Stochastic background from extra dimensions

The existence of extra dimensions is a common feature in almost all quantum theories of gravity. These extra dimensions, whose size and number vary from theory to theory, have a signature on the gravitational stochastic background. Here we review the predictions of the individual theories and the hope of revealing such signals with earthbound detectors

The meteorological model RAMS at Crati Scrl

International audienceAt Crati Scrl an operational version of RAMS 4.3 (Regional Atmospheric Modeling System) was implemented in January 2001. This paper aims to give a first assessment of model performances for quantitative precipitation forecast (QPF). In essence, the effects of enhanced horizontal grid resolution over Calabria, using a 6km spacing domain nested in a 30km resolution parent grid, is studied. To cope with this problem two integrations sets are discussed using two model resolutions. Integrations are performed daily for six months. ECMWF 12:00UTC forecast cycle is used for initial and dynamic boundary conditions. Performances are evaluated by scores computed from model outputs and raingauge measurements coming from Calabrian regional network

The application of LEPS technique for Quantitative Precipitation Forecast (QPF) in Southern Italy

International audienceThis paper reports preliminary results of a Limited area model Ensemble Prediction System (LEPS), based on RAMS, for eight case studies of moderate-intense precipitation over Calabria, the southernmost tip of the Italian peninsula. LEPS aims to transfer the benefits of a probabilistic forecast from global to regional scales in countries where local orographic forcing is a key factor to force convection. To accomplish this task and to limit computational time, in order to implement LEPS operational, we perform a cluster analysis of ECMWF-EPS runs. Starting from the 51 members that forms the ECMWF-EPS we generate five clusters. For each cluster a representative member is selected and used to provide initial and dynamic boundary conditions to RAMS, whose integrations generate LEPS. RAMS runs have 12 km horizontal resolution. Hereafter this ensemble will be referred also as LEPS_12L30. To analyze the impact of enhanced horizontal resolution on quantitative precipitation forecast, LEPS_12L30 forecasts are compared to a lower resolution ensemble, based on RAMS that has 50 km horizontal resolution and 51 members, nested in each ECMWF-EPS member. Hereafter this ensemble will be also referred as LEPS_50L30. LEPS_12L30 and LEPS_50L30 results were compared subjectively for all case studies but, for brevity, results are reported for two "representative" cases only. Subjective analysis is based on ensemble-mean precipitation and probability maps. Moreover, a short summary of objective scores. Maps and scores are evaluated against reports of Calabria regional raingauges network. Results show better LEPS_12L30 performance compared to LEPS_50L30. This is obtained for all case studies selected and strongly suggests the importance of the enhanced horizontal resolution, compared to ensemble population, for Calabria, at least for set-ups and case studies selected in this work

Application of the LEPS technique for Quantitative Precipitation Forecasting (QPF) in Southern Italy: a preliminary study

International audienceThis paper reports preliminary results for a Limited area model Ensemble Prediction System (LEPS), based on RAMS (Regional Atmospheric Modelling System), for eight case studies of moderate-intense precipitation over Calabria, the southernmost tip of the Italian peninsula. LEPS aims to transfer the benefits of a probabilistic forecast from global to regional scales in countries where local orographic forcing is a key factor to force convection. To accomplish this task and to limit computational time in an operational implementation of LEPS, we perform a cluster analysis of ECMWF-EPS runs. Starting from the 51 members that form the ECMWF-EPS we generate five clusters. For each cluster a representative member is selected and used to provide initial and dynamic boundary conditions to RAMS, whose integrations generate LEPS. RAMS runs have 12-km horizontal resolution. To analyze the impact of enhanced horizontal resolution on quantitative precipitation forecasts, LEPS forecasts are compared to a full Brute Force (BF) ensemble. This ensemble is based on RAMS, has 36 km horizontal resolution and is generated by 51 members, nested in each ECMWF-EPS member. LEPS and BF results are compared subjectively and by objective scores. Subjective analysis is based on precipitation and probability maps of case studies whereas objective analysis is made by deterministic and probabilistic scores. Scores and maps are calculated by comparing ensemble precipitation forecasts against reports from the Calabria regional raingauge network. Results show that LEPS provided better rainfall predictions than BF for all case studies selected. This strongly suggests the importance of the enhanced horizontal resolution, compared to ensemble population, for Calabria for these cases. To further explore the impact of local physiographic features on QPF (Quantitative Precipitation Forecasting), LEPS results are also compared with a 6-km horizontal resolution deterministic forecast. Due to local and mesoscale forcing, the high resolution forecast (Hi-Res) has better performance compared to the ensemble mean for rainfall thresholds larger than 10mm but it tends to overestimate precipitation for lower amounts. This yields larger false alarms that have a detrimental effect on objective scores for lower thresholds. To exploit the advantages of a probabilistic forecast compared to a deterministic one, the relation between the ECMWF-EPS 700 hPa geopotential height spread and LEPS performance is analyzed. Results are promising even if additional studies are required

