62 research outputs found

    Ion production rates and cross-sections from the atmospheric observations and comparison with the CLOUD experiment results

    Get PDF
    We present and discuss experimental results obtained from the measurements of cosmic ray fluxes and ion concentrations at different altitudes (from ground level up to 30-35 km) and latitudes (from equator to polar regions) in the Earth's atmosphere. We calculated ionproduction cross-sections and ion production rates from these data sets. The same characteristics are possible to be derived from the CLOUD experimental data using ion concentrations, particle beam intensities, etc. We discuss the methods of estimation of these characteristics in the CLOUD experiment

    Exceptional middle latitude electron precipitation detected by balloon observations: implications for atmospheric composition

    Get PDF
    Energetic particle precipitation leads to ionization in the Earth\u27s atmosphere, initiating the formation of active chemical species which destroy ozone and have the potential to impact atmospheric composition and dynamics down to the troposphere. We report on one exceptionally strong high-energy electron precipitation event detected by balloon measurements in middle latitudes on 14 December 2009 with ionization rates locally comparable to strong solar proton events. This electron precipitation was likely caused by wave-particle interactions in the slot region between the inner and outer radiation belts, connected with still not well understood natural phenomena in the magnetosphere. Satellite observations of odd nitrogen and nitric acid are consistent with wide-spread electron precipitation into magnetic midlatitudes. Simulations with a 3D chemistry-climate model indicate almost complete destruction of ozone in the upper mesosphere over the region where high-energy electron precipitation occurred. Such an extraordinary type of energetic particle precipitation can have major implications for the atmosphere, and their frequency and strength should be carefully studied

    Launch of solar coronal mass ejections and submillimeter pulse bursts

    Get PDF
    The rapid solar spikes (100-500 ms) recently discovered at submillimeter waves bring new possibilities to investigate energetic processes near the solar surface that might have an important role in the launch and propelling of ionized mass away from the Sun. We present a study on the association between the launch time of coronal mass ejections (CMEs) observed by the LASCO instruments on the SOHO spacecraft and the onset of the new kind of rapid solar spikes (100-500 ms) observed at submillimetric waves (212 and 405 GHz) by the new Solar Submm-wave Telescope (SST). We investigated six submm-wave events, all found associated to CMEs. Seven related CME were identified. Five of them were associated with flares with large GOES class soft X-rays, presenting distinct time histories and associations at other energy ranges, and two of them were related to flares behind the solar limb, with simultaneous related activity observed in the visible solar disk. Ultraviolet images from EIT on SOHO show some kind of small or large-scale magnetic activity or brightening for all events. The extrapolation of apparent CME positions to the solar surface show that they occurred nearly coincident in time with the onset of submm-wave pulses for all six events. These results suggest that pulse bursts might be representative of an important early signature of CMEs, especially for events beginning near the center of the solar disk, sometimes identified as "halo" CMEs. They lead to several challenging questions relative to the physical nature of the pulses and its association to the launch and acceleration of coronal mass ejections. Although these evidences may favor multiple rapid energy releases at the origin near the solar surface, they require further research in order to better understand both diagnostics and model descriptions.Fil: Kaufmann, Pierre. Universidade Estadual de Campinas; Brasil. Universidade Presbiteriana Mackenzie; BrasilFil: De Castro, C. Guillermo Giménez. Universidade Presbiteriana Mackenzie; BrasilFil: Makhmutov, Vladimir S.. Universidade Presbiteriana Mackenzie; Brasil. The Russian Academy Of Sciences; RusiaFil: Raulin, Jean Pierre. Universidade Presbiteriana Mackenzie; BrasilFil: Schwenn, Rainer. Max Planck Institute For Solar System Research; AlemaniaFil: Levato, Orlando Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Rovira, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

    Exceptional middle latitude electron precipitation detected by balloon observations: implications for atmospheric composition

    Get PDF
    Energetic particle precipitation leads to ionization in the Earth\u27s atmosphere, initiating the formation of active chemical species which destroy ozone and have the potential to impact atmospheric composition and dynamics down to the troposphere. We report on one exceptionally strong high-energy electron precipitation event detected by balloon measurements in geomagnetic midlatitudes on 14 December 2009, with ionization rates locally comparable to strong solar proton events. This electron precipitation was possibly caused by wave–particle interactions in the slot region between the inner and outer radiation belts, connected with still poorly understood natural phenomena in the magnetosphere. Satellite observations of odd nitrogen and nitric acid are consistent with widespread electron precipitation into magnetic midlatitudes. Simulations with a 3D chemistry–climate model indicate the almost complete destruction of ozone in the upper mesosphere over the region where high-energy electron precipitation occurred. Such an extraordinary type of energetic particle precipitation can have major implications for the atmosphere, and their frequency and strength should be carefully studied

    Analysis of the Variability in the Atmospheric Electric Field and Natural Gamma Radiation in Different Weather Conditions

