bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative assessment of ecotoxicity of urban aerosol
Authors: Turóczi B. , Hoffer A. , Tóth Á. , Kováts N. , Ács A. , Ferincz Á. , Kovács A. , Gelencsér A.
Published: August 2012

Abstract. In addition to its mass concentration, the health effects of urban particulate matter may depend on its particle size distribution and chemical composition. Yet air pollution regulations rely on exclusively bulk PM10 concentration measurements, without regard to their potentially different health effects under different conditions. Aerosols from various sources are well known to contain a plethora of toxic, carcinogenic, mutagenic or teratogenic constituents such as heavy metals and polycyclic aromatic hydrocarbons. Extensive public health studies established the link between mass concentrations of PM2.5 / PM10 and health problems within the population. However, little is known about the relative importance of PM from different sources and the effect of seasonality on the toxicity. Here we present the application of a simple and sensitive method for the direct assessment of the overall ecotoxicity of various PM2.5 / PM10 samples collected on filters. The method is based on the Vibrio fischeri bioluminescence inhibition bioassay that has been standardized for solid samples, representing a relevant biological exposure route. Direct emission samples proved to be significantly more ecotoxic than photochemically processed aerosol, thus marked differences were observed between the ecotoxicities of urban PM10 in summer and winter. These effects of urban PM10 may be useful supplementary indicators besides the mass concentrations of PM2.5 / PM10 in cities.
Evaluation of two isoprene emission models for use in a long-range air pollution model
Authors: Zare A. , Christensen J. H. , Irannejad P. , Brandt J.
Published: August 2012

Abstract. Knowledge about isoprene emissions and concentration distribution is important for chemistry transport models (CTMs), because isoprene acts as a precursor for tropospheric ozone and subsequently affects the atmospheric concentrations of many other atmospheric compounds. Isoprene has a short lifetime, and hence it is very difficult to evaluate its emission estimates against measurements. For this reason, we coupled two isoprene emission models with the Danish Eulerian Hemispheric Model (DEHM), and evaluated the simulated background ozone concentrations based on different models for isoprene emissions. In this research, results of using the two global biogenic emission models; GEIA (Global Emissions Inventory Activity) and MEGAN (the global Model of Emissions of Gases and Aerosols from Nature) are compared and evaluated. The total annual emissions of isoprene for the year 2006 estimated by using MEGAN is 592 Tg yr−1 for an extended area of the Northern Hemisphere, which is 21% higher than that estimated by using GEIA. The overall feature of the emissions from the two models is quite similar, but differences are found mainly in Africa's savannah and in the southern part of North America. Differences in spatial distribution of emission factors are found to be a key source of these discrepancies. In spite of the short life-time of isoprene, a direct evaluation of isoprene concentrations using the two biogenic emission models in DEHM has been made against available measurements in Europe. Results show an agreement between two models simulations and the measurements in general and that the CTM is able to simulate isoprene concentrations. Additionally, investigation of ozone concentrations resulting from the two biogenic emission models show that isoprene simulated by MEGAN strongly affects the ozone production in the African savannah; the effect is up to 10% more than that obtained using GEIA. In contrast, the impact of using GEIA is higher in the Amazon region with more than 8% higher ozone concentrations compared to that of using MEGAN. Comparing the ozone concentrations obtained by DEHM using the two different isoprene models with measurements from Europe and North America, show an agreement on the hourly, mean daily and daily maximum values. However, the average of ozone daily maximum value simulated by using MEGAN is slightly closer to the measured value for the average of all measuring sites in Europe.
Droplet number prediction uncertainties from CCN: an integrated assessment using observations and a global adjoint model
Authors: Moore R. H. , Karydis V. A. , Capps S. L. , Lathem T. L. , Nenes A.
Published: August 2012

Abstract. We use the Global Modeling Initiative (GMI) chemical transport model with a cloud droplet parameterization adjoint to quantify the sensitivity of cloud droplet number concentration to uncertainties in predicting CCN concentrations. Published CCN closure prediction uncertainties for six different sets of simplifying compositional and mixing state assumptions are used as proxies for modeled CCN uncertainty arising from application of those scenarios. It is found that cloud droplet number concentrations are fairly insensitive to CCN-active aerosol number concentrations over the continents (∂Nd/∂Na ~ 10–30%), but the sensitivities exceed 70% in pristine regions such as the Alaskan Arctic and remote oceans. Since most of the anthropogenic indirect forcing is concentrated over the continents, this work shows that the application of Köhler theory and attendant simplifying assumptions in models is not a major source of uncertainty in predicting cloud droplet number or anthropogenic aerosol indirect forcing for the liquid, stratiform clouds simulated in these models. However, it does highlight the sensitivity of some remote areas to pollution brought into the region via long-range transport (e.g. biomass burning) or from seasonal biogenic sources (e.g. phytoplankton as a source of dimethylsulfide in the southern oceans). Since these transient processes are not captured well by the climatological emissions inventories employed by current large-scale models, the uncertainties in aerosol-cloud interactions during these events could be much larger than those uncovered here. This finding motivates additional measurements in these pristine regions, which have recieved little attention to date, in order to quantify the impact of, and uncertainty associated with, transient processes in effecting changes in cloud properties.
Quality assessment of Automatic Dependent Surveillance Contract (ADS-C) wind and temperature observation from commercial aircraft
Authors: de Haan S. , Bailey L. J. , Können J. E.
Published: August 2012

