TY  - CONF
AU  - Stratimirović, Djordje
AU  - Sarvan, Darko
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
AU  - Djurdjević, Vladimir
AU  - Ajtić, Jelena
PY  - 2021
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2371
AB  - U ovom radu razmatramo vremenske serije srednjih nedeljnih specifičnih aktivnosti
berilijuma-7 u vazduhu i temperature na lokaciji Beč (48,22 ºN; 16,35 ºE; 193 m n.v.) u
Austriji, koje su zabeležene od februara 1987. do decembra 2014. godine. Merenja
specifične aktivnosti berilijuma-7 u prizmenom sloju vazduha preuzeta su iz
Radioactivity Environmental Monitoring databank (REMdb) koju održava Objedinjeni
istraživački centar u Ispri, Italija, a podaci za lokalnu temperaturu iz E-OBS gridovane
klimatologije (verzija 15) koji su potom bilinearnom interpolacijom ekstrahovani na
lokaciju uzorkovanja berilijuma-7. Za analizu serija koristili smo korelacionu analizu i
vejvlet transformacije. Vrednost Pirsonovog koeficijenta korelacije od 0,68 ukazuje na
jaku vezu između nedeljnih specifičnih aktivnosti berilijuma-7 i temperature, dok vejvlet
spektri snage pokazuju izraziti godišnji period za obe varijable tokom ispitivanog
vremenskog intervala. Godišnji period dominantno je vidljiv i na kros-korelacionom
spektru. Takođe je uočen blagi fazni pomeraj koji ukazuje da promena specifične
aktivnosti berilijuma-7 merene u prizemnom sloju vazduha prethodi promeni
temperature
PB  - Institut za nuklearne nauke „Vinča“
C3  - Zbornik radova sa XXXI Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 6–8. oktobar, 2021, Beograd, Srbija
T1  - Korelacione karakteristike specifične aktivnosti berilijuma-7 i temperature na dugogodišnjim nizovima nedeljnih vrednosti
SP  - 27
EP  - 31
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2371
ER  - 

@conference{
author = "Stratimirović, Djordje and Sarvan, Darko and Brattich, Erika and Hernández-Ceballos, Miguel Angel and Djurdjević, Vladimir and Ajtić, Jelena",
year = "2021",
abstract = "U ovom radu razmatramo vremenske serije srednjih nedeljnih specifičnih aktivnosti
berilijuma-7 u vazduhu i temperature na lokaciji Beč (48,22 ºN; 16,35 ºE; 193 m n.v.) u
Austriji, koje su zabeležene od februara 1987. do decembra 2014. godine. Merenja
specifične aktivnosti berilijuma-7 u prizmenom sloju vazduha preuzeta su iz
Radioactivity Environmental Monitoring databank (REMdb) koju održava Objedinjeni
istraživački centar u Ispri, Italija, a podaci za lokalnu temperaturu iz E-OBS gridovane
klimatologije (verzija 15) koji su potom bilinearnom interpolacijom ekstrahovani na
lokaciju uzorkovanja berilijuma-7. Za analizu serija koristili smo korelacionu analizu i
vejvlet transformacije. Vrednost Pirsonovog koeficijenta korelacije od 0,68 ukazuje na
jaku vezu između nedeljnih specifičnih aktivnosti berilijuma-7 i temperature, dok vejvlet
spektri snage pokazuju izraziti godišnji period za obe varijable tokom ispitivanog
vremenskog intervala. Godišnji period dominantno je vidljiv i na kros-korelacionom
spektru. Takođe je uočen blagi fazni pomeraj koji ukazuje da promena specifične
aktivnosti berilijuma-7 merene u prizemnom sloju vazduha prethodi promeni
temperature",
publisher = "Institut za nuklearne nauke „Vinča“",
journal = "Zbornik radova sa XXXI Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 6–8. oktobar, 2021, Beograd, Srbija",
title = "Korelacione karakteristike specifične aktivnosti berilijuma-7 i temperature na dugogodišnjim nizovima nedeljnih vrednosti",
pages = "27-31",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2371"
}

Stratimirović, D., Sarvan, D., Brattich, E., Hernández-Ceballos, M. A., Djurdjević, V.,& Ajtić, J.. (2021). Korelacione karakteristike specifične aktivnosti berilijuma-7 i temperature na dugogodišnjim nizovima nedeljnih vrednosti. in Zbornik radova sa XXXI Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 6–8. oktobar, 2021, Beograd, Srbija
Institut za nuklearne nauke „Vinča“., 27-31.
https://hdl.handle.net/21.15107/rcub_veterinar_2371

Stratimirović D, Sarvan D, Brattich E, Hernández-Ceballos MA, Djurdjević V, Ajtić J. Korelacione karakteristike specifične aktivnosti berilijuma-7 i temperature na dugogodišnjim nizovima nedeljnih vrednosti. in Zbornik radova sa XXXI Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 6–8. oktobar, 2021, Beograd, Srbija. 2021;:27-31.
https://hdl.handle.net/21.15107/rcub_veterinar_2371 .

Stratimirović, Djordje, Sarvan, Darko, Brattich, Erika, Hernández-Ceballos, Miguel Angel, Djurdjević, Vladimir, Ajtić, Jelena, "Korelacione karakteristike specifične aktivnosti berilijuma-7 i temperature na dugogodišnjim nizovima nedeljnih vrednosti" in Zbornik radova sa XXXI Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 6–8. oktobar, 2021, Beograd, Srbija (2021):27-31,
https://hdl.handle.net/21.15107/rcub_veterinar_2371 .

TY  - CONF
AU  - Stratimirović, Djordje
AU  - Sarvan, Darko
AU  - Hernández-Ceballos, Miguel Angel
AU  - Ajtić, Jelena
PY  - 2019
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2343
AB  - Beryllium-7, a cosmogenic radionuclide, attaches to aerosols promptly after its formation and thereon descends from the upper troposphere and lower stratosphere to the surface. At the surface, this isotope’s activity concentration is closely monitored as a part of radioactivity measurements in many countries. Since the abundance of beryllium-7 offers an insight into the processes that take place along its trajectory through the atmosphere, it is considered a tracer of air mass history. For this reason, there is an incentive to fully understand its behaviour and the mechanisms that correlate it to meteorological parameters. Our analysis, therefore, looks into one particular aspect of this question – autocorrelation properties of the beryllium-7 records that imply a manner in which this radionuclide’s activity concentration changes with time. The analysis is performed on the measurements taken at three Fenno-Scandinavian sites north of 55 °N: Helsinki (Finland), Kista (Sweden) and Risoe (Denmark), given here in order of descending latitude. The data are taken from the Radioactivity Monitoring Environmental Data Bank (REMdb) and span 1987-2013 for Helsinki, and 1995-2013 for Kista and Risoe. The Helsinki data series is longer and with a higher temporal resolution (approximately once in two days) than the Kista and Risoe series (approximately once a week). For each site, we investigate the wavelet power spectrum and look into the scaling properties of the time series, as well as its trend and periodicities. One of the results that the wavelet analysis offers is a power spectrum scaling exponent β, which is related to the decay of the autocorrelation function of a time series, and effectively points to the existence of a temporal trend. A stationary time series is regarded as long-term correlated for β between 0 and 1. Our study gives β values of 0.77, 0.56 and 0.63 for Helsinki, Kista, and Risoe, respectively. This finding implies a trend in all of the investigated beryllium-7 records, with the strongest trend detected for Helsinki. In addition, the investigated wavelet power spectra show local maxima corresponding to characteristic time intervals of the series. The most prominent peak in each spectrum points to the seasonal cycle, i.e. a periodicity of one year. A further wavelet analysis of the meteorological parameters, such as temperature and precipitation, could shed more light on their possible correlation with the beryllium-7 trends, and, in turn, these findings could allow us to evaluate this radionuclide’s full potential as an atmospheric tracer.
PB  - Niš : Sievert Association
C3  - Book of Abstracts of the International Conference on Radiation Applications, September 16–19, 2019, Beograd, Srbija
T1  - Scaling properties of the beryllium-7 activity concentrations in the surface air in Fenno-Scandinavia
SP  - 26
EP  - 26
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2343
ER  - 

