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Papers by Lennart Robertson

Journal of radioanalytical and nuclear chemistry, May 23, 2024

New data, analyses and modelling are presented concerning the unprecedented mid-May 2010 series o... more New data, analyses and modelling are presented concerning the unprecedented mid-May 2010 series of fission product detections in ground level air on and around the Korean Peninsula. For the first time Ba-140 is revealed at Ussuriysk, for which only La-140 had been reported. Thus aerosol particles containing the same parent-daughter pair Ba-140/La-140 were detected at both Ussuriysk and Okinawa, establishing beyond reasonable doubt that their physical, spatial and temporal origins are the same. Together with Ce-141 and Cs-137, all with short-lived xenon isotope parents, a supercritical fission excursion, which experienced a near prompt filtered vent, is the only viable scenario for their explanation. New modelling suggests that the vent occurred around 9 s after the excursion and that the CTBT-relevant xenon isotopes Xe-133 and Xe-135 were 'quenched' around 25 min later and released some 10-20 h afterwards. Published corroborating seismic and infrasound data of an event at the North Korean nuclear test site 8 min and 45 s past midnight on 12 May 2010 is subsequently reviewed. These papers adopted a conventional depth of the event although the data suggested a shallower one. Despite arguments in the seismic community about its exact nature, it is prudent to test how well the waveform signals marry the radionuclide detection pattern. Thus the location and time are input into a new atmospheric transport model. The advanced software suite MATCH was used in forward mode with prompt and delayed releases, revealing the presence of plumes at each detection site at the time of their first detection and extending over the observed timeframe. Thus a very consistent picture of a shallow low yield nuclear test is obtained. Keywords May 2010 nuclear testing in North Korea • Barium-140 • Co-added gamma spectra • Xenon-133/135 • Seismic and infrasound detections • Atmospheric transport modelling (MATCH)

Journal of Geophysical Research, 2002

During the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campa... more During the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campaign, 16 C 8-C 16 volatile organic compounds (VOCs) were identified in the coastal atmosphere of Mace Head, Ireland. Sampling took place over 24 days, with 12 VOCs routinely quantified. Concentrations were observed in the low Ͻ10-150 parts per trillion by volume range, with levels typically in the order of aldehydes Ͼ ketones Ն n-alkanes. Concentrations of these compounds were also measured in shoreline surface seawater. No relationship was observed between atmospheric concentrations and high/low tide events. Many VOCs revealed a temporal pattern in the atmosphere, with highest concentrations measured during the early morning and lowest concentrations in the afternoon. The strongest pattern was observed for the n-alkanes. However, this was dependent on the prevailing air mass direction and the local meteorology. A Lagrangian box model was applied to assess this diurnal cycle, using seawater emissions as a source (based on the seawater concentrations and observed wind speeds), and depletion via OH radicals and dilution by entrainment as sinks (using measured [OH] and boundary layer height data). The model gave good agreement to the observed concentrations for selected air mass types, predicting the daytime decrease in VOC concentrations due to OH radical chemistry and boundary layer growth, and the subsequent increase in VOC concentrations toward evening as both oxidation chemistry diminished and the mixing layer height fell.

Air Pollution Modeling and Its Application VIII, 1991

A three-dimensional Eulerian dispersion model has been adapted to different air pollution problem... more A three-dimensional Eulerian dispersion model has been adapted to different air pollution problems on meso and regional scale. With some modifications the model can be applied to continuous as well as accidental releases. All meteorological information needed is based on routine weather observations. The purpose is to have three different options of the dispersion model for operational applications on — meso-γ scale (different subregions within Sweden) — meso-β scale (Sweden) — European scale (Europe).

A three-dimensional Eulerian dispersion model has been adapted to dif­ ferent air pollution probl... more A three-dimensional Eulerian dispersion model has been adapted to dif­ ferent air pollution problems on meso and regional scale. With some modi­ fications the model can be applied to continuous as well as accidental releases. All meteorological information needed is based on routine weather observations. The purpose is to have three different options of the dis­ persion model for operational applications on - meso-y scale (different subregions within Sweden) - meso-~ scale (Sweden) - European scale (Europe).

