scholarly journals Moderation of Summertime Heat Island Phenomena via Modification of the Urban Form in the Tokyo Metropolitan Area

2014 ◽  
Vol 53 (8) ◽  
pp. 1886-1900 ◽  
Author(s):  
Sachiho A. Adachi ◽  
Fujio Kimura ◽  
Hiroyuki Kusaka ◽  
Michael G. Duda ◽  
Yoshiki Yamagata ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Air Temperature ◽  
Metropolitan Area ◽  
Urban Form ◽  
Surface Air Temperature ◽  
Heat Island ◽  
Compact City ◽  
Tokyo Metropolitan Area ◽  
Island Effect ◽  
Urban Heat

AbstractThis study investigated the moderation of the urban heat island via changes in the urban form in the Tokyo metropolitan area (TMA). Two urban scenarios with the same population as that of the current urban form were used for sensitivity experiments: the dispersed-city and compact-city scenarios. Numerical experiments using the two urban scenarios as well as an experiment using the current urban form were conducted using a regional climate model coupled with a single-layer urban canopy model. The averaged nighttime surface air temperature in TMA increased by ~0.34°C in the dispersed-city scenario and decreased by ~0.1°C in the compact-city scenario. Therefore, the compact-city scenario had significant potential for moderating the mean areal heat-island effect in the entire TMA. Alternatively, in the central part of the TMA, these two urban-form scenarios produced opposite effects on the surface air temperature; that is, severe thermal conditions worsened further in the compact-city scenario because of the denser population. This result suggests that the compact-city form is not always appropriate for moderation of the urban-heat-island effect. This scenario would need to combine with other mitigation strategies, such as the additional greening of urban areas, especially in the central area. This study suggests that it is important to design a plan to adapt to higher urban temperatures, which are likely to ensue from future global warming and the urban heat island, from several perspectives; that is, designs should take into account not only climatological aspects but also impacts on urban inhabitants.

scholarly journals Seasonal and Diurnal Variations in the Relationships between Urban Form and the Urban Heat Island Effect

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5909
Author(s):  
Ze Liang ◽  
Yueyao Wang ◽  
Jiao Huang ◽  
Feili Wei ◽  
Shuyao Wu ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Urban Form ◽  
Urban Heat Island Effect ◽  
Dominant Factor ◽  
Heat Island ◽  
Relative Contribution ◽  
Island Effect ◽  
Urban Geometry ◽  
Seasonal And Diurnal Variations ◽  
Urban Heat

At the city scale, the diurnal and seasonal variations in the relationship between urban form and the urban heat island effect remains poorly understood. To address this deficiency, we conducted an empirical study based on data from 150 cities in the Jing-Jin-Ji region of China from 2000 to 2015. The results derived from multiple regression models show that the effects of urban geometric complexity, elongation, and vegetation on urban heat island effect differ among different seasons and between day and night. The impacts of urban geometric factors and population density in summer, particularly those during the daytime, are significantly larger than those in winter. The influence of urban area and night light intensity is greater in winter than in summer and is greater during the day than at night. The effect of NDVI is greater in summer during the daytime. Urban vegetation is the factor with the greatest relative contribution during the daytime, and urban size is the dominant factor at night. Urban geometry is the secondary dominant factor in summer, although its contribution in winter is small. The relative contribution of urban geometry shows an upward trend at a decadal time scale, while that of vegetation decreases correspondingly. The results provide a valuable reference for top-level sustainable urban planning.

scholarly journals Study on Riparian Shading Envelope for Wetlands to Create Desirable Urban Bioclimates

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1348
Author(s):  
Abu Taib Mohammed Shahjahan ◽  
Khandaker Shabbir Ahmed ◽  
Ismail Bin Said
Keyword(s):  
Urban Heat Island ◽  
Urban Form ◽  
Water Surface ◽  
Inversion Layer ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Rapid Urbanization ◽  
Island Effect ◽  
Urban Heat ◽  
Riparian Shading