@conference{
author = "Stratimirović, Djordje and Sarvan, Darko and Hernández-Ceballos, Miguel Angel and Ajtić, Jelena",
year = "2019",
abstract = "Beryllium-7, a cosmogenic radionuclide, attaches to aerosols promptly after its formation and thereon descends from the upper troposphere and lower stratosphere to the surface. At the surface, this isotope’s activity concentration is closely monitored as a part of radioactivity measurements in many countries. Since the abundance of beryllium-7 offers an insight into the processes that take place along its trajectory through the atmosphere, it is considered a tracer of air mass history. For this reason, there is an incentive to fully understand its behaviour and the mechanisms that correlate it to meteorological parameters. Our analysis, therefore, looks into one particular aspect of this question – autocorrelation properties of the beryllium-7 records that imply a manner in which this radionuclide’s activity concentration changes with time. The analysis is performed on the measurements taken at three Fenno-Scandinavian sites north of 55 °N: Helsinki (Finland), Kista (Sweden) and Risoe (Denmark), given here in order of descending latitude. The data are taken from the Radioactivity Monitoring Environmental Data Bank (REMdb) and span 1987-2013 for Helsinki, and 1995-2013 for Kista and Risoe. The Helsinki data series is longer and with a higher temporal resolution (approximately once in two days) than the Kista and Risoe series (approximately once a week). For each site, we investigate the wavelet power spectrum and look into the scaling properties of the time series, as well as its trend and periodicities. One of the results that the wavelet analysis offers is a power spectrum scaling exponent β, which is related to the decay of the autocorrelation function of a time series, and effectively points to the existence of a temporal trend. A stationary time series is regarded as long-term correlated for β between 0 and 1. Our study gives β values of 0.77, 0.56 and 0.63 for Helsinki, Kista, and Risoe, respectively. This finding implies a trend in all of the investigated beryllium-7 records, with the strongest trend detected for Helsinki. In addition, the investigated wavelet power spectra show local maxima corresponding to characteristic time intervals of the series. The most prominent peak in each spectrum points to the seasonal cycle, i.e. a periodicity of one year. A further wavelet analysis of the meteorological parameters, such as temperature and precipitation, could shed more light on their possible correlation with the beryllium-7 trends, and, in turn, these findings could allow us to evaluate this radionuclide’s full potential as an atmospheric tracer.",
publisher = "Niš : Sievert Association",
journal = "Book of Abstracts of the International Conference on Radiation Applications, September 16–19, 2019, Beograd, Srbija",
title = "Scaling properties of the beryllium-7 activity concentrations in the surface air in Fenno-Scandinavia",
pages = "26-26",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2343"
}

Stratimirović, D., Sarvan, D., Hernández-Ceballos, M. A.,& Ajtić, J.. (2019). Scaling properties of the beryllium-7 activity concentrations in the surface air in Fenno-Scandinavia. in Book of Abstracts of the International Conference on Radiation Applications, September 16–19, 2019, Beograd, Srbija
Niš : Sievert Association., 26-26.
https://hdl.handle.net/21.15107/rcub_veterinar_2343

Stratimirović D, Sarvan D, Hernández-Ceballos MA, Ajtić J. Scaling properties of the beryllium-7 activity concentrations in the surface air in Fenno-Scandinavia. in Book of Abstracts of the International Conference on Radiation Applications, September 16–19, 2019, Beograd, Srbija. 2019;:26-26.
https://hdl.handle.net/21.15107/rcub_veterinar_2343 .

Stratimirović, Djordje, Sarvan, Darko, Hernández-Ceballos, Miguel Angel, Ajtić, Jelena, "Scaling properties of the beryllium-7 activity concentrations in the surface air in Fenno-Scandinavia" in Book of Abstracts of the International Conference on Radiation Applications, September 16–19, 2019, Beograd, Srbija (2019):26-26,
https://hdl.handle.net/21.15107/rcub_veterinar_2343 .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Djurdjević, Vladimir
AU  - Sarvan, Darko
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
AU  - Zorko, Benjamin
AU  - Todorović, Dragana
PY  - 2019
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2344
AB  - Since 2015, a scientific collaboration network between the University of Belgrade, the University
of Bologna and the Radioactive Monitoring Environmental (REM) group of the European
Commission Joint Research Centre – Ispra, has addressed the characterisation of the beryllium-7
concentration in the surface air recorded across Europe, and its link with meteorological conditions.
A set of studies carried out over this period has been based on the beryllium-7 activity measurements
collected and validated by the Radioactivity Monitoring Environmental Data Bank (REMdb)
(https://rem.jrc.ec.europa.eu/RemWeb/Index.aspx). REMdb makes accessible and understandable
to a wider audience radioactivity measurements made by all European Member States in the air,
water, milk, and mixed diet. Thus, the scientific community is given research opportunities to exploit
a unique collection of almost 5 million environmental radioactivity measurements taken across
Europe since 1988. Our collaboration has also investigated other sets of multidecadal beryllium-7
activity concentrations: 1) sampled in Serbia and measured at the Vinča Institute of Nuclear Sciences,
and 2) sampled in Slovenia and measured at the Jožef Stefan Institute.
This paper compiles our current understanding of the abundance of beryllium-7, which is a
naturally occurring radionuclide, in the surface air in Europe. Beryllium-7 is produced in the upper
troposphere-lower stratosphere (UT-LS) region, where it attaches to fine aerosols and is then
transported through the atmosphere. Due to its origin, it is considered a good tracer of air mass
history, and it can be used as an indicator of different processes in the atmosphere, such as vertical
exchange across the UT-LS region. Based on a number of our previous studies, we here give an
overall picture of the beryllium-7 activity concentration distribution in Europe. We describe its
general decrease from the south of the continent towards the polar region, different periodicities and
outliers identified in the time series, and we make an effort to identify the underlying driving
mechanisms that give rise to this distribution. We also look into temporal trends that show a
statistically significant increase in the beryllium-7 surface concentration. Since temperature is one of
the major factors that influence this radionuclide’s abundance in the air, we speculate that the trends
are affected by the global increase in temperature. For that reason, we intend to further inquire into
the possibility of using the beryllium-7 surface concentration as an indicator of climate change.
PB  - Niš : RAD Centre
C3  - Book of Abstracts of the Seventh International Conference on Radiation in Various Fields of Research, June 10–14, 2019, Herceg Novi, Montenegro
T1  - Temporal and spatial distribution of the beryllium-7 activity concentration in the surface air in Europe
SP  - 9
EP  - 9
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2344
ER  - 

