63 research outputs found
Modelling the urban heat island in Birmingham, UK at the neighbourhood scaleÂ
Cities have higher peak temperatures compared to surrounding rural areas. The urban-rural surface air temperature difference is known as the urban heat island (UHI). As extreme heat exposure can lead to adverse health effects, information on UHI characteristics of cities is important for future urban climate planning strategies. This study applied the ADMS-Urban Temperature and Humidity model to investigate the key processes driving the UHI in Birmingham, UK, at the neighbourhood scale. This model was configured with a range of input datasets (such as meteorological data, landuse data, building data, anthropogenic heat sources etc) and run on the University of Birminghamâs BlueBEAR HPC. This urban climate modelling was evaluated against the temperature measurement datasets from UK Met Office and Weather Underground. The spatiotemporal variations of surface air temperature in Birmingham, UK were captured by this model. This modelling study can be further applied to explore the impacts of local urban head island mitigation strategies
Wohnvorstellungen der mĂ€nnlichen Babyboomer fĂŒr das vierte Lebensalter: Inwiefern unterscheiden sich die Vorstellungen der alleinlebenden im Vergleich zu den in Partnerschaft lebenden mĂ€nnlichen Babyboomer (JahrgĂ€nge 1943 â 1950) bezĂŒglich ihrer Wohnsituation im fragilen Alter und was bedeutet das fĂŒr die Soziale Arbeit?
Die vorliegende Bachelorarbeit befasst sich mit der Thematik âWohnen im Alterâ. Die Arbeit stĂŒtzt sich dabei auf zwei Forschungsbereiche: Die Ăbergangs- und die Alternsforschung. Der Fokus der Bachelorthesis liegt auf den Wohnvorstellungen von den Personen mĂ€nnlichen Geschlechts im Oberwallis, die der Generation der Kriegs- und Nachkriegsbabyboomer (JahrgĂ€nge 1943 â 1950) angehören. Es werden verschiedene theoretische Aspekte (wie Gesellschaftswandel, Wohnmöglichkeiten im Alter, finanzielle und rechtliche Situation, etc.) aufgegriffen, die Auswirkungen auf das Wohnen im Alter haben können
Air quality simulations for London using a coupled regional-to-local modelling system
A coupled regional-to-local modelling system comprising a regional chemistryâclimate model with 5km horizontal resolution (EMEP4UK) and an urban dispersion and chemistry model with explicit road source emissions (ADMS-Urban) has been used to simulate air quality in 2012 across London. The study makes use of emission factors for NOx and NO2 and non-exhaust emission rates of PM10 and PM2.5 which have been adjusted compared to standard factors to reflect real-world emissions, with increases in total emissions of around 30% for these species. The performance of the coupled model and each of the two component models is assessed against measurements from background and near-road sites in London using a range of metrics concerning annual averages, high hourly average concentrations and diurnal cycles. The regional model shows good performance compared to measurements for background sites for these metrics, but under-predicts concentrations of all pollutants except O3 at near-road sites due to the low resolution of input emissions and calculations. The coupled model shows good performance at both background and near-road sites, which is broadly comparable with that of the urban model that uses measured concentrations as regional background, except for PM2.5 where the under-prediction of the regional model causes the coupled model to also under-predict concentrations. Using the coupled model, it is estimated that 13% of the area of London exceeded the EU limit value of 40”gmâ3 for annual average NO2 in 2012, whilst areas of exceedances of the annual average limit values of 40 and 25”gmâ3 for PM10 and PM2.5 respectively were negligible
Using task farming to optimise a street-scale resolution air quality model of the West Midlands (UK)
High resolution air quality models combining emissions, chemical processes, dispersion and dynamical treatments are necessary to develop effective policies for clean air in urban environments, but can have high computational demand. We demonstrate the application of task farming to reduce runtime for ADMS-Urban, a quasi-Gaussian plume air dispersion model. The model represents the full range of source types (point, road and grid sources) occurring in an urban area at high resolution. Here, we implement and evaluate the option to automatically split up a large model domain into smaller sub-regions, each of which can then be executed concurrently on multiple cores of a HPC or across a PC network, a technique known as task farming. The approach has been tested for a large model domain covering the West Midlands, UK (902 km2), as part of modelling work in the WM-Air (West Midlands Air Quality Improvement Programme) project. Compared to the measurement data, overall, the model performs well. Air quality maps for annual/subset averages and percentiles are generated. For this air quality modelling application of task farming, the optimisation process has reduced weeks of model execution time to approximately 35 h for a single model configuration of annual calculations
Measurement of NOx fluxes by eddy covariance from the BT tower, London during the ClearfLo project
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Street-scale air quality modelling for Beijing during a winter 2016 measurement campaign
