http://hdl.handle.net/2122/86 Ricerca nel canale cerca http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/5315 Titolo: An Intercomparison of Precipitable Water Vapor Measurements Obtained During the ECOWAR Field Campaign<br/><br/>Autori: 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.; Dipartimento di Ingegneria e Fisica dell'Ambiente, Università della Basilicata, Potenza, Italy; Esposito, F.; Dipartimento di Ingegneria e Fisica dell'Ambiente, Università della Basilicata, Potenza, Italy; Grieco, G.; Dipartimento di Ingegneria e Fisica dell'Ambiente, Università della Basilicata, Potenza, Italy; Summa, D.; Dipartimento di Ingegneria e Fisica dell'Ambiente, Università della Basilicata, Potenza, Italy; Bianchini, G.; Istituto di Fisica Applicata "Nello Carrara", IFAC-CNR, Sesto Fiorentino, Firenze, Italy; Palchetti, L.; Istituto di Fisica Applicata "Nello Carrara", IFAC-CNR, Sesto Fiorentino, Firenze, Italy; Cacciani, M.; Dipartimento di Fisica, Università di Roma "La Sapienza", Roma, Italy; Di Iorio, T.; Dipartimento di Fisica, Università di Roma "La Sapienza", Roma, Italy; Pavese, G.; Istituto di Metodologie per l’Analisi Ambientale, IMAA-CNR, Tito Scalo, Potenza, Italy; Cimini, D.; CETEMPS, Dipartimento di Fisica, Università di L’Aquila, L’Aquila, Italy; de Zafrah, R. L.; Department of Physics and Astronomy, and Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, U.S.A.<br/><br/>Abstract: In this study we present an intercomparison of measurements of very low water vapor column content obtained with a Ground-Based Millimeter-wave Spectrometer (GBMS), 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 ECOWAR (Earth COoling by WAter vapor Radiation) project which took place on the Western Italian Alps from 3 to 16 March, 2007. Wed, 11 Mar 2009 00:00:00 GMT http://hdl.handle.net/2122/4791 Titolo: Solubility of H2O and CO2 in ultrapotassic melts at 1200 °C and 1250 °C and pressure from 50 to 500 MPa<br/><br/>Autori: Behrens, H.; University of Hannover; Misiti, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Freda, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Vetere, F.; Universià della Calabria; Botcharnikov, R. E.; University of Hannover; Scarlato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: The solubility of H2O-CO2 fluids in a synthetic analogue of a phono-tephritic lava composition from Alban Hills (Central Italy) was experimentally determined from 50 to 500 MPa and 1200 and 1250°C. H2O and CO2 contents in experimental glasses were determined by bulk analytical methods and FTIR spectroscopy. For the quantification of volatile concentrations by IR spectroscopy we have calibrated the absorption coefficients of water-related and carbon-related bands for phono-tephritic compositions. The determined absorption coefficients are 0.62 ± 0.06 L mol-1cm-1 for the band at ~4500 cm-1 (OH groups) and 1.02 ± 0.03 L mol-1cm-1 for the band at ~5200 cm-1 (H2O molecules). The coefficient for the fundamental OH stretching vibration at 3550 cm-1 is 63.9 ± 5.4 L mol-1cm-1. CO2 is bound in the phono-tephritic glass as CO32- exclusively; its concentration was quantified by the peak height of the doublet near the 1500 cm-1 band with the calibrated absorption coefficient of 308 ± 110 L mol-1cm-1. Quench crystals were observed in glasses with water contents exceeding 6 wt% even when using a rapid quench device, limiting the application of IR spectroscopy for water-rich glasses.H2O solubility in the ultrapotassic melts (7.52 wt% K2O) as a function of pressure is similar to the solubility in basaltic melts up to 400 MPa (~8 wt%) but is higher at 500 MPa (up to 10.71 wt%). At 500 MPa and 1200°C, the CO2 capacity of the phono-tephritic melt is about 0.82 wt%. The high CO2 capacity is probably related to the high K2O content of the melt. At both 200 and 500 MPa, the H2O solubility shows a non linear dependence on XfH2O in the whole XfH2O range. The variation of CO2 solubility with XfCO2 displays a pronounced convex shape in particular at 500 MPa, implying that dissolved H2O promotes the solubility of CO2.Our experimental data on CO2 solubility indicate that the interaction between phono-tephritic magma and carbonate rocks occurring in the Alban Hills magmatic system may result in partial dissolution of CO2 from limestone into the magma. However, although the CO2 solubility in phono-tephritic melts is relatively high compared to that in silicic to basaltic melts, the capacity for assimilation of limestone without degassing is nevertheless limited to < 1 wt% at the P-T conditions of the magma chamber below Alban Hills. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/2122/4165 Titolo: EFFECTS OF ENERGETIC SOLAR PARTICLES ON OZONE AND MINOR ATMOSPHERIC COMPONENTS INSIDE THE POLAR REGIONS<br/><br/>Autori: Damiani, A.; INAF-IFSI<br/><br/>Abstract: Solar activity influences the Earth’s environment, in particular the atmosphericozone, by the direct output of the e.m. radiation or through the variability of theincoming cosmic ray flux (solar and galactic particles). Especially energetic particles,arising from huge explosions on the Sun’s surface, travel in the interplanetarymedium and, if the circumstances were favorable, they could enter the terrestrialatmosphere (driven by the geomagnetic field lines of our planet) and reach the polarcap regions (geomagnetic latitude > 60°). There, they provide additional externalenergy and are able to produce ionizations, dissociations, dissociative ionizationsand excitations phenomena by interacting with the minor constituents. The inducedchanges are not confined to the ion chemistry but also to the neutral components. Inthis way a rise of the concentration of HOx and NOx species and the triggering ofcatalytic cycles which lead to short (hours) and medium (days) term ozonedestruction 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 atmosphereduring and after some Solar Energetic Particle (SEP) events recorded during thecurrent solar cycle. Special attention has been paid to the relationship betweenozone and HOx data (retrieved from the Microwave Limb Sounder of EOS AURAsatellite) for four events referred to 2005. The HOx data, recorded for the first timeduring the intense ionization caused by the SEP flux, have pointed out some featuresrelated to these phenomena not wholly captured by the current theoretical models. Inaddition, they have highlighted that the HOx rise is able to destroy the so-called thirdozone peak at the polar latitudes of the winter hemisphere and it occurs also duringmedium intensity events. Besides, the analyses of January 2005 SEP events haveshown that the changes on the hydrogen species leaded to variability in theconcentration and partitioning of chlorine family, not discernible in the summerhemisphere. Further, the use of data coming from the HALOE instrument, referred toSEP events occurred in July 2000 and April 2002, has in short confirmed pastexperimental results. Finally, the study of a little SEP event occurred during May 2003has pointed out that SEP events are not the unique ionization source inside the polarlatitudes during the winter. Sat, 01 Dec 2007 00:00:00 GMT http://hdl.handle.net/2122/4000 Titolo: 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/>Autori: 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 theGround-Based Millimeter wave Spectrometer (GBMS) are discussed. Low amounts ofcolumn water vapor (between 0.5 and 4 mm) are typical of high mountain sites and polarregions, especially during winter, and are difficult to measure accurately because of thelack of sensitivity of conventional instruments to such low PWV contents. Thetechnique used involves the measurement of atmospheric opacity in the range between230 and 280 GHz with a spectral resolution of 4 GHz, followed by the conversion toprecipitable water vapor using a linear relationship. We present the intercomparison of thisdata set with simultaneous PWV observations obtained with Vaisala RS92kradiosondes, a Raman lidar, and an IR Fourier transform spectrometer. These sets ofmeasurements were carried out during the primary field campaign of the Earth Coolingby 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 withthe other three data sets exhibiting a mean difference between observations of 9%. Theconsiderable number of data points available for the GBMS versus lidar PWVcorrelation allows an additional analysis which indicates negligible systematicdifferences between the two data sets. Tue, 01 Jul 2008 00:00:00 GMT http://hdl.handle.net/2122/3524 Titolo: Validation of the Aura Microwave Limb Sounder HNO3 Measurements<br/><br/>Autori: 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 theMicrowave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLSHNO3 product has been greatly improved over that in the previous version (v1.5), withsmoother profiles, much more realistic behavior at the lowest retrieval levels, andcorrection of a high bias caused by an error in one of the spectroscopy files used in v1.5processing. 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 theupper troposphere and lower stratosphere, degrading to 5 km in the middle andupper stratosphere. The impact of various sources of systematic uncertainty has beenquantified through a comprehensive set of retrieval simulations. In aggregate, systematicuncertainties are estimated to induce in the v2.2 HNO3 measurements biases that vary withaltitude between ±0.5 and ±2 ppbv and multiplicative errors of ±5–15% throughout thestratosphere, rising to ±30% at 215 hPa. Consistent with this uncertainty analysis,comparisons with correlative data sets show that relative to HNO3 measurements fromground-based, balloon-borne, and satellite instruments operating in both the infraredand microwave regions of the spectrum, MLS v2.2 HNO3 mixing ratios are uniformly lowby 10–30% throughout most of the stratosphere. Comparisons with in situ measurementsmade from the DC-8 and WB-57 aircraft in the upper troposphere and lowermoststratosphere indicate that the MLS HNO3 values are low in this region as well, but areuseful for scientific studies (with appropriate averaging). Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/2122/3060 Titolo: 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. Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/2122/2796 Titolo: Degassing of gaseous (elemental and reactive) and particulate mercury from Mount Etna volcano (Southern Italy)<br/><br/>Autori: Bagnato, E.; Università di Palermo, Dipartimento CFTA; Aiuppa, A.; Università di Palermo, Dipartimento CFTA; Parello, F.; Università di Palermo, Dipartimento CFTA; Calabrese, S.; Università di Palermo, Dipartimento CFTA; D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Mather, T. A.; Department of Earth Sciences, University of Oxford, UK; McGonigle, A. J. S.; Department of Geography, University of Sheffield, UK; Pyle, D. M.; Department of Earth Sciences, University of Oxford, UK; Wängberg, I.; IVL-Swedish Environmental Research Institute, Göteborg, Sweden<br/><br/>Abstract: There is an urgent need to better constrain the global rates of mercury degassing from natural sources, including active volcanoes. Hitherto, estimates of volcanic fluxes have been limited by the poorly-determined speciation of Hg in volcanic emissions. Here, we present a systematic characterisation of mercury partitioning between gaseous (Hg(g)) and particulate (Hg(p)) forms in the volcanic plume of Mount Etna, the largest open-vent passively degassing volcano on Earth. We demonstrate that mercury transport is predominantly in the gas-phase, with a mean Hg(p)/Hg(g) ratio of ∼0.01 by mass. We also present the first simultaneous measurement of divalent gaseous mercury (HgII(g)) and total gaseous mercury (Hg(g)) in a volcanic plume, which suggests that Hg0(g) is the prevalent form of mercury in this context. These data are supported by the results of model simulations, carried out with HSC thermodynamic software. Based on a mean ‘bulk plume’ Hg/SO2 mass ratio of 8.7×10-6, and a contemporaneous volcanic SO2 flux of 0.8 Mt·yr-1, we estimate an Hg emission rate from Mt. Etna during passive degassing of 5.4 t·y-1 (range, 1.1-10 t·y-1). This corresponds to ~0.6% of global volcanic Hg emissions, and about 5% of Hg released from industrial activities in the Mediterranean area. Thu, 01 Nov 2007 00:00:00 GMT http://hdl.handle.net/2122/2662 Titolo: Assessment of temperature, trace species, and ozone in chemistry-climate model simulations of the recent past<br/><br/>Autori: Eyring, V.; Institut fu¨ r Physik der Atmospha¨re, Deutsches Zentrum fu¨ r Luft- und Raumfahrt, Oberpfaffenhofen, Wessling, Germany; Butchart, N.; Climate Research Division, Met Office, Exeter, UK.; Waugh, D. W.; Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, USA.; Akiyoshi, H.; National Institute for Environmental Studies, Tsukuba, Japan.; Austin, J.; Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA.; Bekki, S.; Service d’Ae´ronomie du Centre National de la Recherche Scientifique, Paris, France.; Bodeker, G. E.; National Institute of Water and Atmospheric Research, Lauder, New Zealand.; Boville, B.; National Center for Atmospheric Research, Boulder, Colorado, USA.; Brühl, C.; Max Planck Institut fu¨ r Chemie, Mainz, Germany.; Chipperfield, M.; Institute for Atmospheric Science, University of Leeds, Leeds, UK.; Cordero, E.; Department of Meteorology, San Jose State University, San Jose, California, USA.; Dameris, M.; Institut fu¨ r Physik der Atmospha¨re, Deutsches Zentrum fu¨ r Luft- und Raumfahrt, Oberpfaffenhofen, Wessling, Germany; Frith, S. M.; Science Systems and Applications, Inc., Lanham, Maryland, USA.; Garcia, A.; National Center for Atmospheric Research, Boulder, Colorado, USA.; Gettelman, A.; National Center for Atmospheric Research, Boulder, Colorado, USA.; Giorgetta, M.; Max Planck Institut fu¨ r Meteorologie, Hamburg, Germany.; Grewe, V.; Institut fu¨ r Physik der Atmospha¨re, Deutsches Zentrum fu¨ r Luft- und Raumfahrt, Oberpfaffenhofen, Wessling, Germany; Jourdain, L.; Service d’Ae´ronomie du Centre National de la Recherche Scientifique, Paris, France.; Kinnison, D. E.; National Center for Atmospheric Research, Boulder, Colorado, USA.; Manzini, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia<br/><br/>Abstract: Simulations of the stratosphere from thirteen coupled chemistry-climate models(CCMs) are evaluated to provide guidance for the interpretation of ozone predictions madeby the same CCMs. The focus of the evaluation is on how well the fields andprocesses that are important for determining the ozone distribution are represented in thesimulations of the recent past. The core period of the evaluation is from 1980 to 1999but long-term trends are compared for an extended period (1960–2004). Comparisons ofpolar high-latitude