Abstract. Aircraft observations of wind and temperature are very important for upper air meteorology. In this article, the quality of the meteorological information of an Automatic Dependent Surveillance-Contract (ADS-C) message is assessed. The ADS-C messages are received at air traffic control centres for surveillance and airline control centres for general aircraft and dispatch management. Comparison against a global numerical prediction (NWP) model and Mode-S Enhanced Surveillance (EHS) derived wind and temperature observations is performed. Almost 16 thousand ADS-C reports with meteorological information were compiled from the Royal Dutch Airlines (KLM) database. The length of the data set is 76 days. The wind and temperature observations are of good quality when compared to the global NWP forecast fields from the European Centre for Medium-Range Weather Forecasts (ECMWF). Comparison of ADS-C wind and temperature observations against Mode-S EHS derived observations in the vicinity of Amsterdam Airport Schiphol shows that the wind observations are of similar quality and the temperature observations of ADS-C are of better quality than those from Mode-S EHS. However, the current ADS-C data set has a lower vertical resolution than Mode-S EHS. High vertical resolution can be achieved by requesting more ADS-C when aircraft are ascending or descending, but could result in increased data communication costs.
Plasma parameter analysis of the Langmuir decay process via Particle-in-Cell simulations
Authors: Diaz M. A. , Zettergren M. , Semeter J. L. , Oppenheim M.
Published: August 2012

Abstract. The beam-plasma mechanism, based on the Langmuir decay process, has been proposed to explain naturally enhanced ion-acoustic lines (NEIALs), which are spectral distortions in incoherent scatter radar (ISR) data frequently observed in the vicinity of auroral arcs. In this work the effect of the Langmuir decay process on the ISR spectrum is studied and compared with an analytical model for different plasma parameters by using an electrostatic parallel particle-in-cell (EPPIC) code. Simulations show that the code is working in accordance with theory for a wide range of beam and plasma values and that the features of the spectrum are sensitive to changes of those values. These results suggest that the EPPIC code might be used to build a spectrum-plasma parameter model which will allow estimation of beam and plasma parameters from observed spectra. Simulations also confirm that background electron density (ne) plays an important role in determining the maximum detectable wavenumber of the enhancement. Specifically, results demonstrate that an increase in ne makes the enhancements of the ion acoustic more likely line at large wavenumbers, a finding consistent with statistical studies showing more frequent NEIAL occurrence near solar maximum. Finally, the simulations expose some inaccuracies of the current theoretical model in quantifying the energy passed from the beam to the Langmuir waves as well as with the range of enhanced wavenumbers. These differences may be attributable to the weak Langmuir turbulent regime assumption used in the theory.
Modern isotope hydrology and controls on δD of plant leaf waxes at Lake El'gygytgyn, NE Russia
Authors: Wilkie K. M. K. , Chapligin B. , Meyer H. , Burns S. , Petsch S. , Brigham-Grette J.
Published: August 2012

Abstract. Stable isotope data from lipid biomarkers and diatom silica recovered from lake sediment cores hold great promise for paleoclimate and paleohydrological reconstructions. However, these records rely on accurate calibration with modern precipitation and hydrologic processes. Here we investigate the stable isotopic composition of modern precipitation, streams, lake water and ice cover, and use these data to constrain isotope systematics of the Lake El'gygytgyn basin hydrology. Compound specific hydrogen isotope ratios determined from modern vegetation are compared with modern precipitation and lake core top sediments. Multi-species net (apparent) fractionation values between source water (precipitation) and leaf wax lipids (mean value is −105 ± 13‰) agree with previous results in arid environments and provide a basis for application of this proxy downcore. We conclude that although there may be some bias towards winter precipitation signal, overall leaf wax lipids record annual average precipitation within the El'gygytgyn Basin.
Proxy benchmarks for intercomparison of 8.2 ka simulations
Authors: Morrill C. , Anderson D. M. , Bauer B. A. , Buckner R. , Gille E. P. , Gross W. S. , Hartman M. , Shah A.
Published: August 2012

Abstract. The Paleoclimate Modelling Intercomparison Project (PMIP3) now includes the 8.2 ka event as a test of model sensitivity to North Atlantic freshwater forcing. To provide benchmarks for intercomparison, we compiled and analyzed high-resolution records spanning this event. Two previously-described anomaly patterns that emerge are cooling around the North Atlantic and drier conditions in the Northern Hemisphere tropics. Newer to this compilation are more robustly-defined wetter conditions in the Southern Hemisphere tropics and regionally-limited warming in the Southern Hemisphere. Most anomalies around the globe lasted on the order of 100 to 150 yr. More quantitative reconstructions are now available and indicate cooling of 1.0 to 1.2 °C and a ~20% decrease in precipitation in parts of Europe, as well as spatial gradients in δ18O from the high to low latitudes. Unresolved questions remain about the seasonality of the climate response to freshwater forcing and the extent to which the bipolar seesaw operated in the early Holocene.
Martian dust devils detector over FPGA
Authors: de Lucas E. , Miguel M. J. , Mozos D. , Vázquez L.
Published: August 2012

