ALBERT

Description: A cloud-to-ground lightning climatology for north-eastern Italy Advances in Science and Research, 10, 77-84, 2013 Author(s): L. Feudale, A. Manzato, and S. Micheletti This study analyzes the spatial distribution and temporal characteristics of cloud-to-ground lightnings (C2G) in the North East of Italy and the neighboring areas of Austria, Slovenia and Croatia. The dataset consists of about 6.5 millions C2G flash records, both positive and negative, observed between January 1995 and December 2011 by the "Centro Elettrotecnico Sperimentale Italiano-Sistema Italiano Rilevamento Fulmini'' (CESI/SIRF), part of the European Cooperation for Lightning Detection (EUCLID) Network. The results show that C2G lightnings concentrate in the foothill regions on the southern flank of the Eastern Alps with a maximum of discharge frequency of 10 lightnings per km 2 per year. The number of C2G strokes varies with the period of the year: the most active period for lightning starts in April and lasts through November with the highest number of C2G strokes happening during the summer months of July and August, with maximum spatial density slightly moving from the mountain to the coastal area. The least frequency of C2G strokes is observed during wintertime. The mean diurnal C2G lightning activity for the whole domain shows a peak around 16:00–17:00 UTC and reaches a minimum around 07:00–09:00 UTC; the mean spatial distribution follows different patterns depending on the period of the day.

Description: Multivariate testing of spatio-temporal consistence of daily precipitation records Advances in Science and Research, 10, 85-90, 2013 Author(s): H. Mächel and A. Kapala The project KLIDADIGI of the German Meteorological Service (DWD) systematically rescues historical daily climate data of Germany by keying and imaging. Up to now, daily nearly gap-free precipitation time series at 118 locations for the period 1901–2000 are collected and extended by digitalization of hand-written protocols. To screen the spatio-temporal consistence of these raw data, we apply principal component analysis (PCA) in S (spatial) mode for daily precipitation records as well as for indices such as the number of rainy days above a certain threshold, intensity and absolute daily maximum in monthly, seasonal or annual resolution. Results of this screening test indicate that the PCA is a useful tool for detection of questionable stations and data preprocessing for further quality control and homogenization.

Description: Digital Climate Atlas of the Carpathian Region Advances in Science and Research, 10, 107-111, 2013 Author(s): I. Antolović, V. Mihajlović, D. Rančić, D. Mihić, and V. Djurdjević The main goal of the CARPATCLIM (Climate of the Carpathian Region) project is to construct the gridded climatological database for the region in a daily temporal resolution for the period 1961–2010 by using 0.1° spatial resolution. The solution of this requirement as well as one of the final products of the CARPATCLIM project is a Digital Climate Atlas which is designed as the main entry point for all the gridded data and maps generated during the project, together with metadata for all data sets (original data as well as data created during the project). With respect to the INSPIRE (Infrastructure for Spatial Information in the European Community) directive, the Digital Climate Atlas is developed as a rich Web GIS (Geographic Information System) application based on modern Web standards offering all necessary tools for climate data visualization and extraction. Another important product of the CARPATCLIM project is the Metadata Catalog which is designed as a tool for searching of climate metadata by various parameters (i.e. period, variable, region etc.).

Description: Analysis of climate hazards in relation to urban designing in Iran Advances in Science and Research, 6, 173-178, 2011 Author(s): S. Alijani and B. Alijani In order to study the climate hazards, daily rainfall and temperature data of 61 weather stations over the country were obtained from the Meteorological Organization of Iran for the 1951–2007 period. The following indices are defined as indications of climate hazards: sultriness of the air or the heat index, cold days with minimum temperature below −5 °C, warm days with maximum temperature above 32 °C, the share of extreme rain days from the annual rainfall. The annual frequencies of these indices are analyzed and the overall hazard index is computed using the Analytical Hierarchical Process method. The results show that the southern coastal areas and central deserts are the most hazardous parts of the country, whereas, the northern Caspian coastal lands and mountainous regions experience lower hazard alerts. The problem of the northern parts is the cold days and that of the southern areas is the hot and humid days. Despite the relatively equal occurrence of torrential rains over the country, they are more harmful in the south than in the other parts of the country.

Description: Soil moisture initialization effects in the Indian monsoon system Advances in Science and Research, 6, 161-165, 2011 Author(s): S. Asharaf, A. Dobler, and B. Ahrens Towards the goal to understand the role of land-surface processes over the Indian sub-continent, a series of soil-moisture sensitivity simulations have been performed using a non-hydrostatic regional climate model COSMO-CLM. The experiments were driven by the lateral boundary conditions provided by the ERA-Interim (ECMWF) reanalysis. The simulation results show that the pre-monsoonal soil moisture has a significant influence on the monsoonal precipitation. Both, positive and negative soil-moisture precipitation (S-P) feedback processes are of importance. The negative S-P feedback process is especially influential in the western and the northern parts of India.

Description: Environmental enrichment for primates in laboratories Advances in Science and Research, 5, 41-56, 2010 Author(s): H. M. Buchanan-Smith Environmental enrichment is a critical component of Refinement, one of the 3Rs underlying humane experimentation on animals. In this paper I discuss why primates housed in laboratories, which often have constraints of space and study protocols, are a special case for enrichment. I outline a framework for categorising the different types of enrichment, using the marmoset as a case study, and summarise the methods used to determine what animals want/prefer. I briefly review the arguments that enrichment does not negatively affect experimental outcomes. Finally I focus on complexity and novelty, choice and control, the underlying features of enrichment that makes it successful, and how combined with a thorough understanding of natural history we can put effective enrichment into practice in laboratories. Throughout the paper I emphasise the need to evaluate enrichment to ensure it is having the desired effect.

Description: Homogenising time series: beliefs, dogmas and facts Advances in Science and Research, 6, 167-172, 2011 Author(s): P. Domonkos In the recent decades various homogenisation methods have been developed, but the real effects of their application on time series are still not known sufficiently. The ongoing COST action HOME (COST ES0601) is devoted to reveal the real impacts of homogenisation methods more detailed and with higher confidence than earlier. As a part of the COST activity, a benchmark dataset was built whose characteristics approach well the characteristics of real networks of observed time series. This dataset offers much better opportunity than ever before to test the wide variety of homogenisation methods, and analyse the real effects of selected theoretical recommendations. Empirical results show that real observed time series usually include several inhomogeneities of different sizes. Small inhomogeneities often have similar statistical characteristics than natural changes caused by climatic variability, thus the pure application of the classic theory that change-points of observed time series can be found and corrected one-by-one is impossible. However, after homogenisation the linear trends, seasonal changes and long-term fluctuations of time series are usually much closer to the reality than in raw time series. Some problems around detecting multiple structures of inhomogeneities, as well as that of time series comparisons within homogenisation procedures are discussed briefly in the study.

Description: National Climate Observing System of Switzerland (GCOS Switzerland) Advances in Science and Research, 6, 95-102, 2011 Author(s): G. Seiz and N. Foppa In recent decades, the global observation of climate and climate change has become increasingly important. The Global Climate Observing System (GCOS) established in 1992 addresses the entire climate system including physical, chemical and biological properties of atmosphere, ocean and land surface. This paper describes the GCOS implementation in Switzerland and highlights some major achievements over the last few years. The Swiss GCOS Office was established at the Federal Office of Meteorology and Climatology MeteoSwiss in February 2006, to coordinate all climate-relevant measurements in Switzerland. The first-ever inventory of the country's long-term climatological data series and international data centres, including an assessment of their future prospects, was compiled in 2007. The National Climate Observing System of Switzerland (GCOS Switzerland) includes long-term climatological data series in the atmosphere and terrestrial domains, international data and calibration centres, satellite-based products and support of climate observations in developing countries. A major milestone in the surface-based atmospheric observations was the definition of the Swiss National Basic Climatological Network (NBCN), consisting of 29 stations of greatest climatological importance. The NBCN was further densified for precipitation with 46 additional daily precipitation stations (NBCN-P). Analysis of the homogenized timeseries of the average temperature in Switzerland shows a total warming of +1.6 °C from 1864 to 2010. In the terrestrial domain, substantial advances were made in all three subdomains hydrosphere, cryosphere and biosphere. As example for the use of satellite data within GCOS Switzerland, the 10-yr MODIS monthly mean cloud fraction climatology over Switzerland from March 2000 to February 2010 is presented, which illustrates the differences in cloud cover between mountainous regions and flatland regions in winter, as well as the north-south gradient in cloud cover over Switzerland in summer.

Description: A modification of the mixed form of Richards equation and its application in vertically inhomogeneous soils Advances in Science and Research, 6, 123-127, 2011 Author(s): F. Kalinka and B. Ahrens Recently, new soil data maps were developed, which include vertical soil properties like soil type. Implementing those into a multilayer Soil-Vegetation-Atmosphere-Transfer (SVAT) scheme, discontinuities in the water content occur at the interface between dissimilar soils. Therefore, care must be taken in solving the Richards equation for calculating vertical soil water fluxes. We solve a modified form of the mixed (soil water and soil matric potential based) Richards equation by subtracting the equilibrium state of soil matrix potential ψ E from the hydraulic potential ψ h . The sensitivity of the modified equation is tested under idealized conditions. The paper will show that the modified equation can handle with discontinuities in soil water content at the interface of layered soils.

Description: Aerosol-assisted CVD synthesis, characterisation and gas-sensing application of gold-functionalised tungsten oxide Journal of Sensors and Sensor Systems, 3, 325-330, 2014 Author(s): F. Di Maggio, M. Ling, A. Tsang, J. Covington, J. Saffell, and C. Blackman Tungsten oxide nanoneedles (NNs) functionalised with gold nanoparticles (NPs) have been integrated with alumina gas-sensor platforms using a simple and effective co-deposition method via aerosol-assisted chemical vapour deposition (AACVD) utilising a novel gold precursor, (NH 4 )AuCl 4 . The gas-sensing results show that gold NP functionalisation of tungsten oxide NNs improves the sensitivity of response to ethanol, with sensitivity increasing and response time decreasing with increasing amount of gold.

Description: Objectifying user attention and emotion evoked by relevant perceived product components Journal of Sensors and Sensor Systems, 3, 315-324, 2014 Author(s): R. Schmitt, M. Köhler, J. V. Durá, and J. Diaz-Pineda A company's aim is to develop products that engage user attention and evoke positive emotions. Customers base their emotional evaluation on product components that are relevant for their perception. This paper presents findings of both identifying relevant product components and measuring emotions evoked by relevant perceived product components. To validate results, the comparison with self-reporting methods identifies similarities and differences between explicit expressed and implicit recorded customer requirements. On the one hand, eye tracking is applied to deduce the attention provoked by perceived product components. In order to link the product strategy with product components, the paper presents results considering the fact that the gaze track is affected by current thoughts. (Köhler et al., 2013, 2014a, b; Köhler and Schmitt, 2012) On the other hand, since self-reporting tools are only useful for obtaining information about the conscious part of customers' emotions, there is a need for measurement methods that measure the changes in physiological signals (bio-signals). Arousal is similar to emotional intensity and is related to the galvanic skin response. Positive or negative emotions are defined by the valence that is measured by facial electromyography. Findings are presented that relate changes in bio-signals on the aesthetical design to the global product impression as well as to emotions and, subsequently, linking changes in physiological signals to the evaluation of semantic concepts and design parameters. The presented approach provides conclusions and valid information about products as well as product components that provoke certain emotions and about product components linked to a certain product concept, which could be part of a product strategy. Consequently, hard facts and special design rules for emotional product design can be deduced.

Description: The future climate characteristics of the Carpathian Basin based on a regional climate model mini-ensemble Advances in Science and Research, 6, 69-73, 2011 Author(s): I. Krüzselyi, J. Bartholy, A. Horányi, I. Pieczka, R. Pongrácz, P. Szabó, G. Szépszó, and Cs. Torma Four regional climate models (RCMs) were adapted in Hungary for the dynamical downscaling of the global climate projections over the Carpathian Basin: (i) the ALADIN-Climate model developed by Météo France on the basis of the ALADIN short-range modelling system; (ii) the PRECIS model available from the UK Met Office Hadley Centre; (iii) the RegCM model originally developed at the US National Center for Atmospheric Research, is maintained at the International Centre for Theoretical Physics in Trieste; and (iv) the REMO model developed by the Max Planck Institute for Meteorology in Hamburg. The RCMs are different in terms of dynamical model formulation, physical parameterisations; moreover, in the completed simulations they use different spatial resolutions, integration domains and lateral boundary conditions for the scenario experiments. Therefore, the results of the four RCMs can be considered as a small ensemble providing information about various kinds of uncertainties in the future projections over the target area, i.e., Hungary. After the validation of the temperature and precipitation patterns against measurements, mean changes and some extreme characteristics of these patterns (including their statistical significance) have been assessed focusing on the periods of 2021–2050 and 2071–2100 relative to the 1961–1990 model reference period. The ensemble evaluation indicates that the temperature-related changes of the different RCMs are in good agreement over the Carpathian Basin and these tendencies manifest in the general warming conditions. The precipitation changes cannot be identified so clearly: seasonally large differences can be recognised among the projections and between the two periods. An overview is given about the results of the mini-ensemble and special emphasis is put on estimating the uncertainties in the simulations for Hungary.

