Special Issue "Urban Design and City Microclimates"

A special issue of Atmosphere (ISSN 2073-4433). This special issue belongs to the section "Biometeorology".

Deadline for manuscript submissions: 30 June 2018

Special Issue Editor

Guest Editor
Prof. Dr. Robert Brown

Department of Landscape Architecture and Urban Planning, Texas A&M University, College Station, USA
Website | E-Mail
Interests: microclimate modification; human energy budget modeling; urban design, landscape architecture

Special Issue Information

Dear Colleagues,

More than half the people in the world now live in cities and this proportion is expected to continue to increase. Global Climate Change (GCC) and Urban Heat Island (UHI) intensification are making cities hotter places to live. Hot cities can have both a chronic and an acute effect on human health. Uncomfortably hot conditions discourage people from spending time outdoors, which has various negative physiological and mental health implications. Current heat waves are more intense, more frequent, and last longer than in the past, leading to acute health effects including hyperthermia and death. Urban designers require solid evidence on how to either reverse or dampen these trends, and they need evidence-based adaptation strategies for redesigning cities so that they will be more thermally-comfortable every day, and particularly safer during extreme heat events.

This Special Issue will explore three important questions that have not been widely addressed in related literature, yet are critical to designing thermally-safe cities. 

 

The first question is: how does the built urban environment modify the climate, at all scales?  Papers that address this issue will measure atmospheric variables before and after modifications to the urban environments. Results will quantify the relative effects of different design interventions.

 

The second question is: how does microclimate affect the energy budget (or heat balance), safety, and thermal comfort level of humans? Studies will measure microclimatic conditions and survey people experiencing those conditions, and will use the results to develop and/or validate human energy budget models. They might also measure physiological characteristics of people, such as core temperature, heart rate variability, or skin temperatures as subjects experience different microclimates.

 

And the third question is: are there new, innovative instruments that can be used to measure microclimates and/or human thermal comfort in urban environments? One example might be an inexpensive miniature anemometer that could be deployed in a network to measure the wind in urban areas. Another example may be the use of unmanned air vehicles in understanding attributes of the urban environment (such as surface temperatures) as compared to in situ or satellite measurements.

Each paper in this Special Issue will include field measurements of microclimatic conditions and/or surveys, perceptions or physical measures of how people experience those conditions. Of particular importance will be the ability of contributions to move beyond simulations or even single point/case measures and to ground-truth and/or calibrate multiple measurement techniques. Finally, each will explain how their conclusions will help to design or redesign cities to make them safer and more thermally comfortable for residents in the context of a changing climate.

Prof. Dr. Robert Brown
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Atmosphere is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • microclimate modification
  • urban heat islands
  • global climate change
  • urban design
  • microclimate measurement
  • instrumentation
  • human thermal comfort
  • human health

Published Papers (2 papers)

View options order results:
result details:
Displaying articles 1-2
Export citation of selected articles as:

Research

Open AccessArticle Analysis and Comparison of Shading Strategies to Increase Human Thermal Comfort in Urban Areas
Atmosphere 2018, 9(3), 91; doi:10.3390/atmos9030091
Received: 13 November 2017 / Revised: 23 February 2018 / Accepted: 27 February 2018 / Published: 1 March 2018
PDF Full-text (4898 KB) | HTML Full-text | XML Full-text
Abstract
With the expected increase in warmer conditions caused by climate change, heat-related illnesses are becoming a more pressing issue. One way that humans can protect themselves from this is to seek shade. The design of urban spaces can provide individuals with a variety
[...] Read more.
With the expected increase in warmer conditions caused by climate change, heat-related illnesses are becoming a more pressing issue. One way that humans can protect themselves from this is to seek shade. The design of urban spaces can provide individuals with a variety of ways to obtain this shade. The objective of this study was to perform a detailed evaluation and comparison of three shading strategies that could be used in an urban environment: shade from a building, from a tree, and from an umbrella. This was done through using field measurements to calculate the impact of each strategy on a thermal comfort index (Comfort Formula (COMFA)) in two urban settings during sunny days of the summer of 2013 and 2014 in London, Canada. Building shade was found to be the most effective cooling strategy, followed by the tree strategy and the umbrella strategy. As expected, the main determinant of this ranking was a strategy’s ability to block incoming shortwave radiation. Further analysis indicated that changes in the convective loss of energy and in longwave radiation absorption had a smaller impact that caused variations in the strategy effectiveness between settings. This suggests that under non-sunny days, these rankings could change. Full article
(This article belongs to the Special Issue Urban Design and City Microclimates)
Figures