@conference{
author = "Ajtić, Jelena and Djurdjević, Vladimir and Sarvan, Darko and Brattich, Erika and Hernández-Ceballos, Miguel Angel and Zorko, Benjamin and Todorović, Dragana",
year = "2019",
abstract = "Since 2015, a scientific collaboration network between the University of Belgrade, the University
of Bologna and the Radioactive Monitoring Environmental (REM) group of the European
Commission Joint Research Centre – Ispra, has addressed the characterisation of the beryllium-7
concentration in the surface air recorded across Europe, and its link with meteorological conditions.
A set of studies carried out over this period has been based on the beryllium-7 activity measurements
collected and validated by the Radioactivity Monitoring Environmental Data Bank (REMdb)
(https://rem.jrc.ec.europa.eu/RemWeb/Index.aspx). REMdb makes accessible and understandable
to a wider audience radioactivity measurements made by all European Member States in the air,
water, milk, and mixed diet. Thus, the scientific community is given research opportunities to exploit
a unique collection of almost 5 million environmental radioactivity measurements taken across
Europe since 1988. Our collaboration has also investigated other sets of multidecadal beryllium-7
activity concentrations: 1) sampled in Serbia and measured at the Vinča Institute of Nuclear Sciences,
and 2) sampled in Slovenia and measured at the Jožef Stefan Institute.
This paper compiles our current understanding of the abundance of beryllium-7, which is a
naturally occurring radionuclide, in the surface air in Europe. Beryllium-7 is produced in the upper
troposphere-lower stratosphere (UT-LS) region, where it attaches to fine aerosols and is then
transported through the atmosphere. Due to its origin, it is considered a good tracer of air mass
history, and it can be used as an indicator of different processes in the atmosphere, such as vertical
exchange across the UT-LS region. Based on a number of our previous studies, we here give an
overall picture of the beryllium-7 activity concentration distribution in Europe. We describe its
general decrease from the south of the continent towards the polar region, different periodicities and
outliers identified in the time series, and we make an effort to identify the underlying driving
mechanisms that give rise to this distribution. We also look into temporal trends that show a
statistically significant increase in the beryllium-7 surface concentration. Since temperature is one of
the major factors that influence this radionuclide’s abundance in the air, we speculate that the trends
are affected by the global increase in temperature. For that reason, we intend to further inquire into
the possibility of using the beryllium-7 surface concentration as an indicator of climate change.",
publisher = "Niš : RAD Centre",
journal = "Book of Abstracts of the Seventh International Conference on Radiation in Various Fields of Research, June 10–14, 2019, Herceg Novi, Montenegro",
title = "Temporal and spatial distribution of the beryllium-7 activity concentration in the surface air in Europe",
pages = "9-9",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2344"
}

Ajtić, J., Djurdjević, V., Sarvan, D., Brattich, E., Hernández-Ceballos, M. A., Zorko, B.,& Todorović, D.. (2019). Temporal and spatial distribution of the beryllium-7 activity concentration in the surface air in Europe. in Book of Abstracts of the Seventh International Conference on Radiation in Various Fields of Research, June 10–14, 2019, Herceg Novi, Montenegro
Niš : RAD Centre., 9-9.
https://hdl.handle.net/21.15107/rcub_veterinar_2344

Ajtić J, Djurdjević V, Sarvan D, Brattich E, Hernández-Ceballos MA, Zorko B, Todorović D. Temporal and spatial distribution of the beryllium-7 activity concentration in the surface air in Europe. in Book of Abstracts of the Seventh International Conference on Radiation in Various Fields of Research, June 10–14, 2019, Herceg Novi, Montenegro. 2019;:9-9.
https://hdl.handle.net/21.15107/rcub_veterinar_2344 .

Ajtić, Jelena, Djurdjević, Vladimir, Sarvan, Darko, Brattich, Erika, Hernández-Ceballos, Miguel Angel, Zorko, Benjamin, Todorović, Dragana, "Temporal and spatial distribution of the beryllium-7 activity concentration in the surface air in Europe" in Book of Abstracts of the Seventh International Conference on Radiation in Various Fields of Research, June 10–14, 2019, Herceg Novi, Montenegro (2019):9-9,
https://hdl.handle.net/21.15107/rcub_veterinar_2344 .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
AU  - Djurdjević, Vladimir
PY  - 2019
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2372
AB  - MeĎu najbitnije faktore koji utiču na specifičnu aktivnost berilijuma-7 u prizemnom
sloju atmosfere spadaju temperatura i količina padavina. U ovom radu stoga
razmatramo njihove vremenske trendove izmeĎu 2000. i 2014. godine, na šest lokacija u
Evropi: Madrid i Bilbao (Španija) na jugu; Beč (Austrija) i Luksemburg (Luksemburg)
u centralnoj oblasti; kao i Riso (Danska) i Ivalo (Finska) na severu kontinenta. Podaci
za specifičnu aktivnost berilijuma-7 preuzeti su iz Radioactivity Environmental
Monitoring data bank (REMdb), a podaci za lokalnu temperaturu i količinu padavina iz
E-OBS gridovane klimatologije (verzija 15) i potom bilinearnom interpolacijom
ekstrahovani na šest lokacija uzorkovanja berilijuma-7. Za dobijanje trendova koristili
smo sezonski Kendalov test, u kome se za svaki mesec tokom godine prvo primeni
Man-Kendalov trend test, a potom se rezultati kombinuju. Statistički značajni (p < 0,05)
pozitivni trendovi specifične aktivnosti berilijuma-7 dobijeni su za četiri lokacije:
Madrid (8,71·10-5 Bq·m-3/god), Bilbao (3,13·10-5 Bq·m-3/god), Luksemburg (4,00·10-5
Bq·m-3/god), i Ivalo (1,91·10-5 Bq·m-3/god), a statistički značajan pozitivan trend
temperature detektovan je samo za Madrid. Naša analiza ukazuje na povećanje
koncentracije berilijuma-7 u Evropi tokom 2000–2014, sa izraţenijim trendom na jugu
nego na severu. MeĎutim, kako dobijeni trendovi za temperaturu i količinu padavina
uglavnom nisu statistički značajni, nije moguće razmotriti njihovu meĎusobnu
povezanost. U budućim analizama ovog problema stoga treba uzeti u obzir duţe
vremenske nizove ovih promenljivih.
PB  - Institut za nuklearne nauke „Vinča"
C3  - Zbornik radova sa XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 2–4. oktobar, 2019, Divčibare, Srbija
T1  - Petnaestogodišnji trendovi specifične aktivnosti berilijuma-7 u vazduhu u Evropi
SP  - 29
EP  - 33
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2372
ER  - 