The purpose of the EUNADICS prototype Early Warning System (EWS) is to proceed the combined use o... more The purpose of the EUNADICS prototype Early Warning System (EWS) is to proceed the combined use of harmonised data products from satellite, ground-based and in situ instruments to produce alerts of airborne hazard (volcanic, dust, smoke and radionuclide clouds), satisfying the requirement of ATM stakeholders 45 (www.eunadics.eu). The alert products developed by EUNADICS EWS (i.e. NRT observations, email notifications and NetCDF Alert data Products, called NCAP) have shown shows the significant interest in using https://doi.org/10.5194/nhess-2021-105 Preprint. Discussion started: 4 May 2021 c © Author(s) 2021. CC BY 4.0 License.

… och Hydrologiska Inst., 1996

... The Swedish precipitation chemistry network. Studies in network design using the MATCH modell... more ... The Swedish precipitation chemistry network. Studies in network design using the MATCH modelling system and statistical methods by Persson, C.; Ullerstig, A.;Robertson, L.; Kindbom, K.; Sjoeberg, K. (Oct 1996) in English. ...

Spridningsberakningar rorande gasutslapp vid ScanDust i Landskrona – bestamning av cyanvatehalter

In early October 2017, the International Atomic Energy Agency (IAEA) was informed by Member State... more In early October 2017, the International Atomic Energy Agency (IAEA) was informed by Member States that low concentrations of Ru-106 were measured in high-volume air samples in Europe from routine monitoring networks. However, no information was given that an accidental release of Ru-106 had taken place. Such events signify the need for prompt and accurate responses from national radiation protection authorities in such cases. This requires that methodologies, suited for operational use, are developed for spatial and temporal localization of the source of contamination based on available monitoring data. For operational use, nuclear decision-support systems (DSSs) should be extended with modules handling such monitoring data automatically, e.g. by employing the European Radiological Data Exchange Platform (EURDEP), and conveying selected data to the national meteorological centre accompanied by a request to run an atmospheric dispersion model in inverse mode. The aim would be to det...

Meso-g scale objective analysis of near surface temperature, humidity and wind, and its applicati... more Meso-g scale objective analysis of near surface temperature, humidity and wind, and its application in air pollution modelling

Acidification problems in developing countries are expected to become more prevalent in the comin... more Acidification problems in developing countries are expected to become more prevalent in the coming decades. Assessments of means of abatement strategies are likely to become of vital interest. This paper presents some preliminary results of modelling of acidic deposition due to anthropogenic emissions of sulfur in Africa and South America, using emission data for 1987. The calculations indicate that the anthropogenic perturbation of the sulfur deposition exceeds 100 mg S m-2yr-1 for southern Africa, areas around the Red Sea, Caribbean Islands, northernmost South America, central Andes, and the eastern parts of Brazil and Argentina. Substantial areas around the major source regions receive more than 250 mg S m-2yr-1. Even higher values are calculated for areas surrounding large cities as Carracas, Lima, Rio de Janeiro and Sao Paulo, Pretoria and around the borderline between Zaire and Zambia

Med syfte att ta fram vindenergi kartor for de svenska kust- och havsomradena har vi gatt vidare ... more Med syfte att ta fram vindenergi kartor for de svenska kust- och havsomradena har vi gatt vidare med de havsvindstudier som genomfordes av SMHI 1983-84.Vi har dels kunnat analysera langre tidsserie ...

Atmospheric Environment, 2017

Air quality implications of volcanic eruptions have gained increased attention recently in associ... more Air quality implications of volcanic eruptions have gained increased attention recently in association with the 2010 Icelandic eruption that resulted in the shutdown of European air space. The emission amount, injection height and prevailing weather conditions determine the extent of the impact through the spatio-temporal distribution of pollutants. It is often argued that in the case of a major eruption in Iceland, like Laki in 1783-1784, that pollutants injected high into the atmosphere lead to substantially increased concentrations of sulfur compounds over continental Europe via long-range transport in the jet stream and eventual large-scale subsidence in a high-pressure system. Using state-of-the-art simulations, we show that the air quality impact of Icelandic volcanoes is highly sensitive to the injection height. In particular, it is the infinitesimal injections into the lower half of the troposphere, rather than the substantial injections into the upper troposphere/lower stratosphere that contribute most to increased pollutant concentrations, resulting in atmospheric haze over mainland Europe/Scandinavia. Besides, the persistent high pressure system over continental Europe/Scandinavia traps the pollutants from dispersing, thereby prolonging the haze.