Description: A Non-Linear Mixed Spectral Finite-Difference 3-D model for planetary boundary-layer flow over complex terrain Advances in Science and Research, 6, 75-78, 2011 Author(s): W. Weng and P. A. Taylor The Non-Linear Mixed Spectral Finite-Difference (NLMSFD) model for surface boundary-layer flow over complex terrain has been extended to planetary boundary-layer flow over topography. Comparisons are made between this new version and the surface layer model. The model is also applied to simulate an Askervein experimental case. The results are discussed and compared with the observed field data.

Description: Correlation between air-sea heat fluxes over the Aegean Sea and the total precipitable water over Europe and North Africa Advances in Science and Research, 6, 63-67, 2011 Author(s): V. P. Papadopoulos, A. Bartzokas, T. Chronis, S. Ruiz, N. Zarokanellos, and G. Ferentinos The relation between the air-sea heat fluxes in the Aegean Sea and the total precipitable water (TPW) over Europe and North Africa is investigated. An one-point linear correlation between the components of surface heat exchange and TPW is employed. During winter and for the shortwave radiation, a dipole of opposite correlation (see-saw teleconnection), is observed between the northeast Europe and the East Mediterranean Sea. This pattern is inverted for the longwave radiation and especially during the summer is limited to a strong positive south pole. Both spatial correlation patterns underline the influence of cloudiness during the winter season and the specific humidity during summer on the radiative fluxes behavior. Regarding the turbulent air-sea heat flux components – latent and sensible heat – the correlation pattern is enhanced. The winter pattern exhibits positive correlation over Europe with the highest values ( r 〉0.75) over the Balkan Peninsula. The identified correlation patterns, although they remain dominant, weaken during the summer. The herein findings suggest that the stronger relation between the TPW and the turbulent fluxes is regulated by the wind regime.

Description: Challenges for Wireless Mesh Networks to provide reliable carrier-grade services Advances in Radio Science, 9, 377-382, 2011 Author(s): D. von Hugo and N. Bayer Provision of mobile and wireless services today within a competitive environment and driven by a huge amount of steadily emerging new services and applications is both challenge and chance for radio network operators. Deployment and operation of an infrastructure for mobile and wireless broadband connectivity generally requires planning effort and large investments. A promising approach to reduce expenses for radio access networking is offered by Wireless Mesh Networks (WMNs). Here traditional dedicated backhaul connections to each access point are replaced by wireless multi-hop links between neighbouring access nodes and few gateways to the backbone employing standard radio technology. Such a solution provides at the same time high flexibility in both deployment and the amount of offered capacity and shall reduce overall expenses. On the other hand currently available mesh solutions do not provide carrier grade service quality and reliability and often fail to cope with high traffic load. EU project CARMEN (CARrier grade MEsh Networks) was initiated to incorporate different heterogeneous technologies and new protocols to allow for reliable transmission over "best effort" radio channels, to support a reliable mobility and network management, self-configuration and dynamic resource usage, and thus to offer a permanent or temporary broadband access at high cost efficiency. The contribution provides an overview on preliminary project results with focus on main technical challenges from a research and implementation point of view. Especially impact of mesh topology on the overall system performance in terms of throughput and connection reliability and aspects of a dedicated hybrid mobility management solution will be discussed.

Description: Meteor radar measurements of mean winds and tides over Collm (51.3° N, 13° E) and comparison with LF drift measurements 2005–2007 Advances in Radio Science, 9, 335-341, 2011 Author(s): C. Jacobi An all-sky VHF meteor radar (MR) has been continuously operated at Collm (51.3° N, 13° E) since summer 2004. The radar measures meteor parameters, diffusion coefficients, and horizontal winds in the mesopause region. There exists a temporal overlap of the MR wind measurements with co-located low-frequency (LF) ionospheric drift measurements until 2007. Comparison of MR and LF semidiurnal tidal phases allows to empirically determine the virtual height overestimation of LF reflection heights due to the group retardation of LF waves. LF reference heights have to be reduced by up to 20 km to match real heights. Correction of LF heights for group retardation allows to determine the wind underestimation by the LF method compared with meteor radar measurements and opens the possibility to continue long-term trend analysis using mesosphere/lower thermosphere winds.

Description: Locomotion and postural behaviour Advances in Science and Research, 5, 23-39, 2010 Author(s): M. Schmidt The purpose of this article is to provide a survey of the diversity of primate locomotor behaviour for people who are involved in research using laboratory primates. The main locomotor modes displayed by primates are introduced with reference to some general morphological adaptations. The relationships between locomotor behaviour and body size, habitat structure and behavioural context will be illustrated because these factors are important determinants of the evolutionary diversity of primate locomotor activities. They also induce the high individual plasticity of the locomotor behaviour for which primates are well known. The article also provides a short overview of the preferred locomotor activities in the various primate families. A more detailed description of locomotor preferences for some of the most common laboratory primates is included which also contains information about substrate preferences and daily locomotor activities which might useful for laboratory practice. Finally, practical implications for primate husbandry and cage design are provided emphasizing the positive impact of physical activity on health and psychological well-being of primates in captivity.

Description: Assessment of climate vulnerability in the Norwegian built environment Advances in Science and Research, 6, 151-153, 2011 Author(s): H. O. Hygen, C. F. Øyen, and A. J. Almås The main trends expected for the change of Norwegian climate for this century are increasing temperatures, precipitation and wind. This indicates a probable increase of climate-related risks to the Norwegian built environment. Through co-operation between the Norwegian Meteorological Institute and SINTEF Building and Infrastructure, building and climate information have been combined to estimate changes in strain to the built environment due to climate change. The results show that the risk of wood decay will increase for the whole country. Almost two million buildings will be subject to an increase in risk of wood decay from medium to high level. Similar analyses have been performed for other climate indices, demonstrating a clear increase in potential damages due to water and humidity, while frost damage probably will decrease.

Description: Atmospheric boundary layer wind profile at a flat coastal site – wind speed lidar measurements and mesoscale modeling results Advances in Science and Research, 6, 155-159, 2011 Author(s): R. Floors, E. Batchvarova, S.-E. Gryning, A. N. Hahmann, A. Peña, and T. Mikkelsen Wind profiles up to 600 m height are investigated. Measurements of mean wind speed profiles were obtained from a novel wind lidar and compared to model simulations from a mesoscale model (WRF-ARW v3.1). It is found that WRF is able to predict the mean wind profile rather well and typically within 1–2 m s −1 to the individual measured values. WRF underpredicts the normalized wind profile, especially for stable conditions. The effect of baroclinicity on the upper part of the wind profile is discussed.

Description: Extreme summer temperatures in Western Europe Advances in Science and Research, 8, 5-9, 2012 Author(s): C. Simolo, M. Brunetti, M. Maugeri, and T. Nanni We discuss the evolution of summer temperature extremes over Western Europe during 1961–2004 in the context of current climate warming. Using a parametric approach, we investigate the role of properties and changes in probability density functions of daily temperatures in modifying the frequency of severe, isolated events. In this perspective, the recent intensification of extremely warm events over Europe turns out to be well consistent with a pure, nonuniform shift of mean values, with no room for conjectures about increasing temperature variability.

Description: Sensitivity of the RMI's MAGIC/Heliosat-2 method to relevant input data Advances in Science and Research, 10, 7-13, 2013 Author(s): C. Demain, M. Journée, and C. Bertrand Appropriate information on solar resources is very important for a variety of technological areas. Based on the potential of retrieving global horizontal irradiance from satellite data, an enhanced version of the Heliosat-2 method has been implemented at the Royal Meteorological Institute of Belgium to estimate surface solar irradiance over Belgium from Meteosat Second Generation at the SEVIRI spatial and temporal resolution. In this contribution, sensitivity of our retrieval scheme to surface albedo, atmospheric aerosol and water vapor contents is investigated. Results indicate that while the use of real-time information instead of climatological values can help to reduce to some extent the RMS error between satellite-retrieved and ground-measured solar irradiance, only the correction of the satellite-derived data with in situ measurements allows to significantly reduce the overall model bias.

Description: Quality control of 10-min air temperature data at RMI Advances in Science and Research, 10, 1-5, 2013 Author(s): C. Bertrand, L. Gonzalez Sotelino, and M. Journée In the '90s, the Royal Meteorological Institute (RMI) of Belgium started to replace its conventional ''manual'' meteorological network by automated weather stations (AWSs). The meteorological measurement network is now fully automated. RMI counts 18 AWSs that made automated observations centrally available in our headquarters in Uccle, Brussels to internal as well as external users. Due to the large increase in the data amount associated with the automation, quality assurance (QA) procedures are being automated. However, human operators continue to play an essential role in the data validation processes. This contribution describes our newly developed semi-automatic quality control (QC) of 10-min air temperature data. After an existence test, the data are checked for limits consistency, temporal consistency and spatial consistency. At the end of these automated checks, a decision algorithm attributes a flag to each particular data. Each day the QC staff analyzes the preceding day observations in the light of the quality flags assigned by automated QA procedures during the night. It is the human decision whether or not a value is accepted.

Description: Large-Eddy Simulation of plume dispersion within various actual urban areas Advances in Science and Research, 10, 33-41, 2013 Author(s): H. Nakayama, K. Jurcakova, and H. Nagai Plume dispersion of hazardous materials within urban area resulting from accidental or intentional releases is of great concern to public health. Many researchers have developed local-scale atmospheric dispersion models using building-resolving computational fluid dynamics. However, an important issue is encountered when determining a reasonable domain size of the computational model in order to capture concentration distribution patterns influenced by urban surface geometries. In this study, we carried out Large-Eddy Simulations (LES) of plume dispersion within various urban areas with a wide range of obstacle density and building height variability. The difference of centerline mean and r.m.s. concentration distributions among various complex urban surface geometries becomes small for downwind distances from the point source greater than 1.0 km. From these results, it can be concluded that a length of a computational model should be at least 1.0 km from a point source.

Description: IP-based mobility management for heterogeneous wireless access Advances in Radio Science, 10, 319-325, 2012 Author(s): H. J. Einsiedler and D. von Hugo Future high quality communication services will be offered in an integrated or converged network infrastructure maintaining both fixed wireless and mobile access via multi-mode user terminals. A support of various scenarios of user and/or terminal mobility within a common IP-based infrastructure requires intelligently designed control protocols. A major challenge is to provide seamless (i.e. lossless and low delay) handover between different radio cells and operator domains to enable continuation of unicast and multicast sessions while using network resources most efficiently. IETF (Internet Engineering Task Force) is specifying related IP mobility management protocols to be applicable also to a flat architecture as envisaged by Next Generation (Mobile) Networks (NGNs/NGMNs). The contribution will describe operator requirements towards such an approach. Both single-domain and multi-domain scenarios will be discussed based on federation ideas. Already existing solutions are taken into consideration and application of solution proposals towards a Distributed Mobility Management (DMM) currently under evaluation within IETF will be outlined.

Description: STF Optimierung von single-bit CT ΣΔ Modulatoren basierend auf skalierten Filterkoeffizienten Advances in Radio Science, 10, 313-317, 2012 Author(s): C. Widemann, C. Zorn, T. Brückner, M. Ortmanns, and W. Mathis Die vorliegende Arbeit beschäftigt sich mit dem Signalübertragungsverhalten von single-bit continuous-time (CT) ΣΔ Modulatoren. Dabei liegt der Fokus der Untersuchung auf dem Peaking der Signaltransferfunktion (STF). Dieser Effekt kann die Performance und die Stabilität des Gesamtsystems negativ beeinflussen, da bei auftretendem STF-Peaking Signale außerhalb des Signalbands verstärkt werden. In dieser Arbeit wird ein neuer Ansatz zur Reduktion des Peakings vorgestellt, der auf der Optimierung der Systemdynamik basiert. Dabei werden die Filterkoeffizienten des Modulators systematisch angepasst. Anhand eines Beispielsystems wird gezeigt, dass der Ansatz genutzt werden kann, um das Übertragungsverhalten des Modulators abhängig vom Ausgangssystem zu verändern. So kann entweder die Systemsperformance verbessert werden, ohne Peaking in der STF zu erzeugen, oder das STF-Peaking reduziert werden, ohne die Systemperformance stark zu beeinflussen.

Description: Differential Algebraic Equations of MOS Circuits and Jump Behavior Advances in Radio Science, 10, 327-332, 2012 Author(s): P. Sarangapani, T. Thiessen, and W. Mathis Many nonlinear electronic circuits showing fast switching behavior exhibit jump effects which occurs when the state space of the electronic system contains a fold. This leads to difficulties during the simulation of these systems with standard circuit simulators. A method to overcome these problems is by regularization, where parasitic inductors and capacitors are added at the suitable locations. However, the transient solution will not be reliable if this regularization is not done in accordance with Tikhonov's Theorem. A geometric approach is taken to overcome these problems by explicitly computing the state space and jump points of the circuit. Until now, work has been done in analyzing example circuits exhibiting this behavior for BJT transistors. In this work we apply these methods to MOS circuits (Schmitt trigger, flip flop and multivibrator) and present the numerical results. To analyze the circuits we use the EKV drain current model as equivalent circuit model for the MOS transistors.

