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Zheng M, Sjolte J, Adolphi F, Aldahan A, Possnert G, Wu M, Muscheler R. Solar and meteorological influences on seasonal atmospheric 7Be in Europe for 1975 to 2018. CHEMOSPHERE 2021; 263:128318. [PMID: 33297251 DOI: 10.1016/j.chemosphere.2020.128318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 06/12/2023]
Abstract
Assessing the transport of natural radionuclides in the atmosphere provides a powerful tool to study air mass circulation. Here, we investigated the seasonal atmospheric distribution of the naturally produced 7Be in surface air over Europe between 40° N and 68° N during the period 1975-2018. The results suggest that the inter-annual variability of 7Be reflects production rates of the radionuclide induced by solar modulation of cosmic rays. Further analysis of the meteorological influences indicates that the meteorological influences on 7Be concentrations are geographically and seasonally dependent. We found that, in general, the tropopause pressure plays an important factor influencing 7Be activity for winter and spring seasons while the sea level pressure and temperature are more dominant during summer and autumn seasons. The combination of tropospheric production rates and meteorological parameters explains 24%-79% variances of the seasonal 7Be activity. We further applied a three-box model to study the influence of stratosphere-troposphere exchanges on 7Be concentrations. The simulation supports that the seasonal cycle of 7Be in Europe is controlled by two main factors: the changing height of the troposphere (seasonality of the tropopause height) and seasonal variations of the stratosphere-troposphere exchanges.
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Affiliation(s)
- Minjie Zheng
- Department of Geology, Lund University, Lund, Sweden.
| | - Jesper Sjolte
- Department of Geology, Lund University, Lund, Sweden
| | - Florian Adolphi
- Department of Geology, Lund University, Lund, Sweden; Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany; Department of Geosciences, University of Bremen, Germany
| | - Ala Aldahan
- Department of Geology, United Arab Emirates University, Al Ain, United Arab Emirates.
| | | | - Mousong Wu
- International Institute for Earth System Science, Nanjing University, Nanjing, China
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Terzi L, Wotawa G, Schoeppner M, Kalinowski M, Saey PRJ, Steinmann P, Luan L, Staten PW. Radioisotopes demonstrate changes in global atmospheric circulation possibly caused by global warming. Sci Rep 2020; 10:10695. [PMID: 32612126 PMCID: PMC7329870 DOI: 10.1038/s41598-020-66541-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/22/2020] [Indexed: 11/19/2022] Open
Abstract
In this paper, we present a new method to study global atmospheric processes and their changes during the last decade. A cosmogenic radionuclide measured at ground-level, beryllium-7, is utilized as a proxy to study atmospheric dynamics. Beryllium-7 has two advantages: First, this radionuclide, primarily created in the lower stratosphere, attaches to aerosols that are transported downwards to the troposphere and travel around the globe with the general atmospheric circulation. By monitoring these particles, we can provide a global, simple, and sustainable way to track processes such as multi-annual variation of the troposphere, tropopause heightening, position and speed of atmospheric interface zones, as well as the poleward movement and stalling patterns of jet streams. Second, beryllium-7 is a product of cosmic rays which are themselves directly linked to solar activity and the earth magnetic field. This study shows whether beryllium-7 observed concentration changes are correlated with such natural processes or independent of them. Our work confirms that major changes in the atmospheric circulation are currently ongoing, even though timeseries are too short to make climatological assessments. We provide solid evidence of significant and progressive changes of the global atmospheric circulation as well as modifications of tropopause heights over the past decade. As the last decade happened to be the warmest on record, this analysis also indicates that the observed changes are, at least to some extent, attributable to global warming.
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Affiliation(s)
- Lucrezia Terzi
- Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium.
