Influential Intensity of Urban Agglomeration on Evolution of Ecoenvironmental Pressure:A Case Study of Changchun,China

In this paper,we study the interactive relationship between the agglomeration of urban elements and the evolution of eco-environmental pressure.We build an index system for evaluating the agglomeration of urban elements and eco-environmental pressure.Using the entropy method and response intensity model,we analyze how urban elements agglomeration influenced eco-environmental pressure in Changchun from 1990 to 2012,eliciting the changing features and influential factors.Ultimately,we conclude there is a significant interactive relationship between the agglomeration of urban elements and the evolution of eco-environmental pressure in Changchun.This is inferred from the degree of this agglomeration in Changchun having increased since 1990,with the degree of eco-environmental pressure first decreasing and then increasing.Alongside this,the impact of urban elements agglomeration on eco-environmental pressure has changed from negative to positive.The main reasons behind this shift are arguably the rapid growth of urban investment and ongoing urbanization.

Evaluation of a Micro-scale Wind Model's Performance over Realistic Building Clusters Using Wind Tunnel Experiments

The simulation performance over complex building clusters of a wind simulation model（Wind Information Field Fast Analysis model, WIFFA） in a micro-scale air pollutant dispersion model system（Urban Microscale Air Pollution dispersion Simulation model, UMAPS） is evaluated using various wind tunnel experimental data including the CEDVAL（Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models） wind tunnel experiment data and the NJU-FZ experiment data（Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data）. The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution（1–5 m） wind fields of a complex neighborhood scale urban building canopy（～ 1 km ×1km） in less than 3 min when run on a personal computer.

SUSTAINABILITY ON THE URBAN SCALE:‘GREEN URBANISM’—MARK Ⅱ

In the essay entitled‘Towards a Sustainable City Centre’(published in JGB Summer 2006),the author reflected on principles how to best integrate ecologically sustainable development(ESD)into urban design.This second paper reports on his continuing research in the area of‘Green Urbanism’.1 Among the most significant environmental challenges of our time are global climate change,excessive fossil fuel de-pendency and the growing demand for energy—all likely to be major challenges of the 21st century and one of the great-est problems facing humanity.In this context,urban design and the fundamental principles of how to shape our cities has barely featured in the greenhouse debate.Much of the debate in related areas has so far circled around ideas about active technology for‘eco-buildings’.This is surprising,since almost half the energy consumed is used in cities and urban built-up areas,and given that avoiding mistakes in urban design at early stages could genuinely lead to more sustain-able cities and less greenhouse gas emission.This article reflects upon practical strategies focused on increasing sustain-ability beyond and within the scope of individual buildings.The paper deals with cross-cutting issues in architecture and urban design and addresses the question of how we can best cohesively integrate all aspects of energy systems,transport systems,waste and water management,passive and active strategies,climatisation and so on,into contemporary urban design and improved environmental performance of our cities.It provides a context for a general debate about the regeneration of the city centre,and discusses how urbanism is affected(and can be expected to be even more affected in future)by the paradigms of ecology.The significance of the research is found in the pressing need for an integration of sustainability principles in the urban design process of cities in South East Asia and the general need for a sustainable city development.It will be of particular relevance to the rapid urban growth of developing cities that have,in the past,frequently been poorly man-aged.Research in sustainable urban design recommends increased harnessing of the energies manifested in the existing fabrics—for instance,through the adaptive re-use of former industrial(brownfield)sites and the upgrade and extension of existing building structures.It is less environmentally damaging to stimulate growth within the established city cen-tre rather than sprawling into new,formerly un-built areas.Two recent examples for the application of such urban de-sign principles are the author’s proposals for the Australian city of Newcastle:the‘City Campus’and‘Port City’projects.