Mega-city Regions Research Articles

Potential for mitigating greenhouse gases through expanding public transport services: A case study for Gauteng Province, South Africa

South Africa’s Province of Gauteng is a fast growing megacity region including the cities of Johannesburg and Tshwane. Increasing population and prosperity lead to a steadily growing energy demand and thereby increasing greenhouse gas (GHG) emissions. One third of the province’s final energy consumption comes from the transport sector, dominated by motorized individual transport. Due to the limited financial resources to fund public transport initiatives, the most cost-effective means to reach the GHG mitigation targets are intended, without jeopardizing the economic growth. Recently, a bus rapid transit (BRT) system (Rea Vaya) and a rapid rail link (Gautrain) have been introduced to enforce the public transport system. In this paper, we investigate planned and possible future network expansions of the BRT and the Gautrain in terms of transport performance, costs of network expansions and GHG mitigation potential. Based on a trip rate model, we show that extensions of the current network can increase passenger numbers significantly (between 320% and 660% between 2013 and 2040 depending on the framework conditions). However, despite these expansions, the modal share of the BRT and the Gautrain in total passenger-kilometres travelled remains below 4% until 2040. This results in a decrease of cumulated GHG emissions of less than 1% until 2040 and relatively high GHG mitigation costs (4948–30045ZAR2013/tCO2e). Nevertheless, a better integration of all public transport systems can increase the attractiveness of the services, which can result in a higher modal shift from private cars and thereby higher GHG emissions reductions at lower costs.

Producer service linkages and city connectivity in the mega-city region of China: A case study of the Pearl River Delta

This paper examines the intra- and inter-firm producer service linkages and city connectivity of the Pearl River Delta (PRD), one of the fastest growing and globalising mega-city regions in China. The study reveals that the rapid growth of producer services in the recent two decades has emerged as a crucial contributor to the formation of the regional network that was previously shaped mainly by manufacturing activities. To provide a better understanding of the mechanisms of mega-city regions, a nexus between the literature on globalisation and mega-city regions and the studies on the service economy must be developed to consider not only intra-firm office connections, but also the linkages of producer services between different firms and economic sectors. Through a questionnaire survey covering 1020 producer service firms in three major PRD cities, we provide evidence that in a manner different from manufacturing activities, producer services linkages, both intra-firm and inter-firm, bind the cities into a hierarchical and localised regional system.

Modelling the impact of megacities on local, regional and global tropospheric ozone and the deposition of nitrogen species

Abstract. We examine the effects of ozone precursor emissions from megacities on present-day air quality using the global chemistry–climate model UM-UKCA (UK Met Office Unified Model coupled to the UK Chemistry and Aerosols model). The sensitivity of megacity and regional ozone to local emissions, both from within the megacity and from surrounding regions, is important for determining air quality across many scales, which in turn is key for reducing human exposure to high levels of pollutants. We use two methods, perturbation and tagging, to quantify the impact of megacity emissions on global ozone. We also completely redistribute the anthropogenic emissions from megacities, to compare changes in local air quality going from centralised, densely populated megacities to decentralised, lower density urban areas. Focus is placed not only on how changes to megacity emissions affect regional and global NOx and O3, but also on changes to NOy deposition and to local chemical environments which are perturbed by the emission changes. The perturbation and tagging methods show broadly similar megacity impacts on total ozone, with the perturbation method underestimating the contribution partially because it perturbs the background chemical environment. The total redistribution of megacity emissions locally shifts the chemical environment towards more NOx-limited conditions in the megacities, which is more conducive to ozone production, and monthly mean surface ozone is found to increase up to 30% in megacities, depending on latitude and season. However, the displacement of emissions has little effect on the global annual ozone burden (0.12% change). Globally, megacity emissions are shown to contribute ~3% of total NOy deposition. The changes in O3, NOx and NOy deposition described here are useful for quantifying megacity impacts and for understanding the sensitivity of megacity regions to local emissions. The small global effects of the 100% redistribution carried out in this study suggest that the distribution of emissions on the local scale is unlikely to have large implications for chemistry–climate processes on the global scale.

