bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of nonlinearity in tsunami generated by submarine earthquake
Authors: Nosov M. A. , Kolesov S. V. , Denisova A. V.
Published: April 2010

Abstract. Rapid co-seismic bottom displacements during strong submarine earthquake give rise to intensive low-frequency elastic oscillations of water layer. Nonlinear energy transfer from the elastic oscillations to long gravitational waves may provide an additional contribution to tsunami. The nonlinear tsunami generation mechanism is examined analytically. Finiteness of bottom elasticity is taken into account. General parameters responsible for amplitude and energy of the nonlinear contribution to tsunami wave are revealed.
Catastrophic glacial multi-phase mass movements: a special type of glacial hazard
Authors: Petrakov D. A. , Chernomorets S. S. , Evans S. G. , Tutubalina O. V.
Published: April 2010

Abstract. Many glacier-related hazards are well typified and studied, but some events stand out from conventional classifications. The Kolka-Karmadon catastrophic event on 20 September 2002 in North Ossetia, North Caucasus, Russia is used as an example of a complex glacier failure exhibiting characteristics such as high mobility, long runout, ultrarapid movement and multiphase behaviour. We consider terminology protocol for glacier hazard classification and then, using the Kolka-Karmadon event and several other examples from around the world, we propose a new term for this family of events. Catastrophic glacier multi-phase mass movement (CGMM) is described and further illustrated by eight major events from Russia, Georgia, Peru, Chile, and Canada. CGMM have a combination of specific features: extraordinary velocities and long-distance runout despite low path angle; progressive fluidisation along travel path; superelevation and run-up of the moving mass, air blast wave in the avalanche flow phase; entrainment of available materials in its path, and the repeated nature of the event. CGMM events may affect areas remote from glaciers which were previously considered as safe.
Numerical study of the response of the ocean to a northerly wind jet in the equatorial Eastern Pacific
Authors: Mosquera K.
Published: April 2010

Abstract. The response of the equatorial and South American coastal ocean circulation to the anomalous March 2002 wind jet extending from the Gulf of Panama to 6° S is studied in a linear ocean model. Two experiments were performed: one without continental boundaries and the other with an eastern boundary at 81° W, representing the American continent. The spatial and temporal structure of the imposed wind anomaly, represented with idealized mathematical functions, is similar to that of the real jet. The duration of the wind jet was six days where the maximum intensity occurred at the third day. The results of the experiments indicate that the wind-jet anomaly over the Gulf of Panama is another source of ocean waves that influence the western coast of South America in the form of coastal Kelvin waves (CKW).
River channel response to runoff variability
Authors: Kargapolova I.
Published: April 2010

Abstract. The focus of this study was to determine river runoff impacts on channel evolution during the last centuries. Comparing a number of maps from the 18th–21th centuries and space images in concert with hydrological data we estimated natural trends, cycles and the intensity of channel formation for periods of high and low runoff. Our analysis for a long period of time enable us assessing mean and maximum rates of erosion and accumulation of river channels and bank dynamics under different conditions. Using links between runoff values and meander size we predict and reconstruct these for several Russian rivers. For forecast validation we use cases of high scale runoff change – water transfer from one basin to another.
The energy spectrum in a barotropic atmosphere
Authors: Kurgansky M. V.
Published: April 2010

Abstract. In a forced-dissipative barotropic model of the atmosphere on a spherical planet, by following mathematical techniques in (Thompson, P. D.: The equilibrium energy spectrum of randomly forced two-dimensional turbulence, Journal of the Atmospheric Sciences, 30, 1593–1598, 1973) but applying them in a novel context of the discrete spectrum on a rotating sphere, the "minus 2" energy spectrum for wavenumbers much greater than a characteristic wavenumber of the baroclinic forcing has been obtained if the forcing is taken in the simplest and most fundamental form. Some observation-based atmospheric kinetic energy spectra, with their slopes lying between "minus 2" and "minus 3" laws, are discussed from the perspective of the deduced "minus 2" energy spectrum.
Potential-vorticity inversion and the wave-turbulence jigsaw: some recent clarifications
Authors: McIntyre M. E.
Published: April 2010

