Trend of Ozone in the free troposphere above Europe

Summary Ozone observations were made one century ago by the Sch?nbein technique at meteorological observatories in the alpine region. Within the intrinsic limitations of the technique, historical readings have been converted to present-time concentrations (p.p.b.v.). The evaluated ozone level in the free troposphere (17 p.p.b.v.) was twice as large as at the surface; comparable values were obtained by chemical and spectroscopic technique in the first half of our century. Furthermore, the reconstructed ozone trend in the free troposphere shows a sharp increase after the ’50s, as already observed at the surface at midlatitudes of the northern hemisphere.     

A comprehensive optical investigation of processes of transformation of the ozonosphere above Tomsk

The results are given on experimental optical research into variations and peculiarities of the time dependence of the total ozone content (TOC) and the influence of an eruption of the Pinatubo Volcano on the stratospheric ozone layer, as well as observations of local negative ozone anomalies and polar stratospheric clouds (PSCs), obtained during lidar and spectrophotometric measurements at the Siberian Lidar Station (56°.5 N, 85°.0 E). It is shown that normal and anomalous deviations in TOC are due to atmospheric dynamics and depend on the amount of anomaly in the atmospheric processes themselves. Under the conditions of considerable loading of the stratosphere with volcanogenic aerosol, a substantial inverse relationship between aerosol and ozone contents is observed. The formation of PSCs and a local TOC decrease correspond to an anomalous thermodynamic state of the troposphere and lower stratosphere. Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 75–82, September, 1998.     

Transport of photochemical ozone along the western Adriatic shore near a petrochemical plant

Summary During the warm months, the whole area surrounding Ravenna's petrochemical plant, which is about 5 km inshore of the northern Adriatic coast (Po Valley region), is subject to photochemical reactions producing high values of ozone concentration. The transport offshore of oxidants' precursors by the land breeze, photochemical reactions and subsequent transport inshore of oxidants by the sea breeze, may cause high concentrations of ozone along the coast up until the late evening. Similar phenomena have already been observed in other coastal regions. Classifying the ozone data into days with different circulations, the following can be seen: on days with W or NW circulation, a regular diurnal variation of ozone correlated with solar radiation is found; with winds from E or SE, the ozone variations are irregular and ozone concentrations can maintain high levels ((40÷70) p.p.b.) even during the nightime. This is a report of the results of several field measurements aimed at showing the ozone production and destruction processes, as well as its recirculation mechanisms under breeze conditions. Paper presented at the 1^o Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome.     

Measurement of the terrestrial ozone concentration by absorption UV spectroscopy

The conditions allowing one to measure the concentration of terrestrial ozone by the open-path DOAS method using a zero line are considered. A technique based on measuring signals at two wavelengths, at least one of which belongs to the ozone absorption UV band, is described. The error of measurements has been estimated. A block-diagram of the optical “open-path” meter for measuring the terrestrial ozone concentration, TrIO-2, is presented. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 832–836, November–December, 2005.     

Ozone deficiency and deficit recovery time at Ispra in 1993 with respect to 1992

Summary Total ozone values measured at Ispra, Italy (45⁰48′ latitude, −8⁰37′ longitude) by a Brewer station during 1992 and 1993 have been compared. The time required in 1993 by ozone to recover the level of the previous year lasted up to the end of July, while for 1992 the recovery to reference ozone values obtained by averaging thirty years of data (1957–1986) taken at Arosa (Switzerland) was about three months shorter. For the first six months of 1993, a mean ozone deficit of the order of 4% with respect to the value for the same period of 1992 has been calculated. An analysis of the UV data taken together with ozone confirmed the anomalous behaviour of ozone in the first half-year of 1993.     

