Parameterization of Convective Transport in a Lagrangian Particle Dispersion Model and Its Evaluation

This paper presents the revision and evaluation of the interface between the convective parameterization by Emanuel and Živkovic´-Rothman and the Lagrangian particle dispersion model “FLEXPART” based on meteorological data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The convection scheme relies on the ECMWF grid-scale temperature and humidity and provides a matrix necessary for the vertical convective particle displacement. The benefits of the revised interface relative to its previous version are presented. It is shown that, apart from minor fluctuations caused by the stochastic convective redistribution of the particles, the well-mixed criterion is fulfilled in simulations that include convection. Although for technical reasons the calculation of the displacement matrix differs somewhat between the forward and the backward simulations in time, the mean relative difference between the convective mass fluxes in forward and backward simulations is below 3% and can therefore be tolerated. A comparison of the convective mass fluxes and precipitation rates with those archived in the 40-yr ECMWF Reanalysis (ERA-40) data reveals that the convection scheme in FLEXPART produces upward mass fluxes and precipitation rates that are generally smaller by about 25% than those from ERA-40. This result is interpreted as positive, because precipitation is known to be overestimated by the ECMWF model. Tracer transport simulations with and without convection are compared with surface and aircraft measurements from two tracer experiments and to 222Rn measurements from two aircraft campaigns. At the surface no substantial differences between the model runs with and without convection are found, but at higher altitudes the model runs with convection produced better agreement with the measurements in most of the cases and indifferent results in the others. However, for the tracer experiments only few measurements at higher altitudes are available, and for the aircraft campaigns the 222Rn emissions are highly uncertain. Other datasets better suitable for the validation of convective transport in models are not available. Thus, there is a clear need for reliable datasets suitable to validate vertical transport in models

ALPNAP – A NEW PROJECT ON TRAFFIC-INDUCED NOISE AND AIR POLLUTION ALONG TRANSPORT ROUTES IN THE ALPS

Abstract. ALPNAP (Monitoring and Minimisation of Traffic-Induced Noise and Air Pollution Along Major Alpine Transport Routes) is a new project financed under the EU Interreg III B Alpine Space Programme. It will run from 2005-2007. A network of eleven institutions has been formed with DLR Institute of Atmospheric Physics as the lead partner. The project aims at the integrated use of advanced science-based methods to monitor, assess, and predict air pollution and noise and their impact on the environment, quality of life and health along major transport routes. These methods are adapted to the Alpine topography and its specific meteorological phenomena which often amplify the levels of concentration and noise. The purpose of the project is to promote these methods to regional and local authorities, to supplement standard methods towards more reliable predictions and scenario assessments, to quantify the limits of emissions if given air quality and noise standards are to be met, and to assess the environmental impact of traffic flow changes due to regulations, new infrastructure, or modal shifts. Previous work has shown that the conditions for the propagation of noise and the dispersion of air pollutants in Alpine valleys are quite different, and often considerably more unfavourable than in flat terrain. Standard models which are still applied in such environments, too, are not adequate. The project aims at demonstrating the advantage of more advanced methods taking into account state-of-the-art scientific tools

COMPARISON OF THE DISPERSION MODEL IN RODOS-LX AND MM5-V3.7-FLEXPART(V6.2). A CASE STUDY FOR THE NUCLEAR POWER PLANT OF ALMARAZ

Dispersion has been calculated for a fictitious scenario of an accidental 137Cs release in a nuclear power plant in Almaraz, Spain, with the Real-time On-line De-cisiOn Support system for nuclear emergencies, RODOS, and the FLEXPART lagrangian particle dispersion model coupled with the PSU/NCAR Mesoscale Model, MM5-V3.7-Flexpart (V6.2). Results show differences in the evolution of the radioactive plume and its spreading through the valley

ALPNAP – A NEW PROJECT ON TRAFFIC-INDUCED NOISE AND AIR POLLUTION ALONG TRANSPORT ROUTES IN THE ALPS

Abstract. ALPNAP (Monitoring and Minimisation of Traffic-Induced Noise and Air Pollution Along Major Alpine Transport Routes) is a new project financed under the EU Interreg III B Alpine Space Programme. It will run from 2005-2007. A network of eleven institutions has been formed with DLR Institute of Atmospheric Physics as the lead partner. The project aims at the integrated use of advanced science-based methods to monitor, assess, and predict air pollution and noise and their impact on the environment, quality of life and health along major transport routes. These methods are adapted to the Alpine topography and its specific meteorological phenomena which often amplify the levels of concentration and noise. The purpose of the project is to promote these methods to regional and local authorities, to supplement standard methods towards more reliable predictions and scenario assessments, to quantify the limits of emissions if given air quality and noise standards are to be met, and to assess the environmental impact of traffic flow changes due to regulations, new infrastructure, or modal shifts. Previous work has shown that the conditions for the propagation of noise and the dispersion of air pollutants in Alpine valleys are quite different, and often considerably more unfavourable than in flat terrain. Standard models which are still applied in such environments, too, are not adequate. The project aims at demonstrating the advantage of more advanced methods taking into account state-of-the-art scientific tools

Coarse and giant particles are ubiquitous in Saharan dust export regions and are radiatively significant over the Sahara

