bluuebunny/crossref_metadata_2025 huggingface dataset:
Procedure to estimate maximum ground acceleration from macroseismic intensity rating: application to the Lima, Perú data from the October-3-1974-8.1-Mw earthquake
Authors: Ocola L.
Published: April 2010

Abstract. Post-disaster reconstruction management of urban areas requires timely information on the ground response microzonation to strong levels of ground shaking to minimize the rebuilt-environment vulnerability to future earthquakes. In this paper, a procedure is proposed to quantitatively estimate the severity of ground response in terms of peak ground acceleration, that is computed from macroseismic rating data, soil properties (acoustic impedance) and predominant frequency of shear waves at a site. The basic mathematical relationships are derived from properties of wave propagation in a homogeneous and isotropic media. We define a Macroseismic Intensity Scale IMS as the logarithm of the quantity of seismic energy that flows through a unit area normal to the direction of wave propagation in unit time. The derived constants that relate the IMS scale and peak acceleration agree well with coefficients derived from a linear regression between MSK macroseismic rating and peak ground acceleration for historical earthquakes recorded at a strong motion station, at IGP's former headquarters, since 1954. The procedure was applied to 3-October-1974 Lima macroseismic intensity data at places where there was geotechnical data and predominant ground frequency information. The observed and computed peak acceleration values, at nearby sites, agree well.
An unified approach to meteorological modelling based on multiple-scales asymptotics
Authors: Klein R.
Published: April 2010

Abstract. In 2003, the author suggested a mathematical framework for the derivation of reduced meteorological models at a Mathematics conference (5th ICIAM, Sydney, Australia), (Klein, 2004). The framework consists of (i) non-dimensionalization of the 3-D compressible flow equations on the rotating sphere, (ii) identification of universal non-dimensional parameters, (iii) distinguished limits between these and additional problem-specific parameters, and (iv) multiple scales expansions in the remaining small parameter ε. This parameter may be interpreted as the cubic root of the centripetal acceleration due to the Earth's rotation divided by the acceleration of gravity, see also Keller (1951), Eq. (10). For the mojority of reduced models of theoretical meteorology that we have come across, the approach allowed us to generate systematic derivations starting directly from the 3-D compressible flow equations on the rotating sphere. The framework's potential fully shows in multiscale interaction studies such as Klein (2006), in which we incorporated bulk microphysics closures for moist processes and derived scale interaction models for deep convection. Currently, we study the structure, evolution, and motion of Hurricane strength H1/H2 vortices (Mikusky, 2007), large-scale stratocumulus cloud decks, and planetary-synoptic scale interaction models which should be relevant for Earth System Models of Intermediate Complexity (EMICs). Here we summarize the general framework and use the example of quasi-geostrophic theory to demonstrate its application.
Towards an analytical understanding of internal wave attractors
Authors: Harlander U.
Published: April 2010

Abstract. Time harmonic inviscid internal wave motions constrained to fully closed domains generically lead to singular velocity fields. In spite of this difficulty, several techniques exist to solve such internal wave boundary value problems. Recently it has been shown that for a domain with the shape of a trapezium, solutions can be written in terms of a double sine Fourier series. However, the solutions were found by a numerical technique and thus not all coefficients of the series are available. Unfortunately, for questions related e.g. to regularization of the inviscid singular solutions, the knowledge of the asymptotic behavior of the spectrum for large wave numbers is essential. Here we discuss solutions of internal wave boundary value problems for which the spectra are known, at least asymptotically. We further describe shortcomings of the found solutions that need to be overcome in the future. Finally, we sketch applications of the solutions in the context of viscous energy dissipation.
Preliminary study of an intense rainfall episode in Corsica, 14 September 2006
Authors: Lambert D. , Argence S.
Published: April 2010

Abstract. A preliminary study of the 14 September 2006 heavy rainfall episode in Corsica is presented. Two sets of initial and coupling fields were used to run the French non-hydrostatic mesoscale model, MESO-NH. Three interactive 2-way nested domains were used, having 150×120, 150×150 and 125×200 grid points and 50 km, 10 km and 2 km mesh sizes. 50 vertical levels were defined. From ground level to 2000 m, the vertical resolution was 60 m, whereas it was 600 m above. Convection was parameterized for the coarser and intermediate domains and assumed to be explicitly resolved for the 2 km grid. At large scale, the situation is well represented by both simulations but, at the fine scale, they present significant differences. Comparison with the observations did not allow the two simulations to be discriminated. Even though the main high-level dynamical ingredients usually associated with rain storms were present in both simulations, their fine scale evolution was not reproduced well. Near the surface, there were significant differences between the two simulations. Vertical motion fields associated with convective phenomena were different in the innermost domain. A cold pool acting as a warm front off the east coast was associated with the main rainfall area over the sea in one simulation whereas in the second one, it seemed that the Corsican mountains acted as a barrier, leading to inland rainfall. This preliminary study gives perspectives for future sensitivity tests. For example, an investigation is planned of the influence of the high level dynamics, the SST and a better description of the orography.
Bias Adjusted Precipitation Threat Scores
Authors: Mesinger F.
Published: April 2010