- Technische Universität Wien, Atominstitut, Austria.
| | - Gerhard Wotawa
- Zentralanstalt für Meteorologie und Geodynamik (ZAMG), Vienna, Austria
| | - Michael Schoeppner
- Provisional Technical Secretariat, Preparatory Commission for the Nuclear-Test-Ban Treaty Organization, International Data Centre, Vienna, Austria
- University of Natural Resources and Life Sciences, Institute of Safety/Security and Risk Sciences, Vienna, Austria
| | - Martin Kalinowski
- Provisional Technical Secretariat, Preparatory Commission for the Nuclear-Test-Ban Treaty Organization, International Data Centre, Vienna, Austria
| | | | | | - Lan Luan
- Indiana University Bloomington, Bloomington, Indiana, USA
| | - Paul W Staten
- Indiana University Bloomington, Bloomington, Indiana, USA
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Bianchi S, Plastino W, Brattich E, Djurdjevic V, Longo A, Hernández-Ceballos MA, Sarvan D, Ajtić J. Analysis of trends, periodicities, and correlations in the beryllium-7 time series in Northern Europe. Appl Radiat Isot 2019; 148:160-167. [PMID: 30959353 DOI: 10.1016/j.apradiso.2019.03.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/27/2019] [Accepted: 03/28/2019] [Indexed: 10/27/2022]
Abstract
The activity concentrations of beryllium-7, a natural radiotracer that is considered as a tracer of the stratospheric-tropospheric exchange, shows a distinct behaviour in Northern Europe compared to the central and southern parts of the continent. In this study, we use the measurements collected at four sampling stations in Scandinavia (Ivalo, Umea, Kista, Risoe) between 2001 and 2010 and investigate their trends, periodicities and residuals with the aim to further understand the common features in the beryllium-7 data records in northern sampling sites. The beryllium-7 activity concentrations exhibit statistically significant positive trends that range from an average value of 1.50%/year to an average value of 2.96%/year. We detect a one-year periodicity in all the sites, and in the southernmost site, Risoe in Denmark, additional higher-frequency harmonics. In the residual time series, we find outliers that represent occurrences of extremely high beryllium-7 activity concentration. Cross-correlations of the beryllium-7 residuals across the four sites decrease with increasing distance; similarly, as indicated by local Hurst exponents the records exhibit long-range correlations that weaken towards the end of the investigated period. To investigate the causes of the detected trends, we also calculate correlations between beryllium-7 and factors related to its production, transport and removal from the atmosphere: in particular, cross-correlations of the beryllium-7 residuals with residuals in sunspot number, local temperature, atmospheric pressure and precipitation, as well as Arctic Oscillation index and North Atlantic Oscillation index. Most of the obtained correlations, however, are not statistically significant, highlighting the need to analyse a longer time period in order to evaluate the impact of different factors on the airborne beryllium-7 activity concentration.
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Affiliation(s)
- Stefano Bianchi
- Department of Mathematics and Physics, Roma Tre University, Via 'della Vasca Navale, 84, I-00146, Rome, Italy.
| | - Wolfango Plastino
- Department of Mathematics and Physics, Roma Tre University, Via 'della Vasca Navale, 84, I-00146, Rome, Italy.
| | - Erika Brattich
- Department of Physics and Astronomy, Alma Mater Studiorum University of Bologna, Via Irnerio 46, 40126, Bologna, BO, Italy.
| | - Vladimir Djurdjevic
- Institute of Meteorology, Faculty of Physics, University of Belgrade, Studentski trg 18, 11000, Belgrade, Serbia.
| | - Alessandro Longo
- Department of Mathematics and Physics, Roma Tre University, Via 'della Vasca Navale, 84, I-00146, Rome, Italy.
| | - Miguel A Hernández-Ceballos
- European Commission, Joint Research Centre, Knowledge for Nuclear Security and Safety Unit Radioactivity Environmental Monitoring Group, Via Enrico Fermi 2749, I-21027, Ispra, VA, Italy.
| | - Darko Sarvan
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000, Belgrade, Serbia.
| | - Jelena Ajtić
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000, Belgrade, Serbia.