We examine the street-scale variation of NOx, NO2, O3 and PM2.5 concentrations in Beijing during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) winter measurement campaign in NovemberâDecember 2016. Simulations are performed using the urban air pollution dispersion and chemistry model ADMS-Urban and an explicit network of road source emissions. Two versions of the gridded Multi-resolution Emission Inventory for China (MEIC v1.3) are used: the standard MEIC v1.3 emissions and an optimised version, both at 3âkm resolution. We construct a new traffic emissions inventory by apportioning the transport sector onto a detailed spatial road map. Agreement between mean simulated and measured pollutant concentrations from Beijing's air quality monitoring network and the Institute of Atmospheric Physics (IAP) field site is improved when using the optimised emissions inventory. The inclusion of fast NOxâO3 chemistry and explicit traffic emissions enables the sharp concentration gradients adjacent to major roads to be resolved with the model. However, NO2 concentrations are overestimated close to roads, likely due to the assumption of uniform traffic activity across the study domain. Differences between measured and simulated diurnal NO2 cycles suggest that an additional evening NOx emission source, likely related to heavy-duty diesel trucks, is not fully accounted for in the emissions inventory. Overestimates in simulated early evening NO2 are reduced by delaying the formation of stable boundary layer conditions in the model to replicate Beijing's urban heat island. The simulated campaign period mean PM2.5 concentration range across the monitoring network (âŒ15â”gâmâ3) is much lower than the measured range (âŒ40â”gâmâ3). This is likely a consequence of insufficient PM2.5 emissions and spatial variability, neglect of explicit point sources, and assumption of a homogeneous background PM2.5 level. Sensitivity studies highlight that the use of explicit road source emissions, modified diurnal emission profiles, and inclusion of urban heat island effects permit closer agreement between simulated and measured NO2 concentrations. This work lays the foundations for future studies of human exposure to ambient air pollution across complex urban areas, with the APHH-China campaign measurements providing a valuable means of evaluating the impact of key processes on street-scale air quality
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Modelling spatiotemporal variations of the canopy layer urban heat island in Beijing at the neighbourhood scale
Information on the spatiotemporal characteristics of Beijing's urbanârural near-surface air temperature difference, known as the canopy layer urban heat island (UHI), is important for future urban climate management strategies. This paper investigates the variation of near-surface air temperatures within Beijing at a neighbourhood-scale resolution (âŒâ100âm) during winter 2016 and summer 2017. We perform simulations using the urban climate component of the ADMS-Urban model with land surface parameters derived from both local climate zone classifications and OpenStreetMap land use information. Through sensitivity simulations, the relative impacts of surface properties and anthropogenic heat emissions on the temporal variation of Beijing's UHI are quantified. Measured UHI intensities between central Beijing (Institute of Atmospheric Physics) and a rural site (Pinggu) during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) campaigns, peak during the evening at âŒâ4.5ââC in both seasons. In winter, the nocturnal UHI is dominated by anthropogenic heat emissions but is underestimated by the model. Higher-resolution anthropogenic heat emissions may capture the effects of local sources (e.g. residential buildings and adjacent major roads). In summer, evening UHI intensities are underestimated, especially during heatwaves. The inability to fully replicate the prolonged release of heat stored in the urban fabric may explain this. Observed negative daytime UHI intensities in summer are more successfully captured when surface moisture levels in central Beijing are increased. However, the spatial correlation between simulated air temperatures and satellite-derived land surface temperatures is stronger with a lower urban moisture scenario. This result suggests that near-surface air temperatures at the urban meteorological site are likely influenced by fine-scale green spaces that are unresolved by the available land cover data and demonstrates the expected differences between surface and air temperatures related to canopy layer advection. This study lays the foundations for future studies of heat-related health risks and UHI mitigation strategies across Beijing and other megacities
Assessing chemistry schemes and constraints in air quality models used to predict ozone in London against the detailed Master Chemical Mechanism
Air pollution is the environmental factor with the greatest impact on human health in Europe. Understanding the key processes driving air quality across the relevant spatial scales, especially during pollution exceedances and episodes, is essential to provide effective predictions for both policymakers and the public. It is particularly important for policy regulators to understand the drivers of local air quality that can be regulated by national policies versus the contribution from regional pollution transported from mainland Europe or elsewhere. One of the main objectives of the Coupled Urban and Regional processes: Effects on AIR quality (CUREAIR) project is to determine local and regional contributions to ozone events. A detailed zero-dimensional (0-D) box model run with the Master Chemical Mechanism (MCMv3.2) is used as the benchmark model against which the less explicit chemistry mechanisms of the Generic Reaction Set (GRS) and the Common Representative Intermediates (CRIv2-R5) schemes are evaluated. GRS and CRI are used by the Atmospheric Dispersion Modelling System (ADMS-Urban) and the regional chemistry transport model EMEP4UK, respectively. The MCM model uses a near-explicit chemical scheme for the oxidation of volatile organic compounds (VOCs) and is constrained to observations of VOCs, NOx, CO, HONO (nitrous