Abstract. Among the wide variety of performance measures available for the assessment of skill of deterministic precipitation forecasts, the equitable threat score (ETS) might well be the one used most frequently. It is typically used in conjunction with the bias score. However, apart from its mathematical definition the meaning of the ETS is not clear. It has been pointed out (Mason, 1989; Hamill, 1999) that forecasts with a larger bias tend to have a higher ETS. Even so, the present author has not seen this having been accounted for in any of numerous papers that in recent years have used the ETS along with bias "as a measure of forecast accuracy". A method to adjust the threat score (TS) or the ETS so as to arrive at their values that correspond to unit bias in order to show the model's or forecaster's accuracy in \\textit{placing} precipitation has been proposed earlier by the present author (Mesinger and Brill, the so-called dH/dF method). A serious deficiency however has since been noted with the dH/dF method in that the hypothetical function that it arrives at to interpolate or extrapolate the observed value of hits to unit bias can have values of hits greater than forecast when the forecast area tends to zero. Another method is proposed here based on the assumption that the increase in hits per unit increase in false alarms is proportional to the yet unhit area. This new method removes the deficiency of the dH/dF method. Examples of its performance for 12 months of forecasts by three NCEP operational models are given.
Simulation of polarimetric radar variables in rain at S-, C- and X-band wavelengths
Authors: Teschl F. , Randeu W. L. , Schönhuber M. , Teschl R.
Published: April 2010

Abstract. Polarimetric radar variables of rainfall events, like differential reflectivity ZDR, or specific differential phase KDP, are better suited for estimating rain rate R than just the reflectivity factor for horizontally polarized waves, ZH. A variety of physical and empirical approaches exist to estimate the rain rate from polarimetric radar observables. The relationships vary over a wide range with the location and the weather conditions. In this study, the polarimetric radar variables were simulated for S-, C- and X-band wavelengths in order to establish radar rainfall estimators for the alpine region of the form R(KDP), R(ZH, ZDR), and R(KDP), ZDR. For the simulation drop size distributions of hundreds of 1-minute-rain episodes were obtained from 2D-Video-Distrometer measurements in the mountains of Styria, Austria. The sensitivity of the polarimetric variables to temperature is investigated, as well as the influence of different rain drop shape models – including recently published ones – on radar rainfall estimators. Finally it is shown how the polarimetric radar variables change with the elevation angle of the radar antenna.
Estimation of the systematic error of precipitation and humidity in the MM5 model
Authors: Ivanov S. , Simmer C. , Palamarchuk J. , Bachner S.
Published: April 2010

Abstract. To comprehensively diagnose model capabilities in simulating atmospheric flow including the relevant microphysical processes, the main prognostic fields of the MM5 model are compared with ERA40 reanalysis data. This approach allows to identify and compare meaningful features of model parameterization schemes and to quantify model errors. Various combinations of schemes for cumulus convection, planetary boundary layer (PBL), microphysics and radiative transfer are used in order to identify those combinations which produce the closest resemblance between model state and reanalysis. The spatial structure of systematic errors, both horizontal and vertical will be described and geographical regions and synoptic situations will be identified, which are associated with pronounced systematic model deviations. The study focused on precipitation and humidity fields as well as on the main thermodynamic atmospheric variables on a coarse resolution grid (about 80 km) over the North Atlantic - Europe region. Our results identify advantages and shortcomings of the various parameterization schemes. They also indicate that, in general, the combination of best schemes does not result in optimal simulations of a particular variable.
Links of the significant wave height distribution in the Mediterranean sea with the Northern Hemisphere teleconnection patterns
Authors: Lionello P. , Galati M. B.
Published: April 2010

Abstract. This study analyzes the link between the SWH (Significant Wave Height) distribution in the Mediterranean Sea during the second half of the 20th century and the Northern Hemisphere SLP (Sea Level Pressure) teleconnection patterns. The SWH distribution is computed using the WAM (WAve Model) forced by the surface wind fields provided by the ERA-40 reanalysis for the period 1958–2001. The time series of mid-latitude teleconnection patterns are downloaded from the NOAA web site. This study shows that several mid-latitude patterns are linked to the SWH field in the Mediterranean, especially in its western part during the cold season: East Atlantic Pattern (EA), Scandinavian Pattern (SCA), North Atlantic Oscillation (NAO), East Atlantic/West Russia Pattern (EA/WR) and East Pacific/ North Pacific Pattern (EP/NP). Though the East Atlantic pattern exerts the largest influence, it is not sufficient to characterize the dominant variability. NAO, though relevant, has an effect smaller than EA and comparable to other patterns. Some link results from possibly spurious structures. Patterns which have a very different global structure are associated to similar spatial features of the wave variability in the Mediterranean Sea. These two problems are, admittedly, shortcomings of this analysis, which shows the complexity of the response of the Mediterranean SWH to global scale SLP teleconnection patterns.
Coupled wave and surge modelling and implications for coastal flooding
Authors: Wolf J.
Published: April 2010