Spectral analysis and trend of total ozone observations at Vigna di Valle

Summary Time series analyses of measurements of total ozone make possible an in-depth climatological study of this important stratospheric gas. The Italian Air Force's Vigna di Valle Observatory (42°N, 12°E, 262 m a.s.l.) provided a time series of monthly averages (January 1958–December 1988) of total ozone. Spectral analysis and running averages were combined to detect medium-(QBOs of estimated (4÷5) DU amplitudes) and long-term fluctuations (possible correlation to 11-year solar cycle) and to filter them, leaving any overlapping trends unaltered. Total ozone trend estimates produced by the present study were +0.1% per decade for the 1959–1987 period and a decrease of −0.4% per decade for the more recent 1970–1987 span, over which a pronounced ozone depletion caused mainly by CFCs is assumed. This study has supported by the CNR-ENEL Project ?Interaction of energy system with human health and environment?.     

Investigation of the ozone formation process in a nanosecond microwave discharge in air and oxygen

Results are presented from an investigation of the dynamics of ozone formation in a freely localized discharge generated by a periodic train of 3-cm nanostructured microwave pulses in oxygen and air at a pressure p=3–30 Torr. Conditions for the efficient generation of ozone in air with the minimum production of nitrogen oxides are demonstrated experimentally. It is shown that when the microwave pulse repetition frequency is high, heating of the gas and the buildup of nitrogen oxides in the discharge in air reduce the ozone formation efficiency while under prolonged exposure the ozone formed initially is destroyed. The energy cost of forming ozone in oxygen and air is determined as a function of the microwave pulse length and repetition frequency and the gas pressure. The lowest energy cost of forming a single ozone molecule in these experiments is 16 eV per molecule for a discharge in air and 4 eV per molecule in oxygen. It was observed that circulating the gas through the discharge zone enhances th ozone formation efficiency. It is shown that there are optimal conditions for ozone formation as a function of the reduced electric field in the plasma. Zh. Tekh. Fiz. 67, 9–18 (March 1997)     

Study of ozone concentration variations in the upper stratosphere using millimeter wave spectroscopy methods

New results of the study of ozone concentration variations in the upper stratosphere over Moscow in the layer at a height of 40 km, which is most sensitive to anthropogenic impacts, are presented. Changes in the ozone concentration and its relation to other atmospheric parameters in cold periods of 2008–2009 and 2009–2010 are analyzed. It was shown that there exist regions with decreased ozone content in the polar vortex and outside of it in air with higher temperature in the upper stratosphere. These phenomena cause deformations of vertical ozone distribution profiles and an appreciable shift of the maximum of the relative content of ozone to lower stratosphere layers.     

Destruction of the ozone layer as a result of a meteoroid falling into the ocean

The falling of a large celestial body into the ocean causes a large number of compounds (for example, HCl, Cl, Br, Na, H₂O, OH, and NO) that destroy ozone molecules directly or indirectly to be ejected to stratospheric altitudes. The bleaching of the atmosphere in the UV range as a result of such ozone destruction creates negative feedback that restores the ozone. The characteristic time for such restoration in the stratosphere decreases sharply with altitude, ranging from several months at 30 km to several days at 20 km. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 5, 360–366 (10 September 1999)     

Measurements of climatic parameters and ground-level ozone at Terra Nova Bay in Antarctica

Summary The results of local meteorology, solar radiation and ground-level ozone measurements taken in Antarctica during the second Italian expedition (December 86–February 87) at Terra Nova Bay are presented. During the summer months the site of the Italian base camp is characterized by a thin strip of deglaciated ground, along which the temperature measurements close to the ground and up to 6 m high show a strongly superdiabatic profile. This irregular trend of the temperature in the surface layer is mainly due to the notable incoming amounts of radiation and to the extreme transparency of the atmosphere. This is also shown by the low values of the ratio between total radiation and diffuse radiation. The ground is thus subjected to intense heating, especially in the warmer hours of the day, while the surface layer of the atmosphere will be characterized by strong upward heat fluxes and by turbulent convective movements. Vertical-temperature-profile measurements show an almost forced persistence in the superdiabatic trend, which tends towards isothermic values only as a resultof rapid variations in the direction and intensity of the wind, connected to the downward flux of cold air masses, shown also by the simultaneous increases in ground-level ozone concentrations which would support the presence of dry-deposition processes in the lower layer. However, the complex local orography and the horizontal discontinuity (sea, deglaciated coast, snow-covered surfaces) do not permit a correct application of profile flux relations, normally used in studies on groundlevel dry-deposition. Paper presented at the IV Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 22–24, 1987, Rome.     