Mineral dust is an important component of the climate system, interacting with radiation, clouds and biogeochemical systems, and impacting atmospheric circulation, air quality, aviation and solar energy generation. These impacts are sensitive 10 to dust particle size distribution (PSD), yet models struggle or even fail to represent coarse (diameter (d) >2.5 μm) and giant (d>20 μm) dust particles and the evolution of the PSD with transport. Here we examine three state-of-the-art airborne observational datasets, all of which measured the full size range of dust (d=0.1 to >100 μm) at different stages during transport, with consistent instrumentation. We quantify the presence and evolution of coarse and giant particles and their contribution to optical properties using airborne observations over the Sahara (from the Fennec field campaign) and in the Saharan Air Layer 15 (SAL) over the tropical eastern Atlantic (from the AER-D field campaign). Observations show significantly more abundant coarse and giant dust particles over the Sahara compared to the SAL: effective diameters of up to 20 μm were observed over the Sahara, compared to 4 μm in the SAL. Excluding giant particles over the Sahara results in significant underestimation of mass concentration (40%), as well as underestimates of both shortwave and 20 longwave extinction (18 and 26% respectively from scattering calculations), while the effects in the SAL are smaller but non-negligible. The larger impact on longwave extinction compared to shortwave implies a bias towards a radiative cooling effect in dust models, which typically exclude giant particles and underestimate coarse mode concentrations. A compilation of published effective diameters against dust age since uplift time suggests that two regimes of dust transport 25 exist. During the initial 1.5 days, both coarse and giant particles are rapidly deposited. During the subsequent 1.5 to 10 days, PSD barely changes with transport, and the coarse mode is retained to a much greater degree than expected from estimates of gravitational sedimentation alone. The reasons for this are unclear, and warrant further investigation in order to improve dust transport schemes, and the associated radiative effects of coarse and giant particles in models

COMPARISON OF THE DISPERSION MODEL IN RODOS-LX AND MM5-V3.7-FLEXPART(V6.2). A CASE STUDY FOR THE NUCLEAR POWER PLANT OF ALMARAZ

Dispersion has been calculated for a fictitious scenario of an accidental 137Cs release in a nuclear power plant in Almaraz, Spain, with the Real-time On-line De-cisiOn Support system for nuclear emergencies, RODOS, and the FLEXPART lagrangian particle dispersion model coupled with the PSU/NCAR Mesoscale Model, MM5-V3.7-Flexpart (V6.2). Results show differences in the evolution of the radioactive plume and its spreading through the valley

Selenium Deficiency Is Associated with Mortality Risk from COVID-19

SARS-CoV-2 infections underlie the current coronavirus disease (COVID-19) pandemic and are causative for a high death toll particularly among elderly subjects and those with comorbidities. Selenium (Se) is an essential trace element of high importance for human health and particularly for a well-balanced immune response. The mortality risk from a severe disease like sepsis or polytrauma is inversely related to Se status. We hypothesized that this relation also applies to COVID-19. Serum samples (n = 166) from COVID-19 patients (n = 33) were collected consecutively and analyzed for total Se by X-ray fluorescence and selenoprotein P (SELENOP) by a validated ELISA. Both biomarkers showed the expected strong correlation (r = 0.7758, p < 0.001), pointing to an insufficient Se availability for optimal selenoprotein expression. In comparison with reference data from a European cross-sectional analysis (EPIC, n = 1915), the patients showed a pronounced deficit in total serum Se (mean ± SD, 50.8 ± 15.7 vs. 84.4 ± 23.4 µg/L) and SELENOP (3.0 ± 1.4 vs. 4.3 ± 1.0 mg/L) concentrations. A Se status below the 2.5th percentile of the reference population, i.e., [Se] < 45.7 µg/L and [SELENOP] < 2.56 mg/L, was present in 43.4% and 39.2% of COVID samples, respectively. The Se status was significantly higher in samples from surviving COVID patients as compared with non-survivors (Se; 53.3 ± 16.2 vs. 40.8 ± 8.1 µg/L, SELENOP; 3.3 ± 1.3 vs. 2.1 ± 0.9 mg/L), recovering with time in survivors while remaining low or even declining in non-survivors. We conclude that Se status analysis in COVID patients provides diagnostic information. However, causality remains unknown due to the observational nature of this study. Nevertheless, the findings strengthen the notion of a relevant role of Se for COVID convalescence and support the discussion on adjuvant Se supplementation in severely diseased and Se-deficient patients

The Community Foehn Classification Experiment

Strong winds crossing elevated terrain and descending to its lee occur over mountainous areas worldwide. Winds fulfilling these two criteria are called “foehn” in this paper although different names exist depending on region, sign of temperature change at onset, and depth of overflowing layer. They affect local weather and climate and impact society. Classification is difficult because other wind systems might be superimposed on them or share some characteristics. Additionally, no unanimously agreed-upon name, definition nor indications for such winds exist. The most trusted classifications have been performed by human experts. A classification experiment for different foehn locations in the Alps and different classifier groups addressed hitherto unanswered questions about the uncertainty of these classifications, their reproducibility and dependence on the level of expertise. One group consisted of mountain meteorology experts, the other two of Masters degree students who had taken mountain meteorology courses, and a further two of objective algorithms. Sixty periods of 48 hours were classified for foehn/no foehn at five Alpine foehn locations. The intra-human-classifier detection varies by about 10 percentage points (interquartile range). Experts and students are nearly indistinguishable. The algorithms are in the range of human classifications. One difficult case appeared twice in order to examine reproducibility of classified foehn duration, which turned out to be 50% or less. The classification dataset can now serve as a testbed for automatic classification algorithms, which - if successful - eliminate the drawbacks of manual classifications: lack of scalability and reproducibility

Advancements in the fabrication and characterization of actinide targets for superheavy element production

The heaviest elements can exclusively be produced in actinide-target based nuclear fusion reactions with intense heavy-ion beams. Ever more powerful accelerators deliver beams of continuously increasing intensity, which brings targets of current technology to their limits and beyond. We motivate efforts to produce targets with improved properties, which calls for a better understanding of targets produced by molecular plating, the current standard method. Complementary analytical methods will help shedding more light on their chemical and physical changes in the beam. Special emphasis is devoted to the aspect of the optimum target thickness and the choice of the backing material