Abstract. The physical causes of coastal flooding due to marine storms are discussed. We examine the costs and impacts of storm surges and waves with reference to the UK. The mechanisms of interaction between waves and the mean circulation due to tides and wind are reviewed. A case study to illustrate the magnitude of surges, waves and their interactions is presented for Liverpool Bay in the eastern Irish Sea. Applications of surge and wave models to the Mediterranean, especially the Adriatic Sea, are considered.
Microphysical effects of Saharan dusts on an orogenic thunderstorm
Authors: Hashino T.
Published: April 2010

Abstract. This study investigates the microphysical sensitivity of an orogenic thunderstorm during Genoa 1992 flood event to the concentration and solubility of nucleating aerosols. Idealized 2-D simulations with a new microphysical scheme and a cloud resolving model showed the solubility of CCN can be as important as their concentration. High solubility cases of CCN led to less accumulation of precipitation on the ground and more fraction of the accumulation produced by heavy precipitation than lower solubility cases. The response of vertical motion to the solubility was different for cases with and without dust layer. The preliminary results show that the ice nucleation processes affected by solubility and dust layer may be detected by remote sensing technology.
Atmospheric circulation patterns associated with extreme precipitation amounts in Greece
Authors: Houssos E. E. , Lolis C. J. , Bartzokas A.
Published: April 2010

Abstract. The main synoptic conditions associated with extreme precipitation amounts in Greece are examined by using a multivariate statistical methodology comprising S-mode Factor Analysis and k-means Cluster Analysis. The following data were used : i) daily precipitation amounts (measured at 06:00 UTC) for the meteorological stations of Hellenikon (Athens), Thessaloniki (northern Greece) and Ioannina (western Greece) and ii) daily (18:00 UTC) 2.5×2.5 grid point values of 500 hPa geopotential height, mean sea-level pressure and 1000–500 hPa thickness at 273 grid points over Europe (10 W to 40 E and 30 N to 60 N), for the period 1970–2002. The dates corresponding to the upper 5% of the frequency distribution of precipitation are selected for each one of the three stations. In total, 369 dates are used, some of them being common among the three stations. The corresponding 369×273 data matrices of 500 hPa geopotential height, mean sea-level pressure and 1000–500 hPa thickness are constructed. The rows refer to the 369 extreme precipitation cases and the columns refer to the 273 grid points. The three matrices are unified into one 369×819 matrix. In order to reduce the dimensionality of the data set, S-mode Factor Analysis is applied to the unified matrix, revealing 7 factors accounting for 85% of the total variance. Finally, k-means Cluster Analysis is applied to the factor scores matrix, classifying the 369 cases into 9 clusters. For each one of the 9 clusters, the mean 18:00 UTC patterns of the above parameters are constructed and presented. These patterns correspond to the main distinct atmospheric circulation structures favoring extreme precipitation amounts in Greece. Most of the patterns are characterized by enhanced cyclonic activity over or near the Greek area. The differences among the 9 circulation structures refer mainly to the position and the intensity of the surface and the upper air synoptic systems involved. Some of the 9 synoptic conditions favor extreme precipitation amounts mainly at one or two of the three stations while some others equally affect the three stations.
Gauging the ungauged basin: a top-down approach in a large semiarid watershed in China
Authors: Barthold F. K. , Sayama T. , Schneider K. , Breuer L. , Vaché K. B. , Frede H.-G. , McDonnell J. J.
Published: April 2010

Abstract. A major research challenge in ungauged basins is to quickly assess the dominant hydrological processes of watersheds. In this paper we present a top-down approach from first field reconnaissance to perceptual model development, model conceptualization, evaluation, rejection and eventually, to a more substantial field campaign to build upon the initial modeling. This approach led us from an initial state where very little was known about catchment behavior towards a more complete view of catchment hydrological processes, including the preliminary identification of water sources and an assessment of the effectiveness of our sampling design.
A method to assess instream water quality – the role of nitrogen entries in a North German rural lowland catchment
Authors: Schmalz B. , Bieger K. , Fohrer N.
Published: April 2010

Abstract. The objective of this study was the detection and assessment of nutrient entry pathways in a complex mesoscale lowland catchment. The central aim was the development of a transferable method for an efficient estimation of instream water quality in rural environments. The investigated Kielstau catchment with a size of approximately 50 km2 is located in the North German lowlands. Land use is dominated by agriculture as well as pasture and is characterised by extensive artificial drainage systems. Additionally wastewater treatment plants influence the river water quality. Six measuring campaigns were carried out over the period of one year. Each time, water quality was assessed at 16 locations along a 12 km longitudinal transect of the stream to consider the influence of each tributary or inflow. The results showed that the applied measuring method was useful to assess nutrient entry pathways into surface waters from diffuse and point sources. Some tributaries increased the main stream NO3-N concentrations especially in autumn. Using a German classification system (LAWA, 1998), the NO3-N results can mostly be assigned to water quality class III (heavily contaminated). Water balance and nitrate loads were modelled with the river basin scale model SWAT (Soil and Water Assessment Tool, Arnold et al., 1998). The measured and modelled discharges showed a good correlation. While nitrate load range and dynamics are well represented during the summer periods, they show a poor correlation during the winter period.
ANN-based sub-surface monitoring technique exploiting electromagnetic features extracted by GPR signals
Authors: Caorsi S. , Stasolla M.
Published: April 2010