Abstract. Digital applications that must be on-board space missions must comply with a very restrictive set of requirements. These include energy efficiency, small volume and weight, robustness and high performance. Moreover, these circuits cannot be repaired in case of error, so they must be reliable or provide some way to recover from errors. These features make reconfigurable hardware (FPGAs, Field Programmable Gate Arrays) a very suitable technology to be used in space missions. This paper presents a Martian dust devil detector implemented on an FPGA. The results show that a hardware implementation of the algorithm presents very good numbers in terms of performance compared with the software version. Moreover, as the amount of time needed to perform all the computations on the reconfigurable hardware is small, this hardware can be used most of the time to realize other applications.
Performance of thermal conductivity probes for planetary applications
Authors: Hütter E. S. , Kömle N. I.
Published: August 2012

Abstract. This work aims to contribute to the development of in situ instruments feasible for space application. Commercial as well as custom-made thermal sensors, based on the transient hot wire technique and suitable for direct measurement of the effective thermal conductivity of granular media, were tested for application under airless conditions. In order to check the ability of custom-made sensors to measure the thermal conductivity of planetary surface layers, detailed numerical simulations predicting the response of the different sensors have been performed. These simulations reveal that for investigations under high vacuum conditions (as they prevail, e.g. on the lunar surface), the derived thermal conductivity values can significantly depend on sensor geometry, axial heat flow, and the thermal contact between probe and surrounding material. Therefore, a careful calibration of each particular sensor is necessary in order to obtain reliable thermal conductivity measurements. The custom-made sensors presented in this work can serve as prototypes for payload to be flown on future planetary lander missions, in particular for airless bodies like the Moon, asteroids and comets, but also for Mars.
Investigating thermal properties of gas-filled planetary regoliths using a thermal probe
Authors: Paton M. D. , Harri A.-M. , Mäkinen T. , Green S. F.
Published: August 2012

Abstract. We introduce a general purpose penetrator, fitted with a heater, for measuring temperature and thermal diffusivity. Due to its simplicity of deployment and operation the penetrator is well suited for remote deployment by spacecraft into a planetary regolith. Thermal measurements in planetary regoliths are required to determine the surface energy balance and to measure their thermal properties. If the regolith is on a planet with an atmosphere a good understanding of the role of convection is required to properly interpret the measurements. This could also help to identify the significant heat and mass exchange mechanisms between the regolith and the atmosphere. To understand the role of convection in our regolith analogues we use a network of temperature sensors placed in the target. In practical applications a penetrator will push material out of the way as it enters a target possible changing its thermal properties. To investigate this effect a custom built test rig, that precisely controls and monitors the motion of the penetrator, is used. The thermal diffusivity of limestone powder and sand is derived by fitting a numerical thermal model to the temperature measurements. Convection seems to play an important role in the transfer of heat in this case. Firstly a diffusion-convection model fits the laboratory data better than a diffusivity-only model. Also the diffusivity derived from a diffusivity-convection model was found to be in good agreement with diffusivity derived using other methods published in the literature. Thermal diffusivity measurements, inspection of the horizontal temperature profiles and visual observations suggests that limestone powder is compacted more readily than sand during entry of the penetrator into the target. For both regolith analogues the disturbance of material around the penetrator was determined to have an insignificant effect on the diffusivity measurements in this case.
Retrieval of ionospheric profiles from the Mars Express MARSIS experiment data and comparison with radio occultation data
Authors: Sánchez-Cano B. , Witasse O. , Herraiz M. , Radicella S. M. , Bauer J. , Blelly P.-L. , Rodríguez-Caderot G.
Published: August 2012

Abstract. Since 2005 the Mars Advanced Radar and Ionospheric Sounding experiment (MARSIS) aboard Mars Express has acquired a unique dataset on the ionosphere of Mars made up of ionospheric soundings taken by the instrument working in its active ionospheric sounding (AIS) mode. These soundings play a role similar to those of modern Terrestrial digisondes in the analysis of our planet ionosphere and have allowed us to dramatically improve our knowledge about the Martian ionosphere. This paper describes this kind of data, which are available from the public Planetary Science Archive, and introduces the MAISDAT tool developed by the European Space Agency to analyze and derive the vertical profile of electron density. Comparisons with radio occultation profiles obtained from Mars Express Radio Science instrument are performed to validate the procedure used in this study.
Design and operation of a field telescope for cosmic ray geophysical tomography
Authors: Lesparre N. , Marteau J. , Déclais Y. , Gibert D. , Carlus B. , Nicollin F. , Kergosien B.
Published: August 2012