@conference{
author = "Ajtić, Jelena and Brattich, Erika and Hernández-Ceballos, Miguel Angel and Djurdjević, Vladimir",
year = "2019",
abstract = "MeĎu najbitnije faktore koji utiču na specifičnu aktivnost berilijuma-7 u prizemnom
sloju atmosfere spadaju temperatura i količina padavina. U ovom radu stoga
razmatramo njihove vremenske trendove izmeĎu 2000. i 2014. godine, na šest lokacija u
Evropi: Madrid i Bilbao (Španija) na jugu; Beč (Austrija) i Luksemburg (Luksemburg)
u centralnoj oblasti; kao i Riso (Danska) i Ivalo (Finska) na severu kontinenta. Podaci
za specifičnu aktivnost berilijuma-7 preuzeti su iz Radioactivity Environmental
Monitoring data bank (REMdb), a podaci za lokalnu temperaturu i količinu padavina iz
E-OBS gridovane klimatologije (verzija 15) i potom bilinearnom interpolacijom
ekstrahovani na šest lokacija uzorkovanja berilijuma-7. Za dobijanje trendova koristili
smo sezonski Kendalov test, u kome se za svaki mesec tokom godine prvo primeni
Man-Kendalov trend test, a potom se rezultati kombinuju. Statistički značajni (p < 0,05)
pozitivni trendovi specifične aktivnosti berilijuma-7 dobijeni su za četiri lokacije:
Madrid (8,71·10-5 Bq·m-3/god), Bilbao (3,13·10-5 Bq·m-3/god), Luksemburg (4,00·10-5
Bq·m-3/god), i Ivalo (1,91·10-5 Bq·m-3/god), a statistički značajan pozitivan trend
temperature detektovan je samo za Madrid. Naša analiza ukazuje na povećanje
koncentracije berilijuma-7 u Evropi tokom 2000–2014, sa izraţenijim trendom na jugu
nego na severu. MeĎutim, kako dobijeni trendovi za temperaturu i količinu padavina
uglavnom nisu statistički značajni, nije moguće razmotriti njihovu meĎusobnu
povezanost. U budućim analizama ovog problema stoga treba uzeti u obzir duţe
vremenske nizove ovih promenljivih.",
publisher = "Institut za nuklearne nauke „Vinča"",
journal = "Zbornik radova sa XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 2–4. oktobar, 2019, Divčibare, Srbija",
title = "Petnaestogodišnji trendovi specifične aktivnosti berilijuma-7 u vazduhu u Evropi",
pages = "29-33",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2372"
}

Ajtić, J., Brattich, E., Hernández-Ceballos, M. A.,& Djurdjević, V.. (2019). Petnaestogodišnji trendovi specifične aktivnosti berilijuma-7 u vazduhu u Evropi. in Zbornik radova sa XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 2–4. oktobar, 2019, Divčibare, Srbija
Institut za nuklearne nauke „Vinča"., 29-33.
https://hdl.handle.net/21.15107/rcub_veterinar_2372

Ajtić J, Brattich E, Hernández-Ceballos MA, Djurdjević V. Petnaestogodišnji trendovi specifične aktivnosti berilijuma-7 u vazduhu u Evropi. in Zbornik radova sa XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 2–4. oktobar, 2019, Divčibare, Srbija. 2019;:29-33.
https://hdl.handle.net/21.15107/rcub_veterinar_2372 .

Ajtić, Jelena, Brattich, Erika, Hernández-Ceballos, Miguel Angel, Djurdjević, Vladimir, "Petnaestogodišnji trendovi specifične aktivnosti berilijuma-7 u vazduhu u Evropi" in Zbornik radova sa XXX Simpozijuma Društva za zaštitu od zračenja Srbije i Crne Gore, 2–4. oktobar, 2019, Divčibare, Srbija (2019):29-33,
https://hdl.handle.net/21.15107/rcub_veterinar_2372 .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
AU  - Sarvan, Darko
AU  - Djurdjević, Vladimir
PY  - 2018
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2347
AB  - Beryllium-7 is a cosmogenic radionuclide that, due to its maximum production in the stratosphere and upper troposphere, has often been used as a tracer of vertical transport processes in the atmosphere. In particular, high concentrations of surface airborne beryllium-7 could be a result of an uncommonly fast descent of air masses from the stratosphere into the troposphere. Hence, our aim is to investigate the maxima in the beryllium-7 surface concentrations to better understand the processes associated with the downward transport from the stratosphere to the troposphere. Fourteen locations in Europe, with latitudes ranging between 37 °N and 69 °N, and longitudes between 6 °W and 28 °E, are analysed in our study. Over the 2001–2010 period, the beryllium-7 surface concentration measurements in the chosen sites were performed mostly once a week, giving a total of about 500 data points per each site. The data are contained within the online Radioactivity Environmental Monitoring (REM) Database. We define the beryllium-7 maxima as values exceeding the 95th percentile calculated for each site. Over 2001–2010, 345 maxima are identified for the investigated 14 sites, out of which 61 maxima (18 %) occurred during three consecutive months: May, June and July 2006. Over this period, i.e. summer 2006, the contribution of detected maxima to the total number of maxima for each site ranged between 4 % and 32 %, with six sites showing a contribution of 20 % or larger. This number of extremely high beryllium-7 specific activities concentrated over only three months marks this period as unique. In an attempt to identify underlying mechanisms that are associated with this exceptional episode of high beryllium-7 surface concentrations, we look into the potential vorticity, surface temperature and pressure, and precipitation maps over the region of interest during the time window when the extremes were observed.
PB  - Niš : RAD Association
C3  - 6th International Conference on Radiation and Applications in Various Fields of Research (RAD), Book of Abstracts, Jun 18-22, 2018, Ohrid, Macedonia
T1  - Extremely high beryllium-7 surface concentrations in Europe: a case study
SP  - 169
EP  - 169
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2347
ER  - 

