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Hernández-Ceballos MA, Brattich E, Ajtić J. Airflow and teleconnection patterns driving the spatial and temporal variability of high 7Be air concentrations in Europe. CHEMOSPHERE 2022; 303:135194. [PMID: 35660056 DOI: 10.1016/j.chemosphere.2022.135194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The long-term monitoring of the cosmogenic 7Be activity concentrations has been used to better understand the influence of large-scale atmospheric circulation dynamics in the troposphere. With an aim, this study analyzes weekly 7Be data from 15 sampling stations in Europe over 2005-2014. We first define peak (or extremely high) events in each station as those activity concentrations above the 90th percentile, and then investigate their temporal and spatial variability. These events are most frequent in the spring and summer seasons, with a notable latitudinal variability in their number. Next, we use back-trajectory cluster analysis to identify the main advection pathways associated with these high concentrations. To achieve this, persistent periods, i.e., sampling periods over which at least 60% of the calculated backward trajectories arriving at a given site correspond to the same airflow pattern, are taken as reference. This method reveals large differences in the association between the airflow patterns observed at different stations in connection with the 7Be peaks. A comparison between stations shows no clear spatial pattern, which suggests a further influence of mesoscale/local physical processes on the surface 7Be activity concentrations. Finally, the main airflow pattern at each sampling site and the associated 7Be peaks, are related to the main teleconnection patterns of large scale and regional climate variability in Europe: North Atlantic Oscillation, Arctic Oscillation, East Atlantic, East Atlantic/Western Russia, Scandinavian pattern and Western Mediterranean Oscillation. The results point out the connection between the negative phases of NAO and We-MO, and the positive phase of EA with the spatial and temporal variability and occurrence of the 7Be peak activity concentrations. These results show a latitudinal division between northern and southern sites, with similar influence of teleconnection patterns, while those located in the central part of Europe present larger variability in the impact of teleconnection patterns.
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Affiliation(s)
| | - E Brattich
- Department of Physics and Astronomy "Augusto Righi", Alma Mater Studiorum University of Bologna, via Irnerio 46, 40126, Bologna (BO), Italy
| | - J Ajtić
- Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000, Belgrade, Serbia
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Russo A, Borras A. Comparison of dimension reduction techniques applied to the analysis of airborne radionuclide activity concentration. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 244-245:106813. [PMID: 35092902 DOI: 10.1016/j.jenvrad.2022.106813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Temporal variation of airborne radionuclide activity concentration is highly influenced by several meteorological parameters. A traditional key tool to perform a combined analysis on these data is Principal Component Analysis (PCA), a linear dimensionality reduction technique that prioritizes the conservation of the data set global structure. While it reveals important information regarding the correlation among the considered variables, the obtained visual representations do not usually allow to clearly discern different clusters of states with common properties. The main goal of this study is applying two recently introduced non linear dimensionality reduction techniques, t-distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP) to a data set composed by 7Be and gross beta (Aβ) activity concentration and other meteorological data gathered in Mallorca (Spain) between 2004 and 2014. Compared to PCA, both algorithms reveal more details on the local structure of the data set. UMAP allows to clearly identify data clusters with different characteristics that are not clearly identified with the alternative techniques.
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Affiliation(s)
- A Russo
- Environmental Radioactivity Laboratory, University of the Balearic Islads, Cra. Valldemossa km 7.5, E-07122, Palma, Spain
| | - A Borras
- Environmental Radioactivity Laboratory, University of the Balearic Islads, Cra. Valldemossa km 7.5, E-07122, Palma, Spain.