Abstract. The cosmic ray muon tomography gives an access to the density structure of geological targets. In the present article we describe a muon telescope adapted to harsh environmental conditions. In particular the design optimizes the total weight and power consumption to ease the deployment and increase the autonomy of the detector. The muon telescopes consist of at least two scintillator detection matrices readout by photosensors via optical fibres. Two photosensor options have been studied. The baseline option foresees one multianode photomultiplier (MAPM) per matrix. A second option using one multipixel photon counter (MPPC) per bar is under development. The readout electronics and data acquisition system developed for both options are detailed. We present a first data set acquired in open-sky conditions.
Results from the intercalibration of optical low-light calibration sources 2011
Authors: Brändström B. U. E. , Enell C.-F. , Widell O. , Hansson T. , Whiter D. , Mäkinen S. , Mikhaylova D. , Axelsson K. , Sigernes F. , Gulbrandsen N. , Schlatter N. M. , Gjendem A. G. , Cai L. , Reistad J. P. , Daae M. , Demissie T. D. , Andalsvik Y. L. , Roberts O. , Poluyanov S. , Chernouss S.
Published: August 2012

Abstract. Following the 38th Annual Meeting on Atmospheric studies by Optical methods at Siuntio in Finland, an intercalibration workshop for optical low-light calibration sources was held in Sodankylä, Finland. The main purpose of this workshop was to provide a comparable scale for absolute measurements of aurora and airglow. All sources brought to the intercalibration workshop were compared to an international standard source (Fritz-Peak) using the Lindau Calibration Photometer built by Wilhelm Barke and Hans Lauche in 1984. The international standard source is on loan from Michael Gadsden, Aberdeen. The results were compared to several earlier intercalibration workshops. It was found that most sources were fairly stable over time with errors in the range of 5–20%. To further validate the results, two sources were also intercalibrated at UNIS, Longyearbyen, Svalbard. Preliminary analysis indicate good agreement with the intercalibration in Sodankylä.
Tomography-like retrieval of auroral volume emission ratios for the 31 January 2008 Hotel Payload 2 event
Authors: Enell C.-F. , Gustavsson B. , Brändström B. U. E. , Sergienko T. I. , Verronen P. T. , Rydesäter P. , Sandahl I.
Published: August 2012

Abstract. Quantitative tomography-like volume estimates of the N2+(1N) emission at 427.8 nm, the O(1S) emission at 557.7 nm and the O(1D) emission at 630.0 nm can be retrieved from data from the Auroral Large Imaging System (ALIS) remote-controlled spectral imagers operated at field stations in northern Sweden and Norway. This paper presents a case study of a quiet auroral arc passing over the common volume of the imagers in the evening of 31 January 2008, before the launch of the Hotel Payload 2 (HotPay 2) rocket from Andøya Rocket Range. The reconstructed spectroscopic ratios at the lower altitudes close to the mesopause region can be used as indicators of the NO and O profiles, as the atomic oxygen O(1S) and O(1D) states are excited partly through chemical reactions. The profiles of the ratios of the volume emission rates ε557.7 and ε427.8 observed by ALIS over northern Norway show nothing unambiguously unusual within the accuracy of the calibration and retrieval, whereas HotPay 2 indicated subsidence of lower thermospheric air, with higher NO concentrations. This is consistent with observations of NO and CO by satellite instruments, which indicate subsidence in vortex filaments only in the NW as seen from the Scandinavian mainland.
Innovations and applications of the VERA quality control
Authors: Mayer D. , Steinacker R. , Steiner A.
Published: August 2012

Abstract. Quality Control (QC) is seen today as an important scientific field to increase the value of observational data. Whereas most QC methods are linked to atmospheric modelling (being part of the data assimilation procedure), in this paper the focus is on the application of a model independent QC method based on data self consistency recently published: VERA-QC. A special challenge is the QC of data in complex terrain which requires special treatment in terms of data selection and data transformation. In this context, some special VERA-QC modules such as the consideration of significant elevation differences of adjacent stations or the consideration of transformed temperature values will be discussed. The system detects gross errors as well as biases and offers objective correction proposals (deviations) for each observation. The essential gross error detection is not only based on the statistical behaviour of station specific deviations, but also on the rate of cost function reduction. Beside a two dimensional application, higher dimensionalities may also be chosen, for instance including the time coordinate. Applications and results are discussed for pressure, temperature and wind as well as for precipitation data which needs, however, a very dense observation network. Real time application of VERA-QC allows the production of high quality fields of meteorological parameters which can be used e.g. for nowcasting as well as for model unbiased validation of prognostic models.
Performance of thermal conductivity probes for planetary applications
Authors: Hütter E. S. , Kömle N. I.
Published: August 2012