    Get PDF
    In recent years the analysis of the variability of the natural gamma radiation and its relationshipwith high atmospheric electric fields in disturbed weather, e.g., thunderstorms, have been important, as well as the relationship between these parameters in fair weather conditions. In this paper we analyze the diurnal variation of the atmospheric electric field and natural gamma radiation, in fair and disturbed weather conditions, recorded in the Argentinian Andes mountain (2552 masl) between April 2018 and February 2019. In fair weather conditions, it was found a higher linear correlation coefficient (R) between the atmospheric electric field diurnal curve and the ‘universal’ Carnegie curve (R=0.93), and a high negative correlation between the atmospheric electric field and natural gamma radiation diurnal curve (R=-0.9). On the other hand, in disturbed weather conditions, we reported thirteen events where it was found intense natural gamma radiation enhancements associated with high atmospheric electric field variability. A maximum of 35 % excess in the natural gamma radiation was detected, which was associated with thunderstorms and rain precipitation. It was observed a high correlation between the excesses of the gamma natural radiation enhancement with the atmospheric electric field values (R=0.80) and with the rain precipitation rate (R=0.59).Fil: Rosa de Oliveira, Rafael Ricardo. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Tacza, José. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; Brasil. Polish Academy of Sciences; ArgentinaFil: Raulin, Jean Pierre. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Szpigel, Sergio. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Makhmutov, Vladimir. Lebedev Physical Institute; RusiaFil: Philippov, Maxim. Lebedev Physical Institute; RusiaFil: Ccopa, Josué. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Marun, Adolfo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Fernandez, German Enzo Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentin

    Exceptional middle latitude electron precipitation detected by balloon observations: Implications for atmospheric composition

    Get PDF
    Energetic particle precipitation leads to ionization in the Earth's atmosphere, initiating the formation of active chemical species which destroy ozone and have the potential to impact atmospheric composition and dynamics down to the troposphere. We report on one exceptionally strong high-energy electron precipitation event detected by balloon measurements in geomagnetic midlatitudes on 14 December 2009, with ionization rates locally comparable to strong solar proton events. This electron precipitation was possibly caused by wave–particle interactions in the slot region between the inner and outer radiation belts, connected with still poorly understood natural phenomena in the magnetosphere. Satellite observations of odd nitrogen and nitric acid are consistent with widespread electron precipitation into magnetic midlatitudes. Simulations with a 3D chemistry–climate model indicate the almost complete destruction of ozone in the upper mesosphere over the region where high-energy electron precipitation occurred. Such an extraordinary type of energetic particle precipitation can have major implications for the atmosphere, and their frequency and strength should be carefully studied

    Formation of Highly Oxygenated Organic Molecules from alpha-Pinene Ozonolysis : Chemical Characteristics, Mechanism, and Kinetic Model Development

    Get PDF
    Terpenes are emitted by vegetation, and their oxidation in the atmosphere is an important source of secondary organic aerosol (SOA). A part of this oxidation can proceed through an autoxidation process, yielding highly oxygenated organic molecules (HOMs) with low saturation vapor pressure. They can therefore contribute, even in the absence of sulfuric acid, to new particle formation (NPF). The understanding of the autoxidation mechanism and its kinetics is still far from complete. Here, we present a mechanistic and kinetic analysis of mass spectrometry data from α-pinene (AP) ozonolysis experiments performed during the CLOUD 8 campaign at CERN. We grouped HOMs in classes according to their identified chemical composition and investigated the relative changes of these groups and their components as a function of the reagent concentration. We determined reaction rate constants for the different HOM peroxy radical reaction pathways. The accretion reaction between HOM peroxy radicals was found to be extremely fast. We developed a pseudo-mechanism for HOM formation and added it to the AP oxidation scheme of the Master Chemical Mechanism (MCM). With this extended model, the observed concentrations and trends in HOM formation were successfully simulated.Peer reviewe

    Experimental particle formation rates spanning tropospheric sulfuric acid and ammonia abundances, ion production rates, and temperatures

    Get PDF
    Binary nucleation of sulfuric acid and water as well as ternary nucleation involving ammonia are thought to be the dominant processes responsible for new particle formation (NPF) in the cold temperatures of the middle and upper troposphere. Ions are also thought to be important for particle nucleation in these regions. However, global models presently lack experimentally measured NPF rates under controlled laboratory conditions and so at present must rely on theoretical or empirical parameterizations. Here with data obtained in the European Organization for Nuclear Research CLOUD (Cosmics Leaving OUtdoor Droplets) chamber, we present the first experimental survey of NPF rates spanning free tropospheric conditions. The conditions during nucleation cover a temperature range from 208 to 298K, sulfuric acid concentrations between 5x10(5) and 1x10(9)cm(-3), and ammonia mixing ratios from zero added ammonia, i.e., nominally pure binary, to a maximum of -1400 parts per trillion by volume (pptv). We performed nucleation studies under pure neutral conditions with zero ions being present in the chamber and at ionization rates of up to 75ion pairs cm(-3)s(-1) to study neutral and ion-induced nucleation. We found that the contribution from ion-induced nucleation is small at temperatures between 208 and 248K when ammonia is present at several pptv or higher. However, the presence of charges significantly enhances the nucleation rates, especially at 248K with zero added ammonia, and for higher temperatures independent of NH3 levels. We compare these experimental data with calculated cluster formation rates from the Atmospheric Cluster Dynamics Code with cluster evaporation rates obtained from quantum chemistry.Peer reviewe
    • …
    corecore