http://hdl.handle.net/2122/85 Wed, 22 May 2013 00:43:51 GMT 2013-05-22T00:43:51Z http://hdl.handle.net/2122/8488 Title: MISR observations of Etna volcanic plumes Authors: Scollo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Kahn, R. A.; Atmospheres Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA.; Nelson, D. L.; Raytheon Company, Pasadena, California, USA.; Coltelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Diner, D. J.; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.; Garay, M. J.; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.; Realmuto, V. J.; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA. Abstract: In the last twelve years, Mt. Etna, located in eastern Sicily, has produced a great number of explosive eruptions. Volcanic plumes have risen to several km above sea level and created problems for aviation and the communities living near the volcano. A reduction of hazards may be accomplished using remote sensing techniques to evaluate important features of volcanic plumes. Since 2000, the Multiangle Imaging SpectroRadiometer (MISR) on board NASA’s Terra spacecraft has been extensively used to study aerosol dispersal and to extract the three-dimensional structure of plumes coming from anthropogenic or natural sources, including volcanoes. In the present work, MISR data from several explosive events occurring at Etna are analyzed using a program named MINX (MISR INteractive eXplorer). MINX uses stereo matching techniques to evaluate the height of the volcanic aerosol with a precision of a few hundred meters, and extracts aerosol properties from the MISR Standard products. We analyzed twenty volcanic plumes produced during the 2000, 2001, 2002–03, 2006 and 2008 Etna eruptions, finding that volcanic aerosol dispersal and column height obtained by this analysis is in good agreement with ground-based observations. MISR aerosol type retrievals: (1) clearly distinguish volcanic plumes that are sulphate and/or water vapor dominated from ash-dominated ones; (2) detect even low concentrations of volcanic ash in the atmosphere; (3) demonstrate that sulphate and/or water vapor dominated plumes consist of smaller-sized particles compared to ash plumes. This work highlights the potential of MISR to detect important volcanic plume characteristics that can be used to constrain the eruption source parameters in volcanic ash dispersion models. Further, the possibility of discriminating sulphate and/or water vapor dominated plumes from ash-dominated ones is important to better understand the atmospheric impact of these plumes Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8488 2011-12-31T23:00:00Z http://hdl.handle.net/2122/7540 Title: Progetto vespa22: Misure presso laboratori Microwave Eurolab Authors: Bertagnolio, P. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Le misure sono state effettuate dal dott. Pietro Paolo Bertagnolio (Università di Siena-Scuola di Dottorato in Scienze Polari) e dal dott. Giovanni muscari (Istituto Nazionale di Geofisica e Vulcanologia-Sezione Roma 2), con la collaborazione e sotto la supervisione dell'ing. Elio Restuccia e Roberto Dal Molin (Istituto Superiore per le Comunicazioni e Tecnologie dell'Informazione) nei mesi di settembre e ottobre 2010. Scopo delle misure è la caratterizzazione accurata della risposta in frequenza e dei diagrammi di radiazione dell'antenna parabolica offset dello spettrometro per osservazioni atmosferiche vespa22 (water Vapour stratospheric Emission SPectrometer for Antarctica at 22 GHz) in sviluppo presso i laboratori dell'INGV di Roma. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/7540 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7539 Title: Changes in atmospheric composition discerned from long-term NDACC measurements: evolution of the winter stratosphere from Thule, Greenland, and the exceptional winters of 2008-2009 and 2010-2011. Authors: Di Biagio, C.; ENEA Centro Ricerche Casaccia - UTMEA, SP 091, via Anguillarese 301 I-00123 Roma (RM) ITALY; Bertagnolio, P. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cacciani, M.; Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma - Italy; di Sarra, A.; ENEA Centro Ricerche Casaccia - UTMEA, SP 091, via Anguillarese 301 I-00123 Roma (RM) ITALY; Eriksen, P.; Danish Meteorological Institute, Lyngbyvej 100, DK-2100 Copenhagen E, Denmark; Fuà, D.; Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185 Roma - Italy; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia Abstract: Several instruments are operational at Thule Air Base (76.5oN, 68.8oW) as part of the Network for Detection of Atmospheric Composition Change. A lidar was installed in 1990 and has been operational particularly during the winter season. Lidar measurements are used to derive the aerosol backscatter ratio between about 10 and 35 km, and the atmospheric temperature (T) profile from 25 up to 70 km, with a resolution of 150 m. A ground-based millimeter-wave spectrometer (GBMS) was installed at Thule in 2001, and has been operational during the winter seasons of 2001-2003 and 2009-2011. The GBMS permits to derive the atmospheric concentration profiles of different chemical species, such as O3, CO, N2O, and HNO3, between about 15 and 80 km at a resolution of 6-8 km. The Arctic winter stratosphere is characterized by a high variability, and detection of trends is particularly difficult. The evolution of the vortex and the temperatures in the lower stratosphere has a large impact on formation of Polar Stratospheric Clouds (PSC) and on the stratosphere chemical evolution. Coldest winters occurred in 1999-2000, and 2004-2005. Intensive measurement campaigns were conducted at Thule Air Base during winters 2008-2009 and 2010-2011. These two winters have been deeply different in their thermal, dynamical and chemical evolution. The 2008-2009 Arctic winter has been characterized by the most intense Sudden Stratospheric Warming (SSW) event ever observed, and the maximum of this warming was detected over Greenland. Thus, ground-based observations of the thermal structure and chemical composition of the middle atmosphere from the station at Thule Air Base have permitted to show the evolution of the phenomenon and its interactions with the dynamical structure of the polar vortex in the region of maximum warming. On the contrary, the 2010-2011 has been a very cold winter, and polar stratospheric clouds have been detected by lidar from mid-February to mid-March at Thule Air Base. This very cold winter, together with the massive formation of PSCs, has caused the record stratospheric ozone loss that is occurring in spring 2011 in the Arctic. In this study, we will present a summary of the measurements of the thermal and chemical stratospheric structure obtained at Thule Air Base between 1990 and 2011, with special attention to the two winters of 2008-2009 and 2010-2011. Sun, 23 Oct 2011 22:00:00 GMT http://hdl.handle.net/2122/7539 2011-10-23T22:00:00Z http://hdl.handle.net/2122/7411 Title: The development of a new 22 GHz microwave spectrometer for monitoring middle atmospheric water vapour at polar latitudes Authors: Bertagnolio, P. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Water vapour is a crucial element of the climate system. Accurate observations of stratospheric humidity are needed in the equatorial belt, where water vapour crosses the tropopause, and in the Polar regions, that are affected the most by climate change trends [IPCC, 2007; Solomon et al., 2010]. Satellite-based observations provide atmospheric composition data with extensive spatial and temporal coverage, but these need to be validated and integrated by ground-based networks like GAW and NDACC Changes in middle atmospheric water vapour on time scales longer than the a satellite mission have been successfully observed by ground-based instruments [Nedoluha et al., 2009]. Several ground-based spectrometers have been developed in the last decades to detect the water vapour rotational emission line at 22.235 GHz with heterodyne microwave receivers [e.g., Nedoluha et al., 2009; Straub et al., 2011, Forkman et al., 2003, De Wachter et al., 2011] (see map on the left). The proposed sites for long-term installation of the new spectrometer are Concordia Station, Antarctica (3233 m asl 75.10°S, 123.3°E, NDACC site) or Thule Air Base, Greenland (76.5°N, 68.8°W; NDACC site) for polar monitoring, or Mount Chacaltaya, Bolivia (5.320 m asl, 16.2ºS, 68.1ºW, GAW site) for tropical observations. Sun, 06 Nov 2011 23:00:00 GMT http://hdl.handle.net/2122/7411 2011-11-06T23:00:00Z http://hdl.handle.net/2122/7360 Title: Development of a 22 GHz ground-based 1 spectrometer for middle atmospheric water vapour monitoring Authors: Bertagnolio, P. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Baskaradas, J. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The water Vapour Emission SPectrometer for Antarctica at 22 GHz (VESPA-22) has been 15 designed for long-term middle atmospheric climate change monitoring and satellite data 16 validation. It observes the water vapour spectral line at 22.235 GHz using the balanced beam17 switching technique. The receiver antenna has been characterized, showing an HPBW of 3.5°and a sidelobe level 40 dB below the main lobe. The receiver front-end has a total gain of 105 dB and a LNA noise temperature of 125 K. A FFT spectrometer (bandwidth 1 GHz, resolution 63 20 kHz) will be used as back-end, allowing the retrieval of H2O concentration profiles in the 20 to 80 km altitude range. The control I/O interface is based on reconfigurable hardware (USB22 CPLD). Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/7360 2011-12-31T23:00:00Z http://hdl.handle.net/2122/6300 Title: 3D volcanic aerosol dispersal: a comparison between misr data and numerical simulations Authors: Scollo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Folch, A.; Barcelona Supercomputing Center, Barcelona, Spain.; Coltelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Realmuto, V. J.; Jet Propulsion Laboratory, California Institute of Technology. Abstract: The three dimensional reconstruction of volcanic plumes is a central goal to enhance our understanding on dispersal processes. In this paper, we use data from the Multi-angle Imaging SpectroRadiometer (MISR) on board NASA’s Terra spacecraft combined with a stereo matching retrieval procedure. We show the potential of MISR in capturing important features of volcanic plumes like column height, optical depth, type and shape of the finest particles of two highly explosive eruptions occurring on Mt. Etna in 2001 and 2002. This work tests how tephra dispersal models reconstruct the 3D shape of volcanic clouds. We compare MISR data with FALL3D, an Eulerian model for the transport and deposition of volcanic ash and aerosols coupled with the Weather Research and Forecasting (WRF) mesoscale meteorological model. Agreement between simulations and MISR data is good regarding both events, although it could be improved by increasing the accuracy of the meteorological data, a better constraint on volcanological input parameters like the height of the eruptive column and improving our understanding of processes such as aggregation phenomena and volcanic cloud microphysics. Description: Accepted for publication in Journal of Geophysical Research. Copyright (2010) American Geophysical Union. Thu, 20 May 2010 22:00:00 GMT http://hdl.handle.net/2122/6300 2010-05-20T22:00:00Z http://hdl.handle.net/2122/4085 Title: Retrieval of foreign-broadened water vapor continuum coefficients from emitted spectral radiance in the H2O rotational band from 240 to 590 cm −1 Authors: Serio, C.; Dip. Ingegeneria e Fisica dell’Ambiente, Università della Basilicata, Potenza, Italy; Masiello, G.; Dip. Ingegeneria e Fisica dell’Ambiente, Università della Basilicata, Potenza, Italy; Esposito, F.; Dip. Ingegeneria e Fisica dell’Ambiente, Università della Basilicata, Potenza, Italy; Di Girolamo, P.; Dip. Ingegeneria e Fisica dell’Ambiente, Università della Basilicata, Potenza, Italy; Di Iorio, T.; Dip. Fisica, Università di Roma ”La Sapienza”, Roma, Italy; Palchetti, L.; Istituto di Fisica Applicata ”Nello Carrara”, IFAC-CNR, Firenze, Italy; Bianchini, G.; Istituto di Fisica Applicata ”Nello Carrara”, IFAC-CNR, Firenze, Italy; Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pavese, G.; Istituto di Metodologie per l’Analisi Ambientale, IMAA-CNR, Potenza, Italy; Rizzi, R.; Dip. Fisica, Università di Bologna, Bologna, Italy; Carli, B.; Istituto di Fisica Applicata ”Nello Carrara”, IFAC-CNR, Firenze, Italy; Cuomo, V.; Istituto di Metodologie per l’Analisi Ambientale, IMAA-CNR, Potenza, Italy Abstract: The paper presents a novel methodology to retrieve the foreign-broadened water vapor continuum absorption coefficients in the spectral range 240 to 590 cm−1 and is the first estimation of the continuum coefficient at wave numbers smaller than 400 cm−1 under atmospheric conditions. The derivation has been accomplished by processing a suitable set of atmospheric emitted spectral radiance observations obtained during the March 2007 Alps campaign of the ECOWAR project (Earth COoling by WAter vapor Radiation). It is shown that, in the range 450 to 600 cm−1, our findings are in good agreement with the widely used Mlawer, Tobin-Clough, Kneizys-Davies (MT_CKD) continuum. Below 450 cm−1 however the MT_CKD model overestimates the magnitude of the continuum coefficient. Sun, 28 Sep 2008 22:00:00 GMT http://hdl.handle.net/2122/4085 2008-09-28T22:00:00Z http://hdl.handle.net/2122/4084 Title: Reply to comment by Rolf Müller and Simone Tilmes on ‘‘Middle atmospheric O3, CO, N2O, HNO3, and temperature profiles during the warm Arctic winter 2001–2002’’ Authors: Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; de Zafra, R. L.; Department of Physics and Astronomy, and Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, New York, USA Abstract: [1] Muscari et