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

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

The transnational Gulf City: Saudi and migrant values of public open spaces in Jeddah

This paper outlines patterns of use, perceived benefits and place attachment relating to public open space in Jeddah, Saudi Arabia, a city in which almost half the residents are born overseas. The methods included case studies representing different recreational landscape typologies, observational analysis and 85 on-site interviews (46% Saudi, 54% migrants). The findings outline the benefits of visiting as a retreat from busy lifestyles, for everyday sociability, for improving health, for religious practice and for mutual support, highlighting dimensions of gender, transnationality and heritage. The paper explores place attachment related to displacement comparing between impacts of migration and of rapid urbanisation. The narratives suggest that experiences shaped by temporality and memory inform emotional geographies for both Saudi and migrant residents. There are differences in patterns of use between resident groups, but the paper concludes that, within a highly stratified society, the public open spaces of Jeddah provide an important resource of shared pleasures and everyday multiculture

Variations of thermospheric composition according to AE-C data and CTIP modelling

Data from the Atmospheric Explorer C satellite, taken at middle and low latitudes in 1975-1978, are used to study latitudinal and month-by-month variations of thermospheric composition. The parameter used is the "compositional <i>Ρ</i>-parameter", related to the neutral atomic oxygen/molecular nitrogen concentration ratio. The midlatitude data show strong winter maxima of the atomic/molecular ratio, which account for the "seasonal anomaly" of the ionospheric F2-layer. When the AE-C data are compared with the empirical MSIS model and the computational CTIP ionosphere-thermosphere model, broadly similar features are found, but the AE-C data give a more molecular thermosphere than do the models, especially CTIP. In particular, CTIP badly overestimates the winter/summer change of composition, more so in the south than in the north. The semiannual variations at the equator and in southern latitudes, shown by CTIP and MSIS, appear more weakly in the AE-C data. Magnetic activity produces a more molecular thermosphere at high latitudes, and at mid-latitudes in summer.<br><br> <b>Key words.</b> Atmospheric composition and structure (thermosphere – composition and chemistry

Directional currents in nocturnal E-region layers

In the mid-latitude E-region, the wind-shear mechanism produces thin ionized layers at levels where the vertical ion velocity is zero. We show that such layers conduct electric current only towards the magnetic equator, and not in the zonal direction. We surmise that this property may influence the electric field distribution in the nocturnal ionosphere, and possibly also the coupling between ion drifts and neutral air winds in the F-region. Detailed case studies of nocturnal layers located near the peak of ion Pedersen conductivity (around 130km) are needed to test this idea.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24070/1/0000322.pd

Informal sport and leisure, urban space and social inequalities: Editors’ Introduction

While informal sport may appear to be a poor relation of formal sport, participation in informal sport is now more popular than organised club sport. The special issue provides an opportunity to showcase international leisure studies research which variously explores the meaning and implications of informal sport as a growing form of collective leisure activity and the wider social affordances – and strains – of collective leisure practices. The Editors’ Introduction focuses on the ways in which informal sport and leisure depend on sometimes hard-won public (parks, city squares, designed leisure spaces) and reused incidental urban space (e.g. post-industrial areas). It sets out the ways in which informal sport and leisure involves marginalised and precarious urban populations, gives rise to co-ethnic and ethnically diverse identifications, secures senses of belonging and citizenship, is gender and age ex/inclusive and is attractive to policy actors. It outlines how the articles collected in the special issue address what are still under-examined aspects of the informal sport phenomenon

Included outside: Evidence synthesis for engaging under-represented groups in nature

Natural England Commissioned Report NECR42

Spatial sampling of the thermospheric vertical wind field at auroral latitudes

Results are presented from two nights of bistatic Doppler measurements of neutral thermospheric winds using Fabry!Perot spectrometers at Mawson and Davis stations in Antarctica. A scanning Doppler imager (SDI) at Mawson and a narrow-field Fabry-Perot spectrometer (FPS) at Davis have been used to estimate the vertical wind at three locations along the great circle joining the two stations, in addition to the vertical wind routinely observed above each station. These data were obtained from observations of the 630.0 nm airglow line of atomic oxygen, at a nominal altitude of 240 km. Low!resolution all-sky images produced by the Mawson SDI have been used to relate disturbances in the measured vertical wind field to auroral activity and divergence in the horizontal wind field. Correlated vertical wind responses were observed on a range of horizontal scales from ~150 to 480 km. In general, the behavior of the vertical wind was in agreement with earlier studies, with strong upward winds observed poleward of the optical aurora and sustained, though weak, downward winds observed early in the night. The relation between vertical wind and horizontal divergence was seen to follow the general trend predicted by Burnside et al. (1981), whereby upward vertical winds were associated with positive divergence and vice versa; however, a scale height approximately 3–4 times greater than that modeled by NRLMSISE-00 was required to best fit the data using this relation