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Kremenchutskii DA. Influence of precipitation on the daily beryllium-7 ( 7Be) activity concentration in the atmospheric surface layer. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 237:106722. [PMID: 34425548 DOI: 10.1016/j.jenvrad.2021.106722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/04/2021] [Accepted: 08/15/2021] [Indexed: 06/13/2023]
Abstract
The paper presents the monitoring results of the temporal variability of daily 7Be activity concentration in the atmospheric surface layer at Sevastopol in 2011-2020. The 7Be activity concentration in individual samples of atmospheric aerosols varies from 0.1 to 13.3 mBq m-3 and averages 4.0 ± 2.0 Bq m-3. Higher 7Be activity concentrations have been observed during the period from May to August while lower concentrations have been measured from December to January. Quantitative estimates of the influence of precipitation (amount, duration, intensity) on the temporal variability of 7Be activity concentration have been obtained. It has been found that daily 7Be activity concentration decrease by 2-82% on the first day with precipitation. It has been shown that an increase in precipitation duration and a decrease in its intensity lead to a more significant decrease in the daily 7Be activity concentration. The estimates of the scavenging coefficient have been obtained; the average value is 0.6 ± 1.0 h-1. An increase in the precipitation intensity or amount is accompanied by a decrease in the 7Be scavenging coefficient. Mean 0.5-folding and residence times of 7Be activity concentration in the atmosphere during a moderate rain event are 2.9 ± 2.2 and 15.4 ± 13.6 h, respectively. The recovery of 7Be activity concentration in the atmosphere after precipitation has been investigated. It has been found that this process takes 1-2 days. The mean value of the reload coefficient is 0.94 ± 0.34 d-1. The relationship between the value of the reload coefficient and local meteorological parameters (air temperature, relative humidity, atmospheric pressure, wind speed, surface net solar radiation flux) has been investigated. No statistically significant correlations at a 95% confidence level between the reload coefficient and the considered meteorological parameters have been revealed. Parameterization describing a decrease in the daily 7Be activity concentration in the atmosphere due to precipitation and its recovery during the precipitation-free period has been introduced.
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Affiliation(s)
- Dmitrii A Kremenchutskii
- Marine Hydrophysical Institute of RAS, Kapitanskaya Street 2, Sevastopol, 299011, Russian Federation.
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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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Leppänen AP. Deposition of naturally occurring 7Be and 210Pb in Northern Finland. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 208-209:105995. [PMID: 31254861 DOI: 10.1016/j.jenvrad.2019.105995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 06/07/2019] [Accepted: 06/13/2019] [Indexed: 06/09/2023]
Abstract
This study presents observations of naturally occurring 7Be and 210Pb in total deposition collected in three deposition sampling stations located in three towns in Northern Finland at Rovaniemi, Sodankylä and Ivalo. The deposition samples were measured in three-month intervals and the collected data covered the years from 1991 to 2017 in Rovaniemi and the years from 1999 to 2017 in Sodankylä and Ivalo. The 7Be deposition was observed to be dependent on the amount of precipitation where higher amount of precipitation meant higher 7Be deposition. The 7Be deposition showed a distinctive seasonal cycle where the highest 7Be deposition values were observed occur during July-September and the lowest values during January-March. From the annual total deposition 72-84% occurred during the months of April-September (2nd and 3rd quarters). The precipitation normalized enrichment factor (α) determined the excess or deficiency of 7Be relative to the amount of rain. The most excess of 7Be in the deposition was observed during April-June (2nd quarter) while the most 7Be depleted precipitation occurred during January-March (1st quarter). The large excess of 7Be in precipitation during April-June (2nd quarter) was an indication of injections of 7Be rich stratospheric air into troposphere. By using simultaneously collected 7Be aerosol concentration data at Rovaniemi and Ivalo, the 7Be deposition velocities were determined. The deposition velocities (VD) were also found to have a strong seasonal cycle where low velocities were observed during winter and higher ones during summer. The 7Be deposition time series were also compared with other time series that are known to affect ground level 7Be aerosol concentrations. These were precipitation, sunspot number (SSN), galactic cosmic ray flux (GCR), Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and Scandinavian Pattern (SCAND) indices. The Pearson correlation and wavelet coherence (WTC) was used to analyze possible correlations between the time series. The analyses showed that the coherences were location dependent. Rovaniemi 7Be deposition data correlated strongly with rain and weakly with the SCAND index at the 6-8 year scale. The Sodankylä 7Be deposition data correlated strongly with the precipitation and SSN and GCR and weakly with AO and NAO indices. Ivalo 7Be deposition data correlated with strongly with 7Be aerosol concentration data, SSN, GCR and NAO index and weakly with the AO index. The WTC analysis revealed anti-phase coherences with the AO and NAO indices at 4-6 year scale. The 210Pb deposition data was sparse and only available from 2011 onwards. 210Pb deposition had a seasonal cycle where higher deposition values were observed during summer and lower ones deposition during winter. The annual 210Pb deposition was determined at Rovaniemi and Sodankylä during 2014. The values of 7Be/210Pb ratio was found to vary significantly seasonally, higher 7Be/210Pb ratios were measured during summer and lower ones during winter.