al. [2007] (hereafter referred to as M07) analyzed Arctic winter stratospheric conditions for 2001–2002 by means of ground-based measurements of stratospheric trace gases and temperature from Thule Air Base, Greenland (76.5°N, 68.7°W). The paper characterized stratospheric air masses observed over Thule from 20 January to 5 March 2002. Topics that were discussed included: the passage of both the polar vortex and the Aleutian high over Thule, with significant changes in ozone mixing ratio and temperature values; variations of measured O3 total column; vertical descent of air masses observed by means of CO measurements; observations of "ozone pockets" [Manney et al., 1995]; the correlation between illumination fraction and ozone mixing ratio at 900 K, indicating the relative significance of dynamics and photochemistry on ozone concentration at this altitude; the complete absence of polar stratospheric clouds, as concurrently monitored with a lidar system at Thule; and a qualitative (not quantitative) estimation of local ozone deficiency by means of N2O/O3 correlations. Müller and Tilmes [2008] (hereafter referred to as MT08) question the significant ozone deficiencies reported by M07 inside the vortex, which, as also pointed out by M07, are difficult to explain by heterogeneous chemistry during the warm winter 2001–2002. Nonetheless, M07 did speculate that heterogeneous activation of halogen compounds during mid-December and early January could have been the origin of the substantial ozone deficiency observed at the end of January/beginning of February in the small portion of the vortex core sampled by the Ground-Based Millimeter-Wave Spectrometer (GBMS). MT08 question this claim, as it "cannot be reconciled with the current understanding of halogen driven chemical ozone destruction in the Arctic." They suggest flaws in the N2O selection criteria used by M07 in order to identify intravortex N2O/O3 correlations, arising from their contention that GBMS measurements of N2O do not have the necessary spatial resolution needed for the task. MT08 favor instead the use of Potential Vorticity (PV) fields from European Centre Medium-Range Weather Forecasts (ECMWF) analyses. [2] As a result of the criticism of MT08, we have looked at N2O/O3 correlations from independent measurements carried out by the Odin Sub-Millimeter Radiometer (Odin/SMR) [Murtagh et al., 2002] and have also reprocessed the GBMS O3 measurements using a different deconvolution technique. The GBMS O3 reanalysis furnishes a significantly smaller qualitative estimate of local ozone loss (here and in the following we use "ozone loss" specifically to indicate an ozone deficiency due to heterogeneous activation of halogen compounds) and is consistent with the Odin/SMR data (section 2). This has resulted in a corrected and enriched version of Figure 9a of M07 (see Figure 2 in section 2). Although we value the comments of MT08 which prompted us to reanalyze GBMS ozone data, correcting and improving Figure 9 of M07 and the related discussion, we do reject some of the comments of MT08 concerning the N2O selection criteria used by M07, and reiterate the choice of GBMS N2O measurements rather than ECMWF PV values to separate air masses located inside, outside, or at the edge of the polar vortex (section 3). Furthermore, we stress that the use of N2O/O3 correlation curves to determine ozone loss inside the vortex, in particular near its edge (a region often called "the outer vortex"), can indeed cause an overestimation of local ozone loss near the vortex edge region and possibly also an overestimation of the vortex averaged loss (section 4). Description: Reply to comment by Rolf Müller and Simone Tilmes on "Middle atmospheric O3, CO, N2O, HNO3, and temperature profiles during the warm Arctic winter 2001–2002" Fri, 19 Sep 2008 22:00:00 GMT http://hdl.handle.net/2122/4084 2008-09-19T22:00:00Z http://hdl.handle.net/2122/3678 Title: Millimeter wave spectroscopic measurements of stratospheric and mesospheric constituents over the Italian Alps: stratospheric ozone Authors: Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cesaroni, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Bianchi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; de Zafra, R. L.; Department of Physics and Astronomy and Institute for Terrestrial and Planetary Atmospheres,; Di Iorio, T.; Dipartimento di Fisica, Università degli Studi di Roma «La Sapienza», Roma, Italy; Fiorucci, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Fuà, D.; Dipartimento di Fisica, Università degli Studi di Roma «La Sapienza», Roma, Italy; Romaniello, V.; Dipartimento di