@conference{
author = "Ajtić, Jelena and Brattich, Erika and Hernández-Ceballos, Miguel Angel and Sarvan, Darko and Djurdjević, Vladimir",
year = "2018",
abstract = "Beryllium-7 is a cosmogenic radionuclide that, due to its maximum production in the stratosphere and upper troposphere, has often been used as a tracer of vertical transport processes in the atmosphere. In particular, high concentrations of surface airborne beryllium-7 could be a result of an uncommonly fast descent of air masses from the stratosphere into the troposphere. Hence, our aim is to investigate the maxima in the beryllium-7 surface concentrations to better understand the processes associated with the downward transport from the stratosphere to the troposphere. Fourteen locations in Europe, with latitudes ranging between 37 °N and 69 °N, and longitudes between 6 °W and 28 °E, are analysed in our study. Over the 2001–2010 period, the beryllium-7 surface concentration measurements in the chosen sites were performed mostly once a week, giving a total of about 500 data points per each site. The data are contained within the online Radioactivity Environmental Monitoring (REM) Database. We define the beryllium-7 maxima as values exceeding the 95th percentile calculated for each site. Over 2001–2010, 345 maxima are identified for the investigated 14 sites, out of which 61 maxima (18 %) occurred during three consecutive months: May, June and July 2006. Over this period, i.e. summer 2006, the contribution of detected maxima to the total number of maxima for each site ranged between 4 % and 32 %, with six sites showing a contribution of 20 % or larger. This number of extremely high beryllium-7 specific activities concentrated over only three months marks this period as unique. In an attempt to identify underlying mechanisms that are associated with this exceptional episode of high beryllium-7 surface concentrations, we look into the potential vorticity, surface temperature and pressure, and precipitation maps over the region of interest during the time window when the extremes were observed.",
publisher = "Niš : RAD Association",
journal = "6th International Conference on Radiation and Applications in Various Fields of Research (RAD), Book of Abstracts, Jun 18-22, 2018, Ohrid, Macedonia",
title = "Extremely high beryllium-7 surface concentrations in Europe: a case study",
pages = "169-169",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2347"
}

Ajtić, J., Brattich, E., Hernández-Ceballos, M. A., Sarvan, D.,& Djurdjević, V.. (2018). Extremely high beryllium-7 surface concentrations in Europe: a case study. in 6th International Conference on Radiation and Applications in Various Fields of Research (RAD), Book of Abstracts, Jun 18-22, 2018, Ohrid, Macedonia
Niš : RAD Association., 169-169.
https://hdl.handle.net/21.15107/rcub_veterinar_2347

Ajtić J, Brattich E, Hernández-Ceballos MA, Sarvan D, Djurdjević V. Extremely high beryllium-7 surface concentrations in Europe: a case study. in 6th International Conference on Radiation and Applications in Various Fields of Research (RAD), Book of Abstracts, Jun 18-22, 2018, Ohrid, Macedonia. 2018;:169-169.
https://hdl.handle.net/21.15107/rcub_veterinar_2347 .

Ajtić, Jelena, Brattich, Erika, Hernández-Ceballos, Miguel Angel, Sarvan, Darko, Djurdjević, Vladimir, "Extremely high beryllium-7 surface concentrations in Europe: a case study" in 6th International Conference on Radiation and Applications in Various Fields of Research (RAD), Book of Abstracts, Jun 18-22, 2018, Ohrid, Macedonia (2018):169-169,
https://hdl.handle.net/21.15107/rcub_veterinar_2347 .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Djurdjević, Vladimir
AU  - Sarvan, Darko
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
PY  - 2017
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2350
AB  - This work presents an overview of the results obtained in
an analysis of the 7Be activity concentrations recorded in
surface air in Helsinki, Finland, over a 25-year period
(1987-2011), and stored in the online Radioactivity
Environmental Monitoring (REM) database.
First, lagged linear correlations of the 7Be specific
activity with several meteorological variables:
tropopause height (TPH); mean, minimum and
maximum temperature; precipitation (Prec); atmospheric
pressure (Press); potential vorticity (PV) at 300 hPa and
200 hPa; solar zenith angle (SZA); and sunspot number
are analysed (Tab. 1). The time lag in the correlation
calculations is allowed to vary between 0 and 7 days for
TPH, meteorological parameters and PV, and between 0
and 31 days for SZA and sunspot number. The
correlations are calculated for the total set of
measurements as well as for different seasons.
C3  - Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania
T1  - Analysis of beryllium-7 variability in northern Europe
SP  - 87
EP  - 87
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2350
ER  - 

@conference{
author = "Ajtić, Jelena and Djurdjević, Vladimir and Sarvan, Darko and Brattich, Erika and Hernández-Ceballos, Miguel Angel",
year = "2017",
abstract = "This work presents an overview of the results obtained in
an analysis of the 7Be activity concentrations recorded in
surface air in Helsinki, Finland, over a 25-year period
(1987-2011), and stored in the online Radioactivity
Environmental Monitoring (REM) database.
First, lagged linear correlations of the 7Be specific
activity with several meteorological variables:
tropopause height (TPH); mean, minimum and
maximum temperature; precipitation (Prec); atmospheric
pressure (Press); potential vorticity (PV) at 300 hPa and
200 hPa; solar zenith angle (SZA); and sunspot number
are analysed (Tab. 1). The time lag in the correlation
calculations is allowed to vary between 0 and 7 days for
TPH, meteorological parameters and PV, and between 0
and 31 days for SZA and sunspot number. The
correlations are calculated for the total set of
measurements as well as for different seasons.",
journal = "Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania",
title = "Analysis of beryllium-7 variability in northern Europe",
pages = "87-87",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2350"
}

Ajtić, J., Djurdjević, V., Sarvan, D., Brattich, E.,& Hernández-Ceballos, M. A.. (2017). Analysis of beryllium-7 variability in northern Europe. in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania, 87-87.
https://hdl.handle.net/21.15107/rcub_veterinar_2350

Ajtić J, Djurdjević V, Sarvan D, Brattich E, Hernández-Ceballos MA. Analysis of beryllium-7 variability in northern Europe. in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania. 2017;:87-87.
https://hdl.handle.net/21.15107/rcub_veterinar_2350 .

Ajtić, Jelena, Djurdjević, Vladimir, Sarvan, Darko, Brattich, Erika, Hernández-Ceballos, Miguel Angel, "Analysis of beryllium-7 variability in northern Europe" in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania (2017):87-87,
https://hdl.handle.net/21.15107/rcub_veterinar_2350 .

TY  - CONF
AU  - Hernández-Ceballos, Miguel Angel
AU  - Brattich, Erika
AU  - Ajtić, Jelena
AU  - Cinelli, G.
AU  - Djurdjević, Vladimir
AU  - Sarvan, Darko
AU  - Tollefsen, T.
PY  - 2017
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2351
AB  - Under the terms of Article 36 of the Euratom Treaty,
European Union Member States (MSs) shall periodically
communicate to the European Commission (EC)
information on environmental radioactivity levels. These
results have been introduced into the Radioactivity
Environmental Monitoring database (REMdb) of the EC
Joint Research Centre (JRC) sited in Ispra (Italy)
(https://rem.jrc.ec.europa.eu/RemWeb/).
The initial purpose of the REMdb was to bring together
environmental radioactivity data produced in the
aftermath of the Chernobyl accident, and to store them in
a harmonised manner. Thus the database has two main
objectives: 1) to collect the environmental radioactivity
data gathered through the national environmental
monitoring programs of the MSs to prepare
comprehensive annual monitoring reports; and 2) to keep
a historical record of the radiological accidents for
scientific studies.
Nowadays, containing nearly two million records of
radioactivity levels in milk, water, air and mixed diet
received from the MSs, the REMdb offers the scientific
community dealing with environmental radioactivity
endless research opportunities.
The records stored in REMdb prior to 2007 are fully
public, while the access to the data from the 2007-2015
period can be granted only after explicit request. This
fact makes the REMdb a useful and unique pillar on
which to perform environmental radioactivity studies at
the European level, and which can be considered as a
liaison platform between national and international
scientific groups conducting collaborative research.
C3  - Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania
T1  - REMdb as a framework for collaborations in environmental radioactivity research
SP  - 65
EP  - 65
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2351
ER  - 

