaminant concentration with trophic level occurred at different rates depending on contaminants. Such differences of biomagnification patterns can be related to physico-chemical properties of the different contaminants.     

Interannual variability of tropospheric NO2 column over central Europe — observations from SCIAMACHY and GEM-AQ model simulations

Spatial and temporal variability of NO₂ tropospheric column over Europe was analyzed for a 3 year period (2008–2010) based on monthly average observations from SCIAMACHY and the GEM-AQ model results. The GEM-AQ model was run in a global variable configuration with a resolution of ～15 km over Central Europe. Spatial averaged time series were calculated for two selected regions in Western and Central Europe in order to assess the seasonal and interannual variability of the tropospheric NO₂. The spatial pattern is similar near large emission sources for consecutive years. However, in remote regions there are differences due to interannual variability of meteorological conditions. Highest tropospheric NO₂ column values (over 150 × 10¹⁵ molecules/cm²) were persistent over the Benelux and over most of the European agglomerations. The general agreement between modelled and observed NO₂ column is good. In the remote areas, the modelled NO₂ column shows weaker gradients than the observed field.     

Seismic Monitoring of Poland–Description and Results of Temporary Seismic Project with Mobile Seismic Network

The paper describes a temporary seismic project aimed at developing the national database of natural seismic activity for seismic hazard assessment, officially called “Monitoring of Seismic Hazard of Territory of Poland” (MSHTP). Due to low seismicity of Poland, the project was focused on events of magnitude range 1–3 in selected regions in order to maximize the chance of recording any natural event. The project used mobile seismic stations and was divided into two stages.Five-year measurements brought over one hundred natural seismic events of magnitudes M_L range 0.5–3.8. Most of them were located in the Podhale region in the Carpathians. Together with previously recorded events this made it possible to conduct a preliminary study on ground motion prediction equation for this region. Only one natural event, of magnitude M_L = 3.8, was recorded outside the Carpathians in a surprising location in central-west Poland.     

Comparison of migration‐based location and detection methods for microseismic events

Microseismic monitoring in the oil and gas industry commonly uses migration‐based methods to locate very weak microseismic events. The objective of this study is to compare the most popular migration‐based methods on a synthetic dataset that simulates a strike‐slip source mechanism event with a low signal‐to‐noise ratio recorded by surface receivers (vertical components). The results show the significance of accounting for the known source mechanism in the event detection and location procedures. For detection and location without such a correction, the ability to detect weak events is reduced. We show both numerically and theoretically that neglecting the source mechanism by using only absolute values of the amplitudes reduces noise suppression during stacking and, consequently, limits the possibility to retrieve weak microseismic events. On the other hand, even a simple correction to the data polarization used with otherwise ineffective methods can significantly improve detections and locations. A simple stacking of the data with a polarization correction provided clear event detection and location, but even better results were obtained for those data combined with methods that are based on semblance and cross‐correlation.