scholarly journals The Role of Green Infrastructure in Enhancing Microclimate Conditions: A Case Study of a Low-Rise Neighborhood in Abu Dhabi

2021 ◽  
Vol 13 (8) ◽  
pp. 4260
Author(s):  
Mahmoud Abu Ali ◽  
Khaled Alawadi ◽  
Asim Khanal
Keyword(s):  
Citizen Science ◽  
Air Temperature ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Urban Heat Islands ◽  
Abu Dhabi ◽  
Design Strategies ◽  
Street Trees ◽  
Cooling Effects

Urban heat islands are characterized by the increased temperature in urban areas compared with the rural surroundings due to human-made interventions that replace natural lands with buildings and roads. This study focuses on the assessment and utilization of using local nature-based solutions such as trees, sensitive landscaping types and design strategies to enhance microclimate in neighborhood streets and the public realm in desert areas, taking Abu Dhabi as a case study. The research utilizes a design-based approach to propose landscaping and layouts of urban street trees in low-rise residential urban areas. In this study, two methods namely an on-site measurement using citizen science, and a numerical simulation model in the ENVI-met software are used. Site-measurements included the tree physical characteristics such as tree height, crown width (crown spread/diameter), and trunk height, and the use of technology (photography and the Fulcrum mobile application, Nikon Forestry pro Laser Rangefinder) and air temperature around trees. ENVI-met included four scenarios: 1—“no-vegetation”, 2—“grass-only”, 3—“existing conditions” and 4—“proposed landscape design”. Grass and three types of local street trees are used in the proposed scenarios including Ghaf, Poinciana, and Temple tree. In addition, a standard of 6 and 8 m spacing between each tree is applied to determine the effect of varying vegetation densities on the outdoor temperature. The combined results using citizen science and the model allowed the identification of particular urban tree species that show substantial cooling effects. This is the case of Poinciana trees, which decreased the air temperature up to 0.9 °C when spaced every six meters in pathways and open unshaded areas amongst alleys, improving the overall thermal conditions in neighborhoods of hot-arid landscapes.

scholarly journals AIR-TEMPERATURE SINGULARITIES AND DIFFERENCES BETWEEN INTRA- AND EXTRA-URBAN WEATHER STATIONS. CASE STUDY: BUCHAREST-FILARET AND BUCHAREST-BĂNEASA

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Nicoleta Ionac ◽  
Bogdan Uritescu ◽  
Elena Grigore ◽  
Dana Maria Constantin ◽  
Alexandru Dumitrescu
Keyword(s):  
Air Temperature ◽  
Urban Areas ◽  
Active Surface ◽  
Interaction Patterns ◽  
Cooling Effects ◽  
Artificial Heat ◽  
Urban Weather ◽  
The City ◽  
Town Area

It is already a well-known fact that air-temperature is the most important climatic factor of differentiation between intra- and extra-urban areas, mainly due to the characteristics of the underlying active surface. Bucharest town-area is no exception to the rule. Ranking as Romania’s largest city, its air-temperature singularities and differences account for the most important example expressing the role that the artificial ground layer may play in the creation of specific urban climates. The thermal differences as well as singularities between the Bucharest town-area (Bucharest-Filaret) and its surroundings (Bucharest-Băneasa) are analyzed by means of multiple air-temperature parameters: hourly measurements (01, 07, 13 and 19 hrs.), daily, monthly, yearly values of maximum, average and minimum means, over a 30 year period (1981-2010). Besides, the analysis of some air-temperature singularities or records highlight the clear differences of air heating processes, mostly due to the different interaction patterns between solar radiation and the underlying active layer, at local scales. However, in general, although the intra-urban areas should keep warmer in summer and cooler in winter, the cooling effects seem to still remain lower in the city because of the greater artificial heat input that is being added to the built-in environment.

scholarly journals Urban Nocturnal Cooling Mediated by Bluespace

2021 ◽  
Author(s):  
Yuanfeng Cui ◽  
Leiqiu Hu ◽  
Zhihua Wang ◽  
Qi Li
Keyword(s):  
Air Temperature ◽  
Urban Areas ◽  
Rate Of Change ◽  
Analytical Models ◽  
Apparent Temperature ◽  
Urban Lakes ◽  
Temperature And Humidity ◽  
Alternative Means ◽  
Near Shore ◽  
Cooling Effects

Abstract The spatiotemporal characteristics of air temperature and humidity mediated by urban bluespace are investigated using a combination of dense network of climatological observations in a medium-sized US city, computational fluid dynamics and analytical modeling approaches. Both numerical simulation and observational results show that the rate of change of hourly averaged air temperature and humidity at 3.5 m over urban areas peaks two hours after sunset, while it decreases with time monotonically over greenspace, indicating different impacts due to presence of urban lakes. The apparent temperature decreases with distance to lakes in urban area due to higher near-shore humidity. This highlights that urban lakes located near city center can deteriorate the nighttime cooling effects due to elevated humidity. Finally, two analytical models are presented to explain the connection between the surface and air temperature as well as the spatial variation of air temperature and humidity adjacent to the urban lakes. These simplified models with parameters being inferred from the network of measurements have reasonably good performance compared to the observations. Compared to other sophisticated numerical simulations, these analytical models offer an alternative means that is easily accessible for evaluating the efficacy of bluespace on urban nocturnal cooling.