@conference{
author = "Hernández-Ceballos, Miguel Angel and Brattich, Erika and Ajtić, Jelena and Cinelli, G. and Djurdjević, Vladimir and Sarvan, Darko and Tollefsen, T.",
year = "2017",
abstract = "Under the terms of Article 36 of the Euratom Treaty,
European Union Member States (MSs) shall periodically
communicate to the European Commission (EC)
information on environmental radioactivity levels. These
results have been introduced into the Radioactivity
Environmental Monitoring database (REMdb) of the EC
Joint Research Centre (JRC) sited in Ispra (Italy)
(https://rem.jrc.ec.europa.eu/RemWeb/).
The initial purpose of the REMdb was to bring together
environmental radioactivity data produced in the
aftermath of the Chernobyl accident, and to store them in
a harmonised manner. Thus the database has two main
objectives: 1) to collect the environmental radioactivity
data gathered through the national environmental
monitoring programs of the MSs to prepare
comprehensive annual monitoring reports; and 2) to keep
a historical record of the radiological accidents for
scientific studies.
Nowadays, containing nearly two million records of
radioactivity levels in milk, water, air and mixed diet
received from the MSs, the REMdb offers the scientific
community dealing with environmental radioactivity
endless research opportunities.
The records stored in REMdb prior to 2007 are fully
public, while the access to the data from the 2007-2015
period can be granted only after explicit request. This
fact makes the REMdb a useful and unique pillar on
which to perform environmental radioactivity studies at
the European level, and which can be considered as a
liaison platform between national and international
scientific groups conducting collaborative research.",
journal = "Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania",
title = "REMdb as a framework for collaborations in environmental radioactivity research",
pages = "65-65",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2351"
}

Hernández-Ceballos, M. A., Brattich, E., Ajtić, J., Cinelli, G., Djurdjević, V., Sarvan, D.,& Tollefsen, T.. (2017). REMdb as a framework for collaborations in environmental radioactivity research. in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania, 65-65.
https://hdl.handle.net/21.15107/rcub_veterinar_2351

Hernández-Ceballos MA, Brattich E, Ajtić J, Cinelli G, Djurdjević V, Sarvan D, Tollefsen T. REMdb as a framework for collaborations in environmental radioactivity research. in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania. 2017;:65-65.
https://hdl.handle.net/21.15107/rcub_veterinar_2351 .

Hernández-Ceballos, Miguel Angel, Brattich, Erika, Ajtić, Jelena, Cinelli, G., Djurdjević, Vladimir, Sarvan, Darko, Tollefsen, T., "REMdb as a framework for collaborations in environmental radioactivity research" in Book of Abstracts of the Fourth International Conference on Environmental Radioactivity: Radionuclides as Tracers of Environmental Processes (ENVIRA2017), 29 May – 2 June, 2017, Vilnius, Lithuania (2017):65-65,
https://hdl.handle.net/21.15107/rcub_veterinar_2351 .

TY  - CONF
AU  - Mitrović, Branislava
AU  - Grdović, Svetlana
AU  - Vranješ, Borjana
AU  - Vićentijević, Mihajlo
AU  - Hernández-Ceballos, Miguel Angel
AU  - Ajtić, Jelena
AU  - Sarvan, Darko
PY  - 2016
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2366
AB  - Activity concentrations of 40K, 238U, 232Th and 137Cs in samples of soil (cultivated and uncultivated), mosses, mushrooms and game meat (wild rabbit, pheasant and wild boar) are measured by gamma-spectrometry technique. The samples were collected from suburban areas of Belgrade city, Serbia, over 2008–2014. Naturally occurring radionuclides in the soil are present at the level characteristic for Serbia. An artificial radionuclide 137Cs is detected in the samples of soil, mosses and mushrooms, which indicates that almost 30 years after the nuclear accident in Chernobyl, this radioisotope is still present in the environment. Since the measured activity concentrations of primordial radionuclides and 137Cs in game meat are below detection limit, these samples can be classified as safe for consumption.
PB  - Niš : University, Faculty of Electronic Engineering
C3  - Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia
T1  - Radioecological investigation in the environment of Belgrade city, Serbia
SP  - 404
EP  - 404
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2366
ER  - 

@conference{
author = "Mitrović, Branislava and Grdović, Svetlana and Vranješ, Borjana and Vićentijević, Mihajlo and Hernández-Ceballos, Miguel Angel and Ajtić, Jelena and Sarvan, Darko",
year = "2016",
abstract = "Activity concentrations of 40K, 238U, 232Th and 137Cs in samples of soil (cultivated and uncultivated), mosses, mushrooms and game meat (wild rabbit, pheasant and wild boar) are measured by gamma-spectrometry technique. The samples were collected from suburban areas of Belgrade city, Serbia, over 2008–2014. Naturally occurring radionuclides in the soil are present at the level characteristic for Serbia. An artificial radionuclide 137Cs is detected in the samples of soil, mosses and mushrooms, which indicates that almost 30 years after the nuclear accident in Chernobyl, this radioisotope is still present in the environment. Since the measured activity concentrations of primordial radionuclides and 137Cs in game meat are below detection limit, these samples can be classified as safe for consumption.",
publisher = "Niš : University, Faculty of Electronic Engineering",
journal = "Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia",
title = "Radioecological investigation in the environment of Belgrade city, Serbia",
pages = "404-404",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2366"
}

Mitrović, B., Grdović, S., Vranješ, B., Vićentijević, M., Hernández-Ceballos, M. A., Ajtić, J.,& Sarvan, D.. (2016). Radioecological investigation in the environment of Belgrade city, Serbia. in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia
Niš : University, Faculty of Electronic Engineering., 404-404.
https://hdl.handle.net/21.15107/rcub_veterinar_2366

Mitrović B, Grdović S, Vranješ B, Vićentijević M, Hernández-Ceballos MA, Ajtić J, Sarvan D. Radioecological investigation in the environment of Belgrade city, Serbia. in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia. 2016;:404-404.
https://hdl.handle.net/21.15107/rcub_veterinar_2366 .