Evolution assessment of china’s three mega-city regions based on entire-array-polygon method

Mega-city region is the mainstream of global urban development and also the dominant model of the neo urbanization process in China. The Beijing-Tianjin-Hebei area, Yangtze River Delta area and Pearl River Delta area are China’s three largest and most mature mega-city regions, the status of which represents the general level of the urban and regional development in China. Based on entire-array-polygon method, this paper makes a comprehensive evolution assessment of the three mega-city regions in terms of urban population index, urban economy index, urban life index, urban culture index and urban primacy index. In terms of general developing level, the three mega-city regions have progressed to optimize the structure. With their respective advantages and disadvantages, the three mega-city regions initially realize a “diversified” regional layout. The difference and gap among the three mega-city regions are obviously decreasing, which contributes to the regional balance of China metropolitan development. The rankings of the three mega-city regions will be in a continuous adjustment. The Beijing-Tianjin-Hebei area is possible to catch up and take the lead.

Underground as City Maker: London Versus Paris, 1863–2013

The London Underground and Paris Métro were very different conceptions, with major impacts on the cities’ development. The Underground almost immediately worked to promote suburban decentralization, while the Métro remained locked inside the city boundaries until well after World War II, inhibiting suburban growth. The Réseau Express Régional served the suburbs after 1970, but it plays a role more like the London Underground than a true regional express network. Meanwhile, London has grown into a vast polycentric mega-city region, extending out for up to 140 km from the capital.

Johor Bahru's response to transnational and national influences in the emerging Straits Mega-City Region

A booming economy and a growing concern for sustainable development is driving many cities in the Asia-Pacific region to progressively redefine their social and physical landscape. A new Straits Transnational Urban Region is emerging as a result of two distinct dynamics: (1) the spill-over of Singapore investments into its surrounding region, and (2) the daily transnational travel of workers, visitors and school children from Johor Bahru, Malaysia, into Singapore. At the same time, the city of Johor Bahru is influenced by Kuala Lumpur, the capital city of Malaysia, through political, administrative and government funding structures.This study compares the linkages and exchanges between Johor Bahru and Singapore with those between Johor Bahru and Kuala Lumpur. It will investigate the prevalent and potential impacts on Johor Bahru brought about by both transnational urbanisation and local forces emanating from the urban hierarchy within the national system.

Increase of aerosol scattering by hygroscopic growth: Observation, modeling, and implications on visibility

In situ measurements of size-resolved aerosol chemical compositions and its optical properties were concurrently carried out at an urban site in mega-city Beijing from October 24 to November 9, 2007. The main objective was to quantitatively study the relationship between aerosol chemical compositions and its hygroscopic properties, to estimate the influence of relative humidity (RH) on aerosol scattering coefficient and to quantitatively investigate visibility impairment due to particle hygroscopic growth. The hygroscopic factor of aerosol scattering coefficient (f(RH)), which is defined as the ratio of aerosol scattering coefficient at wet condition to that at dry condition (RH≤30%), was calculated with the measured aerosol optical properties at dry and ambient conditions. The relationship between f(RH) and RH was fitted by empirical equation and the fitting parameters were calculated. Meanwhile, f(RH) for externally mixed aerosols or internally mixed aerosols was modeled based on size segregated particulate chemical composition. The modeled f(RH) agreed well with the measured f(RH). Empirical formula for atmospheric visibility based on mass concentration of PM2.5 and f(RH) was proposed. The result of this study is not only proven that RH, in addition to the mass concentration of PM2.5, played an important role on visibility impairment, but also provide practical aid for air quality control to improve the visibility in the megacity region of Beijing.

Explaining Governance in Five Mega-City Regions: Rethinking the Role of Hierarchy and Government

With the fundamental rescaling of socio-economic relationships, the mega-city region (MCR) has emerged as an important geographical space for governance. At the same time it is highly fragmented institutionally, making it difficult to overcome collective action problems such as providing regional public transport and protecting open spaces. In practice, different arrangements are employed to address these problems, including hierarchical approaches, competitive self-coordination and joint decision-making. Drawing on experiences in five MCRs in Europe and the US, the relative use and success of these approaches was investigated. The analysis suggests that the composition of the actor constellation (e.g. the number and kind of parties involved) and local political support proved to be important factors in explaining the performance of a particular governance approach. In addition, the findings provide a new appreciation for the role of the state, particularly the national government, in governing MCRs.