Abstract. Two key ideas stand out as crucial to understanding atmosphere-ocean dynamics, and the dynamics of other planets including the gas giants. The first key idea is the invertibility principle for potential vorticity (PV). Without it, one can hardly give a coherent account of even so important and elementary a process as Rossby-wave propagation, going beyond the simplest textbook cases. Still less can one fully understand nonlinear processes like the self-sharpening or narrowing of jets – the once-mysterious "negative viscosity" phenomenon. The second key idea, also crucial to understanding jets, might be summarized in the phrase "there is no such thing as turbulence without waves", meaning Rossby waves especially. Without this idea one cannot begin to make sense of, for instance, momentum budgets and eddy momentum transports in complex large-scale flows. Like the invertibility principle the idea has long been recognized, or at least adumbrated. However, it is worth articulating explicitly if only because it can be forgotten when, in the usual way, we speak of "turbulence" and "turbulence theory" as if they were autonomous concepts. In many cases of interest, such as the well-studied terrestrial stratosphere, reality is more accurately described as a highly inhomogeneous "wave-turbulence jigsaw puzzle" in which wavelike and turbulent regions fit together and crucially affect each other's evolution. This modifies, for instance, formulae for the Rhines scale interpreted as indicating the comparable importance of wavelike and turbulent dynamics. Also, weakly inhomogeneous turbulence theory is altogether inapplicable. For instance there is no scale separation. Eddy scales are not much smaller than the sizes of the individual turbulent regions in the jigsaw. Here I review some recent progress in clarifying these ideas and their implications.
Model of oscillatory instability in vertically-homogeneous atmosphere
Authors: Rutkevich P. B. , Rutkevych P P.
Published: April 2010

Abstract. Existence and repeatability of tornadoes could be straightforwardly explained if there existed instability, responsible for their formation. However, it is well known that convection is the only instability in initially stable air, and the usual convective instability is not applicable for these phenomena. In the present paper we describe an instability in the atmosphere, which can be responsible for intense vortices. This instability appears in a fluid with Coriolis force and dissipation and has oscillatory behaviour, where the amplitude growth is accompanied by oscillations with frequency comparable to the growth rate of the instability. In the paper, both analytical analysis of the linear phase of the instability and nonlinear simulation of the developed stage of the air motion are addressed. This work was supported by the RFBR grant no. 09-05-00374-a.
Precipitation classification at mid-latitudes in terms of drop size distribution parameters
Authors: Caracciolo C. , Porcù F. , Prodi F.
Published: April 2010

Abstract. The drop size distribution (DSD) is a fundamental property of rainfall because the shape of the distribution reflects the physics of rain formation processes. Given the lack of studies on the DSD at mid-latitudes, the present work focuses on the microphysical characterization of precipitation events occurring in Italy, using two different types of disdrometer. A large number of different rain events was collected: they underwent microphysical analysis by computing the Z-R relationships, observing the average DSDs and DSD parameters, fitting the real distribution for different rainfall rate categories and applying convective (C) – stratiform (S) discrimination algorithms. A general agreement with past works at mid-latitudes is found both in the Z-R relationship and in DSD parameters. The rain distribution is well described by a gamma DSD and only in some cases (especially the light rain events) by an exponential DSD. Marked differences are observed in DSD parameters and Z-R relationships between C and S episodes. The use of disdrometers for areas covered by multiparametric radar is suggested and will be performed in the near future.
An investigation of a baroclinic depression that affected the area of Cyprus
Authors: Nicolaides K. , Savvidou K. , Orphanou A. , Michaelides S. C. , Constantinides P. , Papachristodoulou C. , Savvides M.
Published: April 2010

Abstract. The synoptic, dynamic, energetic and thermodynamic conditions during the development of a baroclinic depression which affected the area of Cyprus from 5 to 9 February 2006 are studied. The depression was associated with extreme weather phenomena such as thunderstorms, strong winds, dust and high precipitation accumulations (amounting to 50% of the mean monthly value). The results underline the importance of the dynamic control on the cyclone's development and the important contribution of the system itself in the energetics of the atmosphere. The thermodynamic analysis has proved a very useful tool in identifying the convective potential of the atmosphere at various stages of the development.
Process-oriented statistical-dynamical evaluation of LM precipitation forecasts
Authors: Claußnitzer A. , Langer I. , Névir P. , Reimer E. , Cubasch U.
Published: April 2010

Abstract. The objective of this study is the scale dependent evaluation of precipitation forecasts of the Lokal-Modell (LM) from the German Weather Service in relation to dynamical and cloud parameters. For this purpose the newly designed Dynamic State Index (DSI) is correlated with clouds and precipitation. The DSI quantitatively describes the deviation and relative distance from a stationary and adiabatic solution of the primitive equations. A case study and statistical analysis of clouds and precipitation demonstrates the availability of the DSI as a dynamical threshold parameter. This confirms the importance of imbalances of the atmospheric flow field, which dynamically induce the generation of rainfall.
Certified accuracy of rainfall data as a standard requirement in scientific investigations
Authors: Lanza L. G. , Stagi L.
Published: April 2010