Description: INCA-CE: a Central European initiative in nowcasting severe weather and its applications Advances in Science and Research, 8, 67-75, 2012 Author(s): A. Kann, G. Pistotnik, and B. Bica The INCA-CE ( I ntegrated N owcasting through C omprehensive A nalysis – C entral E urope) project aims at implementing a transnational weather information system as well as applications for different socio-economic sectors to reduce risks of major economic damage and loss of life caused by severe weather. Civil protection and also stakeholders from economic sectors are in a growing need of accurate and reliable short-term weather forecasts. Within INCA-CE, a state-of-the art nowcasting system (INCA) is implemented at weather services throughout the European Union's CE (Central Europe) Programme Area, providing analyses and short term forecasts to the aforementioned end-users. In a coherent approach, the INCA (Integrated Nowcasting through Comprehensive Analysis) system will be adapted for implementation and use in a number of partner countries. Within transregional working groups, the gap between short-term weather information and its downstream activities in hydrological disaster management, civil protection and road management will be bridged and best practice management and measure plans will be produced. A web-based platform for outreach to related socio-economic sectors will initiate and foster a dialogue between weather services and further stakeholders like tourism or the insurance sector, flood authorities for disaster management, and the construction industry for cost-efficient scheduling and planning. Furthermore, the project will produce a compact guideline for policy makers on how to combine structural development aspects with these new features. In the present paper, an outline of the project implementation, a short overview about the INCA system and two case studies on precipitation nowcasts will be given. Moreover, directions for further developments both within the INCA system and the INCA-CE project will be pointed out.

Description: First outcomes from the CNR-ISAC monthly forecasting system Advances in Science and Research, 8, 77-82, 2012 Author(s): D. Mastrangelo, P. Malguzzi, C. Rendina, O. Drofa, and A. Buzzi A monthly probabilistic forecasting system is experimentally operated at the ISAC institute of the National Council of Research of Italy. The forecasting system is based on GLOBO, an atmospheric general circulation model developed at the same institute. The model is presently run on a monthly basis to produce an ensemble of 32 forecasts initialized with GFS-NCEP perturbed analyses. Reforecasts, initialized with ECMWF ERA-Interim reanalyses of the 1989–2009 period, are also produced to determine modelled climatology of the month to forecast. The modelled monthly climatology is then used to calibrate the ensemble forecast of daily precipitation, geopotential height and temperature on standard pressure levels. In this work, we present the forecasting system and a preliminary evaluation of the model systematic and forecast errors in terms of non-probabilistic scores of the 500-hPa geopotential height. Results show that the proposed forecasting system outperforms the climatology in the first two weeks of integrations. The adopted calibration based on weighted bias correction is found to reduce the systematic and the forecast errors.

Description: An overview of drought events in the Carpathian Region in 1961–2010 Advances in Science and Research, 10, 21-32, 2013 Author(s): J. Spinoni, T. Antofie, P. Barbosa, Z. Bihari, M. Lakatos, S. Szalai, T. Szentimrey, and J. Vogt The Carpathians and their rich biosphere are considered to be highly vulnerable to climate change. Drought is one of the major climate-related damaging natural phenomena and in Europe it has been occurring with increasing frequency, intensity, and duration in the last decades. Due to climate change, land cover changes, and intensive land use, the Carpathian Region is one of the areas at highest drought risk in Europe. In order to analyze the drought events over the last 50 yr in the area, we used a 1961–2010 daily gridded temperature and precipitation dataset. From this, monthly 0.1° × 0.1° grids of four drought indicators (Standardized Precipitation-Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), Reconnaissance Drought Indicator (RDI), and Palfai Aridity/Drought Index (PADI)) have been calculated. SPI, SPEI, and RDI have been computed at different time scales (3, 6, and 12 months), whilst PADI has been computed on an annual basis. The dataset used in this paper has been constructed in the framework of the CARPATCLIM project, run by a consortium of institutions from 9 countries (Austria, Croatia, Czech Republic, Hungary, Poland, Romania, Serbia, Slovakia, and Ukraine) with scientific support by the Joint Research Centre (JRC) of the European Commission. Temperature and precipitation station data have been collected, quality-checked, completed, homogenized, and interpolated on the 0.1° × 0.1° grid, and drought indicators have been consequently calculated on the grid itself. Monthly and annual series of the cited indicators are presented, together with high-resolution maps and statistical analysis of their correlation. A list of drought events between 1961 and 2010, based on the agreement of the indicators, is presented. We also discuss three case studies: drought in 1990, 2000, and 2003. The drought indicators have been compared both on spatial and temporal scales: it resulted that SPI, SPEI, and RDI are highly comparable, especially over a 12-month accumulation period. SPEI, which includes PET (Potential Evapo-Transpiration) as RDI does, proved to perform best if drought is caused by heat waves, whilst SPI performed best if drought is mainly driven by a rainfall deficit, because SPEI and RDI can be extreme in dry periods. According to PADI, the Carpathian Region has a sufficient natural water supply on average, with some spots that fall into the ''mild dry'' class, and this is also confirmed by the FAO-UNEP aridity index and the Köppen-Geiger climate classification.

Description: Statistical processing of forecasts for hydrological ensemble prediction: a comparative study of different bias correction strategies Advances in Science and Research, 8, 135-141, 2012 Author(s): I. Zalachori, M.-H. Ramos, R. Garçon, T. Mathevet, and J. Gailhard The aim of this paper is to investigate the use of statistical correction techniques in hydrological ensemble prediction. Ensemble weather forecasts (precipitation and temperature) are used as forcing variables to a hydrologic forecasting model for the production of ensemble streamflow forecasts. The impact of different bias correction strategies on the quality of the forecasts is examined. The performance of the system is evaluated when statistical processing is applied: to precipitation and temperature forecasts only ( pre-processing from the hydrological model point of view), to flow forecasts ( post-processing ) and to both. The pre-processing technique combines precipitation ensemble predictions with an analog forecasting approach, while the post-processing is based on past errors of the hydrological model when simulating streamflows. Forecasts from 11 catchments in France are evaluated. Results illustrate the importance of taking into account hydrological uncertainties to improve the quality of operational streamflow forecasts.

Description: Statistical analysis of inter-arrival times of rainfall events for Italian Sub-Alpine and Mediterranean areas Advances in Science and Research, 8, 171-177, 2012 Author(s): C. Agnese, G. Baiamonte, C. Cammalleri, D. Cat Berro, S. Ferraris, and L. Mercalli In this work a set of time-series of inter-arrival times of rainfall events, at daily scale, was analysed, with the aim to verify the issue of increasing duration of dry periods. The set consists of 12 time-series recorded at rain gauges in 1926–2005, six of them belong to an Italian Sub-Alpine area (Piedmont) and six to a Mediterranean one (Sicily). In order to overcome the problem related to limited sample size for high values of inter-arrival times, the discrete probability polylog-series distribution was used to fit the empirical data from partial (20 yr) time-series. Moreover, a simple qualitative trend analysis was applied to some high quantiles of inter-arrival times as well as to the average extent of rain clusters. The preliminary analysis seems to confirm the issue of increasing duration of dry periods for both environments, which is limited to the ''cold'' season.

Description: Quality control procedures at Euskalmet data center Advances in Science and Research, 8, 129-134, 2012 Author(s): R. Hernández, M. Maruri, K. Otxoa de Alda, J. Egaña, and S. Gaztelumendi The Basque Country Mesonet measures more than 130 000 observations daily from its 85 Automatic Weather Stations (AWS). It becomes clear that automated software is an indispensable tool for quality assurance (QA) of this mesoscale surface observing network. This work describes a set of experimental semi-automatic quality control (QC) routines that is applied at Euskalmet data center. It has paid special attention to level validation design and associated flags, as well as to the system outputs, which are used by meteorologist and maintenance staff.

Description: Comparative verification of different nowcasting systems to support optimisation of thunderstorm warnings Advances in Science and Research, 8, 121-127, 2012 Author(s): K. Wapler, M. Goeber, and S. Trepte The development and use of nowcasting systems should inevitably be accompanied by the development and application of suitable verification methods. A thorough verification strategy is needed to adequately assess the quality of the system and consequently to lead to improvements. Different verification methods for thunderstorms and its attributes are discussed along with the importance of observational data sets. They are applied to two radar-based nowcasting algorithms for a convective season using various observation data sets. The results show, that the combination of the two algorithms outperforms a single algorithm.

Description: Comparison of Large Eddy Simulations of a convective boundary layer with wind LIDAR measurements Advances in Science and Research, 8, 83-86, 2012 Author(s): J. G. Pedersen, M. Kelly, S.-E. Gryning, R. Floors, E. Batchvarova, and A. Peña Vertical profiles of the horizontal wind speed and of the standard deviation of vertical wind speed from Large Eddy Simulations of a convective atmospheric boundary layer are compared to wind LIDAR measurements up to 1400 m. Fair agreement regarding both types of profiles is observed only when the simulated flow is driven by a both time- and height-dependent geostrophic wind and a time-dependent surface heat flux. This underlines the importance of mesoscale effects when the flow above the atmospheric surface layer is simulated with a computational fluid dynamics model.

Description: Has the frequency or intensity of hot weather events changed in Poland since 1950? Advances in Science and Research, 8, 87-91, 2012 Author(s): J. Wibig Various indices of hot weather frequency and intensity were analysed in the area of Poland in the period between 1951 and 2006. An increase of majority of them was shown in the whole year and all summer months but September, when significant decrease in all indices was apparent. The correlation of selected hot weather indices and precipitation totals in a month of hot weather event and the preceding months were also calculated to check if prolonged dry weather can constitute a forcing factor for hot event creation. Because significant correlations appear mainly in the cases when precipitation is for the same month as the hot weather index, it seems that in Poland the presence of high pressure systems is a more important factor of hot event creation than dry weather.

Description: Quality assessment of heterogeneous surface radiation network data Advances in Science and Research, 8, 93-97, 2012 Author(s): R. Becker and K. Behrens The DWD national radiation measurement network comprises 82 automatic sites, 29 manned sites with shaded and unshaded pyranometer and the BSRN station at Lindenberg. The quality assessment routinely applied takes into account the basic astronomical and empirical considerations as well as some interdependencies like total to diffuse flux relation and cross checking with sunshine duration. A more advanced quality assessment approach attempts to routinely utilise timeseries of clear sky radiative transfer simulations for every site. For that purpose a link to cloud coverage obtained from Meteosat second generation geostationary satellite data, highly resolved in time and space, was established. There is a predefined calibration cycle of 30 month for automatic stations. Data analysis on this timescale allows for the detection of sensor degradation, wrong calibration or configuration and other possible local disturbances. Furthermore using satellite cloud mask enables the identification of larger clear sky regions characterized by similar atmospheric conditions. Thus, in a regionalization step correction or recalibration of moderate quality data to a higher level can be considered. The paper provides an overview of DWD surface radiation network and the current activities to improve automatic quality assessment using remotely sensed data and clear sky modeling for the upgrading of radiation data.

Description: On the skill of various ensemble spread estimators for probabilistic short range wind forecasting Advances in Science and Research, 8, 115-120, 2012 Author(s): A. Kann A variety of applications ranging from civil protection associated with severe weather to economical interests are heavily dependent on meteorological information. For example, a precise planning of the energy supply with a high share of renewables requires detailed meteorological information on high temporal and spatial resolution. With respect to wind power, detailed analyses and forecasts of wind speed are of crucial interest for the energy management. Although the applicability and the current skill of state-of-the-art probabilistic short range forecasts has increased during the last years, ensemble systems still show systematic deficiencies which limit its practical use. This paper presents methods to improve the ensemble skill of 10-m wind speed forecasts by combining deterministic information from a nowcasting system on very high horizontal resolution with uncertainty estimates from a limited area ensemble system. It is shown for a one month validation period that a statistical post-processing procedure (a modified non-homogeneous Gaussian regression) adds further skill to the probabilistic forecasts, especially beyond the nowcasting range after +6 h.

Description: Advanced information criterion for environmental data quality assurance Advances in Science and Research, 8, 99-104, 2012 Author(s): A. Düsterhus and A. Hense A new method for testing time series of environmental data for internal inconsistencies is presented. The method divides the dataset into several disjunct blocks. By means of a comparison of the blocks' estimated probability density distributions, each block is compared with the others. In order to judge the differences, four different measures are used and compared: Kullback-Leibler Divergence, Jensen-Shannon Divergence, Earth Mover's Distance and the Root Mean Square. By looking at the resulting patterns, conclusions on possible inconsistencies in the data can be drawn. This paper shows some sensitivitiy tests and gives an example for an application to real data. Furthermore, it is shown, in which cases of errors (shift in mean, shift in variance and rounding), which measure performs best.

Description: Finite element simulation of a local scale air quality model over complex terrain Advances in Science and Research, 8, 105-113, 2012 Author(s): A. Oliver, G. Montero, R. Montenegro, E. Rodríguez, J. M. Escobar, and A. Perez-Foguet In this paper we propose a finite element method approach for modelling the air quality in a local scale over complex terrain. The area of interest is up to tens of kilometres and it includes pollutant sources. The proposed methodology involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion of the plume rise effect in the wind field, and the simulation of transport and reaction of pollutants. We apply our methodology to simulate a fictitious pollution episode in La Palma island (Canary Island, Spain).