Open AccessArticle The Impact of Tipuana tipu Species on Local Human Thermal Comfort Thresholds in Different Urban Canyon Cases in Mediterranean Climates: Lisbon, Portugal
Atmosphere 2018, 9(1), 12; doi:10.3390/atmos9010012
Received: 11 October 2017 / Revised: 19 December 2017 / Accepted: 4 January 2018 / Published: 7 January 2018
PDF Full-text (7921 KB) | HTML Full-text | XML Full-text
Abstract
Based upon the case of Lisbon, this article examined the in-situ effects of vegetation upon pedestrian thermal comfort levels. Focussing specifically upon the historic quarter that often witnesses the highest Tamb values and Urban Heat Island (UHI) intensities during the summer, the
[...] Read more.
Based upon the case of Lisbon, this article examined the in-situ effects of vegetation upon pedestrian thermal comfort levels. Focussing specifically upon the historic quarter that often witnesses the highest Tamb values and Urban Heat Island (UHI) intensities during the summer, the most common urban canyon cases (UCCs) were modelled, along with one of the most commonly used vegetative semi-deciduous species found in the city, Tipuana tipu. Based upon a reference point (RP) system, the assessments were undertaken through the use of a new version of the SkyHelios model, local obtained Grad values, and the modified physiologically equivalent temperature (mPET) index calculated through the human-biometeorological model RayMan. The study identified the in-situ thermo-physiological influences of Tipuana tipu during different periods of the year: (1) during the summer, which revealed considerable reductions of PET/mPET of up to 15.6 °C/11.6 °C during a very hot day (where daily maximum Tamb surpassed 35 °C); and (2) during the winter, which revealed the risks of oversharing as a result of the species keeping its foliage during the winter with reductions of PET/mPET of up to 2.7 °C/2.6 °C. Furthermore, the study utilised the climate tourism/transfer information scheme (CTIS) to categorise and facilitate the interpretation of the results. Full article
(This article belongs to the Special Issue Urban Design and City Microclimates)
Figures

Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Type of Paper:  Article
Tentative title:
The impact of Tipuana Tipu species on local thermo-physiological thresholds in different urban-aspect-ratios in Mediterranean climates: Lisbon, Portugal
Authors: A. Santos Nouri(1), Fröehlich Dominik(2), Maria Matos Silva(1), A. Matzarakis(2)
Affiliation
(1) Faculdade de Arquitetura, Universidade de Lisboa, CIAUD – Centro de Investigação em Arquitetura, Urbanismo e Design, Rua Sá Nogueira, Pólo Universitário, Alto da Ajuda, 1349-055 Lisbon, Portugal; Telephone: +351 213 615 884; Fax: +351 213 625 138
(2) Research Centre Human Biometeorology, Deutscher Wetterdienst, Stefan-Meier-Str. 4, 79104 Freiburg, Germany; Telephone: +46 (0) 69 8062 9610; Fax: +49 (0) 69 8062 9622
Abstract:
Within the contemporary urban fabric, in light of existing and projected aggravations of the climate system, the importance of bottom-up responses at local scales continue to propagate within the interdisciplinary spheres of urban design and planning. Such endeavours are particularly palpable in climates with hot and dry summers which can present considerable strain upon pedestrian thermo-physiological thresholds. As a result, local scale practices such as thermal sensitive public space design present a valuable means to improve the urban microclimate.
In an effort to fortify the bridge between urban climatology and urban design, this article presents a thermal bioclimatic analysis of ‘in-situ’ effects of vegetation upon pedestrian comfort levels. Focussing upon the specific case of Lisbon, particularly its historic quarter, the most common Urban-Aspect-Ratios (AR) were modelled, along with one of the most commonly used vegetative deciduous species found in the city, Tipuana Tipu.
Each analysis was firstly modelled with a designated layout of trees within the centre/lateral areas of the canyon, and secondly, without the presence of vegetation. These examinations were undertaken during summer and winter to identify the bioclimatic results during dissimilar climatic conditions. In order to carry out these calculations, a new version of the SkyHelios model was used to determine the hourly fluctuations of radiation fluxes (Tmrt), and wind speed (v) oscillations. The model was configured to examine precise, single point Sky-View-Factors (SVF) within each assessed canyon in order to identify the different ‘in-situ’ effects of the Tipuana Tipu species. Furthermore, the modified Physiologically Equivalent Temperature (mPET) index was used to supplement the bioclimatic results through the human-biometeorological model Rayman. With the aim of facilitating the comprehension of the outcomes obtained by the study, the Climate Tourism/Transfer Information Scheme (CTIS) was utilized in order to categorise the obtained values against stipulated Physiological Stress (PS) grades.