acid), photolysis frequencies and meteorological parameters measured during the ClearfLo (Clean Air for London) campaign. The sensitivity of the less explicit chemistry schemes to different model inputs has been investigated: Constraining GRS to the total VOC observed during ClearfLo as opposed to VOC derived from ADMS-Urban dispersion calculations, including emissions and background concentrations, led to a significant increase (674% during winter) in modelled ozone. The inclusion of HONO chemistry in this mechanism, particularly during wintertime when other radical sources are limited, led to substantial increases in the ozone levels predicted (223%). When the GRS and CRIv2-R5 schemes are run with the equivalent model constraints to the MCM, they are able to reproduce the level of ozone predicted by the near-explicit MCM to within 40% and 20% respectively for the majority of the time. An exception to this trend was observed during pollution episodes experienced in the summer, when anticyclonic conditions favoured increased temperatures and elevated O3. The in situ O3 predicted by the MCM was heavily influenced by biogenic VOCs during these conditions and the low GRS [O3] : MCM [O3] ratio (and low CRIv2-R5 [O3] : MCM [O3] ratio) demonstrates that these less explicit schemes under-represent the full O3 creation potential of these VOCs. To fully assess the influence of the in situ O3 generated from local emissions versus O3 generated upwind of London and advected in, the time since emission (and, hence, how far the real atmosphere is from steady state) must be determined. From estimates of the mean transport time determined from the NOx : NOy ratio observed at North Kensington during the summer and comparison of the O3 predicted by the MCM model after this time, âŒ60% of the median observed [O3] could be generated from local emissions. During the warmer conditions experienced during the easterly flows, however, the observed [O3] may be even more heavily influenced by London's emissions
Symmetry Energy I: Semi-Infinite Matter
Energy for a nucleus is considered in macroscopic limit, in terms of nucleon
numbers. Further considered for a nuclear system is the Hohenberg-Kohn energy
functional, in terms of proton and neutron densities. Finally,
Skyrme-Hartree-Fock calculations are carried out for a half-infinite
particle-stable nuclear-matter. In each case, the attention is focused on the
role of neutron-proton asymmetry and on the nuclear symmetry energy. We extend
the considerations on the symmetry term from an energy formula to the
respective term in the Hohenberg-Kohn functional. We show, in particular, that
in the limit of an analytic functional, and subject to possible Coulomb
corrections, it is possible to construct isoscalar and isovector densities out
of the proton and neutron densities, that retain a universal relation to each
other, approximately independent of asymmetry. In the so-called local
approximation, the isovector density is inversely proportional to the symmetry
energy in uniform matter at the local isoscalar density. Generalized symmetry
coefficient of a nuclear system is related, in the analytic limit of a
functional, to an integral of the isovector density. We test the relations,
inferred from the Hohenberg-Kohn functional, in the Skyrme-Hartree-Fock
calculations of half-infinite matter. Within the calculations, we obtain
surface symmetry coefficients and parameters characterizing the densities, for
the majority of Skyrme parameterizations proposed in the literature. The
volume-to-surface symmetry-coefficient ratio and the displacement of nuclear
isovector relative to isoscalar surfaces both strongly increase as the slope of
symmetry energy in the vicinity of normal density increases.Comment: 87 pages, 18 figures; discussion of Kohn-Sham method added,
comparison to results in literature broadene
Provision of obstetrics and gynaecology services during the COVID-19 pandemic:a survey of junior doctors in the UK National Health Service
Objective: The COVID-19 pandemic is disrupting health services worldwide. We aimed to evaluate the provision of obstetrics and gynaecology services in the UK during the acute-phase of the COVID-19 pandemic.
Design: Interview-based national survey.
Setting: Womenâs healthcare units in the National Health Service.
Population: Junior doctors in obstetrics and gynaecology.
Methods: Participants were interviewed by members of the UKARCOG traineesâ collaborative between 28th March and 7th of April 2020. We used a quantitative analysis for closed-ended questions and a thematic framework analysis for open comments.
Results: We received responses from 148/155 units (95%), majority of the participants were in years 3-7 of training (121/148, 82%). Most completed specific training drills for managing obstetric and gynaecological emergencies in women with COVID-19 (89/148, 60.1%) and two-persons donning and doffing of Personal Protective Equipment (PPE) (96/148, 64.9%). The majority of surveyed units implemented COVID-19 specific protocols (130/148, 87.8%), offered adequate PPE (135/148, 91.2%) and operated dedicated COVID-19 emergency theatres (105/148, 70.8%).
Most units reduced face-to-face antenatal clinics (117/148, 79.1%), and suspended elective gynaecology services (131/148, 88.5%). The two-week referral pathway for oncology gynaecology was not affected in half of the units (76/148, 51.4%), while half reported a planned reduction in oncology operating (82/148, 55.4%).
Conclusion: The provision of obstetrics and gynaecology services in the UK during the acute phase of the COVID-19 pandemic seems to be in line with current guidelines, but strategic planning is needed to restore routine gynaecology services and ensure safe access to maternity care on the longterm
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