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Affiliation(s)
- Ari-Pekka Leppänen
- Radiation and Nuclear Safety Authority - STUK, Lähteentie 2, 96400, Rovaniemi, Finland.
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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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San Miguel EG, Hernández-Ceballos MA, García-Mozo H, Bolívar JP. Evidences of different meteorological patterns governing 7Be and 210Pb surface levels in the southern Iberian Peninsula. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 198:1-10. [PMID: 30557786 DOI: 10.1016/j.jenvrad.2018.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
7Be, 210Pb and PM10 levels in surface air have been simultaneously measured at two sampling sites in the southern Iberian Peninsula for a period of two years. Each site covers one different meteorological area of the Guadalquivir valley, from the mouth (Huelva) to the middle point (Cordoba). The objective of the present study is to analyse the spatial variability of both natural radionuclides, and to identify and characterise the meteorological patterns associated with similar and different surface concentration levels in this complex region. Concentrations are similar in both sampling sites. 7Be level is in the 0.6-15.5 mBq m-3 range in Huelva and 1.2-13.3 mBq m-3 in Córdoba, 210Pb activity concentrations are between 0.04 and 2.30 mBq m-3 in Huelva, and between 0.03 and 1.2 mBq m-3 in Cordoba, and PM10 concentrations are found to be in the 5.1-81.3 μg m-3 range in Huelva, and 8.2-76.3 μg m-3 in Cordoba, respectively. A linear regression analysis indicates more regional variability for 210Pb than for 7Be between simultaneous measurements. Principal components analysis (PCA) is applied to the datasets and the results reveal that aerosol behaviour is mainly represented by two components, which explain 82% of the total variance. The analysis of surface measurements and meteorological parameters revealed that component F1 groups sampling periods in which the influence of similar meteorological conditions over the region lead to similar 7Be, 210Pb and PM10 concentration levels in both sampling sites. On the other hand, component F2 detaches the 7Be, 210Pb and PM10 concentration levels between monitoring sites, and the meteorological analysis shows how surface concentrations within this component are associated with the development of different mesoscale circulations in each part of the valley. The identification of sampling periods characterised by differences in surface concentrations and wind patterns between stations suggests that the valley could not be considered as one single unit for certain meteorological scenarios. These results evidence how the understanding of wind characteristics within a complex terrain provide some essential knowledge in the regionalization and/or optimization of monitoring networks.
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Affiliation(s)
- E G San Miguel
- Department of Integrated Sciences, Area of Applied Physics, University of Huelva, 21071, Huelva, Spain; Research Center on Natural Resources, Health and the Environment (RENSMA), University of Huelva, 21071, Huelva, Spain.
| | | | - H García-Mozo
- Department of Botany, Ecology and Plant Physiology, Agrifood, Campus of International Excellence (CeiA3), University of Córdoba, Córdoba, Spain
| | - J P Bolívar
- Department of Integrated Sciences, Area of Applied Physics, University of Huelva, 21071, Huelva, Spain; Research Center on Natural Resources, Health and the Environment (RENSMA), University of Huelva, 21071, Huelva, Spain
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