Abstract. This paper elaborates on the rationale behind the proposed standard limits for the accuracy of rainfall intensity measurements obtained from tipping-bucket and other types of rain gauges. Indeed, based on experimental results obtained in the course of international instrument Intercomparison initiatives and specific laboratory tests, it is shown here that the accuracy of operational rain gauges can be reduced to the limits of ±1% after proper calibration and correction. This figure is proposed as a standard accuracy requirement for the use of rain data in scientific investigations. This limit is also proposed as the reference accuracy for operational rain gauge networks in order to comply with quality assurance systems in meteorological observations.
A LEPS approach to the predictability of intense rain storms in the Central Mediterranean basin
Authors: Federico S. , Bellecci C. , Walko R. L.
Published: April 2010

Abstract. This study investigates a method for best member selection of a Limited area model Ensemble Prediction System (LEPS) with the goal to increase quantitative precipitation forecast. A case study that occurred between 22-24 May 2002 over Calabria, southern Italy, is discussed. Mediterranean storms often develop under upper level disturbances which are usually associated with high values of potential vorticity. Anomalously high values of potential vorticity can be identified by the METEOSAT water vapor channel centered around 6.3 μm because they are associated with dark band on the METEOSAT image. This signature offers a chance to identify the upper level disturbance that can be exploited in data void countries as Calabria. The working hypothesis is that the uncertainty in the representation of the upper-level disturbance has a major impact on the precipitation forecast. This issue is utilized in an ensemble forecast where member forecasts are compatible with the analysis and forecast errors. These members are grouped in five clusters by a hierarchical clustering technique which utilizes the height of the dynamical tropopause to compute distances between members. Therefore the members of a cluster have a similar representation of the upper level disturbance. For each cluster a representative member is selected and its pseudo water vapor image is compared with the corresponding METEOSAT 7 water vapor image at a specific time, antecedent to the rain occurrence over Calabria. The subjective evaluation of the comparison allows to gain physical insight in the storm evolution and to select representative members which are more in agreement with the METEOSAT image. Results, even if for a case study, show the feasibility of the methodology that, if confirmed by further investigations, could be valuable in data void countries as the central Mediterranean basin.
Numerical study of two-dimensional moist symmetric instability
Authors: Fantini M. , Malguzzi P.
Published: April 2010

Abstract. The 2-D version of the non-hydrostatic fully compressible model MOLOCH developed at ISAC-CNR was used in idealized set-up to study the start-up and finite amplitude evolution of symmetric instability. The unstable basic state was designed by numerical integration of the equation which defines saturated equivalent potential vorticity qe*. We present the structure and growth rates of the linear modes both for a supersaturated initial state ("super"-linear mode) and for a saturated one ("pseudo"-linear mode) and the modifications induced on the base state by their finite amplitude evolution.
Case studies of selected Project "Flash" events
Authors: Nicolaides K. A. , Michaelides S. C. , Savvidou K. , Orphanou A. , Constantinides P. , Charalambous M. , Michaelides M.
Published: April 2010

Abstract. Flooding is a consequence of the prevailing meteorological situation, the intensity and duration of precipitation, geomorphology, human activities over a geographical region and other factors. Floods result in damage and destruction of infrastructure and private property and, in some cases, in fatalities. Flash floods are sudden and quite localized in extend, characterized by excessive amounts of rainfall within a short period of time and are distinguished from other floods by their degree of severity. The broader knowledge concerning flash floods is useful for the better understanding of the underlying thermodynamic and dynamic mechanisms, as well as the associated physical processes. The wider understanding of flashfloods can form part of an integrated system for short and very short forecasting of these events. In the present study, the synoptic, dynamic and thermodynamic conditions during the development of a baroclinic depression which affected the area of Cyprus on 6 November 2005 are studied. The depression was associated with extreme weather phenomena, such as thunderstorms, a water spout and high precipitation accumulations. The results indicate the importance of the dynamic parameters in the system's development and the thermodynamic analysis has shown the convective potential of the atmosphere.
The impact of hail storms on the agricultural economy of Cyprus and their characteristics
Authors: Nicolaides K. A. , Photiou G. , Savvidou K. , Orphanou A. , Michaelides S. C. , Karakostas T. S. , Charalambous D. , Kannaouros C.
Published: April 2010

Abstract. The contemporary economy of Cyprus is mostly based on services; agriculture was by tradition a strong contributor to the economy of the island, but nowadays its contribution is rather limited. At all times, the agricultural economy suffers from the consequences of weather phenomena such as hail, frost, drought, dust storms, etc. The present study focuses on the impact of hail to the agricultural economy, since hailstorms can straightforwardly destroy crops and plantations. Any knowledge concerning hail is useful for the improved understanding of the underlying thermodynamic and dynamic mechanisms and physical processes associated with its formation. For the investigation of hail as a natural hazard and its contribution to the insurance compensations paid to farmers, hail events and their associated synoptic and dynamic conditions were studied. Hail events were clustered into a "frontal instability hail events" and a "thermal instability hail events" clusters. The spatial distribution of the frequency of hail events was also determined in order to identify geographical areas that are more often hit by hail storms.
Human alterations of the terrestrial water cycle through land management
Authors: Rost S. , Gerten D. , Heyder U.
Published: April 2010

