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W Roether - One of the best experts on this subject based on the ideXlab platform.
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Modelling of the anthropogenic tritium transient and its Decay Product helium-3 in the Mediterranean Sea using a high-resolution regional model
Ocean Science, 2015Co-Authors: Mohammad Ayache, thomas arsouze, J Beuvier, Julien Palmieri, Briac Le-Vu, Philippe Jean-baptiste, Karine Béranger, J C Dutay, W RoetherAbstract:This numerical study provides the first simulation of the anthropogenic tritium invasion and its Decay Product helium-3 (3 He) in the Mediterranean Sea. The simulation covers the entire tritium (3 H) transient generated by the atmospheric nuclear weapons tests performed in the 1950s and early 1960s and is run till 2011. Tritium, helium-3 and their derived age estimates are particularly suitable for studying intermediate and deep-water ventilation and spreading of water masses at intermediate/deep levels. The simulation is made using a high-resolution regional model NEMO (Nucleus for European Modelling of the Ocean), in a regional configuration for the Mediterranean Sea called MED12, forced at the surface with prescribed tritium evolution derived from observations. The simulation is compared to measurements of tritium and helium-3 performed along large-scale transects in the Mediterranean Sea during the last few decades on cruises of R/V Meteor: M5/6, M31/1, M44/4, M51/2, M84/3, and R/V Poseidon: 234. The results show that the input function used for the tritium generates a realistic distribution of the main hydrographic features of the Mediterranean Sea circulation. In the eastern basin, the results highlight the weak formation of Adriatic Deep Water in the model, which explains its weak contribution to the Eastern Mediterranean Deep Water (EMDW) in the Ionian sub-basin. It produces a realistic representation of the Eastern Mediterranean Transient (EMT) signal, simulating a deep-water formation in the Aegean sub-basin at the beginning of 1993, with a realistic timing of deep-water renewal in the eastern basin.
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The transient distributions of nuclear weapon-generated tritium and its Decay Product 3 he in the mediterranean sea, 1952-2011, and their oceanographic potential
Ocean Science, 2013Co-Authors: W Roether, Philippe Jean-baptiste, Elodie Fourre, J. SültenfußAbstract:We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon test- ing in the 1950s and early 1960s, based on essentially all available observations. Tritium in surface waters rose to 20– 30TU in 1964 (TU = 1018 · [3H]/[H]), a factor of about 100 above the natural level, and thereafter declined 30-fold up to 2011. The decline was largely due to radioactive tri- tium Decay, which produced significant amounts of its sta- ble daughter 3He. We present the scheme by which we sep- arate the tritiugenic part of 3He and the part due to release from the sea floor (terrigenic part). We show that the tritiu- genic component can be quantified throughout the Mediter- ranean waters, typically to a ±0.15TU equivalent, mostly because the terrigenic part is low in 3He. This fact makes the Mediterranean unique in offering a potential for the use of tritiugenic 3He as a tracer. The transient distributions of the two tracers are illustrated by a number of sections spanning the entire sea and relevant features of their distributions are noted. By 2011, the 3He concentrations in the top few hun- dred metres had become low, in response to the decreasing tritium concentrations combined with a flushing out by the general westward drift of these waters. Tritium-3He ages in Levantine IntermediateWater (LIW) were obtained repeated in time at different locations, defining transit times from the LIW source region east of Rhodes. The ages showan upward trend with the time elapsed since the surface-water tritium maximum, which arises because the repeated observations represent increasingly slower moving parts of the full transit time spectrum of LIW. The transit time dispersion revealed by this new application of tritium-3He dating is consider- able. We find mean transit times of 12´ s2 yr up to the Strait of Sicily, 18´ s3 yr up to the Tyrrhenian Sea, and 22´ s4 yr up into theWestern Mediterranean. Furthermore, we present full Eastern Mediterranean sections of terrigenic 3He and tritium- 3He age in 1987, the latter one similarly showing an effect of the transit time dispersion.We conclude that the available tri- tium and 3He data, particularly if combined with other tracer data, are useful for constraining the subsurface circulation and mixing of the Mediterranean Sea.
Z. Wa̧s - One of the best experts on this subject based on the ideXlab platform.
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Ascertaining the spin for new resonances Decaying into ${\mathbb{\tau}^{+} \tau^{-}}$ at hadron colliders
The European Physical Journal C, 2013Co-Authors: S. Banerjee, J. Kalinowski, W. Kotlarski, T. Przedzinski, Z. Wa̧sAbstract:Evidence of a new particle with mass ∼125 GeV Decaying into a pair of tau leptons at the Large Hadron Collider spurs interest in ascertaining its spin in this channel. Here we present a comparative study between spin-0 and spin-2 nature of this new particle, using spin correlations and Decay Product directions. The TauSpinner algorithm is used to re-weight distributions from $q \bar{q} \to \gamma/Z \to\tau^{+} \tau^{-}$ sample to simulate a spin-2 state exchange. The method is based on supplementing the Standard Model matrix elements with those arising from presence of a new interaction. Studies with simulated samples demonstrate the discrimination power between these spin hypotheses based on data collected at the Large Hadron Collider.
