Influence Of Urban Morphology Research Articles

Influence of urban morphology on potential of green roofs in regulating local microclimate: A case study of Liège, Belgium

Urban microclimate varies for different urban morphologies in a city necessitating the assessment of impact of green roofs on the local microclimate in such typical morphologies. This paper explores the role of roof greening in regulating the local microclimate in Liège, Belgium, for nine realistic and unique urban morphological archetypes during a heatwave. The urban morphological archetypes are obtained based on a systematic data-driven approach using an extensive list of morphological parameters. Nine scenarios without green roofs and nine scenarios with green roofs are simulated using Solene-microclimat model. Green roofs are introduced only on the existing flat roofs identified using remote-sensing to analyse the realistic impact of roof greening. Our findings suggest that distinct morphologies in the archetypes result in distinctive impact of roof greening on these archetypes. For instance, green roofs can reduce surface temperature effectively in compact high-rise archetypes, whereas green roofs' potential to reduce air temperature is limited. While green roofs can effectively reduce surface and air temperature in compact low-rise archetypes, most compact low-rise archetypes are residential and have fewer flat roofs to green. However, large low-rise archetypes, which are predominantly industrial/commercial, can be retrofitted with green roofs, considering large potential of roof greening. This study provides insight into the interplay between urban morphology, realistic roof greening potential, and the UHI effect on local microclimate, improving our understanding of microclimate regulation with green roofs.

Exploring the relationship between preferred routes for walking exercise and green space layout in a dense urban area: a series of poisson regression models

ABSTRACT The literature considers urban green spaces as a key to promoting physical activity and health. Despite the increasingly recognized walking exercise promotion benefits of urban green spaces, the relationship between walking exercise preferences and green space layout remains unclear. We extracted preferred routes for walking exercise and measured the route heat using a one-year shared data of walking exercise from a mobile outdoor assistant app in the old city of Fuzhou, China. We then evaluated green space layout features within a 500-m buffer zone along the preferred routes in dimensions of scale, form, and function. The relationship between the route heat and green space layout features was analyzed using a series of poisson regression models, with the influence of urban morphology and the built environment allocation being controlled. Results showed that there existed a significant association between preferred routes for walking exercise and the combination of green space layout, urban morphology, and the built environment allocation; the route heat had positive associations with NDVI and comprehensive park area density, and showed negative associations with patch shape index and patch density. This study illustrates the necessity for targeted intervention strategies to promote the development of walkable and healthy urban areas.

Influence of urban morphology on facade solar potential in mixed-use neighborhoods: Block prototypes and design benchmark

Influence of urban morphology on facade solar potential in mixed-use neighborhoods: Block prototypes and design benchmark

The impact of street geometry on outdoor thermal comfort within three different urban forms in severe cold region of China

This paper focuses on the influence of urban morphology on pedestrian outdoor thermal comfort in Harbin, located in the severe cold region of northeast China. Three typical districts with different urban densities and street layouts were investigated. Field measurement and thermal comfort questionnaire survey were carried out from July 2020 to January 2021. Regression analysis was performed and the neutral physiological equivalent temperature (PET) range was 14.5–22.8 °C. In addition, the PET range was 7.9–27.3 °C when 80% of thermal votes were “acceptable”. ENVI-met was verified and utilized to assess the mesoscale and street-scale impact of urban morphology on thermal comfort in hot and cold seasons. Measurement results shows that the PET variation caused by urban morphology was more significant in the transition season, with the maximum PET difference of 7.6 °C observed at the mid-rise district and the minimum value of 4.4 °C in the low-rise area. Simulation results indicate that the average building height significantly affects the background Ta and PET distribution within the block. Mean radiant temperature (MRT) and PET are highly correlated to sky view factor (SVF) in summer, while in winter, PET is related to SVF only in the low-rise district. Based on the thermal comfort calendar in both hot and cold seasons, shallow and medium canyons (0.5 < H/W < 1.5) are more favorable in severe cold climate, and the optimum streets are near the N–S orientation, followed by intermediate orientations, while deeper canyons (H/W > 1.5) are not recommended due to the lack of solar absorption.

Numerical simulation of the impact of urban canopies and anthropogenic emissions on heat island effect in an industrial area: A case study of Angul-Talcher region in India