Abstract. This work aims to contribute to the development of in situ instruments feasible for space application. Commercial as well as custom made thermal sensors, based on the transient hot wire technique and suitable for direct measurement of the effective thermal conductivity of granular media, were tested for application under airless conditions. The investigated media range from compact specimen of well known thermal conductivity used for calibration of the sensors to various granular planetary analogue materials of different shape and grain size. Measurements were performed under gas pressures ranging from 103 hPa down to about 10−5 hPa. It was found that for the inspected granular materials the given pressure decrease results in a decrease of the thermal conductivity by about two orders of magnitude. In order to check the ability of custom-made sensors to measure the thermal conductivity of planetary surface layers, detailed numerical simulations predicting the response of the different sensors have also been performed. Both, measurements and simulations, revealed that for investigations under high vacuum conditions (as they prevail e.g. on the lunar surface) the derived thermal conductivity values can significantly depend on the sensor geometry, the axial heat flow and the thermal contact between probe and surrounding material. Therefore in these cases a careful calibration of each particular sensor is necessary in order to obtain reliable thermal conductivity measurements. The custom-made sensors presented in this work can serve as prototypes for payload to be flown on future planetary lander missions, in particular for airless bodies like the Moon, asteroids and comets, but also for Mars.
Automatic parameterization for magnetometer zero offset determination
Authors: Pudney M. A. , Carr C. M. , Schwartz S. J. , Howarth S. I.
Published: August 2012

Abstract. In-situ magnetic field measurements are of critical importance in understanding how the Sun creates and controls the heliosphere. To ensure the measurements are accurate, it is necessary to track the combined slowly-varying spacecraft magnetic field and magnetometer zero offset – the systematic error in the sensor measurements. For a 3-axis stabilised spacecraft, in-flight correction of zero offsets primarily relies on the use of Alfvénic rotations in the magnetic field. We present a method to automatically determine a key parameter related to the ambient compressional variance of the signal (which determines the selection criteria for identifying clear Alfvénic rotations). We apply our method to different solar wind conditions, performing a statistical analysis of the data periods required to achieve a 70% chance of calculating an offset using Helios datasets. We find that 70% of 40 min data periods in regions of fast solar wind possess sufficient rotational content to calculate an offset. To achieve the same 70% calculation probability in regions of slow solar wind requires data periods of 2 h duration. We also find that 40 min data periods at perihelion compared to 1 h and 40 min data periods at aphelion are required to achieve the same 70% calculation probability. We compare our method with previous work that uses a fixed parameter approach and demonstrate an improvement in the calculation probability of up to 10% at aphelion and 5% at perihelion.
A custom acoustic emission monitoring system for harsh environments: application to freezing-induced damage in alpine rock-walls
Authors: Girard L. , Beutel J. , Gruber S. , Hunziker J. , Lim R. , Weber S.
Published: August 2012

Abstract. We present a custom acoustic emission (AE) monitoring system designed to perform long-term measurements on high-alpine rock-walls. AE monitoring is a common technique for characterizing damage evolution in solid materials. The system is based on a two-channel AE sensor node (AE-node) integrated into a Wireless Sensor Network (WSN) customized for operation in harsh environments. This wireless architecture offers flexibility in the deployment of AE-nodes at any position of the rock-wall that needs to be monitored, within a range of a few hundred meters from a core station connected to the internet. The system achieves near real-time data delivery and allows the user to remotely control the AE detection threshold. In order to protect AE sensors and capture acoustic signals from specific depths of the rock-wall, a special casing was developed. The monitoring system is completed by two probes that measure rock temperature and liquid water content, both probes being also integrated into the WSN. We report a first deployment of the monitoring system on a rock-wall at Jungfraujoch, 3500 m a.s.l., Switzerland. While this first deployment of the monitoring system aims to support fundamental research on processes that damage rock under cold climate, the system could serve a number of other applications, including rock-fall hazard surveillance or structural monitoring of concrete structures.
A new permanent multi-parameter monitoring network in Central Asian high mountains – from measurements to data bases
Authors: Schöne T. , Zech C. , Unger-Shayesteh K. , Rudenko V. , Thoss H. , Wetzel H.-U. , Zubovich A.
Published: August 2012

Abstract. Long-term monitoring of water resources and climate parameters at the scale of river basins requires networks of continuously operated in-situ stations. Since 2009, GFZ and CAIAG, in cooperation with the National Hydrometeorological Services (NHMS), are establishing such a regional monitoring network in Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Afghanistan) which is collecting observations of meteorological and hydrological parameters and delivering them to the end-users. The network design focuses mainly on the higher elevations where the recent decline of monitoring stations and networks established in Soviet times was strongest, and the resulting observational gap hinders research on climate and hydrological change as well as operational tasks in water management such as the seasonal runoff forecast. The newly developed and installed Remotely Operated Multi-Parameter Stations (ROMPS) do not only monitor standard meteorological and hydrological parameters, but also deliver GPS data for atmospheric sounding as well as tectonic studies. The observational data from the ROMPS is transmitted at least once a day to a centralized geo-database infrastructure for long-term storage and data redistribution. Users can access the data manually using a web-interface or automatically using SOS requests; in addition, data is distributed to the NHMS through standard communication and data exchange channels.
Observing desert dust devils with a pressure logger
Authors: Lorenz R. D.
Published: August 2012