Abstract. In this work we consider the problem of determining the dielectric characteristics of sub-surface layers by means of GPR systems. In particular, a suitable electromagnetic feature (the RΓ parameter), strictly related to the geophysical parameters of the scenario, is first extracted from the GPR e.m. signal and then fed to an artificial neural network (ANN) in order to derive the dielectric permittivity of the sub-surface layer.
Resistivity measured by direct and alternating current: why are they different?
Authors: Zadorozhnaya V. Y.
Published: April 2010

Abstract. Mathematical modeling of a little known model of IP referred to as "induced polarization caused by constrictivity of pores" was developed. Polarization occurs in all types of rocks if surface areas and transfer numbers are different for connected pores. The duration of the polarization process depends on two parameters: pore radii of connected capillaries and transfer numbers. During the polarization process all contacts between pores of different transfer numbers will be blocked and the electrical current will flow through the remaining canals. Two phenomena control the amplitude of potential difference at time-on: 1. Successive blockage of pores increases the resistivity of sediments and results in increased measured potential difference. 2. Excess concentration of electrolyte at the boundaries between pores with different radii provides an additional potential. The amplitude of the potential difference (voltage) of such rocks not only depends on solutions filling pore spaces, porosity and tourtuosity of pores channels, but also on ion mobility, diffusion coefficient, and difference of transfer numbers. During time-on a voltage is occurred due to flowing current Ucurr (t) and excess concentration Uexcess (t) at the contacts. However during the time-off only the excess of concentration Uexcess (t) is involved in the diffusion process which tends to level the ion concentration along the pores. It was found that the measured chargeability is proportional to the porosity. Blockage of pores and excess/loss ions at the contacted pores control this physical parameter. However the relationship between resistivity and porosity is very complicated. Mathematical modeling and laboratory measurements both confirmed the membrane IP effect diminishing with increasing salinity of fluid filled pores of rocks. Membrane polarization does not exist on high frequency of electrical current. As a result the resistivity measured by direct and alternating current is different. The new algorithm was tested on laboratory measurements data showing its good agreement with theory. The calculation of pore size distribution using IP laboratory data has been presented. The definition of the membrane IP effect is: "Membrane IP is the successive blockage of inter-pore connections due to the excess distribution of ions during current flow".
Study of the factors affecting the karst volume assessment in the Dead Sea sinkhole problem using microgravity field analysis and 3-D modeling
Authors: Eppelbaum L. V. , Ezersky M. , Al-Zoubi A. , Goldshmidt V. , Legchenko A.
Published: April 2010

Abstract. Thousands of sinkholes have appeared in the Dead Sea (DS) coastal area in Israel and Jordan during two last decades. The sinkhole development is recently associated with the buried evaporation karst at the depth of 25–50 m from earth's surface caused by the drop of the DS level at the rate of 0.8–1.0 m/yr. Drop in the Dead Sea level has changed hydrogeological conditions in the subsurface and caused surface to collapse. The pre-existing cavern was detected using microgravity mapping in the Nahal Hever South site where seven sinkholes of 1–2 m diameter had been opened. About 5000 gravity stations were observed in the area of 200×200 m2 by the use of Scintrex CG-3M AutoGrav gravimeter. Besides the conventional set of corrections applied in microgravity investigations, a correction for a strong gravity horizontal gradient (DS Transform Zone negative gravity anomaly influence) was inserted. As a result, residual gravity anomaly of –(0.08÷0.14) mGal was revealed. The gravity field analysis was supported by resistivity measurements. We applied the Emigma 7.8 gravity software to create the 3-D physical-geological models of the sinkholes development area. The modeling was confirmed by application of the GSFC program developed especially for 3-D combined gravity-magnetic modeling in complicated environments. Computed numerous gravity models verified an effective applicability of the microgravity technology for detection of karst cavities and estimation of their physical-geological parameters. A volume of the karst was approximately estimated as 35 000 m3. The visual analysis of large sinkhole clusters have been forming at the microgravity anomaly site, confirmed the results of microgravity mapping and 3-D modeling.
Dynamics of intense convective rain cells
Authors: Parodi A.
Published: April 2010

Abstract. Intense precipitation events are often convective in nature. A deeper understanding of the properties and the dynamics of convective rain cells is, therefore, necessary both from a physical and operational point of view. The aim of this work is to study the spatial-temporal properties of convective rain cells by using a fully parameterized nonhydrostatic code (Lokal Model) in simplified model configurations. High resolution simulations are performed and it is expected that the deep moist convection and the feedback mechanisms affecting larger scales of motion can then be resolved explicitly and some of the critical constraints of parameterization schemes can be relaxed. The sensitivity of the spatio-temporal properties of simulated cells to spatial resolution and microphysics schemes is investigated and discussed through a direct comparison with typical intense convective cells measured by radars.
Comparing microphysical/dynamical outputs by different cloud resolving models: impact on passive microwave precipitation retrieval from satellite
Authors: Medaglia C. M. , Adamo C. , Baordo F. , Dietrich S. , Di Michele S. , Kotroni V. , Lagouvardos K. , Mugnai A. , Pinori S. , Smith E. A. , Tripoli G. J.
Published: April 2010

Abstract. Mesoscale cloud resolving models (CRM's) are often utilized to generate consistent descriptions of the microphysical structure of precipitating clouds, which are then used by physically-based algorithms for retrieving precipitation from satellite-borne microwave radiometers. However, in principle, the simulated upwelling brightness temperatures (TB's) and derived precipitation retrievals generated by means of different CRM's with different microphysical assumptions, may be significantly different even when the models simulate well the storm dynamical and rainfall characteristics. In this paper, we investigate this issue for two well-known models having different treatment of the bulk microphysics, i.e. the UW-NMS and the MM5. To this end, the models are used to simulate the same 24-26 November 2002 flood-producing storm over northern Italy. The model outputs that best reproduce the structure of the storm, as it was observed by the Advanced Microwave Scanning Radiometer (AMSR) onboard the EOS-Aqua satellite, have been used in order to compute the upwelling TB's. Then, these TB's have been utilized for retrieving the precipitation fields from the AMSR observations. Finally, these results are compared in order to provide an indication of the CRM-effect on precipitation retrieval.
Reconstruction of reflectivity vertical profiles and data quality control for C-band radar rainfall estimation
Authors: Fornasiero A. , Alberoni P. P. , Vulpiani G. , Marzano F. S.
Published: April 2010

Abstract. Microwave Doppler radars are considered a fairly established technique to retrieve rain rate fields from measured reflectivity volumes. However, in a complex orographic environment radar observations are affected by several impairments which should be carefully evaluated. Together with the enhancement of ground-clutter effects, the major limitation is represented by partial or total beam blocking caused by natural obstructions which very often impose to scan at high-elevation angles. These range-related limitations tend to reduce the potential role of operational weather radars in monitoring precipitation amount at ground within mountainous areas since, if either the nature or intensity of rainfall varies with height (e.g., melting effects during stratiform rain), radar returns at higher altitudes may be not representative of surface rain rate. Therefore, before to use the radar data, it is necessary to reduce, as much as possible, this evaluation errors and to estimate the reliability of the processed data. Near to the quality control, are needed quality indexes, taking into account each correction and elaboration step, that could be useful to retrieve a final quality value. In this work, we analyse the main factors that could be affect the efficiency of a reconstruction methodology of near-surface reflectivity fields from high-elevation reflectivity bins, in presence of complex orography. A climatologic schema is applied to infer near-surface reflectivity at a given range interval. The technique is developed in polar coordinates partially taking into account the antenna beam width degradation at longer ranges and overall computational efficiency for operational purposes. Thereafter, it is applied on a rainfall event observed by a C-band Doppler radar operating in S. Pietro Capofiume (Bologna, Italy) and the relation between the reconstruction error and possible quality indicators is analysed and discussed.
Assessing the potential of SWVI (Soil Wetness Variation Index) for hydrological risk monitoring by means of satellite microwave observations
Authors: Lacava T. , Greco M. , Di Leo E. V. , Martino G. , Pergola N. , Romano F. , Sannazzaro F. , Tramutoli V.
Published: April 2010

Abstract. In the last years satellite remote sensing applications in hydrology have considerably progressed. A new multi-temporal satellite data-analysis approach has been recently suggested in order to estimate space-time changes of geophysical parameters possibly related to the increase of environmental and hydro-geological hazards. Such an approach has been already used both for flooded area mapping (using AVHRR data) and for soil wetness index estimation (using AMSU data). In this work, a preliminary sensitivity analysis of the proposed Soil Wetness Variation Index (SWVI) is made in the case of low intensity meteorological events by the comparison with hydrological (precipitation) data. This analysis, as a first step of a more complex work in progress, is targeted to a first evaluation of the reliability of the SWVI in describing soil response to precipitations of different duration and intensity.
Desertification risk assessment in southern Mediterranean areas
Authors: Greco M. , Mirauda D. , Squicciarino G. , Telesca V.
Published: April 2010

Abstract. The paper deals some important aspects concerning the study of desertification phenomenon that has significantly interested all European countries of the Mediterranean basin in the last decades. The territorial sensibility, qualitatively and/or quantitatively, of the risk related to the desertification processes has been valued as grade of susceptibility to the phenomenon in the study area, with respect to the hydraulic and hydrologic conditioning factors. The methodological approach followed is based on the classification of desertification indicators by means of a suitable conceptual model applied to the study area in Basilicata region. The classical desertification indexes have been evaluate referring to the study area generating temporal informative map. To achieve such objective, the historical series of temperatures and rainfall of several gauge-stations have been analysed, and the first results show an increasing trend for the temperature in last years, according to the global scale. An increase of aridity and erosion index values is, also, outlined by the collected data with slight reductions at higher altitudes.
Satellite radiometric remote sensing of rainfall fields: multi-sensor retrieval techniques at geostationary scale
Authors: Marzano F. S. , Cimini D. , Coppola E. , Verdecchia M. , Levizzani V. , Tapiador F. , Turk J. F.
Published: April 2010