Physical and chemical properties of the regional mixed layer of Mexico's Megapolis Part II: evaluation of measured and modeled trace gases and particle size distributions

Abstract. This study extends the work of Baumgardner et al. (2009) in which measurements of trace gases and particles, at a remote, high altitude mountain site, 60 km from Mexico City were analyzed with respect to the origin of the air masses. In the current evaluation, the temperature, water vapor mixing ratio (WMR), ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2) and acyl peroxy nitrate (APN) are simulated with the WRF-Chem chemical transport model and compared with the measurements at the mountain site. Comparisons between the model and measurements are also evaluated for particle size distributions (PSDs) of the mass concentrations of sulfate, nitrate, ammonium and organic mass (OM). The model predictions of the diurnal trends in temperature, WMR and trace gases were generally well correlated; 13 of the 18 correlations were significant at a confidence level of <0.01. Less satisfactory were the average hourly differences between model and measurements that showed predicted values within expected, natural variation for only 10 of the 18 comparisons. The model performed best when comparing with the measurements during periods when the air originated from the east. In that case all six of the parameters being compared had average differences between the model and measurements less than the expected standard deviation. For the cases when the air masses are from the southwest or west northwest, only two of the comparisons from each case showed differences less than the expected standard deviation. The differences appear to be a result of an overly rapid growth of the boundary layer predicted by the model and too much dilution. There also is more O3 being produced, most likely by photochemical production, downwind of the emission sources than is predicted by the model. The measured and modeled PSD compare very well with respect to their general shape and the diameter of the peak concentrations. The spectra are log normally distributed with most of the mass in the accumulation mode centered at 200 ± 20 nm and little observed or predicted changes with respect to the time when the RML is above the Altzomoni research station. Only the total mass changes with time and air mass origin. The invariability of average diameter of the accumulation mode suggests that there is very little growth of the particles by condensation or coagulation after six hours of aging downwind of the major sources of anthropogenic emissions in Mexico's Megapolis. This could greatly simplify parameterization in climate models although it is not known at this time if this invariance can be extended to other megacity regions.

The Relational Geography of the Knowledge Economy in Germany: On Functional Urban Hierarchies and Localised Value Chain Systems

The objective of this contribution is to set out a theoretical context and then to investigate empirically Germany’s functional urban hierarchy based on the relational geography of the knowledge economy. Starting from a conceptual background that brings together the locational behaviour of multibranch, multilocation firms with a value chain approach, it looks at the extent to which this hierarchy is associated with the networking activities of advanced producer services and high-tech firms. The results provide evidence that the functional urban hierarchy in the German space economy is steeper than is claimed by the federal government. A maximum of six polycentric mega-city regions—Munich, Rhine-Main, Hamburg, Rhine-Ruhr, Stuttgart and to a lesser extent Berlin—can be regarded as strategic nodes in the global knowledge economy. A non-nested hierarchy with overlapping and trans-scalar urban networks challenges the traditional view of a nested hierarchy as an organising principle of space.

Diversity As A Unique Constellation of Superimposing Network Logics

In the context of the European city, the regeneration of former industrial sites is a unique opportunity to actively steer urban development. These plots of land gain strategic importance in actively triggering development on the city scale. Ideally, these interventions radiate beyond the individual site and contribute to the strengthening of the location as a whole. International competition between locations is rising and prosperous development a precondition for wealth and wellbeing. This approach to the regeneration of inner city plots makes high demands on all those involved. Our framework suggests a stronger focus of the conceptualization and analysis of idiosyncratic resources, to enable innovative approaches in planning. On the one hand, we are discussing spatially restrained urban plots, which have the capacity and need to be reset. On the other hand, each plot is a knot in the web of relations on a multiplicity of scales. The material city is nested into a set of interrelated scale levels – the plot, the quarter, the city, the region, potentially even the polycentric megacity region. The immaterial relations however span a multicity of scale levels. The challenge is to combine these two perspectives for their mutual benefit. The underlying processes are constitutive to urban space diversity, as urban form shapes urban life and vice versa.