Abstract. A commercial pressure logger has been adapted for long-term field use. Its flash memory affords the large data volume to allow months of pressure measurements to be acquired at the rapid cadence (>1 Hz) required to detect dust devils, small dust-laden convective vortices observed in arid regions. The power consumption of the unit is studied and battery and solar/battery options evaluated for long-term observations. A two-month-long field test is described, and several example dust devil encounters are examined. In addition, a periodic (~20 min) convective signature is observed, and some lessons in operations and correction of data for temperature drift are reported. The unit shows promise for obtaining good statistics on dust devil pressure drops, to permit comparison with Mars lander measurements, and for array measurements.
Geo-neutrinos
Authors: Ludhova L.
Published: August 2012

Abstract. Geo-neutrinos, electron anti-neutrinos produced in β-decays of naturally occurring radioactive isotopes in the Earth, are a unique direct probe of our planet's interior. After a brief introduction about the Earth (mostly for physicists) and the very basics about the neutrinos and anti-neutrinos (mostly for geologists), I describe the geo-neutrinos' properties and the main aims of their study. An overview of the latest experimental results obtained by KamLand and Borexino experiments is provided. A short overview of future perspectives of this new inter-disciplinary field is given.
The KM3NeT project: status and perspectives
Authors: Margiotta A.
Published: August 2012

Abstract. KM3NeT is an international consortium involving more than 300 scientists from 10 EU countries. Its main objective is the construction of a multi-km3 high-energy neutrino telescope in the Mediterranean Sea that will also host an interdisciplinary observatory to marine sciences. KM3NeT has been included in the roadmap of the European Strategy Forum of Research Infrastructures (ESFRI). Very high energy neutrinos are important messengers to study non-thermal phenomena in the Universe. The pioneering ANTARES, NEMO and NESTOR underwater neutrino telescope projects include the extensive R & D knowledge base behind the KM3NeT project. A Technical Design Report has been published which describes the technological solutions chosen for the detector. The present status of the project is presented.
Retrieval of ionospheric profiles from the Mars Express MARSIS experiment data and comparison with radio-occultation data
Authors: Sánchez-Cano B. , Witasse O. , Herraiz M. , Radicella S. M. , Bauer J. , Blelly P.-L. , Rodríguez-Caderot G.
Published: August 2012

Abstract. Since 2005 the Mars Advanced Radar and Ionospheric Sounding experiment (MARSIS) aboard Mars Express has acquired a unique data set on the ionosphere of Mars made up of ionospheric soundings taken by the instrument working in its Active Ionospheric Sounding (AIS) mode. These soundings play a role similar to those of modern Terrestrial digisondes in the analysis of our planet ionosphere and have allowed us to dramatically improve our knowledge about the Martian ionosphere. This paper describes this kind of data, which are available from the public Planetary Science Archive, and introduces the MAISDAT tool developed by the European Space Agency to analyze and derive the vertical profile of electron density. Comparisons with radio-occultation profiles obtained from Mars Express Radio Science instrument are performed to validate the procedure used in this study.
A comparison between soil loss evaluation index and the C-factor of RUSLE: a case study in the Loess Plateau of China
Authors: Zhao W. W. , Fu B. J. , Chen L. D.
Published: August 2012

Abstract. Land use and land cover are most important in quantifying soil erosion. Based on the C-factor of the popular soil erosion model, Revised Universal Soil Loss Equation (RUSLE) and a scale-pattern-process theory in landscape ecology, we proposed a multi-scale soil loss evaluation index (SL) to evaluate the effects of land use patterns on soil erosion. We examined the advantages and shortcomings of SL for small watershed (SLsw) by comparing to the C-factor used in RUSLE. We used the Yanhe watershed located on China's Loess Plateau as a case study to demonstrate the utilities of SLsw. The SLsw calculation involves the delineations of the drainage network and sub-watershed boundaries, the calculations of soil loss horizontal distance index, the soil loss vertical distance index, slope steepness, rainfall-runoff erosivity, soil erodibility, and cover and management practice. We used several extensions within the geographic information system (GIS), and AVSWAT2000 hydrological model to derive all the required GIS layers. We compared the SLsw with the C-factor to identify spatial patterns to understand the causes for the differences. The SLsw values for the Yanhe watershed are in the range of 0.15 to 0.45, and there are 593 sub-watersheds with SLsw values that are lower than the C-factor values (LOW) and 227 sub-watersheds with SLsw values higher than the C-factor values (HIGH). The HIGH area have greater rainfall-runoff erosivity than LOW area for all land use types. The cultivated land is located on the steeper slope or is closer to the drainage network in the horizontal direction in HIGH area in comparison to LOW area. The results imply that SLsw can be used to identify the effect of land use distribution on soil loss, whereas the C-factor has less power to do it. Both HIGH and LOW areas have similar soil erodibility values for all land use types. The average vertical distances of forest land and sparse forest land to the drainage network are shorter in LOW area than that in HIGH area. Other land use types have shorter average vertical distances in HIGH area than that LOW area. SLsw has advantages over C-factor in its ability to specify the subwatersheds that require the land use patterns optimization by adjusting the locations of land uses to minimize soil loss.
Water management simulation games and the construction of knowledge
Authors: Rusca M. , Heun J. , Schwartz K.
Published: August 2012