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Ajtić J, Brattich E, Sarvan D, Djurdjevic V, Hernández-Ceballos MA. Factors affecting the 7Be surface concentration and its extremely high occurrences over the Scandinavian Peninsula during autumn and winter. CHEMOSPHERE 2018; 199:278-285. [PMID: 29448195 DOI: 10.1016/j.chemosphere.2018.02.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/04/2018] [Accepted: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Relationships between the beryllium-7 activity concentrations in surface air and meteorological parameters (temperature, atmospheric pressure, and precipitation), teleconnection indices (Arctic Oscillation, North Atlantic Oscillation, and Scandinavian pattern) and number of sunspots are investigated using two multivariate statistical techniques: hierarchical cluster and factor analysis. The beryllium-7 surface measurements over 1995-2011, at four sampling sites located in the Scandinavian Peninsula, are obtained from the Radioactivity Environmental Monitoring Database. In all sites, the statistical analyses show that the beryllium-7 concentrations are strongly linked to temperature. Although the beryllium-7 surface concentration exhibits the well-characterised spring/summer maximum, our study shows that extremely high beryllium-7 concentrations, defined as the values exceeding the 90th percentile in the data records for each site, also occur over the October-March period. Two types of autumn/winter extremes are distinguished: type-1 when the number of extremes in a given month is less than three, and type-2 when at least three extremes occur in a month. Factor analysis performed for these autumn/winter events shows a weaker effect of temperature and a stronger impact of the transport and production signal on the beryllium-7 concentrations. Further, the majority of the type-2 extremes are associated with a very high monthly Scandinavian teleconnection index. The type-2 extremes that occurred in January, February and March are also linked to sudden stratospheric warmings of the Arctic vortex. Our results indicate that the Scandinavian teleconnection index might be a good indicator of the meteorological conditions facilitating extremely high beryllium-7 surface concentrations over Scandinavia during autumn and winter.
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Affiliation(s)
- J Ajtić
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000, Belgrade, Serbia.
| | - E Brattich
- Department of Physics and Astronomy, Alma Mater Studiorum University of Bologna, Via Irnerio 46, 40126, Bologna, BO, Italy.
| | - D Sarvan
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000, Belgrade, Serbia.
| | - V Djurdjevic
- Institute of Meteorology, Faculty of Physics, University of Belgrade, Studentski trg 18, 11000, Belgrade, Serbia.
| | - M A Hernández-Ceballos
- European Commission, Joint Research Centre, Knowledge for Nuclear Security and Safety Unit Radioactivity Environmental Monitoring Group, Via Enrico Fermi 2749, I-21027, Ispra, VA, Italy.
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Terzi L, Kalinowski M. World-wide seasonal variation of 7Be related to large-scale atmospheric circulation dynamics. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:1-15. [PMID: 28734163 DOI: 10.1016/j.jenvrad.2017.06.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Lucrezia Terzi
- Belgian Nuclear Research Centre (SCK.CEN), Mol, Belgium.
| | - Martin Kalinowski
- Provisional Technical Secretariat, Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Vienna International Centre, P.O. Box 1200, A-1400 Vienna, Austria
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ITOH H, NARAZAKI Y. Meteorological Notes for Understanding the Transport of Beryllium-7 in the Troposphere. ACTA ACUST UNITED AC 2017. [DOI: 10.5453/jhps.52.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Hisanori ITOH
- Department of Earth and Planetary Sciences, Kyushu University
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Masson O, Bieringer J, Brattich E, Dalheimer A, Estier S, Penev I, Ringer W, Schlosser C, Steinkopff T, Steinmann P, Tositti L, Van Beek P, Vismes-Ott AD. Variation in airborne 134Cs, 137Cs, particulate 131I and 7Be maximum activities at high-altitude European locations after the arrival of Fukushima-labeled air masses. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 162-163:14-22. [PMID: 27214283 DOI: 10.1016/j.jenvrad.2016.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 06/05/2023]
Abstract
The Fukushima-labeled air mass arrival, and later the cesium-134 (134Cs), cesium-137 (137Cs) and particulate iodine-131 (hereafter noted 131Ip) maximum levels were registered in Europe at different dates depending on the location. Most of those data were obtained at low-altitude sampling areas. Here, we compare the airborne levels registered at different high-altitude European locations (from 850 m to about 3500 m). The integrated 137Cs activity concentration was not uniform with regard to the altitude even after a long travel time/distance from Japan. Moreover, the relation of integrated 137Cs vs. altitude showed a linear decrease up to an altitude of about 3000 m. A similar trend was noticed for 131Ip (particulate fraction) while it increased above 3000 m. Comparison with 7Be activity concentration showed that, as far as the high altitude location is concerned, the 137Cs and 134Cs maximum concentrations corresponded to the 7Be maximum, suggesting downdraft movements from high tropospheric or stratospheric layers to be responsible for 137,134Cs increase and peak values. This was also confirmed by high potential vorticity and low relative humidity registered during the peak values.