Abstract. This study quantifies current and potential future changes in transpiration, evaporation, interception loss and river discharge in response to land use change, irrigation and climate change, by performing several distinct simulations within the consistent hydrology and biosphere modeling framework LPJmL (Lund-Potsdam-Jena managed Land). We distinguished two irrigation simulations: a water limited one in which irrigation was restricted by local renewable water resources (ILIM), and a potential one in which no such limitation was assumed but withdrawals from deep groundwater or remote rivers allowed (IPOT). We found that the effect of historical land use change as compared to potential natural vegetation was pronounced, including a reduction in interception loss and transpiration by 25.9% and 10.6%, respectively, whereas river discharge increased by 6.6% (climate conditions of 1991–2000). Furthermore, we estimated that about 1170 km3yr−1 of irrigation water could be withdrawn from local renewable water resources (in ILIM), which resulted in a reduction of river discharge by 1.5%. However, up to 1660 km3yr−1 of water withdrawals were required in addition under the assumption that optimal growth of irrigated crops was sustained (IPOT), which resulted in a slight net increase in global river discharge by 2.0% due to return flows. Under the HadCM3 A2 climate and emission scenario, climate change alone will decrease total evapotranspiration by 1.5% and river discharge by 0.9% in 2046–2055 compared to 1991–2000 average due to changes in precipitation patterns, a decrease in global precipitation amount, and the net effect of CO2 fertilization. A doubling of agricultural land in 2046–2055 compared to 1991–2000 average as proposed by the IMAGE land use change scenario will result in a decrease in total evapotranspiration by 2.5% and in an increase in river discharge by 3.9%. That is, the effects of land use change in the future will be comparable in magnitude to the effects of climate change in this particular scenario. On present irrigated areas future water withdrawal will increase especially in regions where climate changes towards warmer and dryer conditions will be pronounced.
GPR based soil electromagnetic parameters determination for subsurface imaging
Authors: Solimene R. , Prisco G. , Soldovieri F.
Published: April 2010

Abstract. The problem of estimating the dielectric permittivity and the electric conductivity of the soil starting from GPR measurements is addressed. A new estimation procedure is proposed and checked against synthetic data generated by a FDTD forward solver. A two-dimensional geometry and a two-layered background medium are considered.
The integration of novel diagnostics techniques for multi-scale monitoring of large civil infrastructures
Authors: Soldovieri F. , Bernini R. , Catapano I. , Crocco L.
Published: April 2010

Abstract. In the recent years, structural monitoring of large infrastructures (buildings, dams, bridges) or more generally man-made structures has raised an increased attention due to the growing interest about safety and security issues and risk assessment through early detection. In this framework, aim of the paper is to introduce a new integrated approach which combines two sensing techniques acting on different spatial and temporal scales. The first one is a distributed optic fiber sensor based on the Brillouin scattering phenomenon, which allows a spatially and temporally continuous monitoring of the structure with a "low" spatial resolution (meter). The second technique is based on the use of Ground Penetrating Radar (GPR), which can provide detailed images of the inner status of the structure (with a spatial resolution less then tens centimetres), but does not allow a temporal continuous monitoring. The paper describes the features of these two techniques and provides experimental results concerning preliminary test cases.
Integrated remote sensing techniques for the detection of buried archaeological adobe structures: preliminary results in Cahuachi (Peru)
Authors: Masini N. , Rizzo E. , Lasaponara R. , Orefici G.
Published: April 2010

Abstract. This paper is focused on the jointly use of satellite Quickbird (QB) images and Ground Probing Radar (GPR) for assessing their capability in the detection of archaeological adobe structures (sun-dried earth material). Such detection is particularly complex. due to the low contrast generally existing between the archaeological features and the background. Two significant test areas were investigated in the Ceremonial Centre of Cahuachi (in the Nasca territory, Southern Peru) dating back to 6th century BC to 4th century AD. Our results showed that both satellite and GPR data provided valuable indications for unearthing precious ancient remains. Our preliminary analyses pointed out that the integrated use of non destructive remote sensing techniques has high potentiality for its important scientific implications and for its significant contributions to cultural resource management.
Sea surface topography reconstruction from X-band radar images
Authors: Serafino F. , Lugni C. , Soldovieri F.
Published: April 2010

Abstract. The paper deals with the feasibility study of the sea state monitoring starting from X-band radar images. The exploitation of radar images allows to achieve a global vision of the sea state compared to the local vision given by the usual sensors as the buoys. The processing approach is based on the formulation of problem as an inverse one where starting from the electromagnetic field backscattered by the sea surface, the information about the sea state are retrieved. The reliability of the inversion procedure is shown by processing synthetic and experimental data where particular attention is focussed to the determination of the sea current and speed of the vessel.
Estimation of convective precipitation: the meteorological radar versus an automatic rain gauge network
Authors: Llasat M. C. , Rigo T. , Ceperuelo M. , Barrera A.
Published: April 2010

Abstract. The estimation of convective precipitation and its contribution to total precipitation is an important issue both in hydrometeorology and radio links. The greatest part of this kind of precipitation is related with high intensity values that can produce floods and/or damage and disturb radio propagation. This contribution proposes two approaches for the estimation of convective precipitation, using the β parameter that is related with the greater or lesser convective character of the precipitation event, and its time and space distribution throughout the entire series of the samples. The first approach was applied to 126 rain gauges of the Automatic System of Hydrologic Information of the Internal Basins of Catalonia (NE Spain). Data are series of 5-min rain rate, for the period 1996-2002, and a long series of 1-min rain rate starting in 1927. Rainfall events were classified according to this parameter. The second approach involved using information obtained by the meteorological radar located near Barcelona. A modified version of the SCIT method for the 3-D analysis and a combination of different methods for the 2-D analysis were applied. Convective rainfall charts and β charts were reported. Results obtained by the rain gauge network and by the radar were compared. The application of the β parameter to improve the rainfall regionalisation was demonstrated.
Extreme flash floods in Barcelona County
Authors: Barrera A. , Barriendos M. , Llasat M. C.
Published: April 2010

Abstract. In this paper the catastrophic and extraordinary floods occurring in Barcelona County (Catalonia, NE Spain) are studied, in order to characterise the temporal evolution of extreme flash floods in that area and their main features. These events usually cause economical losses and major problems for undertaking daily activity in Barcelona city. This kind of floods is a very common feature in the North-east of Spain and they are recorded every year in some point of Catalonia. This contribution also shows the frequency of those events, within the framework of all the floods that have occurred in Barcelona since the 14th century, but also describes the flooded area, urban evolution, impacts and the weather conditions for any of most severe events. The evolution of flood occurrence shows the existence of oscillations in the earlier and later modern age periods that can be attributed to climatic variability, evolution of the perception threshold and changes in vulnerability. A great increase of vulnerability can be assumed for the period 1850-1900. The analysis of the time evolution for the Barcelona rainfall series (1854-2000) shows that no trend exists, although, due to the changes in urban planning, flash-floods impact has changed over this time. The number of catastrophic flash floods has diminished, although the extraordinary ones have increased.
High resolution modelling of the extreme precipitation event over Algiers in November 2001
Authors: Moore S. A. , Wilson C. , Bell S.
Published: April 2010

Abstract. Between 18:00UTC on Friday 9th November and 12:00UTC on Saturday 10th November 2001 260mm of rainfall was recorded at Bouzareah, compared to the November average of just 96mm. This extreme rainfall resulted in landslides and flooding, causing immense damage to the Bab-el-Oued district of Algiers and affected the lives of more than 2000 people. In this paper, key results from a modelling study of this event using the UK Met Office Unified Model at global (60km), regional (20km) and national (4km) horizontal resolutions are described. In general, it is found that the event could be well forecast with increases in resolution leading to better predictions of both the distribution and intensity of the rainfall. The role of the local orography and latent heating are also discussed.
Multi-sensor analysis of extreme events in North-Eastern Italy
Authors: Monai M. , Rossa A. , Formentini G. , Veronese S.
Published: April 2010

Abstract. The North-eastern part of Italy is known to be one of the most rainy regions in Europe. In this paper three extreme events are analysed, using a multi-sensor observing system including a weather radar and a dense telemetric network of surface stations, recording precipitation, wind, temperature and relative humidity. The cases examined comprise two long lasting rainfall events impacting two distinct areas, and a vigorous hail-producing thunderstorm event over the plains. In all cases, inter-comparison between remotely sensed and surface observations, including estimates and measures of precipitation and wind, helps to better understand the behaviour of the atmosphere, thus supporting operational fore- and now-casting. In the case of widespread precipitation, a relation is suggested between the wind speed and direction at medium/low levels with the location of the maximum precipitation relative to the mountains. This reflects the dynamical interaction between the mountain barrier and the atmospheric flux impinging upon it. This flux can be estimated by the automatic weather station of Mt. Cesen, a focal point for a now-casting of the rain in the Veneto Region. Analysis of strong thunderstorm activity makes extensive use of radar data. In the examined case the interaction of a sea breeze-like circulation with a mesoscale trough gave rise to a distinct convergence line that triggered a severe and long-lived hail-producing multi-cell thunderstorm. The hail was successfully detected by the radar's hail detection algorithm.
What happens after the catchment caught the storm? Hydrological processes at the small, semi-arid Weatherley catchment, South-Africa
Authors: Uhlenbrook S. , Wenninger J. , Lorentz S.
Published: April 2010