scholarly journals PARAMETERS OF INTEREST FOR THE DESIGN OF GREEN INFRASTRUCTURE

2019 ◽  
pp. 92-101
Author(s):  
Marija Šperac ◽  
Dino Obradović
Keyword(s):  
Air Quality ◽  
Urban Environment ◽  
Air Temperature ◽  
Green Infrastructure ◽  
Land Surface ◽  
Urban Areas ◽  
Hydrological Cycle ◽  
Urban Environments ◽  
Land Surfaces ◽  
Selection Of

The urbanization process significantly reduced the permeability of land surfaces, which affected the changes of runoff characteristics and the relations in the hydrological cycle. In urban environments, the relationships within the hydrological cycle have changed in quantity, in particular: precipitation, air temperature, evaporation, and infiltration. By applying the green infrastructure (GI) to urban environments is beneficial for the water resources and the social community. GI has an effect on the improvement of ecological, economic, and social conditions. Using GI into urban areas increases the permeability of land surfaces, whereby decreasing surface runoff, and thus the frequency of urban floods. It also has a significant influence on the regulation of air quality, water purification, climate change impact, and the changes in the appearance of the urban environment. When planning and designing the GI, it is necessary to identify the type of GI and determine the size and location of the selected GI. Since each urban environment has its own characteristics, it is necessary to analyze them before deciding on the GI. The paper analyzed meteorological parameters (precipitation, air temperature, insolation, air humidity) affecting the selection of GI types, using the specific example of an urban environment – the City of Osijek, Croatia. Significant parameters when designing GI are operation and maintenance These parameters directly affect the efficiency of GI. The proper selection of GI and its location results in maximum gains: the reduction of land surface drainage - drainage of the sewage system, purification and retention of precipitation at the place of production, the improvement of air quality, and the improvement of living conditions in urban environments

Estimating the expansion of urban areas and urban heat islands (UHI) in Ghana: a case study

2020 ◽  
Author(s):  
Isaac Buo ◽  
Valentina Sagris ◽  
Iuliia Burdun ◽  
Evelyn Uuemaa
Keyword(s):  
Urban Areas ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Urban Heat

scholarly journals Reducing urban heat islands and improving the thermal comfort of residents: A nature-based solution

2021 ◽  
pp. 65-75
Author(s):  
Tomislav Đorđević
Keyword(s):  
Spectral Analysis ◽  
Green Infrastructure ◽  
Land Surface ◽  
Complex Geometry ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Pollution Levels ◽  
Radiation Distribution ◽  
Urban Heat

The benefits of urban blue-green infrastructures are well known: they intercept airborne three-atom particles, thus reducing pollution levels; and they provide shade and cooling by means of evapotranspiration. The focus of this paper is to demonstrate methods such as remote sensing and multi-spectral analysis, which can be a very useful addition to the quantification of blue-green infrastructures for cooling and shading, especially in the highly complex geometry of city blocks. The basic aim of this research is to attempt to reduce urban heat islands and in this way to indirectly increase the comfort of living. A cause/ effect relationship between the envelope of built up structures and the solar radiation distribution on the environment was established by means of multi-spectral analysis, and an estimation was made concerning the lack of vegetation on a specific parcel/block (an important tool for urban planners). This state-of-the-art methodology was applied to the optimized prediction concept of vegetation resources. Now it is possible to create a model that will incorporate this newly-added urban vegetation into urban plans, depending on the evaporation potential that will affect the microclimate of the urban area. Such natural cooling can be measured and adapted and hence aimed at a potential decrease in temperature in areas with UHI emissions. As a case study, part of a seacoast urban block (Abu Dhabi UE,) was analysed with and without a street treeline and green façades and roofs. It was concluded that green infrastructure reduced the land surface temperature by up to 4.5˚C.

scholarly journals ACHIEVING SUSTAINABLE URBANIZATION OF THE NATIONAL THEATRE IN LONDON THROUGH CHANGE OF USE AND FUNCTIONS OF ARCHITECTURE

2021 ◽  
Vol 12 (23) ◽  
pp. 11-21
Author(s):  
Danijela Rogina ◽  
◽  
Radivoje Dinulović ◽  
Keyword(s):  
Urban Space ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Public Spaces ◽  
Urban Spaces ◽  
Urban Forms ◽  
National Theatre ◽  
Sustainable Urbanization ◽  
Key Aspects

The human population is currently on the rise and most Europeans live in urban areas, leading to increased urbanization. The change comes with its challenges, as cities, architecture, and urban spaces need to become more fluid, multi-functional, and innovative. This paper examines whether a change of use of public spaces, and functions of architectural and urban forms, can be used as an element in the implementation of sustainable urbanization. The theoretical framework of this paper focuses on literature findings relating to identified key aspects such as innovative approaches in changes of use — recycling and upcycling, green infrastructure and financial aspects, concepts of “right of the place”, and public participation. These aspects are addressed on both theoretical and practical levels, with the National Theatre in London as a case study. Findings convey that the change of use of spaces can be utilized to achieve sustainable urbanization, together with the management of functions and uses of architectural and urban forms. However, further research is needed with various stakeholders to identify a solid and inherent database, as a foundation on which the most optimal urban spaces would emerge, by identifying new functions and uses of urban space and architecture.