Mitrović, Branislava, Grdović, Svetlana, Vranješ, Borjana, Vićentijević, Mihajlo, Hernández-Ceballos, Miguel Angel, Ajtić, Jelena, Sarvan, Darko, "Radioecological investigation in the environment of Belgrade city, Serbia" in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia (2016):404-404,
https://hdl.handle.net/21.15107/rcub_veterinar_2366 .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Djurdjević, Vladimir
AU  - Sarvan, Darko
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
PY  - 2016
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2365
AB  - The maxima in a large dataset of the beryllium-7 specific activities measured in surface air in
Helsinki, Finland, over 25 years (1987-2011), are analysed. The measurements at this station were
performed with a varying temporal resolution: weekly until 1999, and daily, or once in two days,
in the subsequent years, with a final dataset consisting of more than 4000 measurements. These
data are stored by the online Radioactivity Environmental Monitoring (REM) Database.
The beryllium-7 extremes in this dataset are defined as events with the beryllium-7 specific
activity above the 95thpercentile, or in other words, as the maximum 5 % of the measured values.
Specifically, for the Helsinki data set, this threshold is 4.82·10-3 Bq m-3. The beryllium-7 specific
activity in Helsinki shows a seasonal pattern with the monthly means above 2.00·10-3 Bq m-3
during the warm season (April–September), and below 2.00·10-3 Bq m-3during the cold season
(October–March). The analysis of the extremes shows that 90 % occurred in the warm season,
and the remaining 10 % in the cold season. The occurrence of the extreme beryllium-7 events
during the cold season is therefore of particular interest, and these “cold extremes” are analysed
in more detail.
Amongst the cold extremes, three extreme episodes are identified. These episodes, which
occurred in March 1999, February 2003 and February 2005, show extremely high berrylium-7
specific activities measured over several consecutive days. Potential vorticity and surface
temperature maps over Europe are investigated in attempt to find underlying mechanisms that
cause high concentrations of beryllium-7 in surface air during the cold season.
PB  - Niš : University, Faculty of Electronic Engineering
C3  - Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia
T1  - Analysis of extreme beryllium-7 specific activities in surface air
SP  - 411
EP  - 411
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2365
ER  - 

@conference{
author = "Ajtić, Jelena and Djurdjević, Vladimir and Sarvan, Darko and Brattich, Erika and Hernández-Ceballos, Miguel Angel",
year = "2016",
abstract = "The maxima in a large dataset of the beryllium-7 specific activities measured in surface air in
Helsinki, Finland, over 25 years (1987-2011), are analysed. The measurements at this station were
performed with a varying temporal resolution: weekly until 1999, and daily, or once in two days,
in the subsequent years, with a final dataset consisting of more than 4000 measurements. These
data are stored by the online Radioactivity Environmental Monitoring (REM) Database.
The beryllium-7 extremes in this dataset are defined as events with the beryllium-7 specific
activity above the 95thpercentile, or in other words, as the maximum 5 % of the measured values.
Specifically, for the Helsinki data set, this threshold is 4.82·10-3 Bq m-3. The beryllium-7 specific
activity in Helsinki shows a seasonal pattern with the monthly means above 2.00·10-3 Bq m-3
during the warm season (April–September), and below 2.00·10-3 Bq m-3during the cold season
(October–March). The analysis of the extremes shows that 90 % occurred in the warm season,
and the remaining 10 % in the cold season. The occurrence of the extreme beryllium-7 events
during the cold season is therefore of particular interest, and these “cold extremes” are analysed
in more detail.
Amongst the cold extremes, three extreme episodes are identified. These episodes, which
occurred in March 1999, February 2003 and February 2005, show extremely high berrylium-7
specific activities measured over several consecutive days. Potential vorticity and surface
temperature maps over Europe are investigated in attempt to find underlying mechanisms that
cause high concentrations of beryllium-7 in surface air during the cold season.",
publisher = "Niš : University, Faculty of Electronic Engineering",
journal = "Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia",
title = "Analysis of extreme beryllium-7 specific activities in surface air",
pages = "411-411",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2365"
}

Ajtić, J., Djurdjević, V., Sarvan, D., Brattich, E.,& Hernández-Ceballos, M. A.. (2016). Analysis of extreme beryllium-7 specific activities in surface air. in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia
Niš : University, Faculty of Electronic Engineering., 411-411.
https://hdl.handle.net/21.15107/rcub_veterinar_2365

Ajtić J, Djurdjević V, Sarvan D, Brattich E, Hernández-Ceballos MA. Analysis of extreme beryllium-7 specific activities in surface air. in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia. 2016;:411-411.
https://hdl.handle.net/21.15107/rcub_veterinar_2365 .

Ajtić, Jelena, Djurdjević, Vladimir, Sarvan, Darko, Brattich, Erika, Hernández-Ceballos, Miguel Angel, "Analysis of extreme beryllium-7 specific activities in surface air" in Book of Abstracts of the Fourth International Conference on Radiation and Applications in Various Fields of Research, May 23–27, 2016, Niš, Serbia (2016):411-411,
https://hdl.handle.net/21.15107/rcub_veterinar_2365 .

TY  - JOUR
AU  - Ajtić, Jelena
AU  - Djurdjević, Vladimir
AU  - Sarvan, Darko
AU  - Brattich, Erika
AU  - Hernández-Ceballos, Miguel Angel
PY  - 2016
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2369
AB  - We present an analysis of the maxima in a large dataset of the beryllium-7 specific activities measured in
surface air in Helsinki, Finland, over 25 years (1987-2011), which are stored in the online Radioactivity
Environmental Monitoring (REM) database. The maxima are defined as events with the beryllium-7 specific activity
above the 95th percentile, which, for the Helsinki data set, equals to 4.8210-3 Bqm-3. The beryllium-7 specific activity
in Helsinki shows a seasonal pattern with the monthly means above 2.0010-3 Bqm-3 during the warm season (April–
September), and below 2.0010-3 Bqm-3 during the cold season (October–March). The analysis of the extremes shows
that 10 % occurred in the cold season, and these “cold extremes” are analysed in more detail. Amongst the cold
extremes, three representative “episodes” are identified. The episodes, which occurred in March 1999, February 2003
and February 2005, show extremely high beryllium-7 specific activities measured over several consecutive days.
Anomalies of potential vorticity, sea level pressure and surface temperature, as well as precipitation, over Europe
and the Atlantic are investigated. A brief analysis of one cold extreme, classified as “burst” since it was an isolated
event surrounded by measurements below the 95th percentile, is also presented in an attempt to find common
mechanisms that contribute to both cold extreme episodes and bursts. Scandinavia teleconnection index seems to
represent a good indicator of potentially preferential atmospheric conditions that could lead to cold extreme episode
occurrences in the Scandinavian region.
PB  - Niš : RAD Association
T2  - Radiation & Applications
T1  - Analysis of extreme beryllium-7 specific activities in surface air
VL  - 1
IS  - 3
DO  - 10.21175/RadJ.2016.03.040
ER  - 

