The quadrupole ionosphere

The principal features that might exist in the terrestrial paleoionosphere, if the geomagnetic field were to assume a quadrupole form during a polarity reversal are discussed. Complicated phenomena would be expected to occur at magnetic equators and magnetospherically-driven plasma convection might occur at latitudes where the magnetic field is steeply inclined. The influence of magnetic field strength on ionospheric structure is considered in general terms

Long-term changes in thermospheric composition inferred from a spectral analysis of ionospheric F-region data

A study of ionospheric data recorded at Slough/Chilton, UK, from 1935 to 2012, has revealed longterm changes in the relative strength of the annual and semiannual variability in the ionospheric F2 layer critical frequencies. Comparing these results with data from the southern hemisphere station at Stanley in the Falkland Islands between 1945 and 2012 reveals a trend that appears to be anti-correlated with that at Chilton. The behaviour of foF2 is a function of thermospheric composition and so we argue that the observed long-term changes are driven by composition change. The ionospheric trends share some of their larger features with the trend in the variability of the aa geomagnetic index. Changes to the semi-annual/annual ratio in the Slough/Chilton and Stanley data may therefore be attributable to the variability in geomagnetic activity which controls the average latitudinal extent of the auroral ovals and subsequent thermospheric circulation patterns. Changes in ionospheric composition or thermospheric wind patterns are known to influence the height of the F2 layer at a given location. Long-term changes to the height of the F2 layer have been used to infer an ionospheric response to greenhouse warming. We suggest that our observations may influence such measurements and since the results appear to be dependent on geomagnetic longitude, this could explain why the long-term drifts observed in F2 layer height differ between locations

Sitting outside: conviviality, self-care and the design of benches in urban public space

The urban bench has been romanticised as a location of intimacy and benign social serendipity and problematized with regard to perceptions of unwelcome loitering. In this paper we explore embodied practices of sitting on benches, within an urban context characterised by corporate-led regeneration and impacted by austerity urbanism, imperial history and ongoing racisms. Our schizocartographic methodology enables us to attend to the differentiated and shifting subjectivities and temporalities of bench users, and to emerging counter histories of space. The research is based on the case study of a central square in Woolwich, south-east London. This involved an eclectic combination of methods, including film-making, ethnography and interviews, and a cross-sectoral team of activists, academics and artist. The paper starts by conceptually framing public space with respect to lived experiences of marginalisation, arguing that architectural design is intrinsic to understanding micro-geographies of conviviality and care. The case study material is used first to provide a visual sketch of sitting and watching others in the square and then to address conviviality and the value of visibility and relative proximity in framing a mostly un-panicked multiculture. Thirdly, we discuss agentic, yet critically aware, acts of self-care. Finally, our focus shifts to the design of the benches and the ‘touching experiences’ of bodies sat in various ways, impacted by structural inequalities, yet differentiated by the particularities of individual or collective priorities. In conclusion we argue that attending to the precision of sitting on a bench can illuminate multiple temporalities of urban change in relation to both individual subjectivities and hegemonic structures. Further, the counter histories that emerge can inform policy and practice for inclusive urban design

Oscillation of the Ionosphere at Planetary-Wave Periods

F‐region ionospheric oscillations at planetary‐wave (PW) periods (2–20 days) are investigated, with primary focus on those oscillations transmitted to the ionosphere by PW modulation of the vertically propagating tidal spectrum. Tidal effects are isolated by specifically designed numerical experiments performed with the National Center for Atmospheric Research thermosphere‐ionosphere‐electrodynamics general circulation model for October 2009, when familiar PW and tides are present in the model. Longitude versus day‐of‐month perturbations in topside F‐region electron density (Ne) of order ±30–50% at PW periods occur as a result of PW‐modulated tides. At a given height, these oscillations are mainly due to vertical oscillations in the F layer of order ±15–40 km. These vertical movements are diagnosed in terms of changes in the F2‐layer peak height, ΔhmF2, which are driven by the vertical projections of E × B drifts and field‐aligned in situ neutral winds. E × B drifts dominate at the magnetic equator, while the two sources play more equal roles between 20° and 40° magnetic latitudes in each hemisphere. The in situ neutral wind effect arises from vertical propagation of PW‐modulated tides, whereas the E × B drifts originate from dynamo‐generated electric fields produced by the E‐region component of the same wind field; the former represents a new coupling mechanism for production of ionospheric oscillations at PW periods. Roughly half the above‐mentioned variability in Ne and hmF2 is associated with zonally symmetric (S0) oscillations, which contribute at about half the level of low‐level magnetic activity during October 2009. The thermosphere‐ionosphere‐electrodynamics general circulation model simulates the S0 oscillations in Ne observed from the CHAMP satellite well during this period and reveals that S0 oscillations in E × B play a significant role in driving S0 oscillations in ΔhmF2, in addition to neutral winds