Description: A modified drought index for WMO RA VI Advances in Science and Research, 6, 275-279, 2011 Author(s): S. Pietzsch and P. Bissolli Drought is a phenomenon which can cause large economical impact even in Europe. To assess the magnitude and the spatial extension of drought events, it is important to have a standardized drought index which is applicable for a large climatically heterogeneous region like Europe or the WMO RA VI Region (Europe and the Middle East). Such an index should describe the drought phenomenon adequately, but it should also be derivable from meteorological quantities which are easily and timely available in whole Europe. In a first investigation, some candidates for drought indices were chosen, compared and assessed for applicability in whole Europe. The most appropriate one seems to be the widely known Standardized Precipitation Index (SPI) which is a standardized and handy measurement of drought for any location and requires nothing but precipitation data. However, it has turned out that for some places in the RA VI Region, notably in arid regions in summer, the SPI does not always provide reasonable or easily interpretable results. For that reason, some modifications of the SPI have been tried out and tested statistically. It seems that the gamma distribution of precipitation which is used for computation of the SPI is in fact the most appropriate one and other distributions have not improved the results substantially. On the other hand a so called zero correction, which sets very small precipitation totals to dry values, only dependent on the precipitation distribution, but independent on the individual location delivers more reasonable results. Maps of the new modified drought index and its anomalies from the climate normal are produced quasi-operationally and distributed via the Internet each month. The drought monitoring is part of the monitoring programme of the WMO RA VI Pilot Regional Climate Centre on Climate Monitoring (RCC-CM) hosted by the German Meteorological Service (Deutscher Wetterdienst, DWD), and the maps can be found on its present RCC-CM platform ( http://www.dwd.de/rcc-cm ).

Description: 1961–1990 monthly high-resolution solar radiation climatologies for Italy Advances in Science and Research, 8, 19-25, 2012 Author(s): J. Spinoni, M. Brunetti, M. Maugeri, and C. Simolo We present a methodology for estimating solar radiation climatologies from a sparse network of global radiation and/or sunshine duration records: it allows to obtain high-resolution grids of monthly normal values for global radiation (and for the direct and diffuse components), atmospheric turbidity, and surface absorbed radiation. We discuss the application of the methodology to a preliminary version of an Italian global radiation and sunshine duration data set, which completion is still in progress and present the resulting 1961–1990 monthly radiation climatologies.

Description: Observations and WRF simulations of fog events at the Spanish Northern Plateau Advances in Science and Research, 8, 11-18, 2012 Author(s): C. Román-Cascón, C. Yagüe, M. Sastre, G. Maqueda, F. Salamanca, and S. Viana The prediction of fogs is one of the processes not well reproduced by the Numerical Weather Prediction (NWP) models. In particular, the role of turbulence in the formation or dissipation of fogs is one of the physical processed not well understood, and therefore, not well parameterized by the NWP models. Observational analysis of three different periods with fogs at the Spanish Northern Plateau has been carried out. These periods have also been simulated with the Weather Research and Forecasting (WRF) numerical model and their results have been compared to observations. The study includes a comparison of the skill of different planetary boundary layer (PBL) parameterizations, surface layer schemes and a test of the gravitational settling of clouds/fogs droplets option. A statistical analysis of this comparison has been evaluated in order to study differences between the periods and between the various parameterizations used. The model results for each PBL parameterization were different, depending on the studied period, due to differences in the features of each fog. This fact made it difficult to obtain generalized conclusions, but allowed us to determine which parameterization performed better for each case. In general, judging from the models results of liquid water content (LWC), none of the PBL schemes were able to correctly simulate the fogs, being Mellor-Yamada Nakanishi and Niino (MYNN) 2.5 level PBL scheme the best one in most of the cases. This conclusion is also supported by the root mean square error (RMSE) calculated for different meteorological variables.

Description: Issues faced in digitally re-purposing printed archival material Advances in Science and Research, 6, 271-273, 2011 Author(s): T. M. Dart The Seeing Ear On-Line Library ( http://www.seeingear.org ) is the first general on-line library in the UK and has been providing books in an electronic format to EU users for more than 5 yr. While this provision has been within the context of print-disability, the challenges that the Library has faced and is facing are common to everyone re-purposing printed archival material. Key issues faced by anyone contemplating such a project are the choices of hardware and software, error rates and reduction, feature analysis and extraction, and archival (meta)format. This paper presents an approach to these questions to facilitate the on-line presentation of popular climatological material. This work was supported by the Big Lottery Fund UK.

Description: The French contribution to the Global Climate Observing System Advances in Science and Research, 6, 45-48, 2011 Author(s): R. Juvanon du Vachat France is participating fully in the Global Climate Observing System (GCOS). It incorporates the following four components: meteorological and atmospheric, oceanic, terrestrial, spatial, which will be briefly presented, especially in relation with the monitoring of the climate. The presentation will give an overview of the general principles governing the GCOS system and particularly the concepts used to maintain efficiently this climate observing system for a long period of time ("from research networks to operational networks"). The presentation will cover all the four components of the GCOS system. The whole report has been published in the Fifth National Communication from France to the UNFCCC (United Nations Framework Convention on Climate Change). The presentation will give an overview of the different networks of these four domains devoted to the monitoring of climate and maintained by France and highlighting the strengths and weaknesses of this climate observing system.

Description: WegenerNet climate station network region Feldbach, Austria: network structure, processing system, and example results Advances in Science and Research, 6, 49-54, 2011 Author(s): T. Kabas, A. Leuprecht, C. Bichler, and G. Kirchengast The WegenerNet climate station network is a pioneering weather and climate observation experiment at very high resolution in southeastern Austria. The network comprises 151 meteorological stations within a limited area of approximately 20 km × 15 km centered near the town of Feldbach. Measurements include the parameters air temperature, relative humidity, precipitation amount, and others at selected stations (e.g. wind and soil parameters). The temporal sampling is 5 min except 30 min sampling of soil measurements. All data pass a Quality Control System and the provided data products include station data (~1.4 km × 1.4 km grid) and gridded data (1 km × 1 km and 0.01° × 0.01° grids) on various temporal scales (from 5 min to annual). For application purposes all data are available in near real time (data latency less than 1–2 h in standard operation) via the WegenerNet data portal ( www.wegenernet.org ).

Description: Improving short-term forecasting during ramp events by means of Regime-Switching Artificial Neural Networks Advances in Science and Research, 6, 55-58, 2011 Author(s): C. Gallego, A. Costa, and A. Cuerva Ramp events are large rapid variations within wind power time series. Ramp forecasting can benefit from specific strategies so as to particularly take into account these shifts in the wind power output dynamic. In the short-term context (characterized by prediction horizons from minutes to a few days), a Regime-Switching (RS) model based on Artificial Neural Nets (ANN) is proposed. The objective is to identify three regimes in the wind power time series: Ramp-up, Ramp-down and No-ramp regime. An on-line regime assessment methodology is also proposed, based on a local gradient criterion. The RS-ANN model is compared to a single-ANN model (without regime discrimination), concluding that the regime-switching strategy leads to significant improvements for one-hour ahead forecasts, mainly due to the improvements obtained during ramp-up events. Including other explanatory variables (NWP outputs, local measurements) during the regime assessment could eventually improve forecasts for further horizons.

Description: Development of a longterm dataset of solid/liquid precipitation Advances in Science and Research, 6, 39-43, 2011 Author(s): B. Chimani, R. Böhm, C. Matulla, and M. Ganekind Solid precipitation (mainly snow, but snow and ice pellets or hail as well), is an important parameter for climate studies. But as this parameter usually is not available operationally before the second part of the 20th century and nowadays is not reported by automatic stations, information usable for long term climate studies is rare. Therefore a proxy for the fraction of solid precipitation based on a nonlinear relationship between the percentage of solid precipitation and monthly mean temperature was developed for the Greater Alpine Region of Europe and applied to the existing longterm high resolution temperature and precipitation grids (5 arcmin). In this paper the method is introduced and some examples of the resulting datasets available at monthly resolution for 1800–2003 are given.

Description: An application of ensemble/multi model approach for wind power production forecasting Advances in Science and Research, 6, 35-37, 2011 Author(s): S. Alessandrini, P. Pinson, R. Hagedorn, G. Decimi, and S. Sperati The wind power forecasts of the 3 days ahead period are becoming always more useful and important in reducing the problem of grid integration and energy price trading due to the increasing wind power penetration. Therefore it's clear that the accuracy of this forecast is one of the most important requirements for a successful application. The wind power forecast applied in this study is based on meteorological models that provide the 3 days ahead wind data. A Model Output Statistic correction is then performed to reduce systematic error caused, for instance, by a wrong representation of surface roughness or topography in the meteorological models. For this purpose a training of a Neural Network (NN) to link directly the forecasted meteorological data and the power data has been performed. One wind farm has been examined located in a mountain area in the south of Italy (Sicily). First we compare the performances of a prediction based on meteorological data coming from a single model with those obtained by the combination of models (RAMS, ECMWF deterministic, LAMI). It is shown that the multi models approach reduces the day-ahead normalized RMSE forecast error (normalized by nominal power) of at least 1% compared to the singles models approach. Finally we have focused on the possibility of using the ensemble model system (EPS by ECMWF) to estimate the hourly, three days ahead, power forecast accuracy. Contingency diagram between RMSE of the deterministic power forecast and the ensemble members spread of wind forecast have been produced. From this first analysis it seems that ensemble spread could be used as an indicator of the forecast's accuracy at least for the first three days ahead period.

Description: Multi-methodical realisation of Austrian climate maps for 1971–2000 Advances in Science and Research, 6, 19-26, 2011 Author(s): J. Hiebl, S. Reisenhofer, I. Auer, R. Böhm, and W. Schöner Constantly changing climate, the availability of a higher resolved digital elevation model and further development of geostatistical interpolation methods gave reason for updating the most frequently demanded climate maps out of the Austrian digital climate atlas from 1961–1990 to 1971–2000. To achieve a station density as high as possible, data from eleven national and foreign institutes were collected and gap-filled. According to the climate parameter, different geostatistical interpolation methods (including regionalised multilinear regressions, geographically weighted regressions and curve fitting to base parameter) were applied. The resultant 17 grids concern 30-year-means of air temperature, precipitation and snow parameters as well as derived indices. They are now available for a variety of scientific and planning purposes.

Description: Estimating urban heat island effects on near-surface air temperature records of Uccle (Brussels, Belgium): an observational and modeling study Advances in Science and Research, 6, 27-34, 2011 Author(s): R. Hamdi and H. Van de Vyver In this letter, the Brussels's urban heat island (UHI) effect on the near-surface air temperature time series of Uccle (the national suburban recording station of the Royal Meteorological Institute of Belgium) was estimated between 1955 and 2006 during the summer months. The UHI of Brussels was estimated using both ground-based weather stations and remote sensing imagery combined with a land surface scheme that includes a state-of-the-art urban parameterization, the Town Energy Balance scheme. Analysis of urban warming based on the remote sensing method reveals that the urban bias on minimum air temperature is rising at a higher rate, 2.5 times (2.85 ground-based observed) more, than on maximum temperature, with a linear trend of 0.15 °C (0.19 °C ground-based observed) and 0.06 °C (0.06 °C ground-based observed) per decade respectively. The summer-mean urban bias on the mean air temperature is 0.8 °C (0.9 °C ground-based observed). The results based on remote sensing imagery are compatible with estimates of urban warming based on weather stations. Therefore, the technique presented in this work is a useful tool in estimating the urban heat island contamination in long time series, countering the drawbacks of an ground-observational approach.

Description: Newest developments of ACMANT Advances in Science and Research, 6, 7-11, 2011 Author(s): P. Domonkos, R. Poza, and D. Efthymiadis The seasonal cycle of radiation intensity often causes a marked seasonal cycle in the inhomogeneities (IHs) of observed temperature time series, since a substantial portion of them have direct or indirect connection to radiation changes in the micro-environment of the thermometer. Therefore the magnitudes of temperature IHs tend to be larger in summer than in winter. A new homogenisation method, the Adapted Caussinus – Mestre Algorithm for Networks of Temperature series (ACMANT) has recently been developed which treats appropriately the seasonal changes of IH-sizes in temperature time series. The performance of ACMANT was proved to be among the best methods (together with PRODIGE and MASH) in the efficiency test procedure of COST ES0601 project. A further improved version of the ACMANT is described in this paper. In the new version the ANOVA procedure is applied for correcting inhomogeneities, and with this change the iterations applied in the earlier version have become unnecessary. Some other modifications have also been made, from which the most important one is the new way for estimating the timings of IHs. With these modifications the efficiency of the ACMANT has become even higher, therefore its use is strongly recommended when networks of monthly temperature series from mid- or high geographical latitudes are subjected to homogenisation. The paper presents the main properties and the operation of the new ACMANT.

Description: Sensitivity of a long-range numerical weather forecast model to small changes of model parameters Advances in Science and Research, 6, 13-18, 2011 Author(s): M. B. Gavrilov, G. R. Jovanović, and Z. Janjić Sensitivity of extended-range numerical weather forecasts to small changes of model parameters is studied for two cases. In the first case the Earth radius was perturbed. In the other case changes of the gravity were introduced. The results for the 500 hPa geopotential fields are presented on hemispheric maps and intercompared visually and using RMS differences of the perturbed and reference forecasts. During about the first 10 days of integration the results indicate modest sensitivity of the forecasts to the parameter variation. After this period the forecasts diverge rapidly and start to differ significantly. Repeated integrations on the same computer using the same model setup and the same initial conditions yield identical results.