Abstract. In recent years, simulations have become an important part of teaching activities. The reasons behind the popularity of simulation games are twofold. On the one hand, emerging theories on how people learn have called for an experienced-based learning approach. On the other hand, the demand for water management professionals has changed. Three important developments are having considerable consequences for water management programmes, which educate and train these professionals. These developments are the increasing emphasis on integration in water management, the characteristics and speed of reforms in the public sector and the shifting state-society relations in many countries. In response to these developments, demand from the labour market is oriented toward water professionals who need to have both a specialist in-depth knowledge in their own field, as well as the ability to understand and interact with other disciplines and interests. In this context, skills in negotiating, consensus building and working in teams are considered essential for all professionals. In this paper, we argue that simulation games have an important role to play in (actively) educating students and training the new generation of water professionals to respond to the above-mentioned challenges. At the same time, simulations are not a panacea for learners and teachers. Challenges of using simulation games include the demands it places on the teacher. Setting up the simulation game, facilitating the delivery and ensuring that learning objectives are achieved require considerable knowledge and experience as well as considerable time-inputs of the teacher. Moreover, simulation games usually incorporate a case-based learning model, which may neglect or underemphasize theories and conceptualizations. For simulations to be effective, they have to be embedded in this larger theoretical and conceptual framework. Simulations, therefore, complement rather than substitute traditional teaching methods.
SWAT use of gridded observations for simulating runoff – a Vietnam river basin study
Authors: Vu M. T. , Raghavan S. V. , Liong S. Y.
Published: August 2012

Abstract. Many research studies that focus on basin hydrology have applied the SWAT model using station data to simulate runoff. But over regions lacking robust station data, there is a problem of applying the model to study the hydrological responses. For some countries and remote areas, the rainfall data availability might be a constraint due to many different reasons such as lacking of technology, war time and financial limitation that lead to difficulty in constructing the runoff data. To overcome such a limitation, this research study uses some of the available globally gridded high resolution precipitation datasets to simulate runoff. Five popular gridded observation precipitation datasets: (1) Asian Precipitation Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources (APHRODITE), (2) Tropical Rainfall Measuring Mission (TRMM), (3) Precipitation Estimation from Remote Sensing Information using Artificial Neural Network (PERSIANN), (4) Global Precipitation Climatology Project (GPCP), (5) a modified version of Global Historical Climatology Network (GHCN2) and one reanalysis dataset, National Centers for Environment Prediction/National Center for Atmospheric Research (NCEP/NCAR) are used to simulate runoff over the Dak Bla river (a small tributary of the Mekong River) in Vietnam. Wherever possible, available station data are also used for comparison. Bilinear interpolation of these gridded datasets is used to input the precipitation data at the closest grid points to the station locations. Sensitivity Analysis and Auto-calibration are performed for the SWAT model. The Nash-Sutcliffe Efficiency (NSE) and Coefficient of Determination (R2) indices are used to benchmark the model performance. Results indicate that the APHRODITE dataset performed very well on a daily scale simulation of discharge having a good NSE of 0.54 and R2 of 0.55, when compared to the discharge simulation using station data (0.68 and 0.71). The GPCP proved to be the next best dataset that was applied to the runoff modelling, with NSE and R2 of 0.46 and 0.51, respectively. The PERSIANN and TRMM rainfall data driven runoff did not show good agreement compared to the station data as both the NSE and R2 indices showed a low value of 0.3. GHCN2 and NCEP also did not show good correlations. The varied results by using these datasets indicate that although the gauge based and satellite-gauge merged products use some ground truth data, the different interpolation techniques and merging algorithms could also be a source of uncertainties. This entails a good understanding of the response of the hydrological model to different datasets and a quantification of the uncertainties in these datasets. Such a methodology is also useful for planning on Rainfall-runoff and even reservoir/river management both at rural and urban scales.
Testing the critical exponent in the relation between stress drop of earthquake and lead time of seismic electric signal
Authors: Dologlou E.
Published: August 2012

Abstract. The application of new data in the power law relation between the stress drop of the earthquake and the lead time of the precursory seismic electric signal led to an exponent which falls in the range of the values of critical exponents for fracture and it is in excellent agreement with a previous one found by (Dologlou, 2012). In addition, this exponent is very close to the one reported by Varotsos and Alexopoulos (1984a), which interconnects the amplitude of the precursory seismic electric signals (SES) and the magnitude of the impending earthquake. Hence, the hypothesis that underlying dynamic processes evolving to criticality prevail in the pre-focal area when the SES is emitted is significantly supported.
Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA) analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland
Authors: Booth A. D. , Clark R. A. , Kulessa B. , Murray T. , Carter J. , Doyle S. , Hubbard A.
Published: August 2012