Abstract. The Microwave Infrared Combined Rainfall Algorithm (MICRA) consists in a statistical integration method using the satellite microwave-based rain-rate estimates, assumed to be accurate enough, to calibrate spaceborne infrared measurements on limited sub-regions and time windows. Rainfall retrieval is pursued at the space-time scale of typical geostationary observations, that is at a spatial resolution of few kilometers and a repetition period of few tens of minutes. The actual implementation is explained, although the basic concepts of MICRA are very general and the method is easy to be extended for considering innovative statistical techniques or measurements from additional space-borne platforms. In order to demonstrate the potentiality of MICRA, case studies over central Italy are also discussed. Finally, preliminary results of MICRA validation by ground based remote and in situ measurements are shown and a comparison with a Neural Network (NN) based technique is briefly illustrated.
Analysis of infiltration, seepage processes and slope instability mechanisms during the November 2000 storm event in Tuscany
Authors: Tofani V. , Dapporto S. , Vannocci P. , Casagli N.
Published: April 2010

Abstract. On the days 20-21 November 2000, a storm of exceptional intensity triggered over 50 landslides within the province of Pistoia in Tuscany (Italy). These failures are mostly of complex type, originating as rotational or translational landslides, and transforming into flows. Two of these landslides were investigated in this paper by modelling the ground water infiltration process, the pore water pressure variations, both positive and negative, and the effects of these variations on slope stability during the rainfall event. Morphometric and geotechnical analyses were carried out for both sites through a series of in-situ and laboratory tests, the results of which were used as input for the modelling process. In a first step the surface infiltration rate was simulated using a modified Chu (1978) approach for the Green and Ampt (1911) equations in case of unsteady rainfall together with a surficial water balance. A finite element seepage analysis for transient conditions was then employed to model the changes in pore water pressure during the event, using the computed infiltration rate as the ground surface boundary condition. Finally, once again using the data from the previous step as input, the limit equilibrium Morgenstern-Price (1965) slope stability method was applied to calculate the variations in the factor of safety during the event and thereby determine the most critical time of instability. In both sites this method produced a curve for the factor of safety that indicated that the most critical time for failure occurred a few hours after the peak of rainfall.
Natural risk warning: comparison of two methodologies
Authors: Cavallo A. , Giannoni F.
Published: April 2010

Abstract. The Italian network of "Centri Funzionali" is now reaching operational status both in hydro-meteorological risk forecasting and support to the decision making of administrations that issue natural risk warning. Each centre operates for its district of influence. In order to have a nationwide common standard the National Civil Protection Department proposed a quantitative warning methodology based on the definition of rainfall thresholds correlated to historical damages. In the first phase the thresholds have been defined using two studies that cover all Italy: the VAPI (statistics of extreme rainfall and discharges, see reference) and the AVI (database of historical flood and landslide events and reported damages, see reference). This work presents one year back analysis that compares the new methodology and the one that has been usied since 2000 by the Liguria Region Meteorological Centre with regard to flood warning, pinpointing the performance differences in terms of false and missed alerts.
Calibration of a rainfall-runoff model using radar and raingauge data
Authors: Lopez V. , Napolitano F. , Russo F.
Published: April 2010

Abstract. Since raingauges give pointwise measurements the small scale variability of rainfall fields leads to biases on the estimation for the rainfall over the whole basin. In this context meteorological radars have several advantages since a single site is able to obtain coverage over a wide area with high temporal and spatial resolution. The purpose of this study is to compare the capability of the two different measurement systems in order to give correct input to drive rainfall-runoff models. Therefore a geomorphological model was calibrated, using firstly raingauge data and secondly radar rainfall estimates, for the Treja river basin. In this way it is possible to determine different sets of parameters and the influence of measurement system in hydrological modelling. The results shown that radar rainfall data is able to improve significantly hydrographs reconstructions.
Atmospheric boundary layers in storms: advanced theory and modelling applications
Authors: Zilitinkevich S. S. , Esau I. N. , Baklanov A.
Published: April 2010