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Affiliation(s)
- Olivier Masson
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), BP 3, 13115, St Paul lez Durance, Cedex, France.
| | | | - Erika Brattich
- Laboratorio di Chimica e Radioattività ambientale, University of Bologna, 40126 Bologna, Italy
| | - Axel Dalheimer
- Deutscher Wetterdienst (DWD), Referat TI 24, Frankfurterstraße 135, 63067 Offenbach, Germany
| | - Sybille Estier
- Federal Office of Public Health, (FOPH), Schwarzenburgstrasse 165, CH-3003 Bern, Switzerland
| | - Ilia Penev
- Institute for Nuclear Research and Nuclear Energy (INRNE), 72 Tzarigradsko shosse, Blvd Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria
| | - Wolfgang Ringer
- Austrian Agency for Health and Food Safety (AGES), Radon and Radioecology, 4020 Linz, Austria
| | | | - Thomas Steinkopff
- Deutscher Wetterdienst (DWD), Referat TI 24, Frankfurterstraße 135, 63067 Offenbach, Germany
| | - Philipp Steinmann
- Federal Office of Public Health, (FOPH), Schwarzenburgstrasse 165, CH-3003 Bern, Switzerland
| | - Laura Tositti
- Laboratorio di Chimica e Radioattività ambientale, University of Bologna, 40126 Bologna, Italy
| | - Pieter Van Beek
- Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Observatoire Midi Pyrénées, 14 avenue Edouard Belin, 31400 Toulouse, France
| | - Anne de Vismes-Ott
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), LMRE, 501, Bois des Rames, 91400 Orsay, France
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Hernández-Ceballos MA, Cinelli G, Ferrer MM, Tollefsen T, De Felice L, Nweke E, Tognoli PV, Vanzo S, De Cort M. A climatology of ⁷Be in surface air in European Union. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 141:62-70. [PMID: 25544729 DOI: 10.1016/j.jenvrad.2014.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 06/04/2023]
Abstract
This study presents a European-wide analysis of the spatial and temporal distribution of the cosmogenic isotope (7)Be in surface air. This is the first time that a long term database of 34 sampling sites that regularly provide data to the Radioactivity Environmental Monitoring (REM) network, managed by the Joint Research Centre (JRC) in Ispra, is used. While temporal coverage varies between stations, some of them have delivered data more or less continuously from 1984 to 2011. The station locations were considerably heterogeneous, both in terms of latitude and altitude, a range which should ensure a high degree of representativeness of the results. The mean values of (7)Be activity concentration presented a spatial distribution value ranging from 2.0 to 5.4 mBq/m(3) over the European Union. The results of the ANOVA analysis of all (7)Be data available indicated that its temporal and spatial distributions were mainly explained by the location and characteristic of the sampling sites rather than its temporal distribution (yearly, seasonal and monthly). Higher (7)Be concentrations were registered at the middle, compared to high-latitude, regions. However, there was no correlation with altitude, since all stations are sited within the atmospheric boundary layer. In addition, the total and yearly analyses of the data indicated a dynamic range of (7)Be activity for each solar cycle and phase (maximum or minimum), different impact on stations having been observed according to their location. Finally, the results indicated a significant seasonal and monthly variation for (7)Be activity concentration across the European Union, with maximum concentrations occurring in the summer and minimum in the winter, although with differences in the values reached. The knowledge of the horizontal and vertical distribution of this natural radionuclide in the atmosphere is a key parameter for modelling studies of atmospheric processes, which are important phenomena to be taken into account in the case of a nuclear accident.