Journal of radioanalytical and nuclear chemistry, May 23, 2024

New data, analyses and modelling are presented concerning the unprecedented mid-May 2010 series o... more New data, analyses and modelling are presented concerning the unprecedented mid-May 2010 series of fission product detections in ground level air on and around the Korean Peninsula. For the first time Ba-140 is revealed at Ussuriysk, for which only La-140 had been reported. Thus aerosol particles containing the same parent-daughter pair Ba-140/La-140 were detected at both Ussuriysk and Okinawa, establishing beyond reasonable doubt that their physical, spatial and temporal origins are the same. Together with Ce-141 and Cs-137, all with short-lived xenon isotope parents, a supercritical fission excursion, which experienced a near prompt filtered vent, is the only viable scenario for their explanation. New modelling suggests that the vent occurred around 9 s after the excursion and that the CTBT-relevant xenon isotopes Xe-133 and Xe-135 were 'quenched' around 25 min later and released some 10-20 h afterwards. Published corroborating seismic and infrasound data of an event at the North Korean nuclear test site 8 min and 45 s past midnight on 12 May 2010 is subsequently reviewed. These papers adopted a conventional depth of the event although the data suggested a shallower one. Despite arguments in the seismic community about its exact nature, it is prudent to test how well the waveform signals marry the radionuclide detection pattern. Thus the location and time are input into a new atmospheric transport model. The advanced software suite MATCH was used in forward mode with prompt and delayed releases, revealing the presence of plumes at each detection site at the time of their first detection and extending over the observed timeframe. Thus a very consistent picture of a shallow low yield nuclear test is obtained. Keywords May 2010 nuclear testing in North Korea • Barium-140 • Co-added gamma spectra • Xenon-133/135 • Seismic and infrasound detections • Atmospheric transport modelling (MATCH)

Journal of Geophysical Research, 2002

During the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campa... more During the 1999 New Particle Formation and Fate in the Coastal Environment (PARFORCE) field campaign, 16 C 8-C 16 volatile organic compounds (VOCs) were identified in the coastal atmosphere of Mace Head, Ireland. Sampling took place over 24 days, with 12 VOCs routinely quantified. Concentrations were observed in the low Ͻ10-150 parts per trillion by volume range, with levels typically in the order of aldehydes Ͼ ketones Ն n-alkanes. Concentrations of these compounds were also measured in shoreline surface seawater. No relationship was observed between atmospheric concentrations and high/low tide events. Many VOCs revealed a temporal pattern in the atmosphere, with highest concentrations measured during the early morning and lowest concentrations in the afternoon. The strongest pattern was observed for the n-alkanes. However, this was dependent on the prevailing air mass direction and the local meteorology. A Lagrangian box model was applied to assess this diurnal cycle, using seawater emissions as a source (based on the seawater concentrations and observed wind speeds), and depletion via OH radicals and dilution by entrainment as sinks (using measured [OH] and boundary layer height data). The model gave good agreement to the observed concentrations for selected air mass types, predicting the daytime decrease in VOC concentrations due to OH radical chemistry and boundary layer growth, and the subsequent increase in VOC concentrations toward evening as both oxidation chemistry diminished and the mixing layer height fell.

Air Pollution Modeling and Its Application VIII, 1991

A three-dimensional Eulerian dispersion model has been adapted to different air pollution problem... more A three-dimensional Eulerian dispersion model has been adapted to different air pollution problems on meso and regional scale. With some modifications the model can be applied to continuous as well as accidental releases. All meteorological information needed is based on routine weather observations. The purpose is to have three different options of the dispersion model for operational applications on — meso-γ scale (different subregions within Sweden) — meso-β scale (Sweden) — European scale (Europe).

A three-dimensional Eulerian dispersion model has been adapted to dif­ ferent air pollution probl... more A three-dimensional Eulerian dispersion model has been adapted to dif­ ferent air pollution problems on meso and regional scale. With some modi­ fications the model can be applied to continuous as well as accidental releases. All meteorological information needed is based on routine weather observations. The purpose is to have three different options of the dis­ persion model for operational applications on - meso-y scale (different subregions within Sweden) - meso-~ scale (Sweden) - European scale (Europe).