Abstract. Turbulent planetary boundary layers (PBLs) control the exchange processes between the atmosphere and the ocean/land. The key problems of PBL physics are to determine the PBL height, the momentum, energy and matter fluxes at the surface and the mean wind and scalar profiles throughout the layer in a range of regimes from stable and neutral to convective. Until present, the PBLs typical of stormy weather were always considered as neutrally stratified. Recent works have disclosed that such PBLs are in fact very strongly affected by the static stability of the free atmosphere and must be treated as factually stable (we call this type of the PBL "conventionally neutral" in contract to the "truly neutral" PBLs developed against the neutrally stratified free flow). It is common knowledge that basic features of PBLs exhibit a noticeable dependence on the free-flow static stability and baroclinicity. However, the concern of the traditional theory of neural and stable PBLs was almost without exception the barotropic nocturnal PBL, which develops at mid latitudes during a few hours in the night, on the background of a neutral or slightly stable residual layer. The latter separates this type of the PBL from the free atmosphere. It is not surprising that the nature of turbulence in such regimes is basically local and does not depend on the properties of the free atmosphere. Alternatively, long-lived neutral (in fact only conditionally neutral) or stable PBLs, which have much more time to grow up, are placed immediately below the stably stratified free flow. Under these conditions, the turbulent transports of momentum and scalars even in the surface layer - far away from the PBL outer boundary - depend on the free-flow Brunt-Väisälä frequency, N. Furthermore, integral measures of the long-lived PBLs (their depths and the resistance law functions) depend on N and also on the baroclinic shear, S. In the traditional PBL models both non-local parameters N and S were overlooked. One of possible mechanisms responsible for non-local features of the long-lived PBLs could be the radiation of internal gravity waves (IGW) from the PBL upper boundary to the free atmosphere and the IGW-induced transport of the squared fluctuations of velocity and potential temperature. The free-flow stability plays an especially important role in is the conventionally neutral PBLs (those with the zero potential-temperature flux at the surface: Fθ=0 at z=0, developed against non-zero static stability in the free atmosphere: N>0). The above reasoning obviously calls for a comprehensive revision of the traditional theory. In a series of papers (quoted below in References) an advanced theory has been proposed. It includes the following developments.
Coupling a distributed grid based hydrological model and MM5 meteorological model for flooding alert mapping
Authors: Tomassetti B. , Coppola E. , Verdecchia M. , Visconti G.
Published: April 2010

Abstract. The increased number of extreme rainfall events seems to be one of the common feature of climate change signal all over the world (Easterlin et al., 2000; Meehl et al., 2000). In the last few years a large number of floods caused by extreme meteorological events has been observed over the river basins of Mediterranean area and they mainly affected small basins (few hundreds until few thousands of square kilometres of drainage area) . A strategic goal of applied meteorology is now to try to predict with high spatial resolution the segments of drainage network where floods may occur. A possible way to reach this aim is the coupling of meteorological mesoscale model with high resolution hydrological model. In this work few case studies of observed floods in the Italian Mediterranean area will be presented. It is shown how a distributed hydrological model, using the precipitation fields predicted by MM5 meteorological model, is able to highlight the area where the major floods may occur.
Characteristics of the extreme warm and cold days over Greece
Authors: Varfi M. S. , Karacostas T. S. , Makrogiannis T. J. , Flocas A. A.
Published: April 2010

Abstract. An attempt is made to study the characteristics of the extreme warm and cold days over the major area of Greece. To meet this objective, the daily maximum and minimum air temperature values are used, obtained from seventeen (17) synoptic weather stations, covering the broad study area. The extreme warm and cold days are identified based upon the proposed and adopted criteria, which are applied for the period 1961–2000. Seven regional decadal indices measuring the frequency of occurrence, the magnitude and the intensity of the extreme temperature values are calculated. The study of the indices revealed that after the 70' the frequency of occurrence and the intensity of cold days follow a negative trend, as opposed to the frequency of occurrence and the intensity of the warm days that follow a positive trend. Moreover, the proposed indices confirm the cooling conditions that Greece experienced in the 70's and early 80's and the warming trend afterwards.
Distributed modelling of climate change impacts on snow sublimation in Northern Mongolia
Authors: Wimmer F. , Schlaffer S. , aus der Beek T. , Menzel L.
Published: April 2010

Abstract. Sublimation of snow is an important factor of the hydrological cycle in Mongolia and is likely to increase according to future climate projections. In this study the hydrological model TRAIN was used to assess spatially distributed current and future sublimation rates based on interpolated daily data of precipitation, air temperature, air humidity, wind speed and solar radiation. An automated procedure for the interpolation of the input data is provided. Depending on the meteorological parameter and the data availability for the individual days, the most appropriate interpolation method is chosen automatically from inverse distance weighting, Ordinary Least Squares interpolation, Ordinary or Universal Kriging. Depending on elevation simulated annual sublimation in the period 1986–2006 was 23 to 35 mm, i.e. approximately 80% of total snowfall. Moreover, future climate projections for 2071–2100 of ECHAM5 and HadCM3, based on the A1B emission scenario of the Intergovernmental Panel on Climate Change, were analysed with TRAIN. In the case of ECHAM5 simulated sublimation increases by up to 17% (26...41 mm) while it remains at the same level for HadCM3 (24...34 mm). The differences are mainly due to a distinct increase in winter precipitation for ECHAM5. Simulated changes of the all-season hydrological conditions, e.g. the sublimation-to-precipitation ratio, were ambiguous due to diverse precipitation patterns derived by the global circulation models.
Hydrologic comparison between a lowland catchment (Kielstau, Germany) and a mountainous catchment (XitaoXi, China) using KIDS model in PCRaster
Authors: Zhang X. , Hörmann G. , Fohrer N.
Published: April 2010