Description: Synoptic-mesoscale analysis and numerical modeling of a tornado event on 12 February 2010 in northern Greece Advances in Science and Research, 6, 187-194, 2011 Author(s): I. T. Matsangouras, P. T. Nastos, and I. Pytharoulis Tornadoes are furious convective weather phenomena, with the maximum frequency over Greece during the cold period (autumn, winter).This study analyzes the tornado event that occurred on 12 February 2010 near Vrastama village, at Chalkidiki's prefecture, a non urban area 45 km southeast of Thessaloniki in northern Greece. The tornado developed approximately between 17:10 and 17:35 UTC and was characterized as F2 (Fujita Scale). The tornado event caused several damages to an industrial building and at several olive-tree farms. A synoptic survey is presented along with satellite images, radar products and vertical profile of the atmosphere. Additionally, the nonhydrostatic WRF-ARW atmospheric numerical model (version 3.2.0) was utilized in analysis and forecast mode using very high horizontal resolution (1.333 km × 1.333 km) in order to represent the ambient atmospheric conditions. A comparison of statistical errors between WRF-ARW forecasts and ECMWF analysis is presented, accompanied with LGTS 12:00 UTC soundings (Thessaloniki Airport) and forecast soundings in order to verify the WRF-ARW model. Additionally, a comparison between WRF-ARW and ECMWF thermodynamic indices is also presented. The WRF-ARW high spatial resolution model appeared to simulate with significant accuracy a severe convective event with a lead period of 18 h.

Description: Determining the accuracy of gridded climate data and how this varies with observing-network density Advances in Science and Research, 6, 195-198, 2011 Author(s): T. P. Legg The Met Office National Climate Information Centre regularly produces assessments of mean monthly, seasonal and annual values of weather parameters and their anomalies over the UK. However the gridded values, and corresponding areal-average values, are subject to error. Experiments have been done in an attempt to quantify the mean errors in gridded monthly values and monthly areal averages of temperature and rainfall, and how these errors vary when we artificially thin out the observation network. But there are two additional reasons for this work: firstly we wish to determine how far back we can realistically extend the historical areal series, and secondly, we want to estimate the size of error bars on the historical values. For the UK as a whole, we estimate that error bars of around 0.1 °C would arise for monthly-mean temperatures.

Description: Observations and modelling of 1/ f -noise in weather and climate Advances in Science and Research, 6, 137-140, 2011 Author(s): R. Blender, X. Zhu, and K. Fraedrich Data with power spectra close to S(f) ~1/ f is denoted as 1/ f or flicker noise. High resolution measurements during TOGA/COARE for temperature, humidity, and wind speed (1\,min resolution) reveal 1/ f spectra while precipitation shows no power-law scaling during the same period. However, a binary time series indicating the precipitation events (1 for precipitation, 0 for no precipitation) shows a clear 1/ f spectrum in line with the remaining boundary layer data. For extreme events in time series with 1/ f spectra the return time distribution is well approximated by a Weibull-distribution for short and long return times. The daily discharge of the Yangtze river shows high volatility which is linked to the intra-annual 1/ f spectrum. The discharge fluctuations detected in different time windows are represented by a single function (a so-called data collapse) similar to the universal behavior found for turbulence and various physical systems at criticality. The collapse is well described by the Gumbel distribution.

Description: Climate indicators for Italy: calculation and dissemination Advances in Science and Research, 6, 147-150, 2011 Author(s): F. Desiato, G. Fioravanti, P. Fraschetti, W. Perconti, and A. Toreti In Italy, meteorological data necessary and useful for climate studies are collected, processed and archived by a wide range of national and regional institutions. As a result, the density of the stations, the length and frequency of the observations, the quality control procedures and the database structure vary from one dataset to another. In order to maximize the use of those data for climate knowledge and climate change assessments, a computerized system for the collection, quality control, calculation, regular update and rapid dissemination of climate indicators was developed. The products publicly available through a dedicated web site are described, as well as an example of climate trends estimates over Italy, based on the application of statistical models on climate indicators from quality-checked and homogenised time series.

Description: A study of the 1 and 2 January 2010 sea-storm in the Ligurian Sea Advances in Science and Research, 6, 109-115, 2011 Author(s): F. Pasi, A. Orlandi, L. F. Onorato, and S. Gallino During the last days of 2009 and the first days of 2010, a wide and deep low pressure system over Western Europe generated a very extended and strong southerly pressure gradient on the whole Western Mediterranean Sea with a resulting very rough to high sea state. Over the Ligurian Sea (North Western Mediterranean) the resulting sea state was a combination of a very tuned (in both frequency and direction) swell coming from the south-west, with nearly oceanic peak wave period, and a broader north-westerly wind sea with shorter period. This kind of sea state, not extreme in terms of significant wave height, caused unusual widespread damages to Ligurian coastal structures. In this study, authors investigated the structure of such a combined sea state by analysing numerical weather prediction outputs coming from atmospheric and wave models and comparing them with data coming from ondametric buoys and meteorological stations located in the Ligurian Sea area. As a result, it was found that the forecasting model chain almost correctly predicted the wave height in a first phase, when the sea state was only due to the first south-westerly swell peak, while significantly underestimated the combined sea state, when also the second north-westerly wind sea developed and interacted with the first one. By analysing the structure of directional wave spectra forecasted by the operational wave model and measured by the buoys, authors have attempted to find out the reasons for model deficiencies in forecasting the time evolution of significant parameters characterising the sea state.

Description: Effects of the climate change on regional ozone dry deposition Advances in Science and Research, 6, 103-107, 2011 Author(s): E. Kolozsi-Komjáthy, R. Mészáros, and I. Lagzi This impact study investigates connections between the regional climate change and the tropospheric ozone deposition over different vegetations in Hungary due to the possible changes of atmospheric and environmental properties. The spatial and temporal variability of the dry deposition velocity of ozone was estimated for different time periods (1961–1990 for reference period and two future scenarios: 2021–2050 and 2071–2100). Simulations were performed with a sophisticated deposition model using the RegCM regional climate model results as an input. We found a significant reduction of the ozone deposition velocities during summer months, which predicts less ozone damage to the vegetation in the future. However elevated ozone concentration and changed plant physiology can compensate the effect of this reduction.

Description: Estimating future air-quality due to climate change: the Athens case study Advances in Science and Research, 6, 117-121, 2011 Author(s): K. V. Varotsos, C. Giannakopoulos, and M. Tombrou The aim of this study is to investigate the development of an empirical-statistical model in order to examine the potential impact of increasing future temperatures on ozone exceedance days in the Greater Athens Area. It is based on the concept that temperature is a capable predictor for the ozone concentrations and that in a future climate change world, the likelihood of ozone pollution episodes may increase.

Description: Data-driven exploration of orographic enhancement of precipitation Advances in Science and Research, 6, 129-135, 2011 Author(s): L. Foresti, M. Kanevski, and A. Pozdnoukhov This study presents a methodology to analyse orographic enhancement of precipitation using sequences of radar images and a digital elevation model. Image processing techniques are applied to extract precipitation cells from radar imagery. DEM is used to derive the topographic indices potentially relevant to orographic precipitation enhancement at different spatial scales, e.g. terrain convexity and slope exposure to mesoscale flows. Two recently developed machine learning algorithms are then used to analyse the relationship between the repeatability of precipitation patterns and the underlying topography. Spectral clustering is first used to characterize stratification of the precipitation cells according to different mesoscale flows and exposure to the crest of the Alps. At a second step, support vector machine classifiers are applied to build a computational model which discriminates persistent precipitation cells from all the others (not showing a relationship to topography) in the space of topographic conditioning factors. Upwind slopes and hill tops were found to be the topographic features leading to precipitation repeatability and persistence. Maps of orographic enhancement susceptibility can be computed for a given flow, topography and forecasted smooth precipitation fields and used to improve nowcasting models or correct windward and leeward biases in numerical weather prediction models.

Description: Data validation procedures in agricultural meteorology – a prerequisite for their use Advances in Science and Research, 6, 141-146, 2011 Author(s): J. Estévez, P. Gavilán, and A. P. García-Marín Quality meteorological data sources are critical to scientists, engineers, climate assessments and to make climate related decisions. Accurate quantification of reference evapotranspiration (ET 0 ) in irrigated agriculture is crucial for optimizing crop production, planning and managing irrigation, and for using water resources efficiently. Validation of data insures that the information needed is been properly generated, identifies incorrect values and detects problems that require immediate maintenance attention. The Agroclimatic Information Network of Andalusia at present provides daily estimations of ET 0 using meteorological information collected by nearly of one hundred automatic weather stations. It is currently used for technicians and farmers to generate irrigation schedules. Data validation is essential in this context and then, diverse quality control procedures have been applied for each station. Daily average of several meteorological variables were analysed (air temperature, relative humidity and rainfall). The main objective of this study was to develop a quality control system for daily meteorological data which could be applied on any platform and using open source code. Each procedure will either accept the datum as being true or reject the datum and label it as an outlier. The number of outliers for each variable is related to a dynamic range used on each test. Finally, geographical distribution of the outliers was analysed. The study underscores the fact that it is necessary to use different ranges for each station, variable and test to keep the rate of error uniform across the region.

Description: Geostatistical merging of ground-based and satellite-derived data of surface solar radiation Advances in Science and Research, 6, 1-5, 2011 Author(s): M. Journée and C. Bertrand In this paper, we demonstrate the benefit of using observations from Meteosat Second Generation (MSG) satellites in addition to in-situ measurements to improve the spatial resolution of solar radiation data over Belgium. This objective has been reached thanks to geostatistical methods able to merge heterogeneous data types. Two geostatistical merging methods are evaluated against the interpolation of ground-data only and the single use of satellite-derived information. It results from our analysis that merging both data sources provides the most accurate mapping of surface solar radiation over Belgium.

Description: Twinning European and South Asian river basins to enhance capacity and implement adaptive integrated water resources management approaches – results from the EC-project BRAHMATWINN Advances in Science and Research, 7, 1-9, 2011 Author(s): W.-A. Flügel The EC-project BRAHMATWINN was carrying out a harmonised integrated water resources management (IWRM) approach as addressed by the European Water Initiative (EWI) in headwater river systems of alpine mountain massifs of the twinning Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basins (UBRB) in Europe and Southeast Asia respectively. Social and natural scientists in cooperation with water law experts and local stakeholders produced the project outcomes presented in Chapter 2 till Chapter 10 of this publication. BRAHMATWINN applied a holistic approach towards IWRM comprising climate modelling, socio-economic and governance analysis and concepts together with methods and integrated tools of applied Geoinformatics. A detailed description of the deliverables produced by the BRAHMATWINN project is published on the project homepage http://www.brahmatwinn.uni-jena.de .

Description: Development of responses based on IPCC and "what-if?" IWRM scenarios Advances in Science and Research, 7, 71-81, 2011 Author(s): V. Giannini, L. Ceccato, C. Hutton, A. A. Allan, S. Kienberger, W.-A. Flügel, and C. Giupponi This work illustrates the findings of a participatory research process aimed at identifying responses for sustainable water management in a climate change perspective, in two river basins in Europe and Asia. The chapter describes the methodology implemented through local participatory workshops, aimed at eliciting and evaluating possible responses to flood risk, which were then assessed with respect to the existing governance framework. Socio-economic vulnerability was also investigated developing an indicator, whose future trend was analysed with reference to IPCC scenarios. The main outcome of such activities consists in the identification of Integrated Water Resource Management Strategies (IWRMS) based upon the issues and preferences elicited from local experts. The mDSS decision support tool was used to facilitate transparent and robust management of the information collected and communication of the outputs.

Description: Assessing components of the natural environment of the Upper Danube and Upper Brahmaputra river basins Advances in Science and Research, 7, 21-36, 2011 Author(s): S. Lang, A. Kääb, J. Pechstädt, W.-A. Flügel, P. Zeil, E. Lanz, D. Kahuda, R. Frauenfelder, K. Casey, P. Füreder, I. Sossna, I. Wagner, G. Janauer, N. Exler, Z. Boukalova, R. Tapa, J. Lui, and N. Sharma A comprehensive understanding of the interplay between the natural environment and the human dimension is one of the prerequisites to successful and sustaining IWRM practises in large river basins such as the Upper Brahmaputra river basin or the Upper Danube river basin. These interactions, their dynamics and changes, and the likely future scenarios were investigated in the BRAHMATWINN project with a series of tools from remote sensing and geoinformatics. An integrated assessment of main components of the natural environment in the two river basins as well as in five reference catchments within those basins, has led to the delineation of hydrological response units (HRUs). HRUs are spatial units bearing a uniform behaviour in terms of the hydrological response regime, as a function of physical parameters land use, soil type, water, vegetation cover and climate. Besides the delineated HRUs which are available in a spatially exhaustive manner for all reference catchments, the following information were provided as spatial layers: (1) uniform digital surface models of both the twinned basins and the reference catchments; (2) glacier areas and the magnitude of glacier loss; (3) mountain permafrost distribution and identification of areas particularly affected by permafrost thaw; (4) a consistent land use/land cover information in all reference catchments; and (5) the vulnerabilities of wetlands and groundwater in terms of anthropogenic impact and climate change.

