bluuebunny/crossref_metadata_2025 huggingface dataset:
Space Gravity Spectroscopy - determination of the Earth’s gravitational field by means of Newton interpolated LEO ephemeris Case studies on dynamic (CHAMP Rapid Science Orbit) and kinematic orbits
Authors: Reubelt T. , Austen G. , Grafarend E. W.
Published: April 2010

Abstract. An algorithm for the (kinematic) orbit analysis of a Low Earth Orbiting (LEO) GPS tracked satellite to determine the spherical harmonic coefficients of the terrestrial gravitational field is presented. A contribution to existing long wavelength gravity field models is expected since the kinematic orbit of a LEO satellite can nowadays be determined with very high accuracy in the range of a few centimeters. To demonstrate the applicability of the proposed method, first results from the analysis of real CHAMP Rapid Science (dynamic) Orbits (RSO) and kinematic orbits are illustrated. In particular, we take advantage of Newton’s Law of Motion which balances the acceleration vector and the gradient of the gravitational potential with respect to an Inertial Frame of Reference (IRF). The satellite’s acceleration vector is determined by means of the second order functional of Newton’s Interpolation Formula from relative satellite ephemeris (baselines) with respect to the IRF. Therefore the satellite ephemeris, which are normally given in a Body fixed Frame of Reference (BRF) have to be transformed into the IRF. Subsequently the Newton interpolated accelerations have to be reduced for disturbing gravitational and non-gravitational accelerations in order to obtain the accelerations caused by the Earth’s gravitational field. For a first insight in real data processing these reductions have been neglected. The gradient of the gravitational potential, conventionally expressed in vector-valued spherical harmonics and given in a Body Fixed Frame of Reference, must be transformed from BRF to IRF by means of the polar motion matrix, the precession-nutation matrices and the Greenwich Siderial Time Angle (GAST). The resulting linear system of equations is solved by means of a least squares adjustment in terms of a Gauss-Markov model in order to estimate the spherical harmonics coefficients of the Earth’s gravitational field.Key words. space gravity spectroscopy, spherical harmonics series expansion, GPS tracked LEO satellites, kinematic
Statistical and neural classifiers in estimating rain rate from weather radar measurements
Authors: Christodoulou C. I. , Michaelides S. C.
Published: April 2010

Abstract. Weather radars are used to measure the electromagnetic radiation backscattered by cloud raindrops. Clouds that backscatter more electromagnetic radiation consist of larger droplets of rain and therefore they produce more rain. The idea is to estimate rain rate by using weather radar as an alternative to rain-gauges measuring rainfall on the ground. In an experiment during two days in June and August 1997 over the Italian-Swiss Alps, data from weather radar and surrounding rain-gauges were collected at the same time. The statistical KNN and the neural SOM classifiers were implemented for the classification task using the radar data as input and the rain-gauge measurements as output. The proposed system managed to identify matching pattern waveforms and the rainfall rate on the ground was estimated based on the radar reflectivities with a satisfactory error rate, outperforming the traditional Z/R relationship. It is anticipated that more data, representing a variety of possible meteorological conditions, will lead to improved results. The results in this work show that an estimation of rain rate based on weather radar measurements treated with statistical and neural classifiers is possible.
The combined use of weather radar and geographic information system techniques for flood forecasting
Authors: Baltas E.
Published: April 2010

Abstract. A distributed rainfall-runoff model capable for real time flood forecasting utilizing highly spatial and time resolution data was developed. The study region is located under the WSR-74 S-band 100 km radar umbrella and is equipped with a number of rain gauge recording stations, a permanent installation for flow measurement and a stage recorder. The entire basin was digitized to 2×2 km2 grid squares by implying GIS techniques. A series of rainfall events recorded producing floods were analyzed and processed. The linear channel parameter assigned to each grid-square is based on its location measured by the centroid of the grid square along the channel network. The estimation of the hill-slope and the stream velocity are calculated based on the Geographic Information System (GIS) procedures.
Exploring the use of a column model for the characterization of microphysical processes in warm rain: results from a homogeneous rainshaft model
Authors: Prat O. P. , Barros A. P.
Published: April 2010

Abstract. A study of the evolution of raindrop spectra (raindrop size distribution, DSD) between cloud base and the ground surface was conducted using a column model of stochastic coalescense-breakup dynamics. Numerical results show that, under steady-state boundary conditions (i.e. constant rainfall rate and DSD at the top of the rainshaft), the equilibrium DSD is achieved only for high rain rates produced by midlevel or higher clouds and after long simulation times (~30 min or greater). Because these conditions are not typical of most rainfall, the results suggest that the theoretical equilibrium DSD might not be attainable for the duration of individual rain events, and thus DSD observations from field experiments should be analyzed conditional on the specific storm environment under which they were obtained.
Separation of convective and stratiform precipitation for a precipitation analysis of the local model of the German Weather Service
Authors: Langer I. , Reimer E.
Published: April 2010