@article{
author = "Ajtić, Jelena and Djurdjević, Vladimir and Sarvan, Darko and Brattich, Erika and Hernández-Ceballos, Miguel Angel",
year = "2016",
abstract = "We present an analysis of the maxima in a large dataset of the beryllium-7 specific activities measured in
surface air in Helsinki, Finland, over 25 years (1987-2011), which are stored in the online Radioactivity
Environmental Monitoring (REM) database. The maxima are defined as events with the beryllium-7 specific activity
above the 95th percentile, which, for the Helsinki data set, equals to 4.8210-3 Bqm-3. The beryllium-7 specific activity
in Helsinki shows a seasonal pattern with the monthly means above 2.0010-3 Bqm-3 during the warm season (April–
September), and below 2.0010-3 Bqm-3 during the cold season (October–March). The analysis of the extremes shows
that 10 % occurred in the cold season, and these “cold extremes” are analysed in more detail. Amongst the cold
extremes, three representative “episodes” are identified. The episodes, which occurred in March 1999, February 2003
and February 2005, show extremely high beryllium-7 specific activities measured over several consecutive days.
Anomalies of potential vorticity, sea level pressure and surface temperature, as well as precipitation, over Europe
and the Atlantic are investigated. A brief analysis of one cold extreme, classified as “burst” since it was an isolated
event surrounded by measurements below the 95th percentile, is also presented in an attempt to find common
mechanisms that contribute to both cold extreme episodes and bursts. Scandinavia teleconnection index seems to
represent a good indicator of potentially preferential atmospheric conditions that could lead to cold extreme episode
occurrences in the Scandinavian region.",
publisher = "Niš : RAD Association",
journal = "Radiation & Applications",
title = "Analysis of extreme beryllium-7 specific activities in surface air",
volume = "1",
number = "3",
doi = "10.21175/RadJ.2016.03.040"
}

Ajtić, J., Djurdjević, V., Sarvan, D., Brattich, E.,& Hernández-Ceballos, M. A.. (2016). Analysis of extreme beryllium-7 specific activities in surface air. in Radiation & Applications
Niš : RAD Association., 1(3).
https://doi.org/10.21175/RadJ.2016.03.040

Ajtić J, Djurdjević V, Sarvan D, Brattich E, Hernández-Ceballos MA. Analysis of extreme beryllium-7 specific activities in surface air. in Radiation & Applications. 2016;1(3).
doi:10.21175/RadJ.2016.03.040 .

Ajtić, Jelena, Djurdjević, Vladimir, Sarvan, Darko, Brattich, Erika, Hernández-Ceballos, Miguel Angel, "Analysis of extreme beryllium-7 specific activities in surface air" in Radiation & Applications, 1, no. 3 (2016),
https://doi.org/10.21175/RadJ.2016.03.040 . .

TY  - CONF
AU  - Ajtić, Jelena
AU  - Djurdjević, Vladimir
AU  - Hernández-Ceballos, Miguel Angel
AU  - Brattich, Erika
PY  - 2016
UR  - https://vet-erinar.vet.bg.ac.rs/handle/123456789/2356
AB  - Specific activity of cosmogenic 7
Be in surface air generally shows a spring-summer maximum. However,
extremely high 7
Be concentrations in surface air also occur during winter. The aim of our analysis is to
characterise temporal and spatial prevalence of winter extreme events, and to investigate the associated
synoptic meteorological conditions in northern Europe. Four measurement sites, with an approximate weekly
sampling rate over the 2001–2010 period, are selected from the online Radioactivity Environmental
Monitoring (REM) Database. The extremes in the 7
Be surface concentration are defined as measurements
above the 90th percentile in each location.The results indicate that at each measurement site, 10–20 % of the
extremes occur during winter (November, December, January and February). Two types of 7
Be extremes are
distinguished: 1) approximately half of these occurrences are isolated events detected in one or two stations,
and 2) the other half are events grouped within four months, when at least three 7
Be extremes per month are
observed. The monthly Scandinavia (SCAND) teleconnection index for isolated extreme events (type-1) is
positive and, with only one exception, larger than 0.4, while in the case of type-2 events, the monthly
SCAND is very high (larger than 1).This finding implies that in northern Europe during winter, the
atmospheric conditions associated with a high SCAND index facilitate an occurrence of extreme 7
Be surface
concentration.
C3  - Proceedings of the Second International Conference on Radioecological Concentrations Processes (50 years later), November 6–9, 2016, Seville, Spain
T1  - Winter extremes of beryllium-7 surface concentrations in northern Europe
SP  - I3
UR  - https://hdl.handle.net/21.15107/rcub_veterinar_2356
ER  - 

@conference{
author = "Ajtić, Jelena and Djurdjević, Vladimir and Hernández-Ceballos, Miguel Angel and Brattich, Erika",
year = "2016",
abstract = "Specific activity of cosmogenic 7
Be in surface air generally shows a spring-summer maximum. However,
extremely high 7
Be concentrations in surface air also occur during winter. The aim of our analysis is to
characterise temporal and spatial prevalence of winter extreme events, and to investigate the associated
synoptic meteorological conditions in northern Europe. Four measurement sites, with an approximate weekly
sampling rate over the 2001–2010 period, are selected from the online Radioactivity Environmental
Monitoring (REM) Database. The extremes in the 7
Be surface concentration are defined as measurements
above the 90th percentile in each location.The results indicate that at each measurement site, 10–20 % of the
extremes occur during winter (November, December, January and February). Two types of 7
Be extremes are
distinguished: 1) approximately half of these occurrences are isolated events detected in one or two stations,
and 2) the other half are events grouped within four months, when at least three 7
Be extremes per month are
observed. The monthly Scandinavia (SCAND) teleconnection index for isolated extreme events (type-1) is
positive and, with only one exception, larger than 0.4, while in the case of type-2 events, the monthly
SCAND is very high (larger than 1).This finding implies that in northern Europe during winter, the
atmospheric conditions associated with a high SCAND index facilitate an occurrence of extreme 7
Be surface
concentration.",
journal = "Proceedings of the Second International Conference on Radioecological Concentrations Processes (50 years later), November 6–9, 2016, Seville, Spain",
title = "Winter extremes of beryllium-7 surface concentrations in northern Europe",
pages = "I3",
url = "https://hdl.handle.net/21.15107/rcub_veterinar_2356"
}

Ajtić, J., Djurdjević, V., Hernández-Ceballos, M. A.,& Brattich, E.. (2016). Winter extremes of beryllium-7 surface concentrations in northern Europe. in Proceedings of the Second International Conference on Radioecological Concentrations Processes (50 years later), November 6–9, 2016, Seville, Spain, I3.
https://hdl.handle.net/21.15107/rcub_veterinar_2356

Ajtić J, Djurdjević V, Hernández-Ceballos MA, Brattich E. Winter extremes of beryllium-7 surface concentrations in northern Europe. in Proceedings of the Second International Conference on Radioecological Concentrations Processes (50 years later), November 6–9, 2016, Seville, Spain. 2016;:I3.
https://hdl.handle.net/21.15107/rcub_veterinar_2356 .

Ajtić, Jelena, Djurdjević, Vladimir, Hernández-Ceballos, Miguel Angel, Brattich, Erika, "Winter extremes of beryllium-7 surface concentrations in northern Europe" in Proceedings of the Second International Conference on Radioecological Concentrations Processes (50 years later), November 6–9, 2016, Seville, Spain (2016):I3,
https://hdl.handle.net/21.15107/rcub_veterinar_2356 .