966 research outputs found
Limited Area Numerical Weather Prediction
No full textTwo limited area model derivatives of the numerical weather prediction model COSMO-DE operated by the German Meteorological Service are introduced. The aim is to obtain frequently updated highly re-solved predictions in a limited area as an aerodrome. The predictions include dynamic parameters as wind and turbulence kinetic energy and thermodynamic quantities as temperature and humidity but also the amount of snow, rain and hail. The models are used in the airport environments of Frankfurt (COSMO-FRA) and Munich (COSMO-MUC) for aircraft wake vortex, thunderstorm activity, and wintry weather warning applications, as detailed in Sections 2.1 to 2.4
Calculation of solvent shifts on electronic g-tensors with the conductor-like screening model (COSMO) and its self-consistent generalization to real solvents (Direct COSMO-RS)
No full textThe conductor-like screening model (COSMO) was used to investigate the solvent influence on electronic g-values of organic radicals. The previously studied diphenyl nitric oxide and di-tert-butyl nitric oxide radicals were taken as test cases. The calculations employed spin-unrestricted density functional theory and the BP and B3LYP density functionals. The g-tensors were calculated as mixed second derivative properties with respect to the external magnetic field and the electron magnetic moment. The first-order response of the Kohn−Sham orbitals with respect to the external magnetic field was determined through the coupled-perturbed DFT approach. The spin−orbit coupling operator was treated using an accurate multicenter spin−orbit mean-field (SOMF) approach. Provided that important hydrogen bonds are explicitly modeled by a supermolecule approach and that the basis set is sufficiently saturated, the COSMO calculations lead to accurate predictions of isotropic g-shifts with deviations of not more than 100 ppm relative to experiment. Very accurate results were obtained by employing a recently developed self-consistent modification of the COSMO method to real solvents (COSMO-RS), which we briefly introduce in this paper as direct COSMO-RS (D-COSMO-RS). This model gives isotropic g-shifts of similar high accuracy for water without using the supermolecule approach. This is an important result because it solves many of the problems associated with the supermolecule approach such as local minima and the choice of a suitable model system. Thus, the self-consistent D-COSMO-RS incorporates some specific solvation effects into continuum models, in particular it appears to successfully model the effects of hydrogen bonding. Although not yet widely validated, this opens a novel approach for the calculation of properties which so far only could be calculated by the inclusion of explicit solvent molecules in continuum solvation methods
Postseismic Deformation Monitoring With the COSMO/SKYMED Constellation
No full textCOSMO/SKYMED is currently the unique constellation of synthetic aperture radar (SAR) sensors operative, which is also for civilian use. On April 6, 2009, an Mw 6.3 earthquake struck the city of l'Aquila in Central Italy. The constellation acquired data stacks over the hit area at an unprecedented temporal rate. In this letter, the results obtained by processing several data set via two independent multitemporal differential interferometric SAR techniques are presented to demonstrate the capability of this constellation in postseismic deformations monitoring
The COSmic Monopole Observer (COSMO)
No full textThe COSmic Monopole Observer (COSMO) is an experiment to measure low-level spectral distortions in the isotropic component of the Cosmic Microwave Background (CMB). Deviations from a pure blackbody spectrum are expected at low level (< 1 ppm) due to several astrophysical and cosmological phenomena, and promise to provide important independent information on the early and late phases of the universe. They have not been detected yet, due to the extreme accuracy required, the best upper limits being still those from the COBE-FIRAS mission. COSMO is based on a cryogenic differential Fourier Transform Spectrometer, measuring the spectral brightness difference between the sky and an accurate cryogenic blackbody. The first implementation of COSMO, funded by the Italian PRIN and PNRA programs, will operate from the Concordia station at Dome-C, in Antarctica, and will take advantage of a fast sky-dip technique to get rid of atmospheric emission and its fluctuations, separating them from the monopole component of the sky brightness. Here we describe the instrument design, its capabilities, the current status. We also discuss its subsequent implementation in a balloon-flight, which has been studied within the COSMOS program of the Italian Space Agency
COSMO-SkyMed Full Constellation Orbital Flexibility and Interferometric Capabilities
No full textCOSMO-SkyMed is an Earth Observation space program funded by the Italian Ministry of Research and Italian Ministry of Defence (It-MoD) and conducted by the Italian Space Agency (ASI) in conjunction with It-MoD. In November 2010 the fourth and last COSMO-SkyMed satellite was successfully launched and integrated into the constellation after the positive conclusion of the commissioning phase in January 2011. The four satellites are placed in the same sun-synchronous dawn-dusk frozen orbit, designed in such a way to fulll dual needs and to optimize the performances for a wide range of Civilian applications (e.g. risks management, agriculture/forestry, marine/coastal, geology) and Defence applications (surveillance, intelligence, crisis management, mission planning). Currently the orbital configuration is composed of three satellites (namely PFM, FM#2 and FM#4) with a dierence of 90 deg in their respective anomalies, and a fourth satellite (namely FM#3) in tandem-like conguration with FM#2 (i.e. one-day temporal decorrelation). The aim of this paper is to analyze the orbital fexibility of COSMO-