Abstract. An improved independent precipitation data set with the horizontal resolution of 7×7 km grid over central Europe was generated (Free University of Berlin (FUB)-precipitation analysis). For scale dependent evaluation of the Local model (LM) of the German Weather service, the precipitation data were separated into convective and stratiform fractions. To analyse precipitation amounts an interpolation scheme is used which contains the data set of "present weather" (ww), rain gauges and cloud types from the WMO-network in hourly resolution from the year 1992 until 2004 together with satellite cloud types derived from Meteosat-7 data. The structural analyses of cloud classes from satellite data as well as clouds from the synoptic observations were used to develop a statistical interpolation procedure to build up an independent precipitation analysis in resolution corresponding to the LM grid.
Atmospheric instability analysis and its relationship to precipitation patterns over the western Iberian Peninsula
Authors: Queralt S. , Hernandez E. , Gallego D. , Iturrioz I.
Published: April 2010

Abstract. Thermodynamic and dynamic atmospheric stability indices will be analysed in order to classify the rainfall types occurred in western Iberia and provide information about the associated meteorological phenomena and preferred regional instability sources. In this work, instability sources over the western Iberian Peninsula will be characterised by means of radiosonde station data and reanalysis data sets from the European Centre for Medium-Range Weather Forecasts (ECMWF), for the period 1971–2002. Dynamic stability indices such as the Q vector divergence (dQ) or the potential vorticity anomaly in the 330 K isentropic surface (PV) have been calculated with the aim of establishing different atmospheric stability scenarios. Furthermore, thermodynamic atmospheric stability contribution has been also evaluated with Total Totals index (TT) and moisture availability was inferred from circulation weather types (CWTs). The first results of this work assess the combined dynamic-thermodynamic preferred conditions, synoptic situations and humidity sources, leading to precipitation events over the western Iberian Peninsula and prove the essential role of CWT patterns on the rainfall genesis.
Mapping monthly rainfall data in Galicia (NW Spain) using inverse distances and geostatistical methods
Authors: Mirás-Avalos J. M. , Paz-González A. , Vidal-Vázquez E. , Sande-Fouz P.
Published: April 2010

Abstract. In this paper, results from three different interpolation techniques based on Geostatistics (ordinary kriging, kriging with external drift and conditional simulation) and one deterministic method (inverse distances) for mapping total monthly rainfall are compared. The study data set comprised total monthly rainfall from 1998 till 2001 corresponding to a maximum of 121 meteorological stations irregularly distributed in the region of Galicia (NW Spain). Furthermore, a raster Geographic Information System (GIS) was used for spatial interpolation with a 500×500 m grid digital elevation model. Inverse distance technique was appropriate for a rapid estimation of the rainfall at the studied scale. In order to apply geostatistical interpolation techniques, a spatial dependence analysis was performed; rainfall spatial dependence was observed in 33 out of 48 months analysed, the rest of the rainfall data sets presented a random behaviour. Different values of the semivariogram parameters caused the smoothing in the maps obtained by ordinary kriging. Kriging with external drift results were according to former studies which showed the influence of topography. Conditional simulation is considered to give more realistic results; however, this consideration must be confirmed with new data.
One decade of imaging precipitation measurement by 2D-video-distrometer
Authors: Schönhuber M. , Lammer G. , Randeu W. L.
Published: April 2010

Abstract. The 2D-Video-Distrometer (2DVD) is a ground-based point-monitoring precipitation gauge. From each particle reaching the measuring area front and side contours as well as fall velocity and precise time stamp are recorded. In 1991 the 2DVD development has been started to clarify discrepancies found when comparing weather radar data analyses with literature models. Then being manufactured in a small scale series the first 2DVD delivery took place in 1996, 10 years back from now. An overview on present 2DVD features is given, and it is presented how the instrument was continuously improved in the past ten years. Scientific merits of 2DVD measurements are explained, including drop size readings without upper limit, drop shape and orientation angle information, contours of solid and melting particles, and an independent measurement of particles' fall velocity also in mixed phase events. Plans for a next generation instrument are described, by enhanced user-friendliness the unique data type shall be opened to a wider user community.
Assessment of nutrient entry pathways and dominating hydrological processes in lowland catchments
Authors: Schmalz B. , Tavares F. , Fohrer N.
Published: April 2010

Abstract. The achievement of a good water quality in all water bodies until 2015 is legally regulated since December 2000 for all European Union member states by the European Water Framework Directive (EU, 2000). The aim of this project is to detect nutrient entry pathways and to assess the dominating hydrological processes in complex mesoscale catchments. The investigated Treene catchment is located in Northern Germany as a part of a lowland area. Sandy, loamy and peat soils are characteristic for this area. Land use is dominated by agriculture and pasture. Drainage changed the natural water balance. In a nested approach we examined two catchment areas: a) Treene catchment 517 km2, b) Kielstau catchment 50 km2. The nested approach assists to improve the process understanding by using data of different scales. Therefore these catchments serve not only as an example but the results are transferable to other lowland catchment areas. In a first step the river basin scale model SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) was used successfully to model the water balance. Furthermore the water quality was analysed to distinguish the impact of point and diffuse sources. The results show that the tributaries in the Kielstau catchment contribute high amounts of nutrients, mainly nitrate and ammonium. For the parameters nitrate, ammonium and phosphorus it was observed as a tendency that the annual loads were increasing along the river profile of the Kielstau.
Comparison of different approaches to quantify the reliability of hydrological simulations
Authors: Gattke C. , Schumann A.
Published: April 2010