Research of Spatial Pattern for Coastal Urban Agglomeration of Liaoning Province

With urban agglomeration of coastal Liaoning province as a case, the paper identifies its spatial revolution process lies in the formation stage which is the second stage of the four stages of urban agglomeration, and concludes the macro spatial pattern of the coastal urban agglomeration in Liaoning province into urban compact district; and the meso-level spatial pattern into metropolitan district. Then it further analyzes the evolving tendency of the two spatial patterns, including mega-city region in the macro level and network city in the meso level.

Transportation-Induced Agglomeration Effects and Productivity of Firms in Megacity Region of Paris Basin

This paper undertakes empirical analysis of the relationship between productivity and transportation-induced agglomeration effects in the megacity region of the Paris Basin. The authors believe this to be the first study in the French context to produce elasticities of urban agglomeration economies for different industry sectors. Furthermore, the measure of agglomeration used by the authors explicitly took account of accessibility to economic mass in terms of driving times. This study is the first attempt to investigate the presence of nonlinearities in the relationship between productivity and agglomeration with French data. The findings indicate that transportation-induced agglomeration effects differ across industry groups and are greater for business services; these findings agree with existing evidence for other countries. The results also suggest considerable nonlinearity in the relationship between productivity and transportation-induced agglomeration effects and imply that the conventional estimation of country-level aggregate elasticities is likely to misrepresent the actual magnitude of any productivity gains from agglomeration.

Cloud condensation nuclei (CCN) from fresh and aged air pollution in the megacity region of Beijing

Abstract. Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. CCN properties were measured and characterized during the CAREBeijing-2006 campaign at a regional site south of the megacity of Beijing, China. Size-resolved CCN efficiency spectra recorded for a supersaturation range of S=0.07% to 0.86% yielded average activation diameters in the range of 190 nm to 45 nm. The corresponding effective hygroscopicity parameters (κ) exhibited a strong size dependence ranging from ~0.25 in the Aitken size range to ~0.45 in the accumulation size range. The campaign average value (κ =0.3 ± 0.1) was similar to the values observed and modeled for other populated continental regions. The hygroscopicity parameters derived from the CCN measurements were consistent with chemical composition data recorded by an aerosol mass spectrometer (AMS) and thermo-optical measurements of apparent elemental and organic carbon (EC and OC). The CCN hygroscopicity and its size dependence could be parameterized as a function of only AMS based organic and inorganic mass fractions (forg, finorg) using the simple mixing rule κp ≈ 0.1 · forg + 0.7 · finorg. When the measured air masses originated from the north and passed rapidly over the center of Beijing (fresh city pollution), the average particle hygroscopicity was reduced (κ = 0.2 ± 0.1), which is consistent with enhanced mass fractions of organic compounds (~50%) and EC (~30%) in the fine particulate matter (PM1). Moreover, substantial fractions of externally mixed weakly CCN-active particles were observed at low supersaturation (S=0.07%), which can be explained by the presence of freshly emitted soot particles with very low hygroscopicity (κ < 0.1). Particles in stagnant air from the industrialized region south of Beijing (aged regional pollution) were on average larger and more hygroscopic, which is consistent with enhanced mass fractions (~60%) of soluble inorganic ions (mostly sulfate, ammonium, and nitrate). Accordingly, the number concentration of CCN in aged air from the megacity region was higher than in fresh city outflow ((2.5–9.9) × 103 cm−3 vs. (0.4–8.3) × 103 cm−3 for S=0.07–0.86%) although the total aerosol particle number concentration was lower (1.2 × 104 cm−3 vs. 2.3 × 104 cm−3). A comparison with related studies suggests that the fresh outflow from Chinese urban centers generally may contain more, but smaller and less hygroscopic aerosol particles and thus fewer CCN than the aged outflow from megacity regions.

Public health and medical care for the world's factory: China's Pearl River Delta Region

While the growth of urbanization, worldwide, has improved the lives of migrants from the hinterland, it also raises health risks related to population density, concentrated poverty and the transmission of infectious disease. Will megacity regions evolve into socially infected breeding grounds for the rapid transmission of disease, or can they become critical spatial entities for the protection and promotion of population health? We address this question for the Pearl River Delta Region (PRD) based on recent data from Chinese sources, and on the experience of how New York, Greater London, Tokyo and Paris have grappled with the challenges of protecting population health and providing their populations with access to health care services. In some respects, there are some important lessons from comparative experience for PRD, notably the importance of covering the entire population for health care services and targeting special programs for those at highest risk for disease. In other respects, PRD's growth rate and sheer scale make it a unique megacity region that already faces new challenges and will require new solutions.

