scholarly journals Extensive Roof Greenery as a Response to Heat Islands: Some Problems

2021 ◽  
Vol 29 (4) ◽  
pp. 9-12
Author(s):  
Matej Holečka ◽  
Martin Jamnický ◽  
Matúš Krajčík ◽  
Roman Rabenseifer
Keyword(s):  
Green Roofs ◽  
Urban Heat Islands ◽  
Climate Conditions ◽  
Heat Islands ◽  
Safety Issues ◽  
European Climate ◽  
Societal Pressure ◽  
Urban Heat ◽  
Flat Roof

Abstract Extensive roof greenery is one of the ways to reduce the extent and impact of urban heat islands. A prerequisite is the correct design and operation of both the structural and vegetation part of a roof. If adequate maintenance, especially irrigation of the greenery, cannot be ensured, the use of extensive roof greenery can also be counterproductive. The case study to be presented deals with problems of a flat roof with extensive greenery above an underground garage under Central European climate conditions. Infrequent irrigation leads to extremely high temperatures of the substrate in the summer and makes the purpose of this roof pointless. The contribution analyzes the reason for the failure of the vegetation part of the roof, which was claimed to be maintenance-free, points out fire safety issues, and suggests improvements that might be considered in similar cases. At the present time, which is marked by the climate change crisis, there is great societal pressure to build green roofs. However, if it is not possible to ensure their perfect functionality, it is perhaps better to use classically proven types of roofs, but with greater reflectivity of the top layer surface.

scholarly journals The Impact of Green Roofs on the Parameters of the Environment in Urban Areas—Review

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 792 ◽  
Author(s):  
Dariusz Suszanowicz ◽  
Alicja Kolasa Więcek
Keyword(s):  
Urban Areas ◽  
Central And Eastern Europe ◽  
Single Case ◽  
Green Roofs ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact ◽  
The City

This study presents the results of a review of publications conducted by researchers in a variety of climates on the implementation of ‘green roofs’ and their impact on the urban environment. Features of green roofs in urban areas have been characterized by a particular emphasis on: Filtration of air pollutants and oxygen production, reduction of rainwater volume discharged from roof surfaces, reduction of so-called ‘urban heat islands’, as well as improvements to roof surface insulation (including noise reduction properties). The review of the publications confirmed the necessity to conduct research to determine the coefficients of the impact of green roofs on the environment in the city centers of Central and Eastern Europe. The results presented by different authors (most often based on a single case study) differ significantly from each other, which does not allow us to choose universal coefficients for all the parameters of the green roof’s impact on the environment. The work also includes analysis of structural recommendations for the future model green roof study, which will enable pilot research into the influence of green roofs on the environment in urban agglomerations and proposes different kinds of plants for different kinds of roofs, respectively.

scholarly journals Green roofs and cool materials as retrofitting strategies for urban heat island mitigation: Case study in Belgrade, Serbia

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2309-2324
Author(s):  
Marija Lalosevic ◽  
Mirko Komatina ◽  
Marko Milos ◽  
Nedzad Rudonja
Keyword(s):  
Green Roofs ◽  
Urban Heat Islands ◽  
Temperature Changes ◽  
Heat Islands ◽  
Air Temperatures ◽  
Urban Heat ◽  
Microclimatic Conditions ◽  
Typical Summer ◽  
Planning And Construction ◽  
The Impact

The effect of extensive and intensive green roofs on improving outdoor microclimate parameters of urban built environments is currently a worldwide focus of research. Due to the lack of reliable data for Belgrade, the impact of extensive and intensive green roof systems on mitigating the effects of urban heat islands and improving microclimatic conditions by utilizing high albedo materials in public spaces were studied. Research was conducted on four chosen urban units within existing residential blocks in the city that were representative of typical urban planning and construction within the Belgrade metropolitan area. Five different models (baseline model and four potential models of retrofitting) were designed, for which the temperature changes at pedestrian and roof levels at 07:00, 13:00, 19:00 h, on a typical summer day, and at 01:00 h, the following night in Belgrade were investigated. The ENVI-met software was used to model the simulations. The results of numerical modeling showed that utilizing green roofs in the Belgrade climatic area could reduce air temperatures in the surroundings up to 0.47, 1.51, 1.60, 1.80 ?C at pedestrian level and up to 0.53, 1.45, 0.90, 1.45 ?C at roof level for four potential retrofitting strategies, respectively.

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.

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