Abstract. The focus of this study was to compare different uncertainty estimation approaches to evaluate their ability to predict the total amount of uncertainty in hydrological model predictions. Three different approaches have been compared. Two of them were based on Monte-Carlo sampling and the third approach was based on fitting a probability model to the error series of an optimized simulation. These approaches have been applied to a lumped and a semi-distributed model variant, to investigate the effects of changes in the model structure on the uncertainty assessment. The probability model was not able to predict the total amount of uncertainty when compared with the Monte-Carlo based approaches. The uncertainty related to the simulation of flood events was systematically underestimated.
Information system "BW_Abfluss": regionalisation of flood, mean and low flow parameters
Authors: Blatter A. S. , Liebert J. , Preuss P. A. , Szabadics J. , Ihringer J.
Published: April 2010

Abstract. On behalf of and in close collaboration with the institution of environment, measurements and conservation of the federal state of Baden-Württemberg (Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg/LUBW/ see http://www.lubw.baden-wuerttemberg.de/) an innovative regionnalisation concept has been developed. This concept allows the supply of flood, mean or low flow parameters for 10 790 sites in Baden-Württemberg and an evaluation of the predicted impact of climate change on the flood situation. The extensive data basis for this regionalisation concept with numerous input parameters and varied result reporting made it necessary to select an appropriate database structure. New software was developed to help with the calculations, notably for: – upgrading the official areal water system register (Gewässerkundliches Flächenverzeichnis/GKFV) – proofing tools to maintain consistency – automatic parameter derivation with the software ESRI© ArcInfo. The results were published in electronic form and included a stand-alone geo-information software for easy and fast retrieval of data and results. The objective of this article is to describe the implementation of these new concepts for coupling Geographic Information System (GIS) and database needs to reach the identified requirements.
Determination and ranking of target areas in catchments for the implementation of nitrogen reduction measures
Authors: Tetzlaff B. , Kunkel R. , Schäfer W. , Wendland F.
Published: April 2010

Abstract. The implementation of the EU Water Framework Directive (EU-WFD) forms the background of the WAgriCo-project (Water Resources Management in Cooperation with Agriculture). WagriCo concentrates on the development of nitrogen management options adapted to hydrological and agro-economic site conditions and at demonstrating new participation approaches and technologies suitable for setting-up programmes of measures. The article outlines the conceptual model approach and its application in the pilot region "Große Aue" (Northern Germany). Furthermore the process of delineating priority areas is described, which act as spatial targets for the adaptation of regionally differentiated nutrient reduction measures.
Atmospheric patterns for heavy rain events in the Balearic Islands
Authors: Lana A. , Campins J. , Genovés A. , Jansà A.
Published: April 2010

Abstract. The Balearic Islands, as well as other Mediterranean regions, are occasionally affected by heavy rain events, which can produce numerous damages. This study contributes to improve the understanding of the dynamical mechanisms that produce heavy rain events by means of a classification of their related atmospheric patterns. Heavy rainfall dataset for the Balearic Islands and some gridded atmospheric parameters, derived from the HIRLAM-INM-0.5° analyses, were the data used in this study. Heavy rain events were recorded at a set of pluviometric stations along the Balearics for a period of 9 years, from June 1995 to May 2004. The 1000 hPa and 500 hPa geopotential heights (hereafter φ1000 and φ500), as well as the 850 hPa temperature (T850) were the fields utilized in the classification. By means of a principal components analysis (PCA) the number of variables was reduced. The cluster analysis (CA) was then applied on those new variables and eight atmospheric patterns were finally obtained. Most of the patterns showed a strong relationship between heavy rain events and cyclones.
Mountain torque events in the Mediterranean
Authors: Egger J. , Hoinka K. P.
Published: April 2010

Abstract. Typical events of torques exerted by the Alps are analysed by correlating flow observations in the Mediterranean with these torques. More specifically, events with positive torques with respect to the "rotation axis" at 90° E, 0° N in fall are selected. A trough forms above the western Mediterranean during such an event with a ridge in the west. A separate low pressure system is induced in the lee of the Alps which moves then eastward with the upper-level trough. A linear forecast equation based on potential temperature changes reveals that this Alpine "lee cyclone" is mainly due to warm air advection east of the trough. Precipitation is discussed as well.
The surface climatology of the eastern Mediterranean region obtained in a three-member ensemble climate change simulation experiment
Authors: Krichak S. O. , Alpert P. , Bassat K. , Kunin P.
Published: April 2010