Margit Schwikowski - One of the best experts on this subject based on the ideXlab platform.
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influences of vertical transport and scavenging on aerosol particle surface area and radon Decay Product concentrations at the jungfraujoch 3454 m above sea level
Journal of Geophysical Research, 2000Co-Authors: M Lugauer, D. T. Jost, U Baltensperger, Markus Furger, H W Gaggeler, S Nyeki, Margit SchwikowskiAbstract:Concentrations of the aerosol particle surface area (SA) and aerosol-attached radon Decay Products 214Pb and 212Pb have been measured by means of an aerosol and a radon epiphaniometer at the Jungfraujoch research station (JFJ; 3454 m above sea level, Switzerland). These parameters exhibit a pronounced seasonal cycle with minimum values in winter and maximum values in summer. In summer, pronounced diurnal variations with a maximum at 1800 LST are often present. Highest concentrations and most pronounced diurnal variations occur during anticyclonic weather conditions in summer. Thermally driven vertical transport over alpine topography is responsible for this observation. During this synoptic condition, concentrations vary greatly with the 500 hPa wind direction, exhibiting low concentrations for NW-N winds and high concentrations for weak or S-SW winds. Lead-214 and SA are highly correlated during anticyclonic conditions, indicating transport equivalence of the gaseous 214Pb precursor, 222Rn, and of aerosol particles. When cyclonic lifting is the dominant vertical transport, wet scavenging of aerosol particles can explain the weak correlation of 214Pb and SA. This conclusion is corroborated by the 214Pb/SA ratio, being twice as high during cyclonic than during anticyclonic conditions. Lead-212 is a tracer for the influence of surface contact on a local scale due to its short lifetime of 15.35 hours. The analysis of this parameter suggests that high-alpine surfaces play an important role in thermally driven transport to the JFJ.
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Radon and thoron Decay Product and 210Pb measurements at Jungfraujoch, Switzerland
Atmospheric Environment, 1995Co-Authors: Heinz W. Gäggeler, D. T. Jost, Urs Baltensperger, Margit Schwikowski, Petra SeibertAbstract:Abstract During one year, the atmospheric activity concentrations of the short-lived “radon” (222Rn) and “thoron” (220Rn) Decay Products were measured at Jungfraujoch (3450 m a.s.l.). The measurements were performed using a modified epiphaniometer, with a time resolution of 1 h. In addition, also the long-lived radon Decay Product 210Pb was measured with a time resolution of one month. Strong seasonal variations of all activity concentrations were found, the average summer values being a factor of ten higher than the average winter values. During summer time the activity concentrations of the radon and thoron Decay Products showed. pronounced diurnal variations. During winter these diurnal variations were absent, and the activity concentrations were close to free tropospheric background values. From the ratio between the activity concentrations of the radon Decay Products 214Pb and 210Pb a mean residence time of aerosol particles in the atmosphere of about six days could be estimated. The average activity concentrations of the radon and thoron Decay Products at Jungfraujoch were found to be related to the regional soil temperatures at a near-by low altitude Swiss Midland site and to the static stability of the air mass between this Midland site and the Jungfraujoch. Furthermore, a significant correlation was found between the radon and thoron Decay Product activity concentrations and synoptic situations with higher than average activity concentrations for air flours from NE to SW and lower than average concentrations for air flows from W to N.
Philippe Jean-baptiste - One of the best experts on this subject based on the ideXlab platform.
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Modelling of the anthropogenic tritium transient and its Decay Product helium-3 in the Mediterranean Sea using a high-resolution regional model
Ocean Science, 2015Co-Authors: Mohammad Ayache, thomas arsouze, J Beuvier, Julien Palmieri, Briac Le-Vu, Philippe Jean-baptiste, Karine Béranger, J C Dutay, W RoetherAbstract:This numerical study provides the first simulation of the anthropogenic tritium invasion and its Decay Product helium-3 (3 He) in the Mediterranean Sea. The simulation covers the entire tritium (3 H) transient generated by the atmospheric nuclear weapons tests performed in the 1950s and early 1960s and is run till 2011. Tritium, helium-3 and their derived age estimates are particularly suitable for studying intermediate and deep-water ventilation and spreading of water masses at intermediate/deep levels. The simulation is made using a high-resolution regional model NEMO (Nucleus for European Modelling of the Ocean), in a regional configuration for the Mediterranean Sea called MED12, forced at the surface with prescribed tritium evolution derived from observations. The simulation is compared to measurements of tritium and helium-3 performed along large-scale transects in the Mediterranean Sea during the last few decades on cruises of R/V Meteor: M5/6, M31/1, M44/4, M51/2, M84/3, and R/V Poseidon: 234. The results show that the input function used for the tritium generates a realistic distribution of the main hydrographic features of the Mediterranean Sea circulation. In the eastern basin, the results highlight the weak formation of Adriatic Deep Water in the model, which explains its weak contribution to the Eastern Mediterranean Deep Water (EMDW) in the Ionian sub-basin. It produces a realistic representation of the Eastern Mediterranean Transient (EMT) signal, simulating a deep-water formation in the Aegean sub-basin at the beginning of 1993, with a realistic timing of deep-water renewal in the eastern basin.