Changing urban land use dynamics and associated anthropogenic heat (AH) has increased warming over urban centres. This warming is associated with the Urban Heat Island (UHI) effect and is mainly studied in major cities worldwide. However, predominantly industrial regions can also experience heat island effect due to heat emissions from industrial infrastructure and associated activities. The current study examines the role of the urban morphology and anthropogenic heat over the Angul-Talcher region (industrial region) of Odisha state, India. The region is also referred to as India's highly polluted industrial cluster due to open cast mining and industries. In the present study, Weather Research and Forecast model (WRF) coupled with Single-Layer Urban Canopy Model (WRFUCM) has been modified to examine the impact of urban morphology and anthropogenic heat on the heat island effect over the region. The study refers modified version of WRFUCM as the WRFAH[Gridded] model, which incorporates anthropogenic heat from different industries with stack height information. It was found that the WRF model capabilities have improved in simulating surface meteorological variables such as temperature at 2 m, wind speed, and relative humidity with the inclusion of gridded AH. Urban canopies were estimated to bring in an increase of up to 0.77°C in local near-surface temperatures during daytime and up to 2.12°C during nighttime. AH emissions further increased temperatures by up to 0.32°C during daytime and 0.69°C during nighttime. Maximum heat island intensity with urban canopies is estimated to be 5.62°C which increases to 7.11°C with the inclusion of average AH released at canopy level. However, this has significantly improved to 5.88°C with inputs of industry-specific AH released at stack heights with the WRFAH[Gridded] model against observed maximum heat island intensity of 6.06°C. Overall, the influence of urban morphology was found to be higher than the influence of AH over the region at ground level, and the inclusion of gridded AH in the model showed improved performance for the heat island assessment.

The role of urban planning in climate adaptation: an empirical analysis of UHI in European cities

This paper empirically analyses the relationship between urban form and Urban Heat Island (UHI) in a dataset of 523 European cities that matches remotely sensed land-use and surface temperature data. A UHI anomaly is defined as an uninterrupted streak of days where the temperature differential measured at 12.00 AM between the city core and its surroundings is higher than a given threshold. From this definition, three UHI indicators are obtained: mean intensity, mean duration of the event and occurrence rate. We study the influence of urban morphology on the UHI indictors with a Heckman model. A sample selection bias is detected for mean intensity and mean duration. The estimation results also show that some urban morphological features have a mitigating effect, while some others play a role at the adaptation level.

Influence of atmospheric stability on air ventilation and thermal stress in a compact urban site by large eddy simulation

The assumption of neutral atmosphere in conventional evaluation of air ventilation and thermal stress in a compact urban area with weak wind environment may lead to errors. To assess this effect, this paper presents air ventilation and thermal stress assessment in a real subtropical urban area in Hong Kong by large eddy simulation considering stable, neutral, and unstable stratification. The air ventilation and thermal stress are measured by wind velocity ratio and Universal Thermal Climate Index, respectively. The atmospheric stabilities are quantified by vertical profiles of equivalent potential temperature based on daily radiosonde records in recent five years. The simulated results show that the conventional isothermal assumption underestimates the air ventilation capacity and overestimates the heat stress in the urban area in terms of reduced wind speeds and increased areas of strong heat stress at pedestrian-level height, respectively. The influence of urban morphology on air ventilation and thermal stress is investigated based on two urban geometry indices, namely ground coverage ratio and frontal area ratio. It is found that the ground coverage ratio is more relevant to the urban ventilation and thermal stress, but the correlations are weakened under unstable condition. On the other hand, the influence of the frontal area ratio is little. The findings of this study aim to provide a reference to the amendment of the current air ventilation assessment methodology which neglects the influence of atmospheric stability.

URBAN MORPHOLOGY AND CRIME PATTERNS IN URBAN AREAS: A REVIEW OF THE LITERATURE

The emerging research on urban morphology provide sufficient explorations that result in a better understanding of crime areas and fear of crime in cities. Despite the effort so far, the existing literature on morphology of crime areas and pattern of crime presents different perspectives to the study of crime and spaces, reflecting the varied field of urban morphological research. There is a need to understand these perspectives in view of their directions and inherent limitations for effective understanding of crime pattern and urban morphogenesis in cities. The focus of the paper is on the understanding of different perspectives in the study of crime pattern and urban morphology in setting up an effective mechanism for crime prevention and control. Twenty (20) paper articles and six (6) theses published between 2010 - 2021 were selected based on the Environmental criminological research perspectives from the field of Geography, Urban Planning, Urban Design, Landscape Architecture and Architecture; and systematically reviewed based on their characteristics and then classified according to their relevance to environmental criminology for analysis and drawing of inferences. The findings indicated that, there is inadequate empirical research on the influence of urban morphology on crime pattern in cities. Therefore, the paper recommends for further research to focus on exploring the various links between elements of urban morphology and spatial distribution of crime in areas, and the explanations that could provide for effective crime prevention and control in cities.