Abstract. Two configurations of RegCM3 regional climate model (RCM) have been used to downscale results of two atmosphere-ocean global climate model (AOGCM) simulations of the current (1961–1990) and future climates (2071–2100) over the eastern Mediterranean (EM) region. The RCM domain covering the EM region from northern Africa to central part of Asia Minor with grid spacing of 50 km was used. Three sets of RCM simulations were completed. Results of the RCM experiment support earlier projections of a temperature (annual precipitation) increase (decrease) to the end of 21st century over the EM. The roles of several major factors in controlling uncertainty of the climate change estimates are evaluated. The main uncertainty factors appear to be associated with possible inadequacies in RCM description of the EM-climate-controlling developments over remotely located areas as well as those in the simulations of the global climate and its trends by the AOGCMs.
Natural Hazards and the press in the western Mediterranean region
Authors: Llasat-Botija M. , Llasat M. C. , López L.
Published: April 2010

Abstract. This study analyses press articles published between 1982 and 2005 in an attempt to describe the social perception of natural hazards in Catalonia. The articles included in the database have been classified according to different types of risk. In addition, the study examines the evolution of each type of risk in the press coverage during the study period. Finally, the results have been compared to data provided by insurance companies with respect to compensations paid out for damages. Conclusions show that floods are the most important natural hazard in the region, but that the number of headlines for each event is greater in the case of snowfalls and forest fires. Factors such as the season of the year, the proximity of the affected region to the capital, the topical issues at the time, and the presence of other important news must be considered when the impact in the press is analysed.
Using MSG to monitor the evolution of severe convective storms over East Mediterranean Sea and Israel, and its response to aerosol loading
Authors: Lensky I. M. , Shiff S.
Published: April 2010

Abstract. Convective storms over East Mediterranean sea and Israel were tracked by METEOSAT Second Generation (MSG). The MSG data was used to retrieve time series of the precipitation formation processes in the clouds, the temperature of onset of precipitation, and an indication to aerosol loading over the sea. Strong correlation was found between the aerosol loading and the depth above cloud base required for the initialization of effective precipitation processes (indicated by the effective radius = 15 µm threshold). It seems from the data presented here that the clouds' response to the aerosol loading is very short.
On periodicities in long term climatic variations near 68° N, 30° E
Authors: Kasatkina E. A. , Shumilov O. I. , Krapiec M.
Published: April 2010

Abstract. It is generally believed that the low-frequency variability of climatic parameters seems to be connected to solar cycles. The principal periodicities are: 11-year (Schwabe), 22-year (Hale), 33-year (Bruckner) and 80–100-year (Gleissberg) cycles. The main heliophysical factors acting on climate, the biosphere and the atmosphere are solar irradiance, the intensity of solar and galactic cosmic rays (relativistic charged particles with energies >500 MeV) changing the cloud cover of the atmosphere, and UV-B-radiation. The 11-year and 80–90-year solar cycles are apparent in solar radiation and galactic cosmic ray trends. At the same time the bidecadal Hale cycle, related to a reversal of the main solar magnetic field direction is practically absent in either solar radiation or galactic cosmic ray variations. Besides, nobody can identify any physical mechanisms by which a reversal in the solar magnetic field direction could influence climate. However, the 22-year cycle has been identified in rather many regional climatic (droughts, rainfall, tree growth near 68° N, 30° E) and temperature records all over the world. We discuss here three possible cause of the bidecadal periodicity in climatic records, one of which is associated with a variation of stardust flux inside the Solar System. The most recent observations by the DUST experiment on board the Ulysses spacecraft have shown that the solar magnetic field lost its protective power during the last change of its polarity (the most recent solar maximum), so that the stardust level inside of the Solar System has been enhanced by a factor of three. It is possible that the periodic increases of stardust in the Solar System may influence the amount of extraterrestrial material that falls to the Earth and consequently act on the Earth's atmosphere and climate through alteration of atmospheric transparency and albedo. This material (interstellar dust and/or cometary matter) may also provide nucleation sites and thereby influence precipitation.
An estimate of the impact of transient luminous events on the atmospheric temperature
Authors: Arnone E. , Berg P. , Arnold N. F. , Christiansen B. , Thejll P.
Published: April 2010

Abstract. We present an order of magnitude estimate of the impact of sprites and other transient luminous events (TLEs) on the atmospheric temperature via ozone changes. To address the effects of expected TLE-ozone changes of at most a few percent, we first study the linearity of the radiatively driven response of a stratosphere-mesosphere model and of a general circulation model (GCM) to a range of uniform climatological ozone perturbations. The study is limited to Northern Hemisphere winter conditions, when planetary wave activity is high and the non linear stratosphere-troposphere coupling can be strong. Throughout most of the middle atmosphere of both models, the radiatively driven temperature response to uniform 5% to 20% ozone perturbations shows a close-to linear relationship with the magnitude of the perturbation. A mid-latitude stratopause ozone perturbation is then imposed as an idealised experiment that mimics local temperature gradients introduced by the latitudinal dependence of TLEs. An unrealistically high 20% magnitude is adopted for the regional ozone perturbation to obtain statistical significance in the model response. The local linearity of the radiatively driven response is used to infer a first order estimate of TLE-induced temperature changes of the order of 0.015 K under typical conditions, and less than a peak temperature change of 0.3 K at 60–70 km height in coincidence of extraordinarily active TLE-producing thunderstorms before horizontal mixing quickly occurs. In the latter case, dedicated mesoscale modelling is needed to study the relevance of regional non linear processes which are expected to impact these radiatively driven responses.
A complex geo-scientific strategy for landslide hazard mitigation – from airborne mapping to ground monitoring
Authors: Supper R. , Römer A. , Jochum B. , Bieber G. , Jaritz W.
Published: April 2010

Abstract. After a large landslide event in Sibratsgfäll/Austria several exploration methods were evaluated on their applicability to investigate and monitor landslide areas. The resulting optimised strategy consists of the combined application of airborne electromagnetics, ground geoelectrical measurements and geoelectrical monitoring combined with hydrological and geological mapping and geotechnical modelling. Interdisciplinary communication and discussion was the primary key to assess this complicated hazard situation.
Geomagnetic anomalies observed at volcano Popocatepetl, Mexico
Authors: Kotsarenko A. , Grimalsky V. , Pérez Enríquez R. , Yutsis V. , Koshevaya S. , López Cruz-Abeyro J. A. , Valdez-Gonzalez C. , Villegas Cerón R. A.
Published: April 2010

Abstract. Results of the ULF geomagnetic monitoring of the volcano Popocatepetl (Mexico) and their analysis are summarized and presented for the period 2003–2006. Our analysis reveals some anomalies which are considered to be of local volcanic origin: the EM background in the vicinity of the volcano was found to be significantly noisier than at other reference stations; sporadic strong noise-like geomagnetic activity was observed in the H-component; some geomagnetic pulsations were observed only at the Tlamacas station (located at 4 km near the volcano). The results are discussed in terms of a physical mechanism involving the presence of a second magmatic chamber within the volcano and, finally, further perspective directions to study volcanic geodynamical processes besides the traditional ones are given.
Electromagnetic emission from magnetite plate cracking under seismic processes
Authors: Koshevaya S. , Grimalsky V. , Makarets N. , Kotsarenko A. , Siquieros-Alatorre J. , Perez-Enriquez R. , Juarez-Romero D.
Published: April 2010

Abstract. Electromagnetic emission generated by cracking of a magnetite plate is theoretically investigated. The non-stationary mechanical stresses, produced by moving the tip of a crack and a wave of mechanical unloading in the plate are considered as the sources of the radiation. It is demonstrated that the radiation is produced by the appearance of a non-stationary magnetic moment in the plate.
A multi-institutional and interdisciplinary approach to the assessment of vulnerability and adaptation to climate change in the Peruvian Central Andes: problems and prospects
Authors: Martínez A. G. , Takahashi K. , Núñez E. , Silva Y. , Trasmonte G. , Mosquera K. , Lagos P.
Published: April 2010

Abstract. A local integrated assessment of the vulnerability and adaptation to climate change in the Mantaro River Basin, located in Peruvian Central Andes, was developed between years 2003 to 2005. In this paper we present some lessons learned during the development of this study, emphasizing the multi-institutional and interdisciplinary efforts, briefly showing the methodological aspects, and pointing out the main problems found.
Dry and wet rainy seasons in the Mantaro river basin (Central Peruvian Andes)
Authors: Silva Y. , Takahashi K. , Chávez R.
Published: April 2010

Abstract. Monthly precipitation data from the period of 1970 to 2004 from 38 meteorological stations in the Mantaro river basin were used to classify the rainy seasons (September–April) of each year into anomalously dry or wet, and to determine the basin-wide extent of the anomalies based on the Standardized Precipitation Index (SPI). The wet periods mostly occurred in the early 1970's and during the first half of the 1980's, except for the event that occurred in the 1993/94 period which was the strongest and most generalized in the analyzed period. The dry periods occurred mostly during the second half of the 1980's and the 1990's. Consistent with this, a negative trend in precipitation of 2% per decade was found for the rainy season, due mainly to a stronger trend (−4%/decade) during the peak phase (January–March). Despite previously reported significant negative correlations between El Niño-Southern Oscillation (ENSO) and rainfall during the peak of the rainfall season, the similar amplitude variability of precipitation during the onset phase of the rainfall season (September–December), which is uncorrelated with ENSO, participate to the reduction of the absolute correlation for the full rainfall season. Correlations between rainfall in the Mantaro basin and sea surface temperature (SST) in the tropical Atlantic are significant only near the end of the rainy season, with more rain associated with a weaker north-south difference in SST in the tropical Atlantic.
Frost risks in the Mantaro river basin
Authors: Trasmonte G. , Chavez R. , Segura B. , Rosales J. L.
Published: April 2010

Abstract. As part of the study on the Mantaro river basin's (central Andes of Perú) current vulnerability to climate change, the temporal and spatial characteristics of frosts were analysed. These characteristics included intensity, frequency, duration, frost-free periods, area distribution and historical trends. Maps of frost risk were determined for the entire river basin, by means of mathematical algorithms and GIS (Geographic Information Systems) tools, using minimum temperature – 1960 to 2002 period, geomorphology, slope, land-use, types of soils, vegetation and life zones, emphasizing the rainy season (September to April), when the impacts of frost on agriculture are most severe. We recognized four categories of frost risks: low, moderate, high and critical. The critical risks (with a very high probability of occurrence) were related to high altitudes on the basin (altitudes higher than 3800 m a.s.l.), while the low (or null) probability of occurring risks were found in the lower zones (less than 2500 m a.s.l.). Because of the very intense agricultural activity and the high sensitivity of the main crops (Maize, potato, artichoke) in the Mantaro valley (altitudes between 3100 and 3300 m a.s.l.), moderate to high frost risks can be expected, with a low to moderate probability of occurrence. Another significant result was a positive trend of 8 days per decade in the number of frost days during the rainy season.
Natural hazards for the Earth's civilization from space, 1. Cosmic ray influence on atmospheric processes
Authors: Dorman L. I.
Published: April 2010

Abstract. In this paper we give a short description of global natural disasters for the Earth's civilization from space: 1) Galactic and solar cosmic ray (CR) influence on the atmospheric processes; 2) Impacts of great space magnetic storms during big Forbush-effects in CR, 3) Impacts of great radiation hazards from solar CR during flare energetic particle events, 4) Great impacts on planetary climate during periods of the Solar system capturing by molecular-dust clouds, 5) Catastrophic disasters from nearby Supernova explosions, and 6) Catastrophic disasters from asteroid impacts on the Earth. Some of these problems have been already studied (see e.g. Dorman, 1957, 1963a, b; Dorman and Miroshnichenko, 1968; Dorman, 1972, 1974, 1975a, b, 1978; Velinov et al., 1974; Miroshnichenko, 2001, 2003; Dorman, 2004, 2006, 2008). We present here a detailed treatment of the first disaster only, leaving to future papers the analysis of the other aspects.
The 1755 earthquake in the Algarve (South of Portugal): what would happen nowadays?
Authors: Tedim Pedrosa F. , Gonçalves J.
Published: April 2010

Abstract. The 1755 Lisbon earthquake, which reached a magnitude of 8.5, remains the most powerful and destructive to hit Europe so far. Within minutes, many lives were lost, populations displaced, livelihoods, homes and infrastructures were destroyed. Although frequently associated to the city of Lisbon, one of the most important European cities at the time, this earthquake caused similar damage and casualties, if not greater, in the southwest of the Algarve, where the seismic intensity was estimated at IX-X Mercalli Intensity Scale. Some time later a tsunami increased the number of victims and the amount of damage. In some locations the tsunami caused greater destruction than the earthquake itself. The tsunami hit both coasts of the North Atlantic; however, the more destructive damage occurred in the Portuguese coast, south from Lisbon, in the Gulf of Cadiz and in the Moroccan coast. The downtown of Lisbon was flooded by waves that reached a height of 6 m. The water flooded an area with an extension of around 250 m from the coast. In the Southwest part of Algarve the waves reached a height between 10 and 15 m and the flooded area was much larger. Through the analysis of recent research works on the assessment of the 1755 tsunami parameters and the interpretation of the more reliable historical documents, it is our intention to analyse the destructive power of the tsunami in the Algarve and delimit the flooded area. Using simple techniques of simulation it is our intention to assess the impacts nowadays of the occurrence of a tsunami similar to the one that hit the Algarve in 1755, which would probably affect a greater number of people, buildings and infrastructures. This assessment is an important instrument not only in terms of disaster preparedness but also for the integration of risk mitigation measures in land use planning.
Southern Perú coseismic subsidence: 23 June 2001 8.4-Mw earthquake
Authors: Ocola L.
Published: April 2010

Abstract. The 23-June-2001 8.4-Mw magnitude earthquake partially filled the 1868-seismic-gap in southern Perú. This earthquake produced a thrust faulting dislocation with a rupture that started at about ~200 km SE from the 1996's Nazca earthquake epicenter, and stopped near Ilo, at about 300 km from the epicenter, near a positive gravity anomaly offshore Ilo. The 23-June-2001-earthquake dislocation zone is under the Arequipa sedimentary Basin. Pre- and post-seismic GPS measurements at Camaná and Ilo at SIRGAS-GPS points (SIRGAS: Sistema de Referencia Geocéntrico para América del Sur) and the average sea level pre- and post-seismic event at Mollendo tide gauge provide evidence of a regional subsidence of southern Perú, with 84 cm at Camaná, 16 cm at Ilo, and 15 cm at Mollendo. Field surveys post earthquake document significant subsidence in Camaná resort beaches. Results of a simple dislocation modelling of 23-June-2001 earthquake agree reasonably well with the observed data. However, the coseismic subsidence of southern Perú is at variance with the regional uplift of southern Perú based on Neotectonic studies. This fact, suggests that, in recent geological times, the magnitude of the secular uplift due to tectonic plate converge has been larger than the coseismic deformation recovery.
The impact of an upper tropospheric teleconnection pattern on precipitation extremes over Cyprus
Authors: Hatzaki M. , Lingis P. , Flocas H.A. , Michaelides S. , Oikonomou C.
Published: April 2010

