http://hdl.handle.net/2122/85 Search the Channel search http://www.earth-prints.org/simple-search 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 <br/> <br/>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 <br/> <br/>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 22:58:59 GMT 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’’ <br/> <br/>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 <br/> <br/>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). <br/> <br/>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 22:58:59 GMT http://hdl.handle.net/2122/3678 Title: Millimeter wave spectroscopic measurements of stratospheric and mesospheric constituents over the Italian Alps: stratospheric ozone <br/> <br/>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 <br/> <br/>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. Tue, 29 May 2007 22:58:59 GMT http://hdl.handle.net/2122/3212 Title: Stable isotope ratios in meteoric recharge and groundwater at Mt. Vulture volcano, southern Italy <br/> <br/>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 <br/> <br/>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 22:58:59 GMT