3,336 research outputs found

    Suicide on the railways in Great Britain: a multi-disciplinary analysis

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    As part of wider efforts to reduce suicide on the railways, Network Rail commissioned a programme of research and consultation focusing on railway suicide messaging and communications. The aim of this work was to generate new multi-disciplinary insights and actionable intelligence for the rail industry. The secondary analysis of existing interview and survey data , taken alongside the analysis of online environments , previous ethnographic and anthropological work , and consultations with academic, rail industry and lived experience experts, has enabled us to generate a fairly full and clear picture of how people who are contemplating (or who have contemplated and attempted) suicide on the railways engage with and express the idea of railway suicide, and the types of associations made about that method / location. In short, by bringing together the findings from different studies, and looking for overlaps, common themes, as well as differences, we have been able to develop a good sense of the cultural scripts and discourses that together form ‘railway suicide’ as a knowable and available means of ending one’s life. More specifically, from these sources we have been able to draw out the factors that seemingly attract people to the method/location (quick, lethal, accessible, commonly used method), and also what dissuades them (impact on others - especially the driver, possibility of surviving with injuries, possibility of intervention, fear-inducing method). The logic, in terms of a messaging / communications strategy, would therefore be to challenge the ‘attractors’ (because many are misunderstandings or myths) and try to reinforce or amplify the ‘dissuaders’. There are complexities and difficulties to be considered, though, particularly around risks, possible unintended consequences, and the nuances needed to communicate to different audiences

    Intervening to prevent suicide at railway locations: findings from a qualitative study with front-line staff and rail commuters.

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    For every suicide on the British railway network, at least six potential attempts are interrupted by front-line staff or rail commuters. However, the factors that maximise or hinder the likelihood and effectiveness of such interventions are poorly understood. The aim of the current study was to shed light on the experience of intervening to prevent a suicide at a railway location, including how and why people intervene, and their feelings and reflections in the aftermath. In-depth interviews were carried out with rail commuters (n = 11) and front-line railway staff (n = 10) who had intervened to stop a suicide by train. Data were analysed thematically. Participants had intervened to prevent suicide in several ways, both from afar (e.g. by calling a member of staff) and more directly (verbally or non-verbally), in some cases with no prior training or experience in suicide prevention, and often as a 'quick, gut reaction' given the limited time to intervene. In more 'reasoned' interventions, poor confidence and concerns around safety were the greatest barriers to action. Although often privy to their final outcome, most participants reflected positively on their intervention/s, stressing the importance of training and teamwork, as well as small talk and non-judgemental listening. Suicides in railway environments can present bystanders with little time to intervene. Potential interveners should therefore be resourced as best as possible through clear infrastructure help/emergency points, visibility of station staff and training for gatekeepers

    Satellite radiometric remote sensing of rainfall fields: multi-sensor retrieval techniques at geostationary scale

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    International audienceThe Microwave Infrared Combined Rainfall Algorithm (MICRA) consists in a statistical integration method using the satellite microwave-based rain-rate estimates, assumed to be accurate enough, to calibrate spaceborne infrared measurements on limited sub-regions and time windows. Rainfall retrieval is pursued at the space-time scale of typical geostationary observations, that is at a spatial resolution of few kilometers and a repetition period of few tens of minutes. The actual implementation is explained, although the basic concepts of MICRA are very general and the method is easy to be extended for considering innovative statistical techniques or measurements from additional space-borne platforms. In order to demonstrate the potentiality of MICRA, case studies over central Italy are also discussed. Finally, preliminary results of MICRA validation by ground based remote and in situ measurements are shown and a comparison with a Neural Network (NN) based technique is briefly illustrated

    Snowfall retrieval at X, Ka and W bands : consistency of backscattering and microphysical properties using BAECC ground-based measurements