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Affiliation(s)
- M A Hernández-Ceballos
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy.
| | - G Cinelli
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - M Marín Ferrer
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - T Tollefsen
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - L De Felice
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - E Nweke
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - P V Tognoli
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - S Vanzo
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
| | - M De Cort
- European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Nuclear Security Unit, Via Enrico Fermi 2749, I-21027 Ispra (VA), Italy
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Ioannidou A, Vasileiadis A, Melas D. Time lag between the tropopause height and ⁷Be activity concentrations on surface air. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2014; 129:80-85. [PMID: 24389554 DOI: 10.1016/j.jenvrad.2013.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 11/26/2013] [Accepted: 12/19/2013] [Indexed: 06/03/2023]
Abstract
A strong positive correlation between the seasonal changes of the tropopause height and the concentration of (7)Be in the surface air (R = 0.94, p < 0.0001) was observed at 40°N. Moreover, a strong positive correlation was revealed between the activity concentrations of (7)Be and the temperature T (°C) (R = 0.97, p < 0.001), confirming that the increased rate of vertical transport within the troposphere, especially during warmer months, has as a result the descent to the surface of air masses enriched in (7)Be. The results of the present work suggest that the temperature and the tropopause height are good indicators for transport time of air masses enriched in (7)Be to the surface. Higher values of temperature or tropopause height seem to result to shorter transport times. This is attributed to atmospheric convection which provides an effective mechanism for vertical transport of air masses. Increasing tropospheric temperature has generally as a result that convection penetrates more deeply which in turn leads to an increase in tropopause height. But, the atmospheric procedures do not occur immediately after the fluctuations of correlated factors. Thus, a time lag is expected between the tropopause height and (7)Be activity concentrations on surface air that might be from hours to days or weeks. The result suggests that (7)Be concentrations fully respond within three days after the changes in the tropopause height.
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Affiliation(s)
- A Ioannidou
- Aristotle University of Thessaloniki, Physics Department, Nuclear Physics Laboratory, Thessaloniki 54124, Greece.
| | - A Vasileiadis
- Aristotle University of Thessaloniki, Physics Department, Nuclear Physics Laboratory, Thessaloniki 54124, Greece
| | - D Melas
- Aristotle University of Thessaloniki, Physics Department, Laboratory of Atmospheric Physics, Thessaloniki 54124, Greece
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Jiwen L, Starovoitova VN, Wells DP. Long-term variations in the surface air 7Be concentration and climatic changes. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 116:42-47. [PMID: 23103574 DOI: 10.1016/j.jenvrad.2012.08.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/17/2012] [Accepted: 08/24/2012] [Indexed: 06/01/2023]
Abstract
We have used EML Surface Air Sampling Program (SASP) data to analyze the long-term trend in (7)Be surface concentration and address possible correlation between this long-term trend and climatic changes, namely changes in precipitation patterns and temperature. In this paper we present (7)Be concentration data from 23 sites, spanning over 25 years, all over the world, and extract long-term trend parameter using two independent techniques. The (7)Be concentrations in most stations show a pronounced decreasing trend, potentially corresponding to statistically significant changes in transporting (7)Be from upper atmosphere source to these sites. Weak negative correlation between (7)Be concentration and amount of precipitation was also observed. However, more data from more representative sites around the world are needed the statistical robustness of this trend.
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Affiliation(s)
- Liu Jiwen
- Idaho State University, Idaho Accelerator Center, 1500 Alvin Ricken Dr., Pocatello, ID 83201, USA
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Usoskin IG, Kovaltsov GA, Mironova IA. Cosmic ray induced ionization model CRAC:CRII: An extension to the upper atmosphere. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd013142] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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