Tentative title: Microclimate metrics linked to the use of public spaces: the case of Chillan (“Seat of the Sun”), Chile
Authors: Pamela Smith1 & Cristián Henríquez2
Affiliation:
1Universidad de Chile
2Pontificia Universidad Católica de Chile
Abstract:
Microclimate research is of considerable importance since it is the microclimate which directly affects urban residents. In the configuration of the microclimate, diverse environmental and urban factors are interrelated: vegetation, impermeable surfaces, visible sky ratio (SVF), orientation, proportion of height and width of street construction (H / W), among others. These factors affect the amount of radiation, shade, heat and finally the conditions of thermal comfort. Consequently, they should shape the nature and use of urban public spaces in the city.
The paper presents research carried out in the city of Chillan, a medium size city located on the southern limit of the Chilean Mediterranean domain, at 36º36`s south latitude. Chillan means "Seat of the Sun" in the local indigenous (Mapuche), mapudungún language and provides a good representative example of the experience of warm summers in central and southern Chilean cities. Five public spaces were selected, representing different typologies and relating to different urban background conditions. The distribution of users in these public spaces was observed and counted, and was complemented by photography at different times of the day (12:00, 14:00, 16:00, 18:00 and 20:00), while meteorological parameters were established at different points within the public space. This was undertaken during a heat wave event in the summer of 2016. The variables of impervious surfaces, SVF, H / W, azimuth, shadow, radiation and user use were evaluated. The temperature-humidity index (THI) and actual sensation vote (ASV) were also calculated, and these were contrasted with a survey of perceived thermal comfort.

In all these public spaces in the study, apart from the Estero Las Toscas riverside park, a statistically significant correlation between instrumental thermal comfort and the SVF was established. The pedestrian walkway Arauco revealed the worst comfort conditions, which is explained by its condition as an impervious urban canyon with very little shade. The number of users during the day is related to the particular purpose of the public space and the availability of sun and shade during the day; the recreational parks concentrated the largest number of users in the afternoon, from 18.00 onwards, when the temperature decreased and shade availability increased. In contrast, the number of users in the Arauco walkway and the Plaza de Armas were distributed more homogeneously during the day, since these spaces are associated with the commercial center and access the services. In all cases, around 75% of users use the shade. This city has high density neighborhoods and few vegetated public spaces, consequently the parks have become the only option for facing extreme heat events (residential air cooling systems are still relatively uncommon). Local public environmental management should pay attention to the complex relations between urban climate, public spaces and thermal comfort that directly affect the quality of life of the most vulnerable sectors of the population. This is especially important given the high temperatures and intense heat waves experienced in the city of Chillan during the summer.

Back to Top