scholarly journals A spatially-explicit approach to simulate urban heat islands in complex urban landscapes

2020 ◽  
Author(s):  
Martí Bosch ◽  
Maxence Locatelli ◽  
Perrine Hamel ◽  
Roy P. Remme ◽  
Jérôme Chenal ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Air Temperature ◽  
Urban Areas ◽  
Heat Waves ◽  
Urban Heat Islands ◽  
Land Use Land Cover ◽  
Heat Islands ◽  
Urban Heat ◽  
Cooling Model

Abstract. Mitigating urban heat islands has become an important objective for many cities experiencing heat waves. Despite notable progress, the spatial relationship between land use/land cover patterns and the distribution of air temperature remains poorly understood. This article presents a reusable computational workflow to simulate the spatial distribution of air temperature in urban areas from their land use/land cover data. The approach employs the InVEST urban cooling model, which estimates the cooling capacity of the urban fabric based on three biophysical mechanisms, i.e., tree shade, evapotranspiration and albedo. An automated procedure is proposed to calibrate the parameters of the model to best fit air temperature observations from monitoring stations. In a case study in Lausanne, Switzerland, spatial estimates of air temperature obtained with the calibrated model show that the urban cooling model outperforms spatial regressions based on satellite data. This represents two major advances in urban heat island modeling. First, unlike in black-box approaches, the calibrated parameters of the urban cooling model can be interpreted in terms of the physical mechanisms that they represent and can therefore help understanding how urban heat islands emerge in a particular context. Second, the urban cooling model requires only land use/land cover and reference temperature data and can therefore be used to evaluate synthetic scenarios such as master plans, urbanization prospects, and climate scenarios. The proposed approach provides valuable insights into the emergence of urban heat islands which can serve to inform urban planning and assist the design of heat mitigation policies.

Automated detection of urban heat islands based on satellite imagery, digital surface models, and a low-cost sensor network                                     

2021 ◽  
Author(s):  
Sebastian Schlögl ◽  
Nico Bader ◽  
Julien Gérard Anet ◽  
Martin Frey ◽  
Curdin Spirig ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Rural Areas ◽  
Urban Areas ◽  
Low Cost ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Micro Scale ◽  
Air Temperatures ◽  
Urban Heat

<p>Today, more than half of the world’s population lives in urban areas and the proportion is projected to increase further in the near future. The increased number of heatwaves worldwide caused by the anthropogenic climate change may lead to heat stress and significant economic and ecological damages. Therefore, the growth of urban areas in combination with climate change can increase future mortality rates in cities, given that cities are more vulnerable to heatwaves due to the greater heat storage capacity of artificial surfaces towards higher longwave radiation fluxes.</p><p>To detect urban heat islands and resolve the micro-scale air temperature field in an urban environment, a low-cost air temperature network, including 450 sensors, was installed in the Swiss cities of Zurich and Basel in 2019 and 2020. These air temperature data, complemented with further official measurement stations, force a statistical air temperature downscaling model for urban environments, which is used operationally to calculate hourly micro-scale air temperatures in 10 m horizontal resolution. In addition to air temperature measurements from the low-cost sensor network, the model is further forced by albedo, NDVI, and NDBI values generated from the polar-orbiting satellite Sentinel-2, land surface temperatures estimated from Landsat-8, and high-resolution digital surface and elevation models.</p><p>Urban heat islands (UHI) are processed averaging hourly air temperatures over an entire year for each grid point, and comparing this average to the overall average in rural areas. UHI effects can then be correlated to high-resolution local climate zone maps and other local factors.</p><p>Between 60-80 % of the urban area is modeled with an accuracy below 1 K for an hourly time step indicating that the approach may work well in different cities. However, the outcome may depend on the complexity of the cities. The model error decreases rapidly by increasing the number of spatially distributed sensor data used to train the model, from 0 to 70 sensors, and then plateaus with further increases. An accuracy below 1 K can be expected for more than 50 air temperature measurements within the investigated cities and the surrounding rural areas. </p><p>A strong statistical air temperature model coupled with atmospheric boundary layer models (e.g. PALM-4U, MUKLIMO, FITNAH) will aid to generate highly resolved urban heat island prediction maps that help decision-makers to identify local heat islands easier. This will ensure that financial resources will be invested as efficiently as possible in mitigation actions.</p>

The role of blue and green infrastructure in thermal sensation in public urban areas: A case study of summer days in four Czech cities

2021 ◽  
Vol 66 ◽  
pp. 102683
Author(s):  
Michal Lehnert ◽  
Marek Brabec ◽  
Martin Jurek ◽  
Vladimír Tokar ◽  
Jan Geletič
Keyword(s):  
Green Infrastructure ◽  
Urban Areas ◽  
Thermal Sensation
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