3D building configuration as the driver of diurnal and nocturnal land surface temperatures: Application in Beijing's old city

Urbanization has produced extremely diverse structures of buildings, including horizontal sprawl, vertical growth, and a transition from traditional to modern architecture. Although the influence of urban morphology on urban heat formation is unquestioned, previous research has relied just on the 2D building composition and its influence on diurnal land surface temperatures (DLSTs). However, it is not well known that the 3D building configuration affects nocturnal land surface temperatures (NLSTs) and seasonal variations. In a new approach, a set of 3D landscape metrics, based on both aspects of composition and configuration, is here proposed and tested for spatiotemporal associations to land surface temperatures (LSTs) in Beijing's old city. The combination of classical and modern architecture styles makes this region an ideal laboratory for LST studies in highly different urban structures. Major findings include: 1) 3D landscape metrics effectively and suitably describe the diversity, irregularity and spatial arrangement of buildings; 2) Denser and more compact building patterns result in higher DLSTs, whereas highest NLSTs occur around modern high-rise buildings; 3) 3D landscape metrics have sensitive correlations to DLSTs, but in general NLSTs are closer associated with composition metrics rather than configuration metrics; 4) Both DLST and NLST are most importantly affected by building numbers and nearest distances between buildings; 5) The association between urban morphology and LSTs is fairly stable over all four seasons; with the variation that the summer relationship was relatively lower due to stronger solar radiation and evapotranspiration of urban vegetation.

Microclimate design for open spaces: Ranking urban design effects on pedestrian thermal comfort in summer

The paper presents a study on the influence of urban morphology and urban design parameters such as street and building geometry, landscape elements including vegetation types, water surfaces and material properties and their effects on pedestrian thermal comfort in cities. The data provided by the paper are based on simulations using selected computational tools (ENVI-met, RadTherm and Fluent) and performed for two typical urban spaces, a square and a courtyard. The paper focuses on summer conditions which include increasingly uncomfortable periods. It draws upon studies initiated in the city of Thessaloniki in northern Greece. However, the findings apply to many other cities with similar morphological characteristics and summer design conditions. The results are ranked according to the influence each of the design parameters considered can have on pedestrian thermal comfort. Spatial and temporal variations are highlighted. Special mention is given to the high impact of trees and soil humidity and the contrasting effects of pavement albedo. The paper provides data for use by urban designers in specifying appropriate microclimatic interventions to improve pedestrian comfort.

Influence of Urban Morphology on Outdoor Thermal Comfort in Summer: A Study in Tunis, Tunisia

Influence of Urban Morphology on Outdoor Thermal Comfort in Summer: A Study in Tunis, Tunisia

Mapping the urban microclimatic spatial distribution in a sub-tropical high-density urban environment

Understanding the urban microclimatic spatial distribution and its impact on thermal comfort is important for integrating climatic consideration into urban design process. This article presents a case study in Tsim Sha Tsui and Tai Po of Hong Kong densely built-up areas to investigate the spatial distribution of microclimatic condition. Air temperature (Ta), wind speed (v), relative humidity (RH) and globe temperature (Tg) of 87 locations in two selected sites were measured on a summer day and a winter day respectively. Physiological Equivalent Temperature was calculated to analyse the thermal comfort condition in two sites. Both numerical simulation and geographical mapping approach were used for the estimation of the microclimatic spatial distribution. Results show that the influence of urban morphology on the microclimatic spatial distribution can be well investigated by using numerical simulation while geographical mapping based on measured data shows higher estimation accuracy due to the consideration of anthropogenic heat and other factors associated with human activities. In summary, this article presents a pragmatic approach of mapping the urban microclimatic spatial distribution that can be referenced by architects and urban designers to raise climatic considerations for designing better cities.

Influence of urban morphology on air flow over building arrays

In the present paper we have analysed experimentally (wind tunnel) and numerically (CFD) the impact of some morphological parameters on the flow within and above the urban canopy. In particular, this study is a first attempt in systematically studying the flow in and above urban canopies using simplified, yet more realistic than a simple array of cuboids, building arrays. Current mathematical models would provide the same results for the six case studies presented here (two models by three wind directions), however the measured spatially averaged profiles are quite different from each other.Results presented here highlight that the differences in the spatially averaged vertical profiles are actually significant in all six experimental/numerical cases. Besides the building height variability, other morphological features proved to be a significant factor in shaping flow and dispersion at the local to neighbourhood scale in the urban canopy and directly above: building aspect ratio (or, conversely, the street canyon aspect ratio), the angle between the street canyons and the incoming wind and local geometrical features such as, for example, the presence of much taller buildings immediately upwind of the studied area.

The Influence of Urban Morphology on the Resilience of Cities Following an Earthquake

This paper proposes a conceptual theory of resilience in urbanism and demonstrates its application through a case study. The theory's underpinnings are the attributes of resilience that have been developed in ecological sciences, but have clear parallels in urbanism. They suggest that it may be possible to enhance the resilience of a city through the design of its urban morphology. The paper explores these ideas by examining the relationship between the community's adaptive behaviour and the spaces of the city of Concepción after its 2010 earthquake. This empirical evidence suggests that the role of the urban designer in earthquake-prone cities is perhaps more critical before an earthquake happens and that the more the idea of a resilient urban morphology is embedded as part of daily life, the more effective it is likely to be in the aftermath of a major earthquake.