The purpose of the EUNADICS prototype Early Warning System (EWS) is to proceed the combined use o... more The purpose of the EUNADICS prototype Early Warning System (EWS) is to proceed the combined use of harmonised data products from satellite, ground-based and in situ instruments to produce alerts of airborne hazard (volcanic, dust, smoke and radionuclide clouds), satisfying the requirement of ATM stakeholders 45 (www.eunadics.eu). The alert products developed by EUNADICS EWS (i.e. NRT observations, email notifications and NetCDF Alert data Products, called NCAP) have shown shows the significant interest in using https://doi.org/10.5194/nhess-2021-105 Preprint. Discussion started: 4 May 2021 c © Author(s) 2021. CC BY 4.0 License.

… och Hydrologiska Inst., 1996

... The Swedish precipitation chemistry network. Studies in network design using the MATCH modell... more ... The Swedish precipitation chemistry network. Studies in network design using the MATCH modelling system and statistical methods by Persson, C.; Ullerstig, A.;Robertson, L.; Kindbom, K.; Sjoeberg, K. (Oct 1996) in English. ...

Spridningsberakningar rorande gasutslapp vid ScanDust i Landskrona – bestamning av cyanvatehalter

In early October 2017, the International Atomic Energy Agency (IAEA) was informed by Member State... more In early October 2017, the International Atomic Energy Agency (IAEA) was informed by Member States that low concentrations of Ru-106 were measured in high-volume air samples in Europe from routine monitoring networks. However, no information was given that an accidental release of Ru-106 had taken place. Such events signify the need for prompt and accurate responses from national radiation protection authorities in such cases. This requires that methodologies, suited for operational use, are developed for spatial and temporal localization of the source of contamination based on available monitoring data. For operational use, nuclear decision-support systems (DSSs) should be extended with modules handling such monitoring data automatically, e.g. by employing the European Radiological Data Exchange Platform (EURDEP), and conveying selected data to the national meteorological centre accompanied by a request to run an atmospheric dispersion model in inverse mode. The aim would be to det...

Meso-g scale objective analysis of near surface temperature, humidity and wind, and its applicati... more Meso-g scale objective analysis of near surface temperature, humidity and wind, and its application in air pollution modelling

Acidification problems in developing countries are expected to become more prevalent in the comin... more Acidification problems in developing countries are expected to become more prevalent in the coming decades. Assessments of means of abatement strategies are likely to become of vital interest. This paper presents some preliminary results of modelling of acidic deposition due to anthropogenic emissions of sulfur in Africa and South America, using emission data for 1987. The calculations indicate that the anthropogenic perturbation of the sulfur deposition exceeds 100 mg S m-2yr-1 for southern Africa, areas around the Red Sea, Caribbean Islands, northernmost South America, central Andes, and the eastern parts of Brazil and Argentina. Substantial areas around the major source regions receive more than 250 mg S m-2yr-1. Even higher values are calculated for areas surrounding large cities as Carracas, Lima, Rio de Janeiro and Sao Paulo, Pretoria and around the borderline between Zaire and Zambia

Med syfte att ta fram vindenergi kartor for de svenska kust- och havsomradena har vi gatt vidare ... more Med syfte att ta fram vindenergi kartor for de svenska kust- och havsomradena har vi gatt vidare med de havsvindstudier som genomfordes av SMHI 1983-84.Vi har dels kunnat analysera langre tidsserie ...

Atmospheric Environment, 2017

Air quality implications of volcanic eruptions have gained increased attention recently in associ... more Air quality implications of volcanic eruptions have gained increased attention recently in association with the 2010 Icelandic eruption that resulted in the shutdown of European air space. The emission amount, injection height and prevailing weather conditions determine the extent of the impact through the spatio-temporal distribution of pollutants. It is often argued that in the case of a major eruption in Iceland, like Laki in 1783-1784, that pollutants injected high into the atmosphere lead to substantially increased concentrations of sulfur compounds over continental Europe via long-range transport in the jet stream and eventual large-scale subsidence in a high-pressure system. Using state-of-the-art simulations, we show that the air quality impact of Icelandic volcanoes is highly sensitive to the injection height. In particular, it is the infinitesimal injections into the lower half of the troposphere, rather than the substantial injections into the upper troposphere/lower stratosphere that contribute most to increased pollutant concentrations, resulting in atmospheric haze over mainland Europe/Scandinavia. Besides, the persistent high pressure system over continental Europe/Scandinavia traps the pollutants from dispersing, thereby prolonging the haze.