Effect of electronegative impurities on the generation of ozone in air

A self-consistent numerical model is used to investigate the effect of electronegative impurities on the ozone yield in a dielectric barrier discharge with a pulsed voltage supply, and the range of impurity concentrations giving a substantial (two-or threefold) increase in the ozone yield is established. Sulfur hexafluoride is considered as a representative component having strong electronegative properties. It is shown that a tiny admixture [SF₆]<0.1% can have an appreciable effect on the characteristics of an ozonator. The calculations are compared with published experimental data and given an interpretation. Zh. Tekh. Fiz. 69, 49–52 (January 1999)     

Optical properties of silicon-silicide nanoheterostructures grown by consecutive plasma-epitaxy synthesis

Consecutive plasma-epitaxial synthesis on silicon wafers is used for the first time to fabricate monolithic nanoheterostructures with embedded nanocrystals (NC) of chromium disilicide (Si–NC CrSi₂–Si). It is found that, initially, nanoislands form on the surface and within a coating layer of silicon, followed by the formation of small (10–15 nm) nanocrystals of semiconducting chromium disilicide (CrSi₂) at a high occupation density ((2–3)⋅10¹¹ cm^–2). During formation of silicon-silicide-silicon heterostructures, CrSi₂ nanocrystallites “float up” into the near surface area of the covering silicon layer.     

Phosphorus distribution profiles in 100-silicon using a spin-on source at low temperatures

 Incorporation of phosphorus into silicon from a spin-on dopant layer (SOD) at 400 ^°C is described. Annealing experiments were carried out with SOD films deposited on (100) silicon substrates by using the spin-on technique. Conventional heating on a hotplate in normal atmosphere and a temperature range up to 400 ^°C was used to study the dopant incorporation. After removing the SOD-films one part of the silicon substrates was annealed at higher temperatures. Investigations were carried out by SIMS, SAM, XPS, HTEM, stripping Hall and Van der Pauw measurements before and after the high temperature annealing. Chemical phosphorus concentration profiles obtained from low temperature annealed samples showed diffusion depths of 60–80 nm (extrapolated to a substrate doping level of 10¹⁶ cm^-3) and surface concentrations of 10¹⁹–10²⁰ cm^-3. Electron concentration profiles exhibiting maximum values around 2⋅10¹⁹ cm^-3 could be measured on high temperature annealed samples only. Received: 28 March 1996/Accepted: 19 August 1996     

Domain Formation in DODAB–Cholesterol Mixed Systems Monitored via Nile Red Anisotropy

The effect of the cholesterol (ch) on liposomes composed of the cationic lipid dioctadecyldimethylammonium bromide (DODAB) was assessed by studying both the steady-state and time-resolved fluorescence anisotropy of the dye Nile Red. The information obtained combined with analysis of the steady-state emission and fluorescence lifetime of Nile Red (NR) for different cholesterol concentrations (5–50%) elucidated the presence of “condensed complexes” and cholesterol-rich domains in these mixed systems. The steady-state fluorescence spectra were decomposed into the sum of two lognormal emissions, emanating from two different states, and the effect of temperature on the anisotropy decay of Nile Red for different cholesterol concentrations was observed. At room temperature, the time-resolved anisotropy decays are indicative of NR being relatively immobile (manifest by a high r _∞ value). At higher temperature, rotational times ca. 1 ns were obtained throughout and a trend in increasing hindrance was seen with increase of Ch content.     