Description: Regional climate projections in two alpine river basins: Upper Danube and Upper Brahmaputra Advances in Science and Research, 7, 11-20, 2011 Author(s): A. Dobler, M. Yaoming, N. Sharma, S. Kienberger, and B. Ahrens Projections from coarse-grid global circulation models are not suitable for regional estimates of water balance or trends of extreme precipitation and temperature, especially not in complex terrain. Thus, downscaling of global to regionally resolved projections is necessary to provide input to integrated water resources management approaches for river basins like the Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basin (UBRB). This paper discusses the application of the regional climate model COSMO-CLM as a dynamical downscaling tool. To provide accurate data the COSMO-CLM model output was post-processed by statistical means. This downscaling chain performs well in the baseline period 1971 to 2000. However, COSMO-CLM performs better in the UDRB than in the UBRB because of a longer application experience and a less complex climate in Europe. Different climate change scenarios were downscaled for the time period 1960–2100. The projections show an increase of temperature in both basins and for all seasons. The values are generally higher in the UBRB with the highest values occurring in the region of the Tibetan Plateau. Annual precipitation shows no substantial change. However, seasonal amounts show clear trends, for instance an increasing amount of spring precipitation in the UDRB. Again, the largest trends for different precipitation statistics are projected in the region of the Tibetan Plateau. Here, the projections show up to 50% longer dry periods in the months June to September with a simultaneous increase of about 10% for the maximum amount of precipitation on five consecutive days. For the Assam region in India, the projections also show an increase of 25% in the number of consecutive dry days during the monsoon season leading to prolonged monsoon breaks.

Description: Large scale integrated hydrological modelling of the impact of climate change on the water balance with DANUBIA Advances in Science and Research, 7, 61-70, 2011 Author(s): M. Prasch, T. Marke, U. Strasser, and W. Mauser Future climate change will affect the water availability in large areas. In order to derive appropriate adaptation strategies the impact on the water balance has to be determined on a regional scale in a high spatial and temporal resolution. Within the framework of the BRAHMATWINN project the model system DANUBIA, developed within the project GLOWA Danube (GLOWA Danube, 2010; Mauser and Ludwig, 2002), was applied to calculate the water balance components under past and future climate conditions in the large-scale mountain watersheds of the Upper Danube and the Upper Brahmaputra. To use CLM model output data as meteorological drivers DANUBIA is coupled with the scaling tool SCALMET (Marke, 2008). For the determination of the impact of glacier melt water on the water balance the model SURGES (Weber et al., 2008; Prasch, 2010) is integrated into DANUBIA. In this paper we introduce the hydrological model DANUBIA with the tools SCALMET and SURGES. By means of the distributed hydrological time series for the past from 1971 to 2000 the model performance is presented. In order to determine the impact of climate change on the water balance in both catchments, time series from 2011 to 2080 according to the IPCC SRES emission scenarios A2, A1B, B2 and Commitment are analysed. Together with the socioeconomic outcomes (see Chapter 4) the DANUBIA model results provide the basis for the derivation of Integrated Water Resources Management Strategies to adapt to climate change impacts (see Chapter 9 and 10).

Description: Integration by identification of indicators Advances in Science and Research, 7, 55-60, 2011 Author(s): V. Giannini and C. Giupponi The objective of the BRAHMATWINN research component described in this chapter is to develop integrated indicators with relevance to Integrated Water Resources Management (IWRM) and climate change for the Upper Danube and the Upper Brahmaputra River Basins (UDRB and UBRB), and to foster the integration process amongst the different research activities of the project. Such integrated indicators aim at providing stakeholders, NGOs and GOs with an overview of the present state and trends of the river basins water resources, and at quantifying the impacts of possible scenarios and responses to driving forces, as well as pressures from likely climate change. In the process the relevant indicators have been identified by research partners to model and monitor issues relevant for IWRM in the case study areas. The selected indicators have been validated with the information gathered through the NetSyMoD approach (Giupponi et al., 2008) in workshops with local actors. In this way a strong link between the main issues affecting the basins as perceived by local actors and the BRAHMATWINN activities has been created, thus fostering integration between research outcomes and local needs.

Description: Development and implementation of an Integrated Water Resources Management System (IWRMS) Advances in Science and Research, 7, 83-90, 2011 Author(s): W.-A. Flügel and C. Busch One of the innovative objectives in the EC project BRAHMATWINN was the development of a stakeholder oriented Integrated Water Resources Management System (IWRMS). The toolset integrates the findings of the project and presents it in a user friendly way for decision support in sustainable integrated water resources management (IWRM) in river basins. IWRMS is a framework, which integrates different types of basin information and which supports the development of IWRM options for climate change mitigation. It is based on the River Basin Information System (RBIS) data models and delivers a graphical user interface for stakeholders. A special interface was developed for the integration of the enhanced DANUBIA model input and the NetSyMod model with its Mulino decision support system (mulino mDss) component. The web based IWRMS contains and combines different types of data and methods to provide river basin data and information for decision support. IWRMS is based on a three tier software framework which uses (i) html/javascript at the client tier, (ii) PHP programming language to realize the application tier, and (iii) a postgresql/postgis database tier to manage and storage all data, except the DANUBIA modelling raw data, which are file based and registered in the database tier. All three tiers can reside on one or different computers and are adapted to the local hardware infrastructure. IWRMS as well as RBIS are based on Open Source Software (OSS) components and flexible and time saving access to that database is guaranteed by web-based interfaces for data visualization and retrieval. The IWRMS is accessible via the BRAHMATWINN homepage: http://www.brahmatwinn.uni-jena.de and a user manual for the RBIS is available for download as well.

Description: Large-eddy simulation of plume dispersion within regular arrays of cubic buildings Advances in Science and Research, 6, 79-86, 2011 Author(s): H. Nakayama, K. Jurcakova, and H. Nagai There is a potential problem that hazardous and flammable materials are accidentally or intentionally released within populated urban areas. For the assessment of human health hazard from toxic substances, the existence of high concentration peaks in a plume should be considered. For the safety analysis of flammable gas, certain critical threshold levels should be evaluated. Therefore, in such a situation, not only average levels but also instantaneous magnitudes of concentration should be accurately predicted. In this study, we perform Large-Eddy Simulation (LES) of plume dispersion within regular arrays of cubic buildings with large obstacle densities and investigate the influence of the building arrangement on the characteristics of mean and fluctuating concentrations.

Description: Vulnerability to climate change: people, place and exposure to hazard Advances in Science and Research, 7, 37-45, 2011 Author(s): C. W. Hutton, S. Kienberger, F. Amoako Johnson, A. Allan, V. Giannini, and R. Allen The Human Dimension of the Twinning European and South Asian River Basins to Enhance Capacity and Implement Adaptive Management Approaches Project (EC-Project BRAHMATWINN) is aimed at developing socio-economic tools and context for the effective inclusion of the "Human Dimension" or socio-economic vulnerability into the overall assessment of climate risk in the twinned basins of the Upper Brahmaputra River Basin (UBRB), and the Upper Danube River Basin (UDRB) . This work is conducted in the light of stakeholder/actor analysis and the prevailing legal framework. In order to effectively achieve this end, four key research and associated activities were defined: 1. Identifying stakeholders and actors including: implement an approach to ensure a broad spread of appropriate stakeholder input to the assessment of vulnerability undertaken in Asia and Europe within the research activities of the project. 2. Contextualising legal framework: to provide an assessment of the governance framework relating to socio-environmental policy development within the study site administrative areas leading to the specific identification of related policy and legal recommendations. 3. Spatial analysis and mapping of vulnerability: providing a spatial assessment of the variation of vulnerability to pre-determined environmental stressors across the study areas with an additional specific focus on gender. 4. Inclusion of findings with the broader context of the BRAHMATWINN risk of climate change study through scenarios of hazard and vulnerability (subsequent chapters). This study utilises stakeholder inputs to effectively identify and map relative weightings of vulnerability domains, such as health and education in the context of pre-specified hazards such as flood. The process is underpinned by an adaptation of the IPCC (2001) which characterizes Risk as having the components of Hazard (physiographic component) and Vulnerability (socio-economic component).

Description: Development of adaptive IWRM options for climate change mitigation and adaptation Advances in Science and Research, 7, 91-100, 2011 Author(s): W.-A. Flügel Adaptive Integrated Water Resources Management (IWRM) options related to the impacts of climate change in the twinning basins of the Upper Danube River Basin (UDRB) and the Upper Brahmaputra River Basin (UBRB) are developed based on the results obtained in the different work packages of the BRAHMATWINN project. They have been described and discussed in Chapter 2 till Chapter 9 and the paper is referring to and is integrating these findings with respect to their application and interpretation for the development of adaptive IWRM options addressing impacts of climate change in river basins. The data and information related to the results discussed in Chapter 2 till 8 have been input to the RBIS as a central component of the IWRMS (Chapter 9). Meanwhile the UDRB has been analysed with respect to IWRM and climate change impacts by various projects, i.e. the GLOWA-Danube BMBF funded project (GLOWA Danube, 2009; Mauser and Ludwig, 2002) the UBRB has not been studied so far in a similar way as it was done in the BRAHMATWINN project. Therefore the IWRM option development is focussing on the UBRB but the methodology presented can be applied for the UDRB and other river basins as well. Data presented and analysed in this chapter have been elaborated by the BRAHMATWINN project partners and are published in the project deliverable reports available from the project homepage http://www.brahmatwinn.uni-jena.de/index.php?id=5311&L=2 .

Description: Diagnostic study of the influence of lateral boundary conditions for the REMO RCM simulations over the Carpathian Basin Advances in Science and Research, 6, 87-94, 2011 Author(s): G. Szépszó At the Hungarian Meteorological Service, two experiments were accomplished with the REMO5.0 regional climate model: (1) a simulation of a past period from 1961 to 2000, driven by the ECMWF ERA40 re-analysis data, and (2) a transient run from 1951 to 2100 driven by the ECHAM5/MPI-OM global coupled atmosphere-ocean model using SRES A1B forcing. The integration domain covers continental Europe with 25 km horizontal resolution in both experiments. Present article is dedicated to the investigation of the simulation results for the past period. The results for 1961–1990 were compared on the one hand with observations, and on the other hand, with each other and the corresponding global fields in order to assess the impact of the different lateral boundary conditions on the results focusing on the area of our interest, i.e., Hungary. The evaluation indicated that the re-analysis driven experiment provides warm and in summer dry past climate over the Carpathian Basin, whereas lower temperature and higher precipitation values are obtained when the lateral boundary information is derived from a global climate model. Based on the validation, it is concluded that the temperature characteristics in the simulation-driven case outperformed the experiment forced by quasi-perfect (i.e., re-analysis) data, however, similar apparent conclusion cannot be drawn for precipitation. This paper is undertaking to give deeper insight into the details and possible reasons for these outcomes.

Description: Analysis of present IWRM in the Upper Brahmaputra and the Upper Danube River Basins Advances in Science and Research, 7, 47-54, 2011 Author(s): W.-A. Flügel and A. Bartosch Integrated Water Resources Management (IWRM) is a process which strives towards the sustainable management of water resources in river basins. The approach integrates insights and knowledge from various scientific disciplines comprising natural, socio-economic, and engineering sciences. These three pillars of sustainability are important components of this approach integrating the environmental, economic and social dimension. In the ideal IWRM case planning is based on the river basin scale and therefore is comparatively discussed herein for the two twinning BRAHMATWINN river basins, i.e. the Upper Danube River Basin (UDRB) in Europe and the Upper Brahmaputra River Basin (UBRB) in South Asia. In this chapter major challenges for the implementation of the IWRM process towards a sustainable management of water resources in the two UDRB and UBRB twinning river basins of the BRAHMATWINN project are analysed. The study revealed that in the UDRB the IWRM approach is already part of water management planning and the implementation of the EU Water Framework Directive (WFD) is a good example in this regard. Contrary in the UBRB the implementation of IWRM is just at the beginning phase, only recently is being discussed in the riparian states but has not been implemented in any way so far on the basin scale.

Description: Climatology of persistent deep stable layers in Utah's Salt Lake Valley, USA Advances in Science and Research, 6, 59-62, 2011 Author(s): S. Zhong, X. Xu, X. Bian, and W. Lu The characteristics of winter season persistent deep stable layers (PDSLs) over Utah's Salt Lake Valley are examined using 30-year twice daily rawinsonde soundings. The results highlight the basic climatological characteristics of the PDSLs, including the strengths of the inversion, the frequency of the occurrence, and the duration of the events. The data analyses also reveal linear trend, interannual variability, as well as the relationship between the interannual variability of PDSLs and the variability of large-scale circulations. Finally, the study investigates the large-scale atmosphere conditions accompanying the formation and destruction of the PDSL episodes.

Description: Preliminary step towards comparing large scale features in surface wind field between ERA-Interim re-analysis and a higher resolution simulation Advances in Science and Research, 10, 113-117, 2013 Author(s): A. Boilley, T. Ranchin, and A. Ghennioui The weather research and forecasting model (WRF) is initialized with ERA-Interim re-analysis to produce a higher resolution dataset over a one month period. WRF is supposed to introduce small scale information and maintain the mean large scale features. A detailed spectral analysis is performed to verify this statement. It reveals that consistency in large-scale features is not achieved for wavelengths greater than or equal to 6° even with the activation of spectral nudging.

Description: Comparing different meteorological ensemble approaches: hydrological predictions for a flood episode in Northern Italy Advances in Science and Research, 8, 33-37, 2012 Author(s): S. Davolio, T. Diomede, C. Marsigli, M. M. Miglietta, A. Montani, and A. Morgillo Within the framework of coupled meteorological-hydrological predictions, this study aims at comparing two high-resolution meteorological ensembles, covering short and medium range. The two modelling systems have similar characteristics, as almost the same number of members, the model resolution (about 7 km), the driving ECMWF global ensemble prediction system, but are obtained through different methodologies: the former is a multi-model ensemble, based on three mesoscale models (BOLAM, COSMO, and WRF), while the latter follows a single-model approach, based on COSMO-LEPS (Limited-area Ensemble Prediction System), the operational ensemble forecasting system developed within the COSMO consortium. Precipitation forecasts are evaluated in terms of hydrological response, after coupling the meteorological models with a distributed rainfall-runoff model (TOPKAPI) to simulate the discharge of the Reno river (Northern Italy), for a severe weather episode. Although a single case study does not allow for robust and definite conclusions, the comparison among different predictions points out a remarkably better performance of mesoscale model ensemble forecasts compared to global ones. Moreover, the multi-model ensemble outperforms the single model approach.