SkyMed constellation by performing a survey of the possible orbital interferometric congurations which could be achieved by the full COSMO-SkyMed constellation (e.g. tandem, tandem-like, double one-day tandem conguration, etc), focusing on their main features (e.g. interferometric data takes opportunities, temporal decorrelation, degradation of the temporal performances respect to the nominal equi-phased conguration, etc), highlighting the propellant required for orbital conguration changes and the ways to minimize it, associating them with the main state-of-the-art Civilian and Defence applications that would benefit from them and providing a preliminary quantitative assessment of the interferometric products quality improvement for each orbital configuration
Cosmo/Skymed AO Projects – Advanced 2D and 3D Focusing of Cosmo/Skymed SAR Data
No full textWe present a research project, funded by the Italian Space Agency (ASI), aimed at performing 2D and 3D Focusing of COSMO/SkyMed (CSK) SAR Data. We describe the main objectives of the project, briefly illustrate employed techniques, and finally present the obtained results. The latter show that sub-meter resolution can be achieved in the enhanced spotlight CSK acquisition mode, and that by using 3D focusing it is possible to resolve scatterers at different slant heights within the same range-azimuth resolution cell, even in areas characterized by severe height discontinuities and large thermal dilations effects
Italian COSMO-SkyMed atlas: R-Index and the percentage of measurability of movement
No full textSAR (Synthetic Aperture Radar) satellite interferometry is a helpful remote sensing technique for large areas analyses and monitoring, especially where the study area is difficult to access for practical or for legal reasons. As a result, the use of these techniques has significantly increased over the past three decades. Among the available different satellite constellations displaying different spatial and temporal resolutions, COSMO-SkyMed of the Italian Space Agency (ASI) represents a cutting-edge reality. COSMO-SkyMed constellation, launched in 2007 by ASI, is a valuable Earth observation tool that provides all-weather, day-and-night imaging capabilities with high resolution and a short revisit time. In this study, we produced an atlas for the entire Italian peninsula using two parameters (R-Index and Percentage of measurability of movement), in order to evaluate the quality and a-priori applicability of satellite interferometry data collected by the COSMO-SkyMed constellation. The atlas was obtained by means of the implementation of different model builders in the GIS (Geographical Information Systems) environment, providing a semi-automatic way to generate the above-mentioned outputs. The R-Index describes the likelihood of detecting Permanent Scatterers in mountainous areas, while the Percentage of measurability of movement indicates the percentage of real motion that interferometry can detect at a certain point in the analyzed region. A high-detail Digital Terrain Model (DTM) has been used to identify the most suitable areas for satellite interferometry monitoring and studying. The results of our analysis showed that the R-Index and the Percentage of measurability of movement could be used to pre-evaluate the quality of satellite interferometry data collected by the COSMO-SkyMed constellation. This research has important implications for disaster response, environmental monitoring, and scientific research and is one of a few cases in the world in which a unified representation for an entire country is provided
La fine dell'uomo all'inizio del mondo: principio di pienezza e unigenita natura a partire dal Timeo
No full textScopo di questo saggio è mostrare come, sin dal primo racconto filosofico della cosmogenesi, il Timeo di Platone, l’uomo non risulti necessario né alla nascita né alla durata dell’universo. Per farlo, si sfrutterà la doppia lettura, letterale e metaforica, dell’aggettivo “genetós”, assegnato all’universo sulla base della celeberrima sequenza di Tim., 28 b 1-7 (generato come cominciato nel tempo, generato come causato) e la doppia lettura, di nuovo letterale e metaforica, del sostantivo “dēmiourgós” (demiurgo come artefice, demiurgo come essere). In entrambi i casi, infatti, l’interpretazione metaforica permette di rimpiazzare il punto di vista umano sulla genesi del cosmo (il cosmo è nato nel senso che ha un inizio temporale) e sulla sua causa (il cosmo è stato generato da un artefice come il figlio dal padre e dalla madre o come l’artefatto dall’artigiano) con quello integralmente naturale sugli stessi. Assumendolo, si ha che il cosmo è causato e che la sua causa, sebbene da esso sia distinta, pure non gli è del tutto esterna. In altre parole, la lettura letterale del Timeo è una lettura che interpreta l’ordine morfogenetico del cosmo come qualcosa di trascendente rispetto ad esso perché impostogli da una volontà buona ma umana troppo umana; quella metaforica, di contro, interpreta lo stesso ordine come immanente all’universo, ossia come l’intrinseca legge della sua stessa autoproduzione. Nel primo caso, cioè, l’ordine del cosmo è l’ordine del greco “kósmos”; nel secondo, quello spinoziano indistinguibile dalla textura o connexio rerum.