Design for Diversity: Intercultural Outdoor Places

This publication is a report on the Design for Diversity: Intercultural Outdoor Places symposium that was held on 13th May 2015 at the Showroom in Sheffield, UK. The symposium was organised by the Transnational Urban Outdoors (TUO) research group based at the Department of Landscape, The University of Sheffield. Six speakers from both practice and academia addressed topics related to the value of parks as places of shared leisure, the importance of central locations and how sitting outside can both reflect ethnic diversity and support local cohesion. The publication also includes discussion summaries and links to audio recordings of all talks

EISCAT velocity patterns for theoretical plasma convection models

Theoretical line-of-sight velocities, as would be observed by the EISCAT radar, are computed for idealized models of plasma convection in the polar ionosphere. The calculations give the velocity as a function of range and Universal Time. For several variants of the Volland and Heelis convection models, how the maxima, minima and reversals of velocity depend on beam azimuth is examined. The analysis is designed to be applied to data from the UK-POLAR experiment, an example of which is shown

Participation and wellbeing in urban greenspace: ‘curating sociability’ for refugees and asylum seekers

This paper examines how asylum seekers and refugees experience urban greenspaces. Whilst often overlooked in a focus on support services and integration, we argue that critically exploring the importance of urban greenspaces has wider implications for understanding how asylum seekers and refugees navigate experiences of displacement and resettlement. Drawing on empirical work foregrounding refugee experiences in Berlin, London, and Sheffield, we found that spending time outdoors in local recreational spaces such as parks, can have positive outcomes for wellbeing and inclusion, with the potential to support respite and the beginnings of belonging. However, though there were multiple positive accounts, especially of busier parks and of appreciating nature, many participants were uncertain or anxious about using parks. The interviews highlight the multiple barriers faced by asylum seekers and refugees, regarding information, legibility and in gaining the cultural capital and confidence needed venture out. The varied experiences reflect the diversity of greenspace typologies in Northern European cities, and also how individuals weight up public perceptions and, for some, the insecurity of their legal status. In unpacking the interaction between these barriers, we define and propose ‘curated sociability’ approaches as possible frameworks for supporting egalitarian participation and offering pathways to greater engagement. We conclude by highlighting a range of interventions that offer situated opportunities for asylum seekers and refugees to engage with urban greenspaces, and which provide insights into how the expectations and rules of urban greenspace are actively negotiated and may be rewritten

Landscape Experience and Migration: Superdiversity and the Significance of Urban Public Open Space

This thesis examines how first generation migrants experience urban outdoor places, detailing significant findings and methodological development relating to two research projects. The research is located in Sheffield, England. The first research project (Viewfinder) focuses on young refugees and asylum seekers exploring citywide greenspaces and parks. The second project (Walking Voices) addresses a neighbourhood scale of interest, working with first generation migrant residents to communicate their own stories and experiences of their local area. Creative and participatory research methods were developed for on-site work, using photography and independent audio recording. The research found that spending time outside is an important means by which first generation migrants feel a sense of agency and belonging in a neighbourhood context. Though the research supports use of urban greenspace as beneficial to individual and collective wellbeing, it underlines the critical importance of understanding cultural dimensions – motivations and barriers - to visiting parks and other types of greenspace. Evaluation of a local environment is often shaped by migrants’ experiences of past places, and previous expectations of life in the UK. Place attachment is strengthened by participation and familiarity in a local located community, and often by recognising transcultural connections. The overlapping use of public space by people from different ethnic communities offers opportunities for gradual informal contact and gives a visual shared recognition to the diversity of a neighbourhood. However, the ability to make choices about when to engage with one’s own ethnic group, and when to retreat from the expectations of this ‘public gaze’ was also valued. The thesis examines the implications of these findings for landscape architecture practice, and emphasises that the profession needs to become more culturally literate in responding to the superdiversity of urban contexts, and to difference in social and cultural values with regard to recreation, socialising, and natural places