DIE ERDE – Journal of the Geographical Society of Berlin
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Urban heat island and bioclimatological conditions in a hot-humid tropical city: the example of Akure, Nigeria
Get PDFThe impact of weather on human health has become an issue of increased significance in recent times, considering the increasing rate of urbanisation and the much associated heat island phenomenon. This study examines the urbanisation influence on human bioclimatic conditions in Akure, a medium sized hot-humid tropical city in Nigeria, utilising data from measurements at urban and rural sites in the city. Differences in the diurnal, monthly and seasonal variation of human bioclimatic characteristics between both environments were evaluated and tested for statistical significance. Higher frequencies of high temperatures observed in the city centre suggest a significant heat stress and health risk in this hot-humid city
Investigating public places and impacts of heat stress in the city of Aachen, Germany
Get PDFUnderstanding the role of structure and social aspects regarding heat stress of people in urban areas requires an interdisciplinary scientific approach that connects methods from both natural sciences and social sciences. In this study, we combine three approaches to provide an interdisciplinary analysis of the structure and social components of heat stress in the city of Aachen, Germany. First, we assess the overall spatial structure of the urban heat island using spatially distributed measurements from mobile air temperature recordings on public transport units combined with spatially distributed geo-statistical data. The results indicate that the time of day matters: During the afternoon, areas with a relative low building density, like the industrial area northeast of the inner city, are the warmest, while surfaces in high-building-density areas like the inner city heat up faster during the evening. Second, we combine these measurements with place-based survey data collected in 2010 from residents aged 50 to 92 regarding their individual housing conditions, medical history and social integration to examine the match among heat-based stress of older residents, social conditions and elevated temperatures in their residential quarter. We identify disadvantaged areas for specific already-disadvantaged demographic groups in the city, pointing to a cumulation of inequalities, including heat stress among the most vulnerable. Third, we compare data of biometeorological measurements on urban public squares during the afternoon with results of the micrometeorological model ENVI-met to examine the spatial variability of the inner-city heat load. We complement the modelling results with on-site interviews to evaluate people’s heat perception at the same public places. A simulation shows that additional vegetation would increase thermal comfort at these public places, whereby the heat load assessed using the predicted mean vote (PMV) value would decrease by approximately 60 %. Furthermore, we demonstrate the strengths and weaknesses of heat stress simulation. ENVI-met allows for an overall reasonable representation of heat load during stable atmospheric conditions. However, due to the setup and structure of ENVI-met, large-scale atmospheric changes that occur during the day cannot readily be integrated into ENVI-met simulations
The urban heat island of Basel – seen from different perspectives
Get PDFFor decades thermal infrared satellite imagery has been used for climate studies of a variety of geosystems, including urban areas. Additionally, airborne thermal remotely sensed data can provide high resolution information about urban land surface temperatures (LST). Numerous studies make use of these data for the investigation of urban-rural LST differences, commonly known as the urban heat island (UHI) phenomenon. Most of these studies try to analyse the urban heat island by means of the LST distribution. It seems that the UHI is easy to measure, easy to explain, easy to find, and easy to illustrate. Due to this apparent simplicity some people seem to jump into UHI studies without fully understanding the nature of the phenomenon as far as time and spatial scales, physical processes and the numerous methodological pitfalls inherent to UHI studies are concerned. In this study the use of thermal infrared satellite data with respect to the assessment of the surface UHI is investigated. The need to clearly distinguish between different types of UHI is emphasised by recalling the (surface) temperature and the UHI terminology. The pretended simplicity of UHI effects is in reality a result of complex interactions between local radiation conditions, earth surface heat budget, the urban structure and the boundary layer atmosphere. Different methods may provide completely different results. This paperaims to bring more clearness into the subject by assessing the urban heat island of the city of Basel, Switzerland, by the use of thermal data provided by satellites (Landsat TM/ETM+), helicopter-borne infrared camera (InfraTec VarioCAM®) and ground-based measurements of air temperature profiles. It is shown that UHIs vary essentially with the choice of the respective temperature (LST, air temperature) and height (surface level, street/canopy level, roof level)
Quantification and dating of floodplain sedimentation in a medium-sized catchment of the German uplands: a case study from the Aar Valley in the southern Rhenish Massif, Germany
Get PDFThe distribution, thickness and composition of the floodplain sediments in the valleys of the Aar and its tributaries (Taunus Mountains) were investigated by way of extensive fieldwork at 25 locations. In the entire catchment area, 48.8 million tons of loamy floodplain fines could be assessed. Most of these were deposited since late medieval times due to extensive historical land use and forest clearing, especially in the mining region along the middle course of the Aar. In its lower course, the enhanced sedimentation ofloamy f loodplain sediments started during the Bronze Age
Transnational business networks of African intermediaries in China: Practices of networking and the role of experiential knowledge
Get PDFChinese cities like Hong Kong, Guangzhou or Yiwu have become major ports of call for Sub-Saharan African traders active in the import-export trade of Chinese goods to Africa. This study highlights the role of African intermediaries in the city of Guangzhou, who work as negotiators within the Sino-African trade system. Between 2008 and 2011 33 case studies were conducted, using qualitative interviews and participatory observations. A qualitative network approach was used to investigate the intermediaries’ business practices as they build up multi-local economic relations. Different forms of knowledge embodied in the business practices were of special interest for this paper. Resultsshow the importance of multi-local forms of organisation across different nations and ethnic boundaries as well as the relevance of experiential knowledge for the success of these organisational forms. The findings may open up a research perspective on the organisation of transnational migrant business networks