Per attingere il livello metaforico, tuttavia, è indispensabile: 1. Interpretare l’uscita di scena del demiurgo in Tim., 42 e 7-8; 2. Ridefinire il senso del sostantivo dēmiourgós; 3. Fare un’ipotesi sulla natura di ciò che è presente in Chṓra prima dell’intervento del dio buono (Tim., 52 d 6 – 53 b 7) e, altresì, su quella dei corpi che vi circolano perennemente (Tim., 49 a 5 - 52 d 1). Gli alleati di cui questa impresa può giovarsi sono, invece, quei filosofi che, come Bruno, Spinoza e Whitehead, hanno variamente: 1) giurato contro il dualismo delle sostanze detto anche “biforcazione della natura”; 2) abbandonato una concezione solo difettiva della donna-materia in favore di una attiva ; 3) preferito un modello autoerotico o batteriologico della generazione incentrato sull’autosufficienza della natura a uno solo edipico di stampo prevalentemente artigianale e sessuale; 4) pensato il divenire come processo senza opporlo all’essere; 5) rinunciato all’opposizione tra ordine e disordine, isomorfa, insegna Bergson nel quarto capitolo dell’Evoluzione creatrice a quella tra essere e nulla; 6) scommesso sull’immanenza delle idee – l’ordine – alle cose – la natura
COSMO-SkyMed Constellation Configurations: Current Status and Possible Evolutions
No full textCOSMO-SkyMed is an Earth Observation space programme funded by the Italian Ministry of Research and Italian Ministry of Defence (It-MoD) and conducted by the Italian Space Agency (ASI) in conjunction with It-MoD.
In November 2010 the fourth and last COSMO-SkyMed satellite was successfully launched. It was integrated into the operational constellation after the positive conclusion of the commissioning phase in January 2011.
The four satellites are placed in the same sun-synchronous dawn-dusk frozen orbit, designed in such a way to fulfil dual needs and to optimize the performances for a wide range of Civilian applications (e.g. risks management, agriculture/forestry, marine/coastal, geology) and Defence applications (surveillance, intelligence, crisis management, mission planning). The baseline four-satellite constellation configuration foresees that the satellites are placed on the same orbital plane with a difference of 90, 180, 270 and 360 deg in their respective anomalies.
Currently the orbital configuration is composed of three satellites (namely PFM, FM#2 and FM#4) placed with a difference of 0, 180, and 270 deg in their respective anomalies, while a fourth satellite
(namely FM#3) is placed in a tandem-like configuration with FM#2 (i.e. one-day temporal decorrelation).
The aim of this paper is to analyze the orbital flexibility of COSMO-SkyMed constellation by performing a survey of the possible orbital interferometric configurations which could be achieved by the full COSMO-SkyMed constellation (e.g. tandem, tandem-like, double one-day tandem configuration, etc), focusing on their main features (e.g. temporal decorrelation, degradation of the temporal performances respect to the nominal equi-phased configuration, etc), highlighting the manoeuvres required for orbital configuration changes
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