Abstract. The objective of this study is to estimate the duration, frequency and intensity of precipitation extreme episodes in Cyprus, in relation with the two phases of the Eastern Mediterranean teleconnection Pattern (EMP), during winter for the period 1958–2005. A standardised teleconnection index was employed to determine the phases (positive and negative) and the strength of the EMP. The identification of the precipitation extremes was performed with the aid of four climatic indices. It was found that during the positive phase of the pattern, the length of dry periods reduces while that of wet periods increases, being followed by increase of frequency of extreme wet days and precipitation intensity. On the contrary, during the negative phase, the dry spells become longer in accordance with shortening of the wet spells, decrease of the number of extreme wet days and precipitation intensity.
Iberian autumnal precipitation characterization through observed, simulated and reanalysed data
Authors: Morata A. , Luna M. Y. , Martín M. L. , Sotillo M. G. , Valero F.
Published: April 2010

Abstract. A 44-year (1958–2001) homogeneous Mediterranean high-resolution atmospheric database was generated through dynamical downscaling within the HIPOCAS Project framework. The present work attempts to provide a validation of the monthly 41-autumnal (1961–2001) HIPOCAS precipitation over the Iberian Peninsula, being also provided an evaluation of its improvement versus current global reanalysis data sets. A statistical comparative analysis between observed, HIPOCAS and global reanalyses precipitation data sets was carried out, highlighting the noticeable agreement existing between the observed and the HIPOCAS precipitation data sets in terms of not only time and spatial distribution, but also in terms of total amount of precipitation. A principal component analysis is carried out showing that the patterns derived from the HIPOCAS data largely capture the main characteristics of the studied field. Moreover, it is worth to note that the HIPOCAS patterns reproduce accurately the observed regional characteristics linked to the main orographic features of the study domain.
Decadal changes in extreme daily precipitation in Greece
Authors: Nastos P. T. , Zerefos C. S.
Published: April 2010

Abstract. The changes in daily precipitation totals in Greece, during the 45-year period (1957–2001) are examined. The precipitation datasets concern daily totals recorded at 21 surface meteorological stations of the Hellenic National Meteorological Service, which are uniformly distributed over the Greek region. First and foremost, the application of Factor Analysis resulted in grouping the meteorological stations with similar variation in time. The main sub groups represent the northern, southern, western, eastern and central regions of Greece with common precipitation characteristics. For representative stations of the extracted sub groups we estimated the trends and the time variability for the number of days (%) exceeding 30 mm (equal to the 95% percentile of daily precipitation for eastern and western regions and equal to the 97.5% percentile for the rest of the country) and 50 mm which is the threshold for very extreme and rare events. Furthermore, the scale and shape parameters of the well fitted gamma distribution to the daily precipitation data with respect to the whole examined period and to the 10-year sub periods reveal the changes in the intensity of the precipitation.
Mesoscale convective systems in Spain: instability conditions and moisture sources involved
Authors: Queralt S. , Hernandez E. , Gallego D. , Lorente P.
Published: April 2010

Abstract. Source-receptor water vapor content areas are analyzed for a particular case of deep mesoscale convective system (MCS) developed over the Mediterranean margin of Spain in October 1982. The aim of this work is to study simultaneously the atmospheric instability conditions and water vapour fluxes which finally resulted in very severe precipitation rates, reaching up to 600 mm in a single day. Humidity amounts and transport are quantified along the trajectories computed from a lagrangian particle simulation model (FLEXPART6.2). To evaluate the precipitation probability, the water vapor content and both thermodynamic and dynamic atmospheric instability components were assessed. The October 1982 Iberian MCS occurred as a consequence of a deep cutoff low detected between 500 and 200 hPa levels. The dynamical instability was measured through potential vorticity anomalies and Q vector divergence, which presented their maximum and minimum centers respectively over south-eastern Iberia. Synoptic and dynamic instability conditions were obtained from the ERA-40 reanalysis dataset. It is observed that during this severe weather episode, the specific humidity increased along the lowest and easternmost trajectories, which are mainly spread over the Mediterranean Sea.
Operational flood-forecasting in the Piemonte region – development and verification of a fully distributed physically-oriented hydrological model
Authors: Rabuffetti D. , Ravazzani G. , Barbero S. , Mancini M.
Published: April 2010

