Validation and verification of the Atmospheric Radionuclide Transport Model (ARTM)

Aufgrund der Tatsache, dass die Immissionen radioaktiver Nuklide, resultierend aus den Freisetzungen kerntechnischer Anlagen in Deutschland, im Vergleich zum natürlich vorkommenden radioaktiven Untergrund zu gering sind, um effizient in der Umgebung der Anlagen gemessen werden zu können, ist das Bundesamt für Strahlenschutz (BfS) zum Schutz der Bevölkerung dazu angehalten, deren Ausbreitung zu simulieren und die maximale Personendosis zu berechnen. Während seit den 1970er Jahren Gauß-Fahnenmodelle in Gebrauch waren, hat die Entwicklung immer neuerer und schnellerer Rechenmaschinen Anreize zur Entwicklung des realistischeren Lagrange-Teilchenmodell gesetzt, welche in naher Zukunft für behördliche Zwecke zur Bewertung der Strahlenexposition durch radioaktive Emissionen zum Einsatz kommen sollen. Eines dieser Lagrange-Teilchenmodelle – entwickelt für Langzeitausbreitungen – ist das Atmosphärische-Radionuklid-Transport-Modell (ARTM). In dieser Arbeit wird ARTM anhand realer und fiktiver Szenarien, in welchen das Programmverhalten und seine Simulationsergebnisse untersucht werden, verifiziert und validiert. Eine intensive Sensitivitätsanalyse einiger ausgewählter Modelleingabeparameter und deren Auswirkung auf die Ergebnisse wurde durchgeführt, um die programminternen mathematischen Algorithmen zu verifizieren. ARTM wurde auch zur Validierung und zur Evaluierung der Simulationsergebnisse auf zwei Szenarien angewendet, bei denen Immissionsmessdaten vorhanden waren. Diese Untersuchungen – zuzüglich eines Vergleichs mit dem Kurzzeitausbreitungsmodell LASAIR (Lagrange-Simulation der Ausbreitung und Inhalation von Radionukliden) – zeigen den Anwendungsbereich von ARTM auf und wo noch weitere Entwicklungen nötig sind.Due to the fact that the immissions resulting from the release of radioactive nuclides from nuclear facilities in Germany are too small in comparison to the natural radioactive background to be efficiently measured in their vicinity, the German Federal Office for Radiation Protection (BfS) is obliged to simulate their distribution and calculate the maximum dose rates in order to protect the population. While since the 1970’s Gaussian plume models have been in use, the advent of fast modern computing machines has triggered the development towards the more realistic Lagrangian particle models which shall be used for regulatory purposes in order to assess the radiation exposure from radioactive emissions in the near future. One of these Lagrangian models, developed for simulating long-term emissions, is the Atmospheric Radionuclide Transport Model (ARTM). In this work, ARTM is verified and validated for several real and fictive scenarios, in which both the behaviour of the programme and its simulation results are studied. An intensive sensitivity study on a selection of model input parameters and their effect on results is performed in order to verify the programme-internal mathematical algorithms. ARTM is also applied to two scenarios where measurement data were available in order to validate and evaluate the simulation results. These studies, plus a comparison with the short-term model LASAIR (Lagrange Simulation of Dispersion and Inhalation of Radionuclides), demonstrate the range of usability for ARTM and where further development is needed

Validation and verification of the Atmospheric Radionuclide Transport Model (ARTM)

Aufgrund der Tatsache, dass die Immissionen radioaktiver Nuklide, resultierend aus den Freisetzungen kerntechnischer Anlagen in Deutschland, im Vergleich zum natürlich vorkommenden radioaktiven Untergrund zu gering sind, um effizient in der Umgebung der Anlagen gemessen werden zu können, ist das Bundesamt für Strahlenschutz (BfS) zum Schutz der Bevölkerung dazu angehalten, deren Ausbreitung zu simulieren und die maximale Personendosis zu berechnen. Während seit den 1970er Jahren Gauß-Fahnenmodelle in Gebrauch waren, hat die Entwicklung immer neuerer und schnellerer Rechenmaschinen Anreize zur Entwicklung des realistischeren Lagrange-Teilchenmodell gesetzt, welche in naher Zukunft für behördliche Zwecke zur Bewertung der Strahlenexposition durch radioaktive Emissionen zum Einsatz kommen sollen. Eines dieser Lagrange-Teilchenmodelle – entwickelt für Langzeitausbreitungen – ist das Atmosphärische-Radionuklid-Transport-Modell (ARTM). In dieser Arbeit wird ARTM anhand realer und fiktiver Szenarien, in welchen das Programmverhalten und seine Simulationsergebnisse untersucht werden, verifiziert und validiert. Eine intensive Sensitivitätsanalyse einiger ausgewählter Modelleingabeparameter und deren Auswirkung auf die Ergebnisse wurde durchgeführt, um die programminternen mathematischen Algorithmen zu verifizieren. ARTM wurde auch zur Validierung und zur Evaluierung der Simulationsergebnisse auf zwei Szenarien angewendet, bei denen Immissionsmessdaten vorhanden waren. Diese Untersuchungen – zuzüglich eines Vergleichs mit dem Kurzzeitausbreitungsmodell LASAIR (Lagrange-Simulation der Ausbreitung und Inhalation von Radionukliden) – zeigen den Anwendungsbereich von ARTM auf und wo noch weitere Entwicklungen nötig sind.Due to the fact that the immissions resulting from the release of radioactive nuclides from nuclear facilities in Germany are too small in comparison to the natural radioactive background to be efficiently measured in their vicinity, the German Federal Office for Radiation Protection (BfS) is obliged to simulate their distribution and calculate the maximum dose rates in order to protect the population. While since the 1970’s Gaussian plume models have been in use, the advent of fast modern computing machines has triggered the development towards the more realistic Lagrangian particle models which shall be used for regulatory purposes in order to assess the radiation exposure from radioactive emissions in the near future. One of these Lagrangian models, developed for simulating long-term emissions, is the Atmospheric Radionuclide Transport Model (ARTM). In this work, ARTM is verified and validated for several real and fictive scenarios, in which both the behaviour of the programme and its simulation results are studied. An intensive sensitivity study on a selection of model input parameters and their effect on results is performed in order to verify the programme-internal mathematical algorithms. ARTM is also applied to two scenarios where measurement data were available in order to validate and evaluate the simulation results. These studies, plus a comparison with the short-term model LASAIR (Lagrange Simulation of Dispersion and Inhalation of Radionuclides), demonstrate the range of usability for ARTM and where further development is needed