Abstract. The knowledge of water flow pathways and residence times in a catchment are essential for predicting the hydrological response to a rain storm event. Different experimental techniques are available to study these processes, which are briefly reviewed in this paper. To illustrate this, recent findings from the Weatherley catchment a 1.5 km2 semi-arid headwater in South-Africa, are reported in this paper. Beside classical hydrometric measurements of precipitation and runoff different experimental techniques were applied to explore flow paths (i.e. soil moisture and groundwater measurements, natural tracers, and 2-D electrical resistivity tomographies (ERT)).
Theoretical derivation of the index flood
Authors: Gioia A. , Fiorentino M. , Iacobellis V. , Margiotta M. R.
Published: April 2010

Abstract. The expected value of the annual flood is always needed for attaining reliable estimates of the return period of floods. In particular, the accuracy of its estimate is crucial for ungauged basins, where regional analysis is to be invoked. The main goal of this research was to search for an index flood formula suitable to explicate the influence of basin characteristics such as geomorphology, vegetation, soil and climate. This formula, due to unavoidable overparameterization, more than being suggested for technical use, allows sensitivity analyses of simpler formulae to basin features. This study was mainly based on the theoretical distribution of floods developed by Iacobellis and Fiorentino (2000). In particular, the relationship that they derived for the first order moment was analyzed and simplified by assuming the Gumbel distribution as a first order approximation for the distributions of floods and rainfall intensities. The results were validated with regard to data recorded in some basins located in Southern Italy, in a climatically end geologically heterogeneous territory.
Monitoring of rainfall by ground-based passive microwave systems: models, measurements and applications
Authors: Marzano F. S. , Cimini D. , Ware R.
Published: April 2010

Abstract. A large set of ground-based multi-frequency microwave radiometric simulations and measurements during different precipitation regimes are analysed. Simulations are performed for a set of frequencies from 22 to 60 GHz, representing the channels currently available on an operational ground-based radiometric system. Results are illustrated in terms of comparisons between measurements and model data in order to show that the observed radiometric signatures can be attributed to rainfall scattering and absorption. An inversion algorithm has been developed, basing on the simulated data, to retrieve rain rate from passive radiometric observations. As a validation of the approach, we have analyzed radiometric measurements during rain events occurred in Boulder, Colorado, and at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains (SGP) site in Lamont, Oklahoma, USA, comparing rain rate estimates with available simultaneous rain gauge data.
Orographic influences in rainfall downscaling
Authors: Badas M. G. , Deidda R. , Piga E.
Published: April 2010

Abstract. The problem of rainfall downscaling in a mountainous region is discussed, and a simple methodology aimed at introducing spatial heterogeneity induced by orography in downscaling models is proposed. This procedure was calibrated and applied to rainfall data retrieved by the high temporal resolution rain gage network of the Sardinian Hydrological Survey.
STORM3: a new flood forecast management and monitoring system in accordance with the recent Italian national directive
Authors: Burastero A. , Pintus F. , Rossi L. , Versace C.
Published: April 2010

Abstract. The effectiveness of alert systems for civil protection purposes, defined as the ability to minimize the level of risk in a region subjected to an imminent flood event, strongly depends on availability and exploitability of information. It also depends on technical expertise and the ability to easily manage the civil protection actions through the organization into standardized procedures. Hydro-geologic and hydraulic risk estimation, based on the combination of different technical issues (in this case meteorological, hydro-geological, hydraulic matters), but also socio-economic ones, requires the integration between quasi-static and time-varying information within the same operative platform. Beside the real-time data exchange, a Decision Support System must provide tools which enable knowledge sharing among the civil protection centres. Moreover, due to the amount and heterogeneity of information, quality procedures become necessary to handle all forecasting and monitoring routines within operative centres, according to the latest national directive. In Italy procedures on the civil protection matter have been condensed into the Prime Minister's Directive (27 February 2004. STORM3, an innovative management and monitoring System for real-time flood forecasting and warning, takes in the Directive, supporting the operator step by step within the different phases of civil protection activities.
Evaluation of the hydro-meteorological chain in Piemonte Region, north western Italy - analysis of two HYDROPTIMET test cases
Authors: Rabuffetti D. , Milelli M. , Graziadei M. , Mercogliano P. , Oberto E.
Published: April 2010