Fisica, Università degli Studi di Roma «La Sapienza», Roma, Italy; Zuccheretti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Measurements of rotational lines emitted by middle atmospheric trace gases have been carried out from the Alpine station of Testa Grigia (45.9°N, 7.7°E, elev. 3500 m) by means of a Ground-Based Millimeter-wave Spectrometer (GBMS). Observations of species such as O3, HNO3, CO, N2O, HCN, and HDO took place during 4 winter periods, from February 2004 to March 2007, for a total of 116 days of measurements grouped in about 18 field campaigns. By studying the pressure-broadened shape of emission lines the vertical distribution of the observed constituents is retrieved within an altitude range of ∼17-75 km, constrained by the 600 MHz pass band and the 65 kHz spectral resolution of the back-end spectrometer. This work discusses the behavior of stratospheric O3 during the entire period of operation at Testa Grigia. Mid-latitude O3 columnar content as estimated using GBMS measurements can vary by large amounts over a period of very few days, with the largest variations observed in December 2005, February 2006, and March 2006, confirming that the northern winter of 2005-2006 was characterized by a particularly intense planetary wave activity. The largest rapid variation from maximum to minimum O3 column values over Testa Grigia took place in December 2006 and reached a relative value of 72% with respect to the average column content for that period. During most GBMS observation times much of the variability is concentrated in the column below 20 km, with tropospheric weather systems and advection of tropical tropospheric air into the lower stratosphere over Testa Grigia having a large impact on the observed variations in column contents. Nonetheless, a wide variability is also found in middle stratospheric GBMS O3 measurements, as expected for mid-latitude ozone. We find that O3 mixing ratios at ∼32 km are very well correlated with the solar illumination experienced by air masses over the previous ∼15 days, showing that already at 32 km altitude ozone photochemistry dominates over transport processes. The correlation of lower stratospheric ozone concentrations with potential vorticity as an indicator of transport is instead not as clear-cut, due to very complex mixing processes that characterize stratospheric air at mid-latitudes. Correlations of O3 over Testa Grigia with stratospheric tracers such as N2O and HCN, also observed by means of the GBMS, are planned for the future, in order to better characterize lower stratospheric dynamics and therefore lower stratospheric ozone concentrations at mid-latitudes. Thu, 31 May 2007 22:00:00 GMT http://hdl.handle.net/2122/3678 2007-05-31T22:00:00Z http://hdl.handle.net/2122/3212 Title: Stable isotope ratios in meteoric recharge and groundwater at Mt. Vulture volcano, southern Italy Authors: Paternoster, M.; Department of Geological Sciences, University of Basilicata, Campus Macchia Romana,; Liotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia Abstract: A rain gauge network consisting of five sites located at different altitudes, ranging from 320 to 1285 m.a.s.l., was installed at Mt. Vulture volcano (southern Italy). Rain water samples were collected monthly over a two-year period and their isotopic composition (d18O and dD) was analyzed. During the same period, circulating groundwater was sampled from 24 springs and wells distributed throughout the study area. Monthly isotopic composition values were used to determine the local meteoric water line (LMWL). Its slope is slightly lower than the relationship defined by Longinelli and Selmo (Longinelli, A., Selmo, E., 2003. Isotopic composition of precipitation in Italy: a first overall map. J. Hydrol. 270, 75–88) for southern Italy. The groundwater samples analyzed were distributed essentially along the LMWL. The weighted local meteoric water line (WLMWL), defined through the mean values weighted by the rainfall amount, however, may define in a short range the meteoric end-member in the local hydrological cycle more precisely. Since most of the groundwater sampling locations do not show seasonal variations in their stable isotope values, the flow system appears to be relatively homogeneous. The mean altitude of the recharge by rainfall infiltration was estimated on the basis of the local vertical isotopic gradient d18O. A few springs, which show anomalous isotopic values, reveal more regional circulation systems, associated with tectonic structures responsible for the ascent of deeper water. Tue, 25 Sep 2007 22:00:00 GMT http://hdl.handle.net/2122/3212 2007-09-25T22:00:00Z