Mineralogy of a Mudstone at Yellowknife Bay, Gale Crater, Mars

Sedimentary rocks at Yellowknife Bay (Gale Crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, Ca-sulfates, Fe oxide/hydroxides, Fe-sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 Å indicating little interlayer hydration. The Cumberland smectite has basal spacing at ~13.2 Å as well as ~10 Å. The ~13.2 Å spacing suggests a partially chloritized interlayer or interlayer Mg or Ca facilitating H_2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time

Atmospheric Drag, Occultation 'N' Ionospheric Scintillation (ADONIS) mission proposal: Alpbach Summer School 2013 team orange

The Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation mission (ADONIS) studies the dynamics of the terrestrial thermosphere and ionosphere in dependency of solar events over a full solar cycle in Low Earth Orbit (LEO). The objectives are to investigate satellite drag with in-situ measurements and the ionospheric electron density profiles with radio occultation and scintillation measurements. A constellation of two satellites provides the possibility to gain near real-time data (NRT) about ionospheric conditions over the Arctic region where current coverage is insufficient. The mission shall also provide global high-resolution data to improve assimilative ionospheric models. The low-cost constellation can be launched using a single Vega rocket and most of the instruments are already space-proven allowing for rapid development and good reliability. From July 16 to 25, 2013, the Alpbach Summer School 2013 was organised by the Austrian Research Promotion Agency (FFG), the European Space Agency (ESA), the International Space Science Institute (ISSI) and the association of Austrian space industries Austrospace in Alpbach, Austria. During the workshop, four teams of 15 students each independently developed four different space mission proposals on the topic of “Space Weather: Science, Missions and Systems”, supported by a team of tutors. The present work is based on the mission proposal that resulted from one of these teams’ efforts

Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation (ADONIS) mission proposal

The Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation mission (ADONIS) studies the dynamics of the terrestrial thermosphere and ionosphere in dependency of solar events over a full solar cycle in Low Earth Orbit (LEO). The objectives are to investigate satellite drag with in-situ measurements and the ionospheric electron density profiles with radio occultation and scintillation measurements. A constellation of two satellites provides the possibility to gain near real-time data (NRT) about ionospheric conditions over the Arctic region where current coverage is insufficient. The mission shall also provide global high-resolution data to improve assimilative ionospheric models. The low-cost constellation can be launched using a single Vega rocket and most of the instruments are already space-proven allowing for rapid development and good reliability. From July 16 to 25, 2013, the Alpbach Summer School 2013 was organised by the Austrian Research Promotion Agency (FFG), the European Space Agency (ESA), the International Space Science Institute (ISSI) and the association of Austrian space industries Austrospace in Alpbach, Austria. During the workshop, four teams of 15 students each independently developed four different space mission proposals on the topic of “Space Weather: Science, Missions and Systems”, supported by a team of tutors. The present work is based on the mission proposal that resulted from one of these teams’ efforts

Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation (ADONIS) mission proposal

International audienceThe Atmospheric Drag, Occultation 'N' Ionospheric Scintillation mission (ADONIS) studies the dynamics of the terrestrial thermosphere and ionosphere in dependency of solar events over a full solar cycle in Low Earth Orbit (LEO). The objectives are to investigate satellite drag with in-situ measurements and the ionospheric electron density profiles with radio occultation and scintillation measurements. A constellation of two satellites provides the possibility to gain near real-time data (NRT) about ionospheric conditions over the Arctic region where current coverage is insufficient. The mission shall also provide global highresolution data to improve assimilative ionospheric models. The low-cost constellation can be launched using a single Vega rocket and most of the instruments are already space-proven allowing for rapid development and good reliability

Isotope ratios of H, C, and O in CO2 and H2O of the Martian atmosphere

Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and O-18/O-16 in water and C-13/C-12, O-18/O-16, O-17/O-16, and (CO)-C-13-O-18/(CO)-C-12-O-16 in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established similar to 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing