Analysis of heat wave features and urban heat island effect under climate change

2020 ◽  
Author(s):  
Ye Tian ◽  
Klaus Fraedrich ◽  
Feng Ma
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Extreme Events ◽  
Climate Models ◽  
Heat Waves ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Island Effect ◽  
Urban Heat

<p>Extreme events such as heat waves occurred in urban have a large influence on human life due to population density. For urban areas, the urban heat island effect could further exacerbate the heat stress of heat waves. Meanwhile, the global climate change over the last few decades has changed the pattern and spatial distribution of local-scale extreme events. Commonly used climate models could capture broad-scale spatial changes in climate phenomena, but representing extreme events on local scales requires data with finer resolution. Here we present a deep learning based downscaling method to capture the localized near surface temperature features from climate models in the Coupled Model Intercomparison Project 6 (CMIP6) framework. The downscaling is based on super-resolution image processing methods which could build relationships between coarse and fine resolution. This downscaling framework will then be applied to future emission scenarios over the period 2030 to 2100. The influence of future climate change on the occurrence of heat waves in urban and its interaction with urban heat island effect for ten most densely populated cities in China are studied. The heat waves are defined based on air temperature and the urban heat island is measured by the urban-rural difference in 2m-height air temperature. Improvements in data resolution enhanced the utility for assessing the surface air temperature record. Comparisons of urban heat waves from multiple climate models suggest that near-surface temperature trends and heat island effects are greatly affected by global warming. High resolution climate data offer the potential for further assessment of worldwide urban warming influences.</p>

Can climate adaptation solutions fix the urban heat island? An assessment of the thermal conditions during heat waves in Vienna impacted by climate change and urban development scenarios for the mid-21st-century

2020 ◽  
Author(s):  
Paul Hamer ◽  
Heidelinde Trimmel ◽  
Philipp Weihs ◽  
Stéphanie Faroux ◽  
Herbert Formayer ◽  
...  
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Heat Wave ◽  
Air Temperature ◽  
Urban Areas ◽  
Climate Adaptation ◽  
Heat Waves ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Urban Heat

<p>Climate change threatens to exacerbate existing problems in urban areas arising from the urban heat island. Furthermore, expansion of urban areas and rising urban populations will increase the numbers of people exposed to hazards in these vulnerable areas. We therefore urgently need study of these environments and in-depth assessment of potential climate adaptation measures.</p><p>We present a study of heat wave impacts across the urban landscape of Vienna for different future development pathways and for both present and future climatic conditions. We have created two different urban development scenarios that estimate potential urban sprawl and optimized development concerning future building construction in Vienna and have built a digital representation of each within the Town Energy Balance (TEB) urban surface model. In addition, we select two heat waves of similar frequency of return representative for present and future conditions (following the RCP8.5 scenario) of the mid 21<sup>st</sup> century and use the Weather Research and Forecasting Model (WRF) to simulate both heat wave events. We then couple the two representations urban Vienna in TEB with the WRF heat wave simulations to estimate air temperature, surface temperatures and human thermal comfort during the heat waves. We then identify and apply a set of adaptation measures within TEB to try to identify potential solutions to the problems associated with the urban heat island.</p><p>Global and regional climate change under the RCP8.5 scenario causes the future heat wave to be more severe showing an increase of daily maximum air temperature in Vienna by 7 K; the daily minimum air temperature will increase by 2-4 K. We find that changes caused by urban growth or densification mainly affect air temperature and human thermal comfort local to where new urbanisation takes place and does not occur significantly in the existing central districts.</p><p>Exploring adaptation solutions, we find that a combination of near zero-energy standards and increasing albedo of building materials on the city scale accomplishes a maximum reduction of urban canyon temperature of 0.9 K for the minima and 0.2 K for the maxima. Local scale changes of different adaption measures show that insulation of buildings alone increases the maximum wall surface temperatures by more than 10 K or the maximum mean radiant temperature (MRT) in the canyon by 5 K.  Therefore, additional adaptation to reduce MRT within the urban canyons like tree shade are needed to complement the proposed measures.</p><p>This study concludes that the rising air temperatures expected by climate change puts an unprecedented heat burden on Viennese inhabitants, which cannot easily be reduced by measures concerning buildings within the city itself. Additionally, measures such as planting trees to provide shade, regional water sensitive planning and global reduction of greenhouse gas emissions in order to reduce temperature extremes are required.</p><p>We are now actively seeking to apply this set of tools to a wider set of cases in order to try to find effective solutions to projected warming resulting from climate change in urban areas.</p>

100 Years of Climate Change: A Night-Time Audio Walk

Leonardo ◽  
2011 ◽  
Vol 44 (1) ◽  
pp. 68-69
Author(s):  
Drew Hemment ◽  
Yara El-Sherbini ◽  
Carlo Buontempo ◽  
John Tweddle
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Urban Climate ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Night Time ◽  
Island Effect ◽  
Urban Heat ◽  
Local Impacts ◽  
Short Walk

100 Years of Climate Change is an artwork inspired by the insight that we might experience 100 years of climate change by taking a short walk of 100 metres. Investigation of the local impacts of the Urban Heat Island effect culminated in a night-time audio walk to open up awareness of the urban climate.

scholarly journals Does historic construction suffer or benefit from the urban heat island effect in Ghent and global warming across Europe?

2019 ◽  
Vol 46 (11) ◽  
pp. 1032-1042 ◽  
Author(s):  
Isabeau Vandemeulebroucke ◽  
Klaas Calle ◽  
Steven Caluwaerts ◽  
Tim De Kock ◽  
Nathan Van Den Bossche
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Urban Heat Island Effect ◽  
City Centre ◽  
Heat Island ◽  
Freeze Thaw ◽  
Island Effect ◽  
Northern Latitudes ◽  
Urban Heat ◽  
The City

Renovating historical buildings with valuable facades often includes interior retrofitting, perhaps entailing an increased durability risk. However, the urban heat island effect and the ongoing climate change might mitigate the severity of frost action and mould growth. By means of heat air moisture (HAM) simulations in Delphin, this study evaluates interior retrofitting of solid masonry on three scales. First, the sensitivity to the intra-urban climatic differences of the freeze–thaw cycles in Ghent is analysed. Secondly, the spatial pattern of freeze–thaw behaviour across Europe is assessed. Finally, the influence of observed climate change on the European freeze–thaw pattern is investigated. A decreasing number of critical freeze–thaw cycles is found when comparing the rural area with the city centre of Ghent. Furthermore, due to climate change, the number of freeze–thaw cycles across Europe generally decreases as well, except at northern latitudes exposed to increased wind-driven rain loads.

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