Description: The effect of weather and its changes on emotional state – individual characteristics that make us vulnerable Advances in Science and Research, 6, 281-290, 2011 Author(s): Z. Spasova Given the proven effects of weather on the human organism, an attempt to examine its effects on a psychological and emotional level has been made. Emotions affect the bio tone, working ability, and concentration; hence their significance in various domains of economic life such as health care, education, transportation, and tourism. The present pilot study was conducted in Sofia, Bulgaria over a period of eight months, using five psychological methods: Eysenck Personality Questionnaire, State-Trait Anxiety Inventory, Test for Self-assessment of the emotional state, Test for evaluation of moods and Test ''Self-confidence-Activity-Mood''. The Fiodorov-Chubukov's complex-climatic method was used to characterize meteorological conditions in order to include a maximal number of meteorological elements in the analysis. Sixteen weather types are defined depending on the meteorological elements values according to this method. Abrupt weather changes from one day to another, defined by the same method, were also considered. The results obtained by t-test showed that the different categories of weather led to changes in the emotional status, which indicates a character either positive or negative for the organism. The abrupt weather changes, according to expectations, have negative effects on human emotions – but only when a transition to the cloudy weather or weather type, classified as ''unfavorable'', has been realized. The relationship between weather and human emotions is rather complicated since it depends on individual characteristics of people. One of these individual psychological characteristics, marked by the dimension ''neuroticism'', has a strong effect on emotional reactions in different weather conditions. Emotionally stable individuals are more ''resistant'' to the weather influence on their emotions, while those who are emotionally unstable have a stronger dependence on the impacts of weather.

Description: On the predictability of outliers in ensemble forecasts Advances in Science and Research, 8, 53-57, 2012 Author(s): S. Siegert, J. Bröcker, and H. Kantz In numerical weather prediction, ensembles are used to retrieve probabilistic forecasts of future weather conditions. We consider events where the verification is smaller than the smallest, or larger than the largest ensemble member of a scalar ensemble forecast. These events are called outliers. In a statistically consistent K -member ensemble, outliers should occur with a base rate of 2/( K +1). In operational ensembles this base rate tends to be higher. We study the predictability of outlier events in terms of the Brier Skill Score and find that forecast probabilities can be calculated which are more skillful than the unconditional base rate. This is shown analytically for statistically consistent ensembles. Using logistic regression, forecast probabilities for outlier events in an operational ensemble are calculated. These probabilities exhibit positive skill which is quantitatively similar to the analytical results. Possible causes of these results as well as their consequences for ensemble interpretation are discussed.

Description: The role of nocturnal Low-Level-Jet in nocturnal convection and rainfalls in the west Mediterranean coast: the episode of 14 December 2010 in northeast of Iberian Peninsula Advances in Science and Research, 8, 27-31, 2012 Author(s): J. Mazón and D. Pino The night of 14 December 2010 radar images of the Spanish Weather Agency recorded a large rain band that moved offshore at the Northeast coast of the Iberian Peninsula. MM5 mesoscale model is used to study the atmospheric dynamics during that day. A Nocturnal Low Level Jet (NLLJ) generated by an inertial oscillation that brings cold air to the coast from inland has been simulated in the area. This cold air interacts with a warmer air mass some kilometers offshore. According to the MM5 mesoscale model simulation, the cold air enhances upward movements of the warm air producing condensation. Additionally, there is a return flow to the coastline at 600–900 m high. This warm air mass interacts again with the cold air moving downslope, also producing condensation inland. The simulation for the night before this episode shows large drainage winds with a NLLJ profile, but no condensation areas. The night after the 14th the simulation also shows drainage winds but without a NLLJ profile. However, an offshore convergence area was produced with a returned flow, but no condensation inland occurred. This fact is in agreement with radar observations which reported no precipitation for these two days. Consequently, NLLJ in combination with a synoptic wind over the sea could enhance condensation and eventually precipitation rates in the Mediterranean Iberian coast.

Description: Evening transitions of the atmospheric boundary layer: characterization, case studies and WRF simulations Advances in Science and Research, 8, 39-44, 2012 Author(s): M. Sastre, C. Yagüe, C. Román-Cascón, G. Maqueda, F. Salamanca, and S. Viana Micrometeorological observations from two months (July–August 2009) at the CIBA site (Northern Spanish plateau) have been used to evaluate the evolution of atmospheric stability and turbulence parameters along the evening transition to a Nocturnal Boundary Layer. Turbulent Kinetic Energy thresholds have been established to distinguish between diverse case studies. Three different types of transitions are found, whose distinctive characteristics are shown. Simulations with the Weather Research and Forecasting-Advanced Research WRF (WRF-ARW) mesoscale model of selected transitions, using three different PBL parameterizations, have been carried out for comparison with observed data. Depending on the atmospheric conditions, different PBL schemes appear to be advantageous over others in forecasting the transitions.

Description: The historical pathway towards more accurate homogenisation Advances in Science and Research, 8, 45-52, 2012 Author(s): P. Domonkos, V. Venema, I. Auer, O. Mestre, and M. Brunetti In recent years increasing effort has been devoted to objectively evaluate the efficiency of homogenisation methods for climate data; an important effort was the blind benchmarking performed in the COST Action HOME (ES0601). The statistical characteristics of the examined series have significant impact on the measured efficiencies, thus it is difficult to obtain an unambiguous picture of the efficiencies, relying only on numerical tests. In this study the historical methodological development with focus on the homogenisation of surface temperature observations is presented in order to view the progress from the side of the development of statistical tools. The main stages of this methodological progress, such as for instance the fitting optimal step-functions when the number of change-points is known (1972), cutting algorithm (1995), Caussinus – Lyazrhi criterion (1997), are recalled and their effects on the quality-improvement of homogenisation is briefly discussed. This analysis of the theoretical properties together with the recently published numerical results jointly indicate that, MASH, PRODIGE, ACMANT and USHCN are the best statistical tools for homogenising climatic time series, since they provide the reconstruction and preservation of true climatic variability in observational time series with the highest reliability. On the other hand, skilled homogenizers may achieve outstanding reliability also with the combination of simple statistical methods such as the Craddock-test and visual expert decisions. A few efficiency results of the COST HOME experiments are presented to demonstrate the performance of the best homogenisation methods.

Description: DRIAS: a step toward Climate Services in France Advances in Science and Research, 6, 179-186, 2011 Author(s): J. Lémond, Ph. Dandin, S. Planton, R. Vautard, C. Pagé, M. Déqué, L. Franchistéguy, S. Geindre, M. Kerdoncuff, L. Li, J. M. Moisselin, T. Noël, and Y. M. Tourre DRIAS (Providing access to Data on French Regionalized climate scenarios and Impacts on the environment and Adaptation of Societies) is a 2-yr project (2010–2012). It is funded by the GICC (Management and Impact of Climate Change) program of the French Ministry of Ecology, Sustainable Development, Transportation, and Housing (MEDDTL). DRIAS is to provide easy access to French regional climate data and products in order to facilitate mitigation and adaptation studies. The DRIAS project focuses on existing French regional climate projections obtained from national modelling groups such as: IPSL, CERFACS, and CNRM. It is more than a data server, it also delivers all kinds of climate information from numerical data to tailored climate products. Moreover, guidance is to be provided to end-users in order to promote best practices and know-how. Whilst the project is coordinated by the Department of Climatology at Météo-France, a multidisciplinary group of users and stakeholders at large concerned by climate change issues is also involved with the project. The ultimate goal will be to identify societal needs, validate the decision making processes, and thus facilitate exchanges between producers and practitioners. Key results from the DRIAS project will contribute to the implementation of French Climate Services.

Description: "CITY 2020+": assessing climate change impacts for the city of Aachen related to demographic change and health – a progress report Advances in Science and Research, 6, 261-270, 2011 Author(s): C. Schneider, C. Balzer, M. Buttstädt, K. Eßer, S. Ginski, J. Hahmann, G. Ketzler, M. Klemme, A. Kröpelin, H. Merbitz, S. Michael, T. Sachsen, A. Siuda, M. Weishoff-Houben, M. F. Brunk, W. Dott, H. Hofmeister, C. Pfaffenbach, C. Roll, and K. Selle The research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the city of Aachen as a case study. CITY 2020+ develops strategies, options and tools for planning and developing sustainable future city structures. The investigation focuses on how urban environment, political structure and residential behaviour can best be adapted, with attention to the interactions among structural, political, and sociological configurations and their impacts on human health. The interdisciplinary research is organized in three clusters. Within the first cluster, strategies of older people exposed to heat stress, and their networks as well as environmental health risks according to atmospheric conditions are examined. The second cluster addresses governance questions, urban planning and building technologies as well as spatial patterns of the urban heat island. The third cluster includes studies on air quality related to particulate matter and a historical perspective of city development concerning environmental issues and climate variability. However, it turns out that research topics that require an interdisciplinary approach are best addressed not by pre-structuring the work into related sub-projects but through combining them according to shared methodological approaches. Examples illustrating this rather practical approach within ongoing research are presented in this paper.

Description: Wind turbines in icing conditions: performance and prediction Advances in Science and Research, 6, 245-250, 2011 Author(s): S. Dierer, R. Oechslin, and R. Cattin Icing on structures is an important issue for wind energy developments in many regions of the world. Unfortunately, information about icing conditions is mostly rare due to a lack of measurements. Additionally, there is not much known about the operation of wind turbines in icing conditions. It is the aim of the current study to investigate the effect of icing on power production and to evaluate the potential of icing forecasts to help optimizing wind turbine operation. A test site with two Enercon E-82 turbines was set up in the Jura region in Switzerland in order to study the turbines' behaviour in icing conditions. Icing forecasts were performed by using an accretion model driven by results of the mesoscale weather forecast model WRF. The icing frequency at the test site is determined from pictures of a camera looking at the measurement sensors on the nacelle. The results show that the site is affected by frequent icing: 11.5 days/year of meteorological icing and 41.5 days/year of instrumental icing were observed corresponding to a factor of about four. The comparison of power production with and without blade heating shows that blade heating results in a 3.5% loss and operation without blade heating results in a 10% loss of the annual power production due to icing. Icing forecasts are performed for winter 2009/2010. Simulated and observed icing events agree well and also coincide with periods of power drop. Thus, the results suggest that icing forecasts can help to optimize the operation of wind parks in icing conditions.

Description: Meteorological observations of the coastal boundary layer structure at the Bulgarian Black Sea coast Advances in Science and Research, 6, 251-259, 2011 Author(s): D. Barantiev, M. Novitsky, and E. Batchvarova Continuous wind profile and turbulence measurements were initiated in July 2008 at the coastal meteorological observatory of Ahtopol on the Black Sea (south-east Bulgaria) under a Bulgarian-Russian collaborative program. These observations are the start of high resolution atmospheric boundary layer vertical structure climatology at the Bulgarian Black Sea coast using remote sensing technology and turbulence measurements. The potential of the measurement program with respect to this goal is illustrated with examples of sea breeze formation and characteristics during the summer of 2008. The analysis revealed three distinct types of weather conditions: no breeze, breeze with sharp frontal passage and gradually developing breeze. During the sea breeze days, the average wind speed near the ground (from sonic anemometer at 4.5 m and first layer of sodar at 30–40 m) did not exceed 3–4 m s −1 . The onset of breeze circulation was detected based on surface layer measurements of air temperature (platinum sensor and acoustic), wind speed and direction, and turbulence parameters. The sodar measurements revealed the vertical structure of the wind field.

Description: 3-D transponder antennas for future SHF RFID applications Advances in Radio Science, 9, 401-405, 2011 Author(s): R. Zichner and R. R. Baumann The radio frequency identification (RFID) technology is omnipresent since a few years. Some of the most popular fields of application are the use for security tasks, for logistics and for the consumer segment. For example, chip card or key ring sized RFID transponders can allow wireless access to secured rooms. The number of applications for wireless data transmission for the identification and tracking of objects increases every year. There is a large development need for highly functional and inexpensive RFID transponders due to the ever-increasing demand on improved reliability, higher data rates and read and write ranges of the RFID systems. Therefore, research was performed on new 3-D transponder antennas for the Super High Frequency Band around 5.8 GHz. Additionally, wave propagation effects and the influence of different dielectric environments were considered. Parallel to the design of the novel antenna structures, the printing process for inexpensive manufacturing was investigated. The gained results are the basis for prospective RFID applications.

Description: Traditional protection ratios in FM sound broadcasting – still appropriate for interference management? Advances in Radio Science, 9, 391-396, 2011 Author(s): J. Philipp A detailed analysis of the measurement procedures recommended by the International Telecommunication Union (ITU) shows that – with proper definition of audio quality – the FM broadcasting system can provide an audio signal-to-noise ratio of no better than 40 dB, when the interference in the neighboring channels exhausts the limits established by the internationally agreed protection ratios. Thus any attempt to relax the protection, be it motivated by the desire to implement additional FM or new digital services in the FM band, would inevitably degrade reception quality of existing services to levels hardly acceptable by broadcast listeners.