Hierarchical Hough all-sky search for periodic gravitational waves in LIGO S5 data

We describe a new pipeline used to analyze the data from the fifth science run (S5) of the LIGO detectors to search for continuous gravitational waves from isolated spinning neutron stars. The method employed is based on the Hough transform, which is a semi-coherent, computationally efficient, and robust pattern recognition technique. The Hough transform is used to find signals in the time-frequency plane of the data whose frequency evolution fits the pattern produced by the Doppler shift imposed on the signal by the Earth's motion and the pulsar's spin-down during the observation period. The main differences with respect to previous Hough all-sky searches are described. These differences include the use of a two-step hierarchical Hough search, analysis of coincidences among the candidates produced in the first and second year of S5, and veto strategies based on a $\chi^2$ test.Comment: 7 pages, 2 figures, Amaldi08 proceedings, submitted to JPC

Testing Theories of Gravity with a Spherical Gravitational Wave Detector

We consider the possibility of discriminating different theories of gravity using a recently proposed gravitational wave detector of spherical shape. We argue that the spin content of different theories can be extracted relating the measurements of the excited spheroidal vibrational eigenmodes to the Newman-Penrose parameters. The sphere toroidal modes cannot be excited by any metric GW and can be thus used as a veto.Comment: latex file, 16 pages, 1 figur

Numerical simulation of Crotone flood: Storm evolution

A nested-grid primitive equation model (RAMS, version 4.3) is used to simulate a high-precipitation (HP) storm which occurred in Calabria, Southern Italy. Storm produced intense rainfall over the city of Crotone, in the central Ionian coast of Calabrian peninsula, during the morning of 14 October 1996. Precipitation spell lasted for two hours, was highly localized and rainfall rates were intense (> 60 mm/h). The aim of this paper is to reproduce precipitation measured by raingauges and to highlight local and synoptic conditions that determined the storm, in order to acquire insight into the convective environment that produced the event. Four telescoping nested grids allow to simulate scales ranging from the synoptic scale down to the high-precipitation storm. All convection in the simulation is initiated by resolving explicitly vertical motion and subsequent condensation-latent heating from the model microphysics;no warm bubbles are used to start or trigger the storm. The model is able to well simulate measured precipitation both in terms of total precipitation and rain intensity. Also the position of the major spell is acceptable

Quantitative precipitation forecast of the Soverato flood: The role of orography and surface fluxes

During the night between 9 and 10 September 2000 a strong flood occurred in Soverato, a small town of Ionian coast of Calabria, killing 13 people. This was the top of an intense precipitation event occurred over the region during 8th, 9th, 10th September. In this paper the study of this event is performed, both analysing the synoptical aspects and using a numerical meteorological model either to reproduce the precipitation fields or to highlight some mesoscale features that determined the very intense and abundant rainfall. After a short description of the case study and presentation of measured rainfall fields, simulations are discussed. The study is based on three numerical simulations performed using the CSU-RAMS model (Regional mesoscale Modeling System) developed at Colorado State University and daily used at Crati Scrl to produce weather forecasts over Calabria peninsula. The first run is the control case and assesses the model ability to reproduce the flood cumulated rainfall by comparison with rain gauge data collected by the “Istituto Idrografico e Mareografico-Dipartimento di Catanzaro”. Second simulation is made to assess the influence of orographic barriers on the precipitation field, while third simulation evaluates the sensitivity to latent and sensible heat fluxes. Results indicate that the model simulate in satisfactory way the location and amount of rainfall, even if some problems are open and require more investigations

Villa Santa Maria a Potenza: un antico Orto Botanico

Si presenta una breve storia dell’Orto Botanico di Potenza, istituito nel 1823. Parte dell’area originale è attualmente un parco comunale denominato Villa Santa Maria. Viene quindi analizzata la situazione attuale e vengono delineate alcune prospettive per il futuro.A brief history of the Botanical Garden of Potenza, Italy, established in 1823 is presented. Part­ of the original area is presently a city park known as Villa Santa Maria. The current situation is then ana­ lysed and some perspectives for the future outlined