Abstract. Seismic amplitude-versus-angle (AVA) methods are a powerful means of quantifying the physical properties of subglacial material, but serious interpretative errors can arise when AVA is measured over a thinly-layered substrate. A substrate layer with a thickness less than 1/4 of the seismic wavelength, λ, is considered "thin", and reflections from its bounding interfaces superpose and appear in seismic data as a single reflection event. AVA interpretation of subglacial till can be vulnerable to such thin-layer effects, since a lodged (non-deforming) till can be overlain by a thin (metre-scale) cap of dilatant (deforming) till. We assess the potential for misinterpretation by simulating seismic data for a stratified subglacial till unit, with an upper dilatant layer between 0.1–5.0 m thick (λ / 120 to > λ / 4, with λ = 12 m). For dilatant layers less than λ / 6 thick, conventional AVA analysis yields acoustic impedance and Poisson's ratio that indicate contradictory water saturation. A thin-layer interpretation strategy is proposed, that accurately characterises the model properties of the till unit. The method is applied to example seismic AVA data from Russell Glacier, West Greenland, in which characteristics of thin-layer responses are evident. A subglacial till deposit is interpreted, having lodged till (acoustic impedance = 4.26±0.59 × 106 kg m−2 s−1) underlying a water-saturated dilatant till layer (thickness < 2 m, Poisson's ratio ~ 0.5). Since thin-layer considerations offer a greater degree of complexity in an AVA interpretation, and potentially avoid misinterpretations, they are a valuable aspect of quantitative seismic analysis, particularly for characterising till units.
On the Magnetogravitational Instability of a Ferromagnetic Dust Cloud in the Presence of Nonuniform Rotation
Authors: Dhiman Joginder S. , Dadwal Rekha
Published: August 2012

The effect of a nonuniform magnetic field on the gravitational instability of a nonuniformly rotating infinitely extending axisymmetric cylinder in a homogenous ferromagnetic medium has been studied. The propagation of the wave is allowed along radial direction. A general dispersion relation, using the normal mode analysis method on the perturbation equations of the problem, is obtained. It is found that Bel and Schatzman criterion determines the gravitational instability of this general problem. Thus, it appears that the effect of non-uniform magnetic field on the gravitational instability as discussed by (Dhiman and Dadwal, 2010) is marginalized by the magnetic polarizability of ferrofluid.
Designing and Evaluating an Innovative Solar Air Collector with Transpired Absorber and Cover
Authors: Zomorodian Ali , Zamanian Maryam
Published: August 2012

Applying solar collectors is a popular tool for harnessing solar energy. In this work, a flat plate solar air collector was investigated under direct solar radiation in an endeavor to enhance the thermal efficiency of solar air collector with a slatted glass cover, perforated absorber aluminum sheets (porosity 0.0177, 0.0314 and absorber thickness of 1.25, 2.5 mm) which is the most suitable for a solar dryer. The effects of porosity and thickness on absorber performance of collector were evaluated. Six levels of air mass flow rates (0.0056 to 0.0385 kg m−2 s−1) were adopted. The tests were conducted in three replications on very clear sky days in September and October. The experimental results showed that thermal efficiency of collector was increased by an increase in the porosity of the absorber. The absorber with lower porosity showed a better thermal efficiency at lower air mass flux. In the minimum air flow rate, absorber efficiency with porosity 0.0177 and 0.0314 was 0.31 and 0.29, respectively, whereas at the maximum flow, efficiency showed an enormous change of 0.83 and 0.88, respectively. This solar air heater can be used for drying agricultural products, heating the space of greenhouse, and so forth.
Modelling the Role of Diagnosis, Treatment, and Health Education on Multidrug-Resistant Tuberculosis Dynamics
Authors: Maliyoni M. , Mwamtobe P. M. M. , Hove-Musekwa S. D. , Tchuenche J. M.
Published: August 2012

Tuberculosis, an airborne disease affecting almost a third of the world’s population remains one of the major public health burdens globally, and the resurgence of multidrug-resistant tuberculosis in some parts of sub-Saharan Africa calls for concern. To gain insight into its qualitative dynamics at the population level, mathematical modeling which require as inputs key demographic and epidemiological information can fill in gaps where field and lab data are not readily available. A deterministic model for the transmission dynamics of multi-drug resistant tuberculosis to assess the impact of diagnosis, treatment, and health education is formulated. The model assumes that exposed individuals develop active tuberculosis due to endogenous activation and exogenous re-infection. Treatment is offered to all infected individuals except those latently infected with multi-drug resistant tuberculosis. Qualitative analysis using the theory of dynamical systems shows that, in addition to the disease-free equilibrium, there exists a unique dominant locally asymptotically stable equilibrium corresponding to each strain. Numerical simulations suggest that, at the current level of control strategies (with Malawi as a case study), the drug-sensitive tuberculosis can be completely eliminated from the population, thereby reducing multi-drug resistant tuberculosis.