Abstract. A hydrological model for real time flood forecasting to Civil Protection services requires reliability and rapidity. At present, computational capabilities overcome the rapidity needs even when a fully distributed hydrological model is adopted for a large river catchment as the Upper Po river basin closed at Ponte Becca (nearly 40 000 km2). This approach allows simulating the whole domain and obtaining the responses of large as well as of medium and little sized sub-catchments. The FEST-WB hydrological model (Mancini, 1990; Montaldo et al., 2007; Rabuffetti et al., 2008) is implemented. The calibration and verification activities are based on more than 100 flood events, occurred along the main tributaries of the Po river in the period 2000–2003. More than 300 meteorological stations are used to obtain the forcing fields, 10 cross sections with continuous and reliable discharge time series are used for calibration while verification is performed on about 40 monitored cross sections. Furthermore meteorological forecasting models are used to force the hydrological model with Quantitative Precipitation Forecasts (QPFs) for 36 h horizon in "operational setting" experiments. Particular care is devoted to understanding how QPF affects the accuracy of the Quantitative Discharge Forecasts (QDFs) and to assessing the QDF uncertainty impact on the warning system reliability. Results are presented either in terms of QDF and of warning issues highlighting the importance of an "operational based" verification approach.
Rain area delineation by means of multispectral cloud characterization from satellite
Authors: Torricella F. , Cattani E. , Levizzani V.
Published: April 2010

Abstract. The identification of precipitation areas by microwave based rain algorithms can be improved by means of cloud classification schemes based on multispectral observations. Several recent studies have demonstrated the potential of cloud microphysical and optical characterization for the improvement of passive microwave rain estimates, especially in detecting likely precipitating pixels over land. The multispectral sensing capabilities of MODIS onboard Aqua are exploited to characterize the cloudy scenario, using a twofold approach: a) an RGB technique to qualitatively identify the different cloud systems on the basis of the combination of radiances measured in three selected channels, and b) a quantitative description of cloud top in terms of optical thickness (τ), effective radius (Re) and top temperature (Tc). The information gathered by the multispectral analysis of the cloud field from MODIS is contrasted with the rain intensity at the ground as derived from the AMSR-E operational algorithm, to assess the statistical relationships between microphysical parameters and the rain intensity for such nearly simultaneous and co-located observations.
Effects of sub-grid variability of precipitation and canopy water storage on climate model simulations of water cycle in Europe
Authors: Wang D. , Anagnostou E. N. , Wang G.
Published: April 2010

Abstract. The impact of sub-grid variability of precipitation and canopy water storage is investigated over Central-South Europe by applying a new canopy interception scheme into the Community Atmosphere Model (CAM, Version 3) coupled with the Community Land Model (CLM, Version 3). The study shows that while sub-grid variability exerts great impact on the land surface water budget, the impact on the atmospheric hydrological processes is small and only exception being the Mediterranean region. In this region, incorporation of sub-grid variability is shown to reduce precipitation up to 1 mm/day (or ~8% relative to mean precipitation). The evapotranspiration ratio (ratio of evapotranspiration to total precipitation) exhibited insignificant deviations between the simulations with sub-grid variability and the ones without, which indicates that the local source of moisture is not the cause of the reduced precipitation. On the other hand, inducing sub-grid variability alters the large-scale circulation, which transports less water vapor form Atlantic Ocean to inland areas thus reducing precipitation in the Mediterranean region.
Cell-tracking with lightning data from LINET
Authors: Betz H. D. , Schmidt K. , Oettinger W. P. , Montag B.
Published: April 2010

Abstract. A new lightning detection network (LINET) has been developed at the University of Munich, which locates and reports both cloud discharges and cloud-to-ground strokes with high accuracy. The network started operation in May 2006; since then lightning data for Europe are being delivered to many scientific groups, and to the German Weather Service (DWD) on an operational basis (powered by nowcast GmbH, Germany). Using about 90 lightning sensors in 17 countries, an area from longitude 10° W–25° E to latitude 35° N–65° N is covered. Further expansion is in the planning stage with the aim to attain higher efficiency for Mediterranean storms. The total lightning capability, not readily available otherwise in large areas, is particularly helpful because it can provide useful information about the development of severe weather and strong storm cells. A cell-tracking module has been developed that allows the investigation of lightning parameters for specific convective cells. Present efforts are devoted to the question for what kind of storms and to what extent lightning-based cell tracking allows improved nowcasting. Numerous case studies have been carried out and typical examples will be presented.
Mesoscale GPS Zenith Delay assimilation during a Mediterranean heavy precipitation event
Authors: Yan X. , Ducrocq V. , Poli P. , Jaubert G. , Walpersdorf A.
Published: April 2010

Abstract. The impact of assimilating Zenith Total delay (ZTD) observations from a mesoscale ground-based GPS network over Western Europe is evaluated for the heavy precipitation event of 5–9 September 2005 over Southern France. The ZTD assimilation is performed using a three dimensional variational data assimilation system at the 9.5-km horizontal resolution. Then using as initial conditions the 3DVAR analyses with and without assimilation of ZTD, we perform 2.4-km non-hydrostatic MESO-NH simulations. The results of the fine-scale simulations indicate that assimilation of ZTD help to improve the forecast of the tropospheric water vapour content and the quantitative precipitation forecast. We have also assessed through single observation experiments the influence of the formulation of the observation operator which is used to compute the model equivalent ZTD.