Charge transfer mechanism in high-purity silicon-basedn +-π-p + structures

Results of experimental investigations into current-voltage characteristics of n⁺-π-p⁺ structures based on high-purity silicon doped with boron are presented. It is shown that the I–V characteristic at high injection levels is described by Stafeev's theory, when the thickness d of the π-region is smaller than or close to three ambipolar diffusion lengths L_a. For a current density J above (3–50) A/cm² at varying temperatures, the I–V characteristic obeys a relation usually occurring in the case where charge-carrier recombination in the n⁺ and p⁺-regions dominates that found in the π-region. The effect of mutual electron-hole scattering on the behavior of the I–V characteristic is evident at J>630 A/cm³. For d/L_a=9, the I–V characteristic at high injection levels is treated by the theory of double carrier injection into a semiconductor with consideration for diffusion corrections. In the temperature range below 200–276 K, the I–V curve for all samples studied exhibits a linear dependence on J followed by a portion corresponding to a maximum occupancy of recombination levels by injected electrons. Here the Fe or Au donor levels presumably act as recombination levels. The electron and hole capture areas (cross sections) by recombination centers are roughly estimated. Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 35–45, July 2000.     

On the absorption of ozone by organic solvents: the role played by gas transfer through the gas-liquid separation surface

The absorption of ozone by organic liquids (chloroform, heptane, and carbon tetrachloride) was studied in bubbling reactors and reactors without bubbling. After the “burning out” of solvent impurities reacting with ozone at high rates, a stationary regime was established with the ozone concentration different from that at the entrance of the reactor, which was indicative of the occurrence of a side reaction with ozone consumption. This reaction did not influence the results of the determination of the general unsaturation of the substances analyzed.     

Infrared luminescence of erbium-doped sodium lead germanate glass

The infrared optical properties of Er³⁺ ions are reported for 60GeO₂–20PbO–20Na₂O glass for two Er₂O₃ concentrations. From the optical absorption spectra, the Judd–Ofelt (J–O) parameters have been obtained and have been used to calculate radiative lifetimes and stimulated emission cross sections. A narrow emission band peaked at 1536 nm with exponential decay for both Er concentrations is observed. The measured lifetime decreases for increasing Er concentration, its value being very close, in the case of the lowest doping level, to the radiative lifetime calculated from J–O analysis. This, together with the relatively high emission cross section makes this glass suitable for laser applications.     

Microwave radiometric sensing of the upper atmosphere above Nizhny Novgorod

We describe the equipment and methods of observation of variation of the state of some stratospheric and mesospheric gas components and present the results of measurements of the time and space ozone variations at altitudes of from 20 to 70 km above Nizhny Novgorod: the seasonal and diurnal variation and “ozone clouds.” The seasonal variation of ozone content at altitudes exceeding 22 km and the vertical distribution of ozone are compared with the measurement results obtained from the TOMS and CRISTA satellites. We also show the results of observations of mesospheric carbon monoxide. Institute of Applied Physics of the Russian Academy of Sciences. Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 11, pp. 1405–1423, November, 1998.     

Measurement of tropospheric O3, SO2 and aerosol from a volcanic emission event using new multi-wavelength differential-absorption lidar techniques

We present measurements of tropospheric O₃, SO₂ and aerosol from a volcanic emission event using new multi-wavelength differential absorption lidar (DIAL) techniques that enable us to remove the mutual effects between O₃ and SO₂ from the raw measurements. The aerosol extinction coefficient is retrieved directly from the lidar return signal at the “off” wavelength and is used to estimate aerosol effects on O₃ and SO₂measurements. Null error, statistical error, and absorption cross-section error are also analyzed. The O₃ and SO₂ concentrations at height between 1000 m and 2000 m for a volcanic event on September 10, 2001 were about 20 ppb and 10–35 ppb, respectively, with an error less than 10 ppb. The measured SO₂ concentration was much higher than the normal SO₂ background value (∼1 ppb) in the troposphere. We also measured O₃ concentrations from 13 December 2000 to 06 January 2001 and investigated O₃ diurnal variation during a 24-hour period on November 24, 2000. A high O₃ concentration of about 250 ppb was observed in late December 2000. PACS 42.68.Wt; 42.68.Kh; 42.68.Jg