Abstract. The KIDS model (Kielstau Discharge Simulation model) is a simple rainfall-runoff model developed originally for the Kielstau catchment. To extend its range of application we applied it to a completely different catchment, the XitaoXi catchment in China. Kielstau is a small (51 km2) lowland basin in Northern Germany, with large proportion of wetland area. And XitaoXi is a mesoscale (2271 km2) mountainous basin in the south of China. Both catchments differ greatly in size, topography, landuse, soil properties, and weather conditions. We compared two catchments in these features and stress on the analysis how the specific catchment characteristics could guide the adaptation of KIDS model and the parameter estimation for streamflow simulation. The Nash and Sutcliffe coefficient was 0.73 for Kielstau and 0.65 for XitaoXi. The results suggest that the application of KIDS model may require adjustments according to the specific physical background of the study basin.
The role of hydrological model complexity and uncertainty in climate change impact assessment
Authors: Ludwig R. , May I. , Turcotte R. , Vescovi L. , Braun M. , Cyr J.-F. , Fortin L.-G. , Chaumont D. , Biner S. , Chartier I. , Caya D. , Mauser W.
Published: April 2010

Abstract. Little quantitative knowledge is as yet available about the role of hydrological model complexity for climate change impact assessment. This study investigates and compares the varieties of different model response of three hydrological models (PROMET, Hydrotel, HSAMI), each representing a different model complexity in terms of process description, parameter space and spatial and temporal scale. The study is performed in the Ammer watershed, a 709 km2 catchment in the Bavarian alpine forelands, Germany. All models are driven and validated by a 30-year time-series (1971–2000) of observation data. It is expressed by objective functions, that all models, HSAMI and Hydrotel due to calibration, perform almost equally well for runoff simulation over the validation period. Some systematic deviances in the hydrographs and the spatial patterns of hydrologic variables are however quite distinct and thus further discussed. Virtual future climate (2071–2100) is generated by the Canadian Regional Climate Model (vers 3.7.1), driven by the Coupled Global Climate Model (vers. 2) based on an A2 emission scenario (IPCC 2007). The hydrological model performance is evaluated by flow indicators, such as flood frequency, annual 7-day and 30-day low flow and maximum seasonal flows. The modified climatic boundary conditions cause dramatic deviances in hydrologic model response. HSAMI shows tremendous overestimation of evapotranspiration, while Hydrotel and PROMET behave in comparable range. Still, their significant differences, like spatially explicit patterns of summerly water shortage or spring flood intensity, highlight the necessity to extend and quantify the uncertainty discussion in climate change impact analysis towards the remarkable effect of hydrological model complexity. It is obvious that for specific application purposes, water resources managers need to be made aware of this effect and have to take its implications into account for decision making. The paper concludes with an outlook and a proposal for future research necessities.
Aconcagua peak geodynamics from GPS observations, Mendoza, Argentina: preliminary results
Authors: Mateo M. L. , Lenzano L. E. , Moreiras S. M.
Published: April 2010

Abstract. In 2005, the SIGMA Program (Mount Aconcagua GNSS Research System) was implemented to investigate the geodynamics of the Aconcagua mountain region in the Central Andes. For this purpose, a continuously recording GPS station, ACON, was installed on the summit of Mount Aconcagua at 6.292 m a.s.l. The installation required special technology to support the equipment under extreme climatic conditions. The power supply system was optimized in 2008, so that a greater quantity of data could be recorded. This, in turn, will lead to more accurate estimates of displacement of the Aconcagua peak. Preliminary results from the ACON station indicate an average horizontal velocity of 0.023±0.0001 m/yr toward NE in 2 time windows between 2006 and 2008.
A Terrestrial Reference Frame (TRF), coordinates and velocities for South American stations: contributions to Central Andes geodynamics
Authors: Mackern M. V. , Mateo M. L. , Robin A. M. , Calori A. V.
Published: April 2010

Abstract. Satellite positioning systems allow the fixing of the location of a point on the Earth's surface with very good precision and accuracy. To do this, however, it is necessary to determine the point coordinates taking account the reference system and the movements that affect them because of tectonic plate movements. These reference systems are materialized by a significant number of continuous measurement stations in South America. In SIRGAS (Sistema de Referencia Geocéntrico para las Américas), there are four Analysis Centers that process the data collected from satellites of the Global Navigation Satellite Systems (GNSS), with the primary purpose to maintain the international terrestrial reference frame through calculation of the coordinates and velocities of the continuous GNSS stations of the SIRGAS-CON Network. In this work, we demonstrate the quality of the solutions from CIMA, one of the SIRGAS official processing centers operating in Mendoza, Argentina, in comparison with other South American processing centers. The importance of precise calculations of coordinates and velocities in a global frame is also shown. Finally, we give estimations of velocities from stations located within deformation zones in the Central Andes.