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The transient distributions of nuclear weapon-generated tritium and its Decay Product 3 he in the mediterranean sea, 1952-2011, and their oceanographic potential
Ocean Science, 2013Co-Authors: W Roether, Philippe Jean-baptiste, Elodie Fourre, J. SültenfußAbstract:We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon test- ing in the 1950s and early 1960s, based on essentially all available observations. Tritium in surface waters rose to 20– 30TU in 1964 (TU = 1018 · [3H]/[H]), a factor of about 100 above the natural level, and thereafter declined 30-fold up to 2011. The decline was largely due to radioactive tri- tium Decay, which produced significant amounts of its sta- ble daughter 3He. We present the scheme by which we sep- arate the tritiugenic part of 3He and the part due to release from the sea floor (terrigenic part). We show that the tritiu- genic component can be quantified throughout the Mediter- ranean waters, typically to a ±0.15TU equivalent, mostly because the terrigenic part is low in 3He. This fact makes the Mediterranean unique in offering a potential for the use of tritiugenic 3He as a tracer. The transient distributions of the two tracers are illustrated by a number of sections spanning the entire sea and relevant features of their distributions are noted. By 2011, the 3He concentrations in the top few hun- dred metres had become low, in response to the decreasing tritium concentrations combined with a flushing out by the general westward drift of these waters. Tritium-3He ages in Levantine IntermediateWater (LIW) were obtained repeated in time at different locations, defining transit times from the LIW source region east of Rhodes. The ages showan upward trend with the time elapsed since the surface-water tritium maximum, which arises because the repeated observations represent increasingly slower moving parts of the full transit time spectrum of LIW. The transit time dispersion revealed by this new application of tritium-3He dating is consider- able. We find mean transit times of 12´ s2 yr up to the Strait of Sicily, 18´ s3 yr up to the Tyrrhenian Sea, and 22´ s4 yr up into theWestern Mediterranean. Furthermore, we present full Eastern Mediterranean sections of terrigenic 3He and tritium- 3He age in 1987, the latter one similarly showing an effect of the transit time dispersion.We conclude that the available tri- tium and 3He data, particularly if combined with other tracer data, are useful for constraining the subsurface circulation and mixing of the Mediterranean Sea.
J. Sültenfuß - One of the best experts on this subject based on the ideXlab platform.
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The transient distributions of nuclear weapon-generated tritium and its Decay Product 3 he in the mediterranean sea, 1952-2011, and their oceanographic potential
Ocean Science, 2013Co-Authors: W Roether, Philippe Jean-baptiste, Elodie Fourre, J. SültenfußAbstract:We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon test- ing in the 1950s and early 1960s, based on essentially all available observations. Tritium in surface waters rose to 20– 30TU in 1964 (TU = 1018 · [3H]/[H]), a factor of about 100 above the natural level, and thereafter declined 30-fold up to 2011. The decline was largely due to radioactive tri- tium Decay, which produced significant amounts of its sta- ble daughter 3He. We present the scheme by which we sep- arate the tritiugenic part of 3He and the part due to release from the sea floor (terrigenic part). We show that the tritiu- genic component can be quantified throughout the Mediter- ranean waters, typically to a ±0.15TU equivalent, mostly because the terrigenic part is low in 3He. This fact makes the Mediterranean unique in offering a potential for the use of tritiugenic 3He as a tracer. The transient distributions of the two tracers are illustrated by a number of sections spanning the entire sea and relevant features of their distributions are noted. By 2011, the 3He concentrations in the top few hun- dred metres had become low, in response to the decreasing tritium concentrations combined with a flushing out by the general westward drift of these waters. Tritium-3He ages in Levantine IntermediateWater (LIW) were obtained repeated in time at different locations, defining transit times from the LIW source region east of Rhodes. The ages showan upward trend with the time elapsed since the surface-water tritium maximum, which arises because the repeated observations represent increasingly slower moving parts of the full transit time spectrum of LIW. The transit time dispersion revealed by this new application of tritium-3He dating is consider- able. We find mean transit times of 12´ s2 yr up to the Strait of Sicily, 18´ s3 yr up to the Tyrrhenian Sea, and 22´ s4 yr up into theWestern Mediterranean. Furthermore, we present full Eastern Mediterranean sections of terrigenic 3He and tritium- 3He age in 1987, the latter one similarly showing an effect of the transit time dispersion.We conclude that the available tri- tium and 3He data, particularly if combined with other tracer data, are useful for constraining the subsurface circulation and mixing of the Mediterranean Sea.