temperatures show that most CCMs have only small biases in theNorthern Hemisphere in winter and spring, but still have cold biases in the SouthernHemisphere spring below 10 hPa. Most CCMs display the correct stratospheric responseof polar temperatures to wave forcing in the Northern, but not in the SouthernHemisphere. Global long-term stratospheric temperature trends are in reasonableagreement with satellite and radiosonde observations. Comparisons of simulations ofmethane, mean age of air, and propagation of the annual cycle in water vapor show a widespread in the results, indicating differences in transport. However, for around half themodels there is reasonable agreement with observations. In these models the mean age ofair and the water vapor tape recorder signal are generally better than reported in previousmodel intercomparisons. Comparisons of the water vapor and inorganic chlorine (Cly)fields also show a large intermodel spread. Differences in tropical water vapor mixingratios in the lower stratosphere are primarily related to biases in the simulated tropicaltropopause temperatures and not transport. The spread in Cly, which is largest in the polarlower stratosphere, appears to be primarily related to transport differences. In general theamplitude and phase of the annual cycle in total ozone is well simulated apart from thesouthern high latitudes. Most CCMs show reasonable agreement with observed total Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/2122/2571 Titolo: Seismicity and crustal structure in the Italian region: a new review using a synthesis of DSS results and updated catalogues of earthquakes<br/><br/>Autori: Cassinis, R.; Viale Lombardia 30, 20131 Milano, Italy; Solarino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia<br/><br/>Abstract: Both historical and instrumental updated catalogues of the earthquakes in the Italianregion, are used to compare the location of the epicentres and the focal depth ofseismic events with the structure of the Earth crust as determined by the Deep SeismicSoundings (DSS) and according to a published interpretative synthesis. In the past,several attempts were made to do this on the same subject; however, the investigationsconcerned only some areas of the region, when both the seismic activity and theinterpretation of DSS profiles were often based upon inhomogeneous or preliminarydata. In this work, we profit from the most recent and complete database of Italianseismicity, to extend the study to the whole peninsula. The comparison confirms thatthe seismicity occurs more frequently where structural changes are observed by theDSS profiles. The main activity seems to originate in the upper, brittle crust;nevertheless, even the shallow events are particularly concentrated where tectonicfeatures were discovered in the lower crust or at the Moho boundary. The hypocenterstend to deepen where a process of active subduction is occurring. It is believed that theresults described herewith could be used as additional elements for the study ofseismogenesis. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/2122/2492 Titolo: Isotopic composition of the precipitations in the central Mediterranean: origin marks and orographic precipitation effects<br/><br/>Autori: Liotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Valenza, M.; Dipartimento di Chimica e Fisica della Terra, Universita` degli Studi di Palermo, Palermo, Italy.<br/><br/>Abstract: The isotopic composition of the rainfall in northwestern Sicily (Italy, centralMediterranean) was investigated in the period February 2002 to March 2003. A rain gaugenetwork was installed and sampled monthly. The monthly values of the D and 18O ratiosshowed a wide range that reflected seasonal climatic variations. Mean weightedvalues were used to define an isotopic model of precipitation. Temporal variations indeuterium excess were also investigated. Using mean volume weighted values, the LocalMeteoric Water Line (LMWL) can be represented by the equation: dD = 4.7d18O 8.2(r2 = 0.96). Deuterium excess (d = dD 8d18O) was found to be strongly related toorography. The coastline samples were characterized by mean weighted deuterium excessvalues close to 12.5%; samples from inland areas showed values of 16%, while samplestaken from the main reliefs showed values close to 19%. In inland areas, isotopicexchange between raindrops and moisture could shift the deuterium excess values slightly.On the higher reliefs, the interaction between falling raindrops and orographic cloudscould shift the deuterium excess values significantly. The low slope of the LMWL couldbe referred to the high deuterium excess values of the higher sites and is related toorographic precipitation rather than to evaporation processes during the fall of theraindrops. The results obtained suggest that local orographic features may significantlychange the isotopic composition of precipitation. Sun, 01 Jan 2006 00:00:00 GMT