Targeted urban heat mitigation strategies using urban morphology databases and micro-climate modelling to examine the urban heat profile

Author(s):  
Kerry Nice ◽  
Ashley Broadbent

<p>Strategies for urban heat mitigation often make broad and non-specific recommendations (i.e. plant more trees) without accounting for local context. As a result, resources might be allocated to areas of lesser need over those where more urgent interventions are needed. Also, these interventions might return less than optimal results if local conditions are not considered. This project aims to assist with these interventions by providing a method to examine the urban heat profile of a city through an automated systematic approach. Using urban morphology information from databases such as WUDAPT, areas of cities are clustered into representative local climate zones (LCZs) and modelled at a micro-scale using localised features and properties. This bottom up modelling approach, using the VTUF-3D, UMEP, and TARGET models, allows these areas to be assessed in detail for their human thermal comfort performance and provide a city-wide heat map of thermal comfort. It also allows mitigation scenarios to be tested and targeted for each cluster type. A case study performed using this method for Melbourne is presented.</p>

2020 ◽  
Author(s):  
Ines Langer ◽  
Alexander Pasternack ◽  
Uwe Ulbrich

<p>Urban areas show higher nocturnal temperature comparing to rural areas, which is denoted by urban heat island. This effect can intensify the impact of global warming in urban areas especially during heat waves, that leads to higher energy demand for cooling the building and higher thermal stress for residents.  </p><p>The aim of this study is to identify the Urban Heat Island (UHI) effect during the heat spell 2018 and 2019 in order to calculated human thermal comfort for Berlin. Berlin, the capital city of Germany covers an area of 892km<sup>2</sup> and its population is growing, therefore more residential areas will be planned in future through higher building. The methodology of this research is to divide Berlin into Local Climate Zones (LCZ's) regarding the concept of Stewart & Oke (2012). Then to evaluate the accuracy of this concept using 30 microclimate stations. Estimating the magnitude of urban heat island and its seasonal changes in combination with human thermal perception in different LCZ during summer time is another objective of this research. </p><p>Ten LCZ's for Berlin were selected, as class 1 (compact high rise), class 3 (compact low rise), class 7 (lightweight low-rise), class C (bush, scrub), class E (bare rock or paved) and class F (bare soil or sand) don't exist in Berlin. Class A (dense trees) is with a fraction of 18.6% in a good agreement with the percentage of dense trees reported from the city administration of Berlin (18.4%), class G (water) has a coverage of 5.1% through our classification instead of 6.7% reported by the city administration. In summary, the LCZ 1-10 cover 59.3% (more than half) of the city area.</p><p>Regarding temperature measurements, which represent a hot summer day with calm wind and clear sky the difference of Local Climate Zones will be calculated and the temperature variability in every LCZ's regarding sky view factor values show the hot spot of the city.</p><p>The vulnerability of LCZ's to heat stress will be ranked and discussed regarding ventilation and other factors.</p><p> </p><p>Literature</p><p>Matzarakis, A. Mayer, H., Iziomon, M. (1999) Applications of a universal thermal index: Physiological equivalent temperature: Intern. J. of Biomet 43 (2), 76-84.</p><p>Stewart, I.D., Oke, T.R. (2012) Local climate zones for urban temperature studies. Bull. Amer. Meteor. Soc. 93 1879-1900. DOI: 10.1175/BAMS-D-11-00019.1.</p><p> </p>


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3577
Author(s):  
Fatma Balany ◽  
Anne WM Ng ◽  
Nitin Muttil ◽  
Shobha Muthukumaran ◽  
Man Sing Wong

Research on urban heat mitigation has been growing in recent years with many of the studies focusing on green infrastructure (GI) as a strategy to mitigate the adverse effects of an urban heat island (UHI). This paper aims at presenting a review of the range of findings from GI research for urban heat mitigation through a review of scientific articles published during the years 2009–2020. This research includes a review of the different types of GI and its contribution for urban heat mitigation and human thermal comfort. In addition to analysing different mitigation strategies, numerical simulation tools that are commonly used are also reviewed. It is seen that ENVI-met is one of the modelling tools that is considered as a reliable to simulate different mitigation strategies and hence has been widely used in the recent past. Considering its popularity in urban microclimate studies, this article also provides a review of ENVI-met simulation results that were reported in the reviewed papers. It was observed that the majority of the research was conducted on a limited spatial scale and focused on temperature and human thermal comfort.


Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 438 ◽  
Author(s):  
Tong Lyu ◽  
Riccardo Buccolieri ◽  
Zhi Gao

In the context of urbanization, research on urban microclimate and thermal comfort has become one of the themes of eco-city design. Sky view factor (SVF), one of the parameters of urban spatial form, combines multiple morphological information, such as plane opening, aspect ratio, and building density and has an important impact on the urban microclimate. However, there is still no clear research conclusion on the correlation between SVF and microclimate. In this paper, nine Local Climate Zone (LCZ) models are used and typical summer meteorological conditions of Nanjing are applied as an attempt to partially fill this gap. The calculated microclimate and thermal comfort indices include air temperature (AT), surface temperature (ST), relative humidity (RH), wind speed (WS), mean radiant temperature (MRT), and predicted mean vote (PMV). Results show that the local effect of urban morphology on thermal comfort can be retrieved from the use of comprehensive parameters such as SVF (which takes into account the building height, layout, and density) whose distribution in the investigated models showed to be correlated with MRT, so did PMV under low wind speed conditions.


2018 ◽  
Author(s):  
Nathalie Long ◽  
Thomas Gardes ◽  
Julia Hidalgo ◽  
Valéry Masson ◽  
Robert Schoetter

This article presents the development and application to a set of French urban agglomerations of a method for Local Climate Zones (LCZ) attribution using the open-source language R. The LCZs classify the urban fabric at high spatial scale (such as a block of houses) according to its morphological characteristicsand land use. The LCZ classification is carried out for 42 urban agglomerations and is then related to urban heat island intensity (UHII) obtained from numerical simulations at a spatial resolution of 250m. The objective is to study the adequacy of the LCZ classification to characterise the impact of urban morphology on the UHII. The variance analysis (ANOVA) carried out confirms the highly significant relationship between LCZs and the UHII for a given urban agglomeration. For all the urban agglomerations in the sample, linear regression models show a significant correlation between the percentages of surface covered by different LCZ and the mean UHII for the time periods tested (21-23 UTC), with adjusted coefficients of determination higher than 0.40.


2016 ◽  
Vol 65 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Dragan D. Milošević ◽  
Stevan m. Savić ◽  
Vladimir Marković ◽  
Daniela Arsenović ◽  
Ivan Šećerov

2018 ◽  
Author(s):  
Nathalie Long ◽  
Thomas Gardes ◽  
Julia Hidalgo ◽  
Valéry Masson ◽  
Robert Schoetter

This article presents the development and application to a set of French urban agglomerations of a method for Local Climate Zones (LCZ) attribution using the open-source language R. The LCZs classify the urban fabric at high spatial scale (such as a block of houses) according to its morphological characteristicsand land use. The LCZ classification is carried out for 42 urban agglomerations and is then related to urban heat island intensity (UHII) obtained from numerical simulations at a spatial resolution of 250m. The objective is to study the adequacy of the LCZ classification to characterise the impact of urban morphology on the UHII. The variance analysis (ANOVA) carried out confirms the highly significant relationship between LCZs and the UHII for a given urban agglomeration. For all the urban agglomerations in the sample, linear regression models show a significant correlation between the percentages of surface covered by different LCZ and the mean UHII for the time periods tested (21-23 UTC), with adjusted coefficients of determination higher than 0.40.


Author(s):  
Fatma balany ◽  
A.W.M Ng ◽  
Nitin Muttil ◽  
Shobha Muthukumaran ◽  
Man Sing Wong

Research on urban heat mitigation has been growing in recent years with many of the studies focusing on green infrastructure (GI) as a strategy to mitigate the adverse effects of Urban Heat Island (UHI). This paper aims at presenting a review of the range of findings from GI research for urban heat mitigation through a review of scientific articles published during the years 2009-2019. This research includes a review of the different types of GI and its contribution for urban heat mitigation and human thermal comfort. In addition to analyzing different mitigation strategies, numerical simulation tools that are commonly used are also reviewed. It is seen that ENVI-met is one of the modelling tools that is considered as a reliable tool to simulate different mitigation strategies and hence has been widely used in the recent past. Considering its popularity in urban microclimate studies, this article also provides a review of ENVI-met simulation results that were reported in the reviewed papers. It was observed that the majority of the research was conducted on a limited spatial scale and focused on temperature and human thermal comfort.


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