Description: Equitable access to spectrum in further development of the Geneva 2006 frequency plan Advances in Radio Science, 9, 397-400, 2011 Author(s): J. Philipp Since the frequency plan of the Regional Radiocommunication Conference Geneva 2006 has come into force, many attempts have been made towards its enhancement. The preliminary results, however, seem not to be compliant with elementary principles of distribution justice. Therefore, the planning principles which lead to the observed imbalance will be scrutinized. Furthermore it will be shown that the utilization of spectrum can be advanced in a balanced way when the same (necessary) condition for "equitable access", which has been used by a group of middle European countries for the construction of the original frequency plan, is applied to plan refinements as well. The necessary condition mentioned consists simply in the parity of the number of coverages (constituted of disjoint allotments) configured in the plan for each country. In order to be able to plan enhancements, the concept of coverage number has to be generalized to the case of incomplete coverages of potentially overlapping allotments. The computation of coverage numbers is straightforward and renders the concept of coverage number parity a useful tool to be applied as a necessary condition in testing a frequency plan variant for equitable access.

Description: A monthly precipitation database for Spain (1851–2008): reconstruction, homogeneity and trends Advances in Science and Research, 8, 1-4, 2012 Author(s): M. Y. Luna, J. A. Guijarro, and J. A. López The compilation and reconstruction of a dataset integrated by 66 long monthly precipitation series, covering mainland Spain and the Balearic Islands, is presented. The reconstruction is based on the hypothesis that the cessation of data recording at one observatory is followed by the establishment of a new observatory very close to the closed one. In order to detect and adjust for possible multiple change points or shifts that could exist in the precipitation series, the R-package CLIMATOL V2.0 is used. This method enables to take advantage of the whole historical Spanish precipitation network in the detection and correction of inhomogeneities. The analysis of annual precipitation trends indicate a high temporal variability. Negative trends dominate for the period 1951–2008 but not for all observatories. On the other hand, positive trends can be detected in the northern Spain for 1902–2008.

Description: Equivalent circuit models of two-layer flexure beams with excitation by temperature, humidity, pressure, piezoelectric or piezomagnetic interactions Journal of Sensors and Sensor Systems, 3, 187-211, 2014 Author(s): U. Marschner, G. Gerlach, E. Starke, and A. Lenk Two-layer flexure beams often serve as basic transducers in actuators and sensors. In this paper a generalized description of their stimuli-influenced mechanical behavior is derived. For small deflection angles this description includes a multi-port circuit or network representation with lumped elements for a beam part of finite length. A number of coupled finite beam parts model the dynamic behavior including the first natural frequencies of the beam. For piezoelectric and piezomagnetic interactions, reversible transducer models are developed. The piezomagnetic two-layer beam model is extended to include solenoid and planar coils. Linear network theory is applied in order to determine network parameters and to simplify the circuit representation. The resulting circuit model is the basis for a fast simulation of the dynamic system behavior with advanced circuit simulators and, thus, the optimization of the system. It is also a useful tool for understanding and explaining this multi-domain system through basic principles of general system theory.

Description: A simple method to recover the graphene-based chemi-resistor signal Journal of Sensors and Sensor Systems, 3, 241-244, 2014 Author(s): F. Fedi, F. Ricciardella, M. L. Miglietta, T. Polichetti, E. Massera, and G. Di Francia We present the development of a simple and fast method for restoring exhaust graphene-based chemi-resistors used for NO 2 detection. Repeatedly exposing the devices to gases or to air for more than 2 days, an overall worsening of the sensing signal is observed; we hypothesized that the poisoning effect in both cases is caused by the exposure to NO 2 . Starting from this hypothesis and from the observation that NO 2 is soluble in water, we performed a recovery method consisting in the dipping of exhaust devices into ultrapure water at 100 °C for 60 s. The device performances are compared with those obtained after the restoration is achieved using the typical annealing under vacuum method.

Description: Devices based on series-connected Schottky junctions and β-Ga 2 O 3 /SiC heterojunctions characterized as hydrogen sensors Journal of Sensors and Sensor Systems, 3, 231-239, 2014 Author(s): S. Nakagomi, K. Yokoyama, and Y. Kokubun Field-effect hydrogen gas sensor devices were fabricated with the structure of a series connection between Schottky junctions and β-Ga 2 O 3 /6H-SiC heterojunctions. β-Ga 2 O 3 thin films were deposited on n-type and p-type 6H-SiC substrates by gallium evaporation in oxygen plasma. These devices have rectifying properties and were characterized as hydrogen sensors by a Pt electrode. The hydrogen-sensing properties of both devices were measured in the range of 300–500 °C. The Pt/Ga 2 O 3 /n-SiC device revealed hydrogen-sensing properties as conventional Schottky diode-type devices. The forward current of the Pt/Ga 2 O 3 /p-SiC device was significantly increased under exposure to hydrogen. The behaviors of hydrogen sensing of the devices were explained using band diagrams of the Pt/Ga 2 O 3 /SiC structure biased in the forward and reverse directions.

Description: Catalytic and thermal characterisations of nanosized PdPt / Al 2 O 3 for hydrogen detection Journal of Sensors and Sensor Systems, 3, 273-280, 2014 Author(s): T. Mazingue, M. Lomello-Tafin, M. Passard, C. Hernandez-Rodriguez, L. Goujon, J.-L. Rousset, F. Morfin, and J.-F. Laithier Palladium platinum (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects. These remarkable properties have been studied by measuring the temperature variations of alumina (Al 2 O 3 ) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterisations and catalytic activity of PdPt / Al 2 O 3 systems synthesised by co-impregnation will be presented. Catalytic characterisations show that the system is already active at room temperature and that this activity sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process improves the activity, and very high conversion can be reached even at room temperature. The thermal response (about 3 °C) of only 1 mg of PdPt / Al 2 O 3 is reversible, and the time response is about 5 s. The integration of PdPt / Al 2 O 3 powder on a flat substrate has been realised by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.

Description: Large-eddy simulation of pollutant dispersion from a ground-level area source over urban street canyons with irreversible chemical reactions Advances in Science and Research, 11, 89-91, 2014 Author(s): T. Z. Du, C.-H. Liu, and Y. B. Zhao In this study, the dispersion of chemically reactive pollutants is calculated by large-eddy simulation (LES) in a neutrally stratified urban canopy layer (UCL) over urban areas. As a pilot attempt, idealized street canyons of unity building-height-to-street-width (aspect) ratio are used. Nitric oxide (NO) is emitted from the ground surface of the first street canyon into the domain doped with ozone (O 3 ). In the absence of ultraviolet radiation, this irreversible chemistry produces nitrogen dioxide (NO 2 ), developing a reactive plume over the rough urban surface. A range of timescales of turbulence and chemistry are utilized to examine the mechanism of turbulent mixing and chemical reactions in the UCL. The Damköhler number ( Da ) and the reaction rate ( r ) are analyzed along the vertical direction on the plane normal to the prevailing flow at 10 m after the source. The maximum reaction rate peaks at an elevation where Damköhler number Da is equal or close to unity. Hence, comparable timescales of turbulence and reaction could enhance the chemical reactions in the plume.

Description: Thermal imaging as a modern form of pyrometry Journal of Sensors and Sensor Systems, 3, 265-271, 2014 Author(s): U. Kienitz Pyrometers and thermography cameras used to be characterized by different specifications and technical definitions. After an analysis of the market situation and the physical basics, the following article describes common methods to determine optical and thermal key parameters. Based on this, aspects of future sensor developments and certain applications of infrared (IR) cameras are discussed. (This article was first published in the journal tm – Technisches Messen, Vol. 81, No. 3, 2014 , a volume which is dedicated to the memory of Prof. Dr.-Ing. habil. Ludwig Walther.)

Description: Selective detection of hazardous VOCs for indoor air quality applications using a virtual gas sensor array Journal of Sensors and Sensor Systems, 3, 253-263, 2014 Author(s): M. Leidinger, T. Sauerwald, W. Reimringer, G. Ventura, and A. Schütze An approach for detecting hazardous volatile organic compounds (VOCs) in ppb and sub-ppb concentrations is presented. Using three types of metal oxide semiconductor (MOS) gas sensors in temperature cycled operation, formaldehyde, benzene and naphthalene in trace concentrations, reflecting threshold limit values as proposed by the WHO and European national health institutions, are successfully identified against a varying ethanol background of up to 2 ppm. For signal processing, linear discriminant analysis is applied to single sensor data and sensor fusion data. Integrated field test sensor systems for monitoring of indoor air quality (IAQ) using the same types of gas sensors were characterized using the same gas measurement setup and data processing. Performance of the systems is reduced due to gas emissions from the hardware components. These contaminations have been investigated using analytical methods. Despite the reduced sensitivity, concentrations of the target VOCs in the ppb range (100 ppb of formaldehyde; 5 ppb of benzene; 20 ppb of naphthalene) are still clearly detectable with the systems, especially when using the sensor fusion method for combining data of the different MOS sensor types.

Description: Aerosol-deposited BaFe 0.7 Ta 0.3 O 3-δ for nitrogen monoxide and temperature-independent oxygen sensing Journal of Sensors and Sensor Systems, 3, 223-229, 2014 Author(s): M. Bektas, D. Hanft, D. Schönauer-Kamin, T. Stöcker, G. Hagen, and R. Moos The gas sensing properties of resistive gas sensors of BaFe 0.7 Ta 0.3 O 3-δ (BFT30) prepared by the so-called aerosol deposition method, a method to manufacture dense ceramic films at room temperature, were investigated. The electrical response of the films was investigated first under various oxygen concentrations and in a wide temperature range between 350 and 900 °C. Between 700 and 900 °C, the conductivity of BaFe 0.7 Ta 0.3 O 3-δ (BFT30) depends on the oxygen concentration with a slope of almost 1/4 in the double-logarithmic plot vs. oxygen partial pressure. In addition, the sensor response is temperature independent. BFT30 responds fast and reproducibly to changing oxygen partial pressures even at 350 °C. The cross-sensitivity has been investigated in environments with various gases (C 3 H 8 , NO, NO 2 , H 2 , CO, CO 2 , and H 2 O) in synthetic air between 350 and 800 °C. BFT30 exhibits good sensing properties to NO between 350 and 400 °C in the range from 1.5 to 2000 ppm with a high selectivity to the other investigated gas species. Thus this semiconducting ceramic material is a good candidate for a temperature-independent oxygen sensor at high temperatures with the application in exhausts and for a selective nitrogen monoxide (NO) sensor at low temperatures for air quality monitoring.

Description: Metal oxide semiconductor gas sensor self-test using Fourier-based impedance spectroscopy Journal of Sensors and Sensor Systems, 3, 213-221, 2014 Author(s): M. Schüler, T. Sauerwald, and A. Schütze For the self-test of semiconductor gas sensors, we combine two multi-signal processes: temperature-cycled operation (TCO) and electrical impedance spectroscopy (EIS). This combination allows one to discriminate between irreversible changes of the sensor, i.e., changes caused by poisoning, as well as changes in the gas atmosphere. To integrate EIS and TCO, impedance spectra should be acquired in a very short time period, in which the sensor can be considered time invariant, i.e., milliseconds or less. For this purpose we developed a Fourier-based high-speed, low-cost impedance spectroscope. It provides a binary excitation signal through an FPGA (field programable gate array), which also acquires the data. To determine impedance spectra, it uses the ETFE (empirical transfer function estimate) method, which calculates the impedance by evaluating the Fourier transformations of current and voltage. With this approach an impedance spectrum over the range from 61 kHz to 100 MHz is acquired in ca. 16 μs. We carried out TCO–EIS measurements with this spectroscope and a commercial impedance analyzer (Agilent 4294A), with a temperature cycle consisting of six equidistant temperature steps between 200 and 450 °C, with lengths of 30 s (200 °C) and 18 s (all others). Discrimination of carbon monoxide (CO) and methane (CH 4 ) is possible by LDA (linear discriminant analysis) using either TCO or EIS data, thus enabling a validation of results by comparison of both methods.

Description: Characterization of ash particles with a microheater and gas-sensitive SiC field-effect transistors Journal of Sensors and Sensor Systems, 3, 305-313, 2014 Author(s): C. Bur, M. Bastuck, A. Schütze, J. Juuti, A. Lloyd Spetz, and M. Andersson Particle emission from traffic, power plants or, increasingly, stoves and fireplaces poses a serious risk for human health. The harmfulness of the particles depends not only on their size and shape but also on adsorbates. Particle detectors for size and concentration are available on the market; however, determining content and adsorbents is still a challenge. In this work, a measurement setup for the characterization of dust and ash particle content with regard to their adsorbates is presented. For the proof of concept, ammonia-contaminated fly ash samples from a coal-fired power plant equipped with a selective non-catalytic reduction (SNCR) system were used. The fly ash sample was placed on top of a heater substrate situated in a test chamber and heated up to several hundred degrees. A silicon carbide field-effect transistor (SiC-FET) gas sensor was used to detect desorbing species by transporting the headspace above the heater to the gas sensor with a small gas flow. Accumulation of desorbing species in the heater chamber followed by transfer to the gas sensor is also possible. A mass spectrometer was placed downstream of the sensor as a reference. A clear correlation between the SiC-FET response and the ammonia spectra of the mass spectrometer was observed. In addition, different levels of contamination can be distinguished. Thus, with the presented setup, chemical characterization of particles, especially of adsorbates which contribute significantly to the harmfulness of the particles, is possible.