Abstract. The HYDROPTIMET Project, Interreg IIIB EU program, is developed in the framework of the prediction and prevention of natural hazards related to severe hydro-meteorological events and aims to the optimisation of Hydro-Meteorological warning systems by the experimentation of new tools (such as numerical models) to be used operationally for risk assessment. The object of the research are the Mesoscale weather phenomena and the response of watersheds with size ranging from 102 to 103 km2. Non-hydrostatic meteorological models are used to catch such phenomena at a regional level focusing on the Quantitative Precipitation Forecast (QPF). Furthermore hydrological Quantitative Discharge Forecast (QDF) are performed by the simulation of run-off generation and flood propagation in the main rivers of the interested territory. In this way observed data and QPF are used, in a real-time configuration, for one-way forcing of the hydrological model that works operationally connected to the Piemonte Region Alert System. The main hydro-meteorological events that interested Piemonte Region in the last years are studied, these are the HYDROPTIMET selected test cases of 14-18 November 2002 and 23-26 November 2002. The results obtained in terms of QPF and QDF offer a sound basis to evaluate the sensitivity of the whole hydro-meteorological chain to the uncertainties in the numerical simulations. Different configurations of non-hydrostatic meteorological models are also analysed.
Assimilation of reprocessed ERS scatterometer data into ECMWF weather analysis on the Mediterranean Sea
Authors: Crapolicchio R. , Lecomte P. , Hersbach H.
Published: April 2010

Abstract. Since the launch of ERS-1 in 1991 and ERS-2 in 1995, carrying a C-band Scatterometer, a data set of more than thirteen years of backscattered signal from the Earth surface is available for exploitation. With its global coverage, day or night and all-weather operation, ERS Scatterometer data offer unique opportunity for long-term studies and research. To fulfill the needs of the scientific community, the European Space Agency (ESA) has developed the project: Advanced Scatterometer Processing System (ASPS). Main scope of the project is to provide with state-of-the-art algorithm, high quality and homogenous Scatterometer measurements (sigma nought) of the Earth surface and high quality wind field over the Oceans by re-processing the entire ERS mission. Additional scope is to provide on experimental basis scientific products in high resolution tailored for the emerging Scatterometer application on Ice and Land. The ASPS project is now in a pre-operational phase and the scope of the paper is to give to the scientific community an overview of the ASPS data and show the assimilation of the data into the ECMWF weather analysis system. ASPS data hopefully will help the scientific community to better understand and monitor the Earth's climate changes and to protect our environment.
Simulations of deep convection in the Mediterranean area using 3DVAR of conventional and non-conventional data
Authors: Ferretti R. , Faccani C. , Cimini D. , Marzano F. S. , Memmo A. , Cucurull L. , Pacione R.
Published: April 2010

Abstract. In autumn deep convection in the Mediterranean region is a common phenomenon. The local events characterized by deep convection are still a difficult task even for high resolution numerical weather prediction. Three flood cases, produced by convection either embedded in a large scale system or locally developed, occurring in Italy, are presented. All these case were not correctly forecasted: Sardinia (Cagliari, 13 November 1999); Calabria (Soverato, 7 September 2000) and Sicily (Catania, 16 September 2003). The first case occurred during the Mesoscale Alpine Programme (MAP) campaign, therefore a lot of data are available; for the second one only data from SSM/I and local rain-gauge are available; the third one occurred during the operational experimentation of the TOUGH project. The last one was not well predicted even using the operational assimilation of ground based GPS. To improve the forecast of these cases the assimilation of several data is tested. The variational assimilation performed using 3DVAR of GPS, SSM/I and surface and upper air data is applied to improve the Initial Conditions of the Sicily case. The Sardinia case is improved using either GPS and surface data, whereas for the Soverato case only ZTD is assimilated. The experiments are performed using the MM5 model from Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR); the model is initialized using the new Initial Conditions produced by the variational assimilation of conventional and non conventional data. The results show that the assimilation of the retrieved quantities does produces large improvement in the precipitation forecast. Large sensitivity to the assimilation of surface data and brightness temperature from SSM/I is found.
Detecting trends of extreme rainfall series in Sicily
Authors: Bonaccorso B. , Cancelliere A. , Rossi G.
Published: April 2010

Abstract. The objective of the study is to assess the presence of linear and non linear trends in annual maximum rainfall series of different durations observed in Sicily. In particular, annual maximum rainfall series with at least 50 years of records starting from the 1920’s are selected, and for each duration (1, 3, 6, 12 and 24 h) the Student’s t test and theMann- Kendall test, respectively, for linear and non linear trend detection, are applied also by means of bootstrap techniques. The effect of trend on the assessment of the return period of a critical event is also analysed. In particular, return periods related to a storm, recently occurred along the East Coast of Sicily, are computed by estimating parameters based on several sub-series extracted from the whole observation period. Such return period estimates are also compared with confidence intervals computed by bootstrap. Results indicate that for shorter durations, the investigated series generally exhibit increasing trends while as longer durations are considered, more and more series exhibit decreasing trends.
Geomorphological features and monitoring of a large and complex landslide near Avigliano urban area (South Italy)
Authors: Sdao F. , Pascale S. , Rutigliano P.
Published: April 2010

