http://hdl.handle.net/2122/86 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4165 Title: EFFECTS OF ENERGETIC SOLAR PARTICLES ON OZONE AND MINOR ATMOSPHERIC COMPONENTS INSIDE THE POLAR REGIONS <br/> <br/>Authors: Damiani, A.; INAF-IFSI <br/> <br/>Abstract: Solar activity influences the Earth’s environment, in particular the atmospheric ozone, by the direct output of the e.m. radiation or through the variability of the incoming cosmic ray flux (solar and galactic particles). Especially energetic particles, arising from huge explosions on the Sun’s surface, travel in the interplanetary medium and, if the circumstances were favorable, they could enter the terrestrial atmosphere (driven by the geomagnetic field lines of our planet) and reach the polar cap regions (geomagnetic latitude > 60°). There, they provide additional external energy and are able to produce ionizations, dissociations, dissociative ionizations and excitations phenomena by interacting with the minor constituents. The induced changes are not confined to the ion chemistry but also to the neutral components. In this way a rise of the concentration of HOx and NOx species and the triggering of catalytic cycles which lead to short (hours) and medium (days) term ozone destruction occur. Finally, also no-reactive reservoir species (e.g., HNO3, HCl, HOCl) are involved in these processes and endure large variations. The present thesis highlights the chemical variability of the middle atmosphere during and after some Solar Energetic Particle (SEP) events recorded during the current solar cycle. Special attention has been paid to the relationship between ozone and HOx data (retrieved from the Microwave Limb Sounder of EOS AURA satellite) for four events referred to 2005. The HOx data, recorded for the first time during the intense ionization caused by the SEP flux, have pointed out some features related to these phenomena not wholly captured by the current theoretical models. In addition, they have highlighted that the HOx rise is able to destroy the so-called third ozone peak at the polar latitudes of the winter hemisphere and it occurs also during medium intensity events. Besides, the analyses of January 2005 SEP events have shown that the changes on the hydrogen species leaded to variability in the concentration and partitioning of chlorine family, not discernible in the summer hemisphere. Further, the use of data coming from the HALOE instrument, referred to SEP events occurred in July 2000 and April 2002, has in short confirmed past experimental results. Finally, the study of a little SEP event occurred during May 2003 has pointed out that SEP events are not the unique ionization source inside the polar latitudes during the winter. Wed, 28 Nov 2007 22:58:59 GMT http://hdl.handle.net/2122/4000 Title: Measurements of low amounts of precipitable water vapor by millimeter wave spectroscopy: An intercomparison with radiosonde, Raman lidar, and Fourier transform infrared data <br/> <br/>Authors: Fiorucci, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Di Girolamo, P.; Università della Basilicata; Esposito, F.; Università della Basilicata; Grieco, G.; Università della Basilicata; Summa, D.; Università della Basilicata; Bianchini, G.; Istituto di Fisica Applicata, CNR; Palchetti, L.; Istituto di Fisica Applicata, CNR; Cacciani, M.; Università di Roma "La Sapienza"; Di Iorio, T.; Università di Roma "La Sapienza"; Pavese, G.; Istituto di Metodologie per l'Analisi Ambientale, CNR; Cimini, D.; Università di L'Aquila; de Zafra, R.; State University of New York at Stony Brook <br/> <br/>Abstract: Observations of very low amounts of precipitable water vapor (PWV) by means of the Ground-Based Millimeter wave Spectrometer (GBMS) are discussed. Low amounts of column water vapor (between 0.5 and 4 mm) are typical of high mountain sites and polar regions, especially during winter, and are difficult to measure accurately because of the lack of sensitivity of conventional instruments to such low PWV contents. The technique used involves the measurement of atmospheric opacity in the range between 230 and 280 GHz with a spectral resolution of 4 GHz, followed by the conversion to precipitable water vapor using a linear relationship. We present the intercomparison of this data set with simultaneous PWV observations obtained with Vaisala RS92k radiosondes, a Raman lidar, and an IR Fourier transform spectrometer. These sets of measurements were carried out during the primary field campaign of the Earth Cooling by Water vapor Radiation (ECOWAR) project which took place at Breuil-Cervinia (45.9N, 7.6E, elevation 1990 m) and Plateau Rosa (45.9N, 7.7E, elevation 3490 m), Italy, from 3 to 16 March 2007. GBMS PWV measurements show a good agreement with the other three data sets exhibiting a mean difference between observations of 9%. The considerable number of data points available for the GBMS versus lidar PWV correlation allows an additional analysis which indicates negligible systematic differences between the two data sets. Sat, 28 Jun 2008 22:58:59 GMT http://hdl.handle.net/2122/3524 Title: Validation of the Aura Microwave Limb Sounder HNO3 Measurements <br/> <br/>Authors: Santee, M. L.; JPL, California Institute of Technology, Pasadena, USA; Lambert, A.; JPL, California Institute of Technology, Pasadena, USA; Read, W. G.; JPL, California Institute of Technology, Pasadena, USA; Livesey, N. J.; JPL, California Institute of Technology, Pasadena, USA; Cofield, R. E.; JPL, California Institute of Technology, Pasadena, USA; Cuddy, D. T.; JPL, California Institute of Technology, Pasadena, USA; Daffer, W. H.; JPL, California Institute of Technology, Pasadena, USA; Drouin, B. J.; JPL, California Institute of Technology, Pasadena, USA; Froidevaux, L.; JPL, California Institute of Technology, Pasadena, USA; Fuller, R. A.; JPL, California Institute of Technology, Pasadena, USA; Jarnot, R. F.; JPL, California Institute of Technology, Pasadena, USA; Knosp, B. W.; JPL, California Institute of Technology, Pasadena, USA; Manney, G. L.; JPL, California Institute of Technology, Pasadena, USA; Perun, V. S.; JPL, California Institute of Technology, Pasadena, USA; Snyder, W. V.; JPL, California Institute of Technology, Pasadena, USA; Stek, P. C.; JPL, California Institute of Technology, Pasadena, USA; Thurstans, R. P.; JPL, California Institute of Technology, Pasadena, USA; Wagner, P. A.; JPL, California Institute of Technology, Pasadena, USA; Waters, J. W.; JPL, California Institute of Technology, Pasadena, USA; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia <br/> <br/>Abstract: We assess the quality of the version 2.2 (v2.2) HNO3 measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLS HNO3 product has been greatly improved over that in the previous version (v1.5), with smoother profiles, much more realistic behavior at the lowest retrieval levels, and correction of a high bias caused by an error in one of the spectroscopy files used in v1.5 processing. The v2.2 HNO3 data are scientifically useful over the range 215 to 3.2 hPa, with single-profile precision of 0.7 ppbv throughout. Vertical resolution is 3–4 km in the upper troposphere and lower stratosphere, degrading to 5 km in the middle and upper stratosphere. The impact of various sources of systematic uncertainty has been quantified through a comprehensive set of retrieval simulations. In aggregate, systematic uncertainties are estimated to induce in the v2.2 HNO3 measurements biases that vary with altitude between ±0.5 and ±2 ppbv and multiplicative errors of ±5–15% throughout the stratosphere, rising to ±30% at 215 hPa. Consistent with this uncertainty analysis, comparisons with correlative data sets show that relative to HNO3 measurements from ground-based, balloon-borne, and satellite instruments operating in both the infrared and microwave regions of the spectrum, MLS v2.2 HNO3 mixing ratios are uniformly low by 10–30% throughout most of the stratosphere. Comparisons with in situ measurements made from the DC-8 and WB-57 aircraft in the upper troposphere and lowermost stratosphere indicate that the MLS HNO3 values are low in this region as well, but are useful for scientific studies (with appropriate averaging). Sun, 29 Oct 2006 22:58:59 GMT http://hdl.handle.net/2122/3060 Title: Googas: catalogo on line delle principali emissioni gassose del territorio italiano <br/> <br/>Abstract: Googas is an on line database of the main gas emissions of the Italian territory. The database includes the results of researches done by INGV and by various Italian Universities in the framework of the INGV-DPC-V5 (2004-2006) named “Diffuse degassing in Italy”, founded by INGV and Italian Civil Defence. The database is accessible trough an interface based on Google Maps, which allows to locate the gas emissions on an on line georeferenced map. For each gas manifestation are available:1) name and coordinates; 2) image of the emission, 3) description of the gas emission, 4) type of gas emission, 5) main gas component (i.e. CO2, H2O, CH4, N2 etc.) and chemical and isotopic composition of gas (when available); 6) temperature, 7) gas flux magnitude, 8) method of gas flux measurement, 9) gas hazard, 10) scientific references,11) downloadable files and 11) contacts of researchers that have worked at the site. At this time (2007), the database includes data from 271 gas emissions of Italy. Googas è un catalogo on line delle principali emissioni gassose del territorio italiano. Il database è stato realizzato sulla base delle ricerche condotto dall’INGV e da varie università italiane nell’ambito del progetto INGV-DPC-V5 (2004-2006) “Diffuse degassing in Italy” finanziato dall’INGV e dal Dipartimento di Protezione Civile Italiana. Il database è accessibile attraverso una interfaccia basata su Google Maps che permette di localizzare le emissioni gassose sul territorio. Per ogni emissione gassosa è presente una scheda contenente: 1) nome e coordinate; 2) fotografia dell’emissione, 3) descrizione, 4) tipologia dell’emissione, 5) componente principale del gas (es.. CO2, H2O, CH4, N2 etc.) e composizione chimica ed isotopica (quando disponibile); 6) temperatura, 7) quantificazione del flusso di gas, 8) metodo di misura e stima del flusso, 9) pericolosità, 10) riferimenti bibliografici,11) materiale supplementare scaricabile e 11) contatti dei ricercatori che hanno studiato l’emissione gassosa. Al momento (2007), il database contiene dati relative a 271 emissioni gassose italiane. Sun, 29 Oct 2006 22:58:59 GMT