MANAGING THE LAGOS MEGACITY AND ITS GEOSPATIAL IMPERATIVE

Abstract. Lagos has assumed the Megacity status and it is projected to have its population doubled in the first quarter of this century. The Megacity has extended beyond the administrative boundary of the state, which is also one of the fastest growing urban agglomerations in the world. Information is the most vital component of urban management; however, a survey of the spatial data infrastructure of the city proves it derisory or out-of-date, thereby creating a void between urban development and its management. This has led to a sporadic growth of slums and unplanned settlements which now accounts for over 60 % of the city. To avoid an impasse, it is necessary to review the level of geospatial technologies used at the local level and recommend formidable means of integration in the decision making process. This paper examines the level of geospatial technologies the 20 local governments of Lagos State and within the Megacity region and suggests success factors.

Interlocking Firm Networks in the German Knowledge Economy. On Local Networks and Global Connectivity


 
 
 the knowledge economy is a key driver of spatial development in metropolitan regions. a relational perspec- tive on its business activities emphasizes the importance of knowledge-intensive firms and their networking strategies. the aim of this paper is to analyse the spatial networking patterns created by the interaction of knowledge-intensive firms and to place these activities in the theoretical context of the knowledge economy. Our central question is which large-scale interlocking networks and functional urban hi- erarchies are produced by advanced Producer services and High-Tech firms located in Germany. The intra-firm loca- tional networks of these companies are analysed on three spatial scales: global, national and regional. the empirical findings show that the functional urban hierarchy in the german city system proves to be steeper than is claimed by the political debate on german Mega-city regions.
 
 

Public-Private Partnership (PPP) in Housing Provision in Lagos Megacity Region, Nigeria

The adoption of Public-Private Partnership (PPP) in housing provision in Nigeria is intended to increase urban housing stock and address housing affordability and accessibility challenges. However, to date, very little is known about how PPP housing schemes have addressed these challenges. This paper therefore explores the extent to which PPP in housing provision has so far contributed to solving the housing challenges in the Lagos Megacity Region of Nigeria. The paper presents the result of a cross-sectional survey of operators of PPP schemes and housing consumers in the study area. The results show that the PPP approach is basically a formal joint venture partnership involving government providing land at subsidised cost and the provision of serviced plots or construction of housing units by private sector partners. Although the approach has provided affordable serviced plots and housing units for a few high income elites, it has contributed very little to the volume of housing units available to low-income people in Lagos. The paper suggests the adoption of a uniform policy on PPP in housing provision and the establishment of a co-ordinating agency. In addition, government involvement in the provision of infrastructure in PPP housing schemes could increase the affordable housing stock accessible to low-income people in the city.

Comparison of waste prevention behaviors among three Japanese megacity regions in the context of local measures and socio-demographics

Waste prevention behaviors (WPBs) should be investigated separately from recycling behaviors and analyzed in the context of local policies and measures. Previous studies on WPBs have been mainly conducted in the USA and Europe (mainly in the UK), and studies in Japan have remained very limited to date. Moreover, the effects of socio-demographic factors have been rarely described correctly based on appropriate large sampling. In this study, we conducted an on-line questionnaire survey and obtained 8000 respondents in three megacity regions (Tokyo, Osaka, and Aichi) in Japan. Among these three regions, Osaka respondents showed significantly lower practice rates in nine of 18 WPBs. Particularly in My-bag behavior, the charging of plastic shopping bags strongly affects the practice rate. As shown in the results, local policies and measures affect WPBs. Based on the practice rates, latent four factors were extracted by factor analysis. Multiple regression analysis revealed that gender and age significantly affect WPB factors before local policy effects.

Governance and Planning of Mega-city Regions. Jiang Xu and Anthony G. O. Yeh, eds

Governance and Planning of Mega-city Regions. Jiang Xu and Anthony G. O. Yeh, eds