Shifting corporate geographies in global cities of the South: Mexico City and Johannesburg as case studies
Get PDFoai:ojs.die-erde.org:article/1Global city research links the expansion of advanced producer services in major cities to the internationalisation of real estate markets as well as to the spread of (mainly) high-rise office complexes. This research, however, has based its findings mainly on cases of the Global North. This paper examines, based on Grant and Nijman’s (2002) suggestion that the “internal spatial organisation of gateway cities in the less-developed world” reflects “the city’s role in the global political economy”, which patterns occur in two metropoles of the Global South. In addition to this, the analysis focuses especially on the driving forces behind the changes in corporate geographies. The analysis is placed in Mexico City and Johannesburg and based on real estate market data (offices) as well as background documents on urban development. The outcome shows that in these cities, local transformation processes of the real estate market and office space location are indeed considerably shaped by global market dynamics. However, the findings also indicate that there is no clear scale dependence of the territorial form. In order to comprehensively understand the changes in the corporate geographies therefore, it is necessary to direct more attention to local and national dynamics. The restructuring of the built environment in both cities can only be grasped fully by considering the particular role of local and national governments. This additional entry point to an understanding of shifting corporate geographies helps to put recent dynamics of global capitalism and politics of urban neoliberalism in perspective
Learning from the Past? Why 'Creative Industries' can hardly be Creted by Local/Regional Government Policies
Get PDFUS regional economist Richard Florida has developed simple, but very popular ideas to foster regional economic growth: attracting and haltening of members of the so-called ‘creative class’ by steering the focus of local government development policies for culture, tolerance (towards ethnic and other kinds of minorities) and knowledge. Members of the creative class, characterised by indicators of talent, technology and tolerance, should feel at home in the cities – the result of which would be that creatives either stay in the city where they already lived before or move to those cities which possess the named characteristics. The larger the number of creative people in a city, the better the economic performance of the city. Why that? Because, as Florida postulates, creative people produce economic value added for the region where they live as they more often (than non-creative people) start successful firms and more often engage in highgrowth sectors of the economy. Furthermore they are assumed – as an aggregate – to be able to attract existent firms: ‘jobs follow (creative) people’ instead of ‘people follow jobs’ to cite an old, but – thanks to Florida – still modern debate among economists. As Florida in his own empirical studies focuses on U.S. metropolitan areas only, there is a need to close the significant research gap in terms of empirical evidence outside the U.S., given the great popularity of his ideas among policy-makers outside the U.S. In the paper five of Florida’s main hypotheses are discussed in an explorative approach based upon the available literature. None of these hypothesesreceive sufficient support. Consequently, it will hardly be possible to create creative industries by developing related government policies. Comparing government policies in favour of creative industries with government policies of former eras (when, e.g., clusters or high-tech regions belonged to the targets of such policies) there is not much empirical evidence that policymakers are able or even willing to learn from previous experiences – and failures
Of voyeuristic safari tours and responsible tourism with educational value: Observing moral communication in slum and township tourism in Cape Town and Mumbai
Get PDFSightseeing in the poorest quarters of southern hemisphere cities has been observed occurring in Cape Town, Rio de Janeiro, Mumbai and many other cities. The increasing global interest in touring poor urban environments is accompanied by a strong morally charged debate; so far, this debate has not been critically addressed. This article avoids asking if slum tourism is good or bad, but instead seeks a second-order observation, i.e. to investigate under what conditions the social praxis of slum tourism is considered as good or bad, by processing information on esteem or disesteem among tourists and tour providers. Special attention is given to any relation between morality and place, and the thesis posited is that the moral charging of slum tourism is dependent on the presence of specific preconceived notions of slums and poverty. This shall be clarified by means of references to two empirical case studies carried out in (1) Cape Town in 2007 and 2008 and (2) Mumbai in 2009
The Cultural and Creative Industries: Organisational and Spatial Challenges to their Governance
Get PDFThe Cultural and Creative Industries (CCI) have a distinct geography, one that is dynamic and that has until recently been poorly documented and underexplained. The aim of this paper is to briefly review the changing terrain of analyses of the CCI in order to turn an analytic focus onto the challenge of policy-making in the field of the cultural and creative industries. The structure of the paper follows four steps. First, we outline the shifting nature of governance in nation states and regions; second, we highlight the corresponding shifts occurring in the organisation of the cultural and creative industries, and the field of cultural policy; third, we consider the need to resolve governance and the cultural and creative industries. Finally, we outline some responses to this challenge
Characterisation of the Rota Wewa tank cascade system in the vicinity of Anuradhapura, Sri Lanka
Get PDFA complex and sustainable watershed management strategy was implemented in Sri Lanka during the ancient Anuradhapuraperiod, from the 5th century BC to the 11th century AD. Like modern watershed management strategies, it focused on flood prevention, soil erosion control, water quality control and water storage for irrigation. Tank cascade systems were the key element of these ancient watershed management installations. The wewas investigated were constructed in valleys characterised by fluvial accumulation. Sedimentological analyses of these tank cascade systems show that a precise age determination and the reconstruction of sediment and water f luxes as triggered by human-environment interactions are difficult. This is caused by theshallow character of the wewas leading to the steady redeposition of the tank sediments by wave motions during the wet season and agricultural use of the desiccated wewas during the dry season. Beyond, the sediments analysed allow to distinguish between the weathered parent bedrock and the overlying sediments. A differentiation between wewa deposits and the underlying fluvial deposits remains challenging