The Environmental Impact of Gateways and Hubs in International Air Transportation

国际航空运输是全球经济一体化的基础。连接遥远城市的能力依赖于一个复杂的航空互连系统。地理学家长期以来一直对描述和建模连接网络以及由此产生的可达性水平及其对全球系统的重要性感兴趣。集线器和网关等概念在日常使用中，表明已经开发了特殊基础设施以允许处理长距离交互的地方。这个研究项目的目的是在空中网络的空间组织和这种结构对环境可能产生的影响之间建立联系。该项目将审查这种安排的各种形式的成本和效益：通常被称为轮辐系统（在主要枢纽之间输送通道）和点对点系统（提供更方便的直接联系）的模式。从根本上说，枢纽之间的大量流量与点对点之间更直接但必然更稀薄的流量之间的对比，构成了一组复杂的权衡。本研究计画的目的是发展衡量不同网路安排之相对优点的方法。该项目将从运输成本的角度审查有效流量与这种流量可能造成相当严重的环境影响之间的紧张关系。该项目将检查各种飞机航程和尺寸配置的燃油效率。这个主题对枢纽的位置有影响，并最终可能对选择航空客运机队以适应首选交互模式的最佳方式产生影响。该项目旨在综合两种截然不同的观点，一种是从单个飞机的能耗出发，另一种是从整体网络的角度出发。迄今为止的研究都倾向于从一个方面或另一个方面来解决这个问题，研究将加深对系统及其元素之间相互依存关系的理解。为了实现该项目的目标，将在模拟网络的模型中开发和测试业务和网络效率观点之间的创新联系。由于航空运输渗透到日常生活中，这个项目有几个社会意义。该项目的影响将包括教育方面的影响，以及提高人们对运输领域范围经济和规模经济的普遍认识。具体来说，这些结果将提供对航空乘客互动的环境和经济成本的更完整的理解。该项目还将把对燃料使用和排放的审查更集中地纳入航空运输系统的运作和规划模式。这项研究将有助于解释枢纽作为相互作用焦点的方式，以及对从改善航空安全到了解疾病流行病学等一系列应用具有影响的扩散模型。这些主题已被证明很难定量确定，而运输网络分析将提供在空间背景下测量这些元素的工具。该项目可能会影响网络评估和测量的方式。

International air transportation is fundamental to the integration of global economies. The ability to connect far flung cities depends on an elaborate system of airline interconnections. Geographers have long had an interest in describing and modeling the networks of links and the resultant levels of accessibility and their importance to global systems. Concepts such as hubs and gateways are in everyday use and indicate places that have developed special infrastructure to permit handling of long distance interactions.The purpose of this research project is to develop a linkage between the spatial organization of air networks and the possible implications of that structure for the environment. The project will examine the costs and benefits in variants of such arrangements: patterns that are often referred to as hub and spoke systems (which channel flows between major hubs) and point to point systems (which provide more convenient direct linkages). At base, the contrast between heavy flows between hubs and more direct but necessarily thinner flows between point to point pairs, poses a complex set of trade-offs. The purpose of this research project is to develop measures of the relative merits of alternative network arrangements. The project will examine the tension between efficient flows from a transport cost point of view, and the potential for such flows to impose rather heavy environmental impacts. The project will examine the fuel efficiency of various aircraft range and size configurations. The topic has ramifications for the location of hubs, and ultimately may have implications for the best way to select an air passenger fleet to accommodate the preferred patterns of interactions. The project aims to synthesize two contrasting views, one from the energy consumption of individual aircraft and the other from the overall network viewpoint. Research to date has tended to come at this problem from one side or the other and the research will develop an increased understanding of the interdependence between systems and their elements. To achieve the project's objectives, innovative linkages between operational and network efficiency points of view will be developed and tested in models of a simulated network. Because of the penetration of air transportation into everyday life, this project has several societal implications. The impacts of the project will range from educational ones to heightened awareness of the prevalence of economies of scope and scale in transportation. Specifically the results will provide a more complete understanding of the environmental and economic costs of air passenger interaction. The project will also bring the examination of fuel use and emissions more centrally into models of the operation and planning of air transport systems. The research will contribute to explanations of the ways that a hub serves as a focal point for interactions, and for models of diffusion which have implications for a range of application from improving airline security to understanding disease epidemiology. These topics have proven quite difficult to pin down quantitatively, and a transport network analysis will provide the tools to measure these elements in a spatial context. The project is likely to influence the way networks are assessed and measured.