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    Radar-based snowfall intensity retrieval is investigated at centimeter and millimeter wavelengths using co-located ground-based multi-frequency radar and video-disdrometer observations. Using data from four snowfall events, recorded during the Biogenic Aerosols Effects on Clouds and Climate (BAECC) campaign in Finland, measurements of liquid-water-equivalent snowfall rate S are correlated to radar equivalent reflectivity factors Z(e), measured by the Atmospheric Radiation Measurement (ARM) cloud radars operating at X, Ka and W frequency bands. From these combined observations, power-law Z(e)-S relationships are derived for all three frequencies considering the influence of riming Using microwave radiometer observations of liquid water path, the measured precipitation is divided into lightly, moderately and heavily rimed snow. Interestingly lightly rimed snow events show a spectrally distinct signature of Z(e)-S with respect to moderately or heavily rimed snow cases. In order to understand the connection between snowflake microphysical and multi-frequency backscattering properties, numerical simulations are performed by using the particle size distribution provided by the in situ video disdrometer and retrieved ice particle masses. The latter are carried out by using both the T-matrix method (TMM) applied to soft-spheroid particle models with different aspect ratios and exploiting a pre-computed discrete dipole approximation (DDA) database for rimed aggregates. Based on the presented results, it is concluded that the soft-spheroid approximation can be adopted to explain the observed multifrequency Z(e)-S relations if a proper spheroid aspect ratio is selected. The latter may depend on the degree of riming in snowfall. A further analysis of the backscattering simulations reveals that TMM cross sections are higher than the DDA ones for small ice particles, but lower for larger particles. The differences of computed cross sections for larger and smaller particles are compensating for each other. This may explain why the soft-spheroid approximation is satisfactory for radar reflectivity simulations under study.Peer reviewe

    Interpretation of observed microwave signatures from ground dual polarization radar and space multi-frequency radiometer for the 2011 Grímsvötn volcanic eruption

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    Abstract. The important role played by ground-based microwave weather radars for the monitoring of volcanic ash clouds has been recently demonstrated. The potential of microwaves from satellite passive and ground-based active sensors to estimate near-source volcanic ash cloud parameters has been also proposed, though with little investigation of their synergy and the role of the radar polarimetry. The goal of this work is to show the potentiality and drawbacks of the X-band dual polarization (DPX) radar measurements through the data acquired during the latest Grímsvötn volcanic eruptions that took place in May 2011 in Iceland. The analysis is enriched by the comparison between DPX data and the observations from the satellite Special Sensor Microwave Imager/Sounder (SSMIS) and a C-band single polarization (SPC) radar. SPC, DPX, and SSMIS instruments cover a large range of the microwave spectrum, operating respectively at 5.4, 3.2, and 0.16–1.6 cm wavelengths

    3DVAR assimilation of SSM/I data over the sea for the IOP2b MAP case

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    International audienceData assimilation by 3DVAR of data from the Special Sensor Microwave/Imager (SSM/I) has been performed to study the IOP2b case (19-21 September 1999) of the Mesoscale Alpine Programme (MAP). Only data over the sea surface are used to avoid the contamination of the surface emissivity. Moreover, the rainy data are filtered out because the assimilation algorithm of 3DVAR does not take into account the scattering processes. SSM/I data are assimilated in two different ways: as Brightness Temperature directly, or as Precipitable Water and surface wind speed retrieved from the Brightness Temperature. The effect of the thinning of the observations has been studied and a set of sensitivity test cases has been carried out; the one by one removal of the SSM/I frequencies from the initial dataset allows to evaluate their impact on the Initial Conditions. A few experiments are performed using these new Initial Conditions to initialize the MM5 (PSU/NCAR) model. The results show that the assimilation of the retrieved quantities, i.e. Precipitable Water and surface wind speed, does not produces large improvement in the Initial Conditions. Vice versa, the assimilation of the Brightness temperatures produces a large variability of the Initial Conditions. The forecast experiments show that the model is very sensitive to the 22GHz and 37GHz frequencies
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