Abstract. This paper reports the results of geological and geomorphological surveys and the first results of a still in progress GPS monitoring campaign, taken on a large and ancient landslide located near Avigliano town (Basilicata region, South Italy). The landslide occurs on structurally complex clayey-marly terrains and it is classifiable as a multiple and complex roto-translational-earthflow landslide. In the last years this landslide has been affected by frequent reactivations that have been the cause of grave damages to the urban structures in the area. During January 2004, in order to monitor the present kinematics of the landslide body, a GPS network was installed. Until today several GPS surveys have been carried out. The results of GPS data analysis show centimetres level motions going on the landslide. The final goal of the research will be to define a hazard evaluation and an evolution model of the landslide, using the integrated information coming from GPS and geomorphological surveys.
Rain microstructure retrievals using 2-D video disdrometer and C-band polarimetric radar
Authors: Thurai M. , Bringi V. N. , Petersen W. A.
Published: April 2010

Abstract. Measurements using the 2-D video disdrometer (2DVD) taken during a heavy rainfall event in Huntsville, Alabama, are analysed. The 2DVD images were processed to derive the rain microstructure parameters for each individual drop, which in turn were used as input to the T-matrix method to compute the forward and back scatter amplitudes of each drop at C-band. The polarimetric radar variables were then calculated from the individual drop contribution over a finite time period, e.g., 1 min. The calculated co-polar reflectivity, differential reflectivity, specific differential propagation phase and the co-polar correlation coefficient were compared with measurements from a C-band polarimetric radar located 15 km away. An attenuation-correction method based on the specific differential propagation phase was applied to the co-polar and differential reflectivity data from the C-band radar, after ensuring accurate radar calibration. Time series comparisons of the parameters derived from the 2DVD and C-band radar data show very good agreement for all four quantities, the agreement being sometimes better than the computations using the 1-min drop size distribution and bulk assumptions on rain microstructure (such as mean shapes and model-based assumptions for drop orientation). The agreement is particularly improved in the case of co-polar correlation coefficient since this parameter is very sensitive to variation of shapes as well as orientation angles. The calculations mark the first attempt at utilizing experimentally derived "drop- by-drop" rain microstructure information to compute the radar polarimetric parameters and to demonstrate the value of utilizing the 2-D video disdrometer for studying rain microstructure under various precipitation conditions. Histograms of drop orientation angles as well as the most probable drop shapes and the corresponding variations were also derived and compared with prior results from the 80 m fall "artificial rain" experiment.
Relationship between forecast precipitation relative errors and skill scores: the case of rare event frequencies
Authors: Tartaglione N.
Published: April 2010

Abstract. This paper addresses the problem of the relationship between skill scores and forecast rainfall relative errors. The problem is approached by using synthetic time series of rainfall data representing the observations. It is assumed that the magnitude of the relative error is known. The forecasts are constructed by adding errors to the observations. We use a threshold to dichotomise forecasts and observations to obtain the skill scores. We perform 1000 simulations for each error magnitude in order to obtain the mean values and uncertainties of the scores. We consider two different precipitation regimes, and we show the influence of these regimes on the precipitation. We find that the relationship between forecast errors and skill scores is strongly influenced by the event frequencies, which in turn depend on the precipitation regime. We find that only when the event frequency of the two regimes is made similar by changing the threshold, the relationship between the scores and relative errors is similar. This suggests that a comparison between two forecast precipitation datasets should account for the difference (if any) in precipitation regimes.
Intensity-dependent parameterization of elevation effects in precipitation analysis
Authors: Haiden T. , Pistotnik G.
Published: April 2010

Abstract. Elevation effects in long-term (monthly to inter-annual) precipitation data have been widely studied and are taken into account in the regionalization of point-like precipitation amounts by using methods like external drift kriging and cokriging. On the daily or hourly time scale, precipitation-elevation gradients are more variable, and difficult to parameterize. For example, application of the annual relative precipitation-elevation gradient to each 12-h sub-period reproduces the annual total, but at the cost of a large root-mean-square error. If the precipitation-elevation gradient is parameterized as a function of precipitation rate, the error can be substantially reduced. It is shown that the form of the parameterization suggested by the observations conforms to what one would expect based on the physics of the orographic precipitation process (the seeder-feeder mechanism). At low precipitation rates, orographic precipitation is "conversion-limited", thus increasing roughly linearly with precipitation rate. At higher rates, orographic precipitation becomes "condensation-limited" thus leading to an additive rather than multiplicative orographic precipitation enhancement. Also it is found that for large elevation differences it becomes increasingly important to take into account those events where the mountain station receives precipitation but the valley station remains dry.