Climate change and rapid urbanization are adversely affecting the urban environment by exacerbating the widely reported urban heat island effect in Dhaka, Bangladesh. Two wetland areas with variable riparian shadings in the warm-humid conditions of urban Dhaka were investigated through field campaigns on microclimatic parameters for their cooling potential on the surrounding urban fabric. It was observed that an inversion layer of fully saturated air develops over the water surface of wetland, suppressing evaporation from the wetland water surface layer, which was effectively reducing the heat exchange between the water surface and the air layer above it through its action as an insulating vapor blanket. Due to this effect, the wetland was unable to render as a source of coolth for the surrounding overheated urban area. This effect of the inversion layer was more pronounced in the urban wetland without riparian shading either by the urban form or tree canopy. A multiphysics simulation study conducted on the selected urban wetlands indicates the effect of differential shading pattern on the relation between fetch and inversion layer thickness. This research hypothesizes that the wetland can act as an urban adaption measure against the urban heat island effect by potentially transforming them into an urban cooling island (UCI) towards a favorable urban bioclimate.

scholarly journals Impact of a Detailed Urban Parameterization on Modeling the Urban Heat Island in Beijing Using TEB-RAMS

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Lei Jiang ◽  
Lixin Lu ◽  
Lingmei Jiang ◽  
Yuanyuan Qi ◽  
Aqiang Yang
Keyword(s):  
Land Use ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Metropolitan Area ◽  
Atmospheric Modeling ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Urban Heat ◽  
Four Levels ◽  
Geometric Morphology

The Town Energy Budget (TEB) model coupled with the Regional Atmospheric Modeling System (RAMS) is applied to simulate the Urban Heat Island (UHI) phenomenon in the metropolitan area of Beijing. This new model with complex and detailed surface conditions, called TEB-RAMS, is from Colorado State University (CSU) and the ASTER division of Mission Research Corporation. The spatial-temporal distributions of daily mean 2 m air temperature are simulated by TEB-RAMS during the period from 0000 UTC 01 to 0000 UTC 02 July 2003 over the area of 116°E~116.8°E, 39.6°N~40.2°N in Beijing. The TEB-RAMS was run with four levels of two-way nested grids, and the finest grid is at 1 km grid increment. An Anthropogenic Heat (AH) source is introduced into TEB-RAMS. A comparison between the Land Ecosystem-Atmosphere Feedback model (LEAF) and the detailed TEB parameterization scheme is presented. The daily variations and spatial distribution of the 2 m air temperature agree well with the observations of the Beijing area. The daily mean 2 m air temperature simulated by TEB-RAMS with the AH source is 0.6 K higher than that without specifying TEB and AH over the metropolitan area of Beijing. The presence of urban underlying surfaces plays an important role in the UHI formation. The geometric morphology of an urban area characterized by road, roof, and wall also seems to have notable effects on the UHI intensity. Furthermore, the land-use dataset from USGS is replaced in the model by a new land-use map for the year 2010 which is produced by the Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences (CAS). The simulated regional mean 2 m air temperature is 0.68 K higher from 01 to 02 July 2003 with the new land cover map.

Reduction Effects of Urban Heat Island by Water-Retentive Pavement

2012 ◽  
Vol 724 ◽  
pp. 147-150 ◽  
Author(s):  
Ree Ho Kim ◽  
Jong Bin Park ◽  
Jung Soo Mun ◽  
Jung Hun Lee
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Asphalt Pavement ◽  
Sensible Heat Flux ◽  
Heat Island ◽  
Sensible Heat ◽  
Summer Period ◽  
Island Effect ◽  
Urban Heat

Recently, increasing of impervious surface as concrete or asphalt pavement with urban development brought increasing of air temperature in city. So many researchers have explored ways to reduce the urban heat island effect and water-retentive or water absorbing pavements have been found to be very effective. In this study, to evaluate the reduction effects of urban heat reduction of water-retentive pavement, surface temperature of pavement, air temperature, wind speed and albedo were measured for 3 years (2008~2010, summer period). And the intensity of sensible heat flux was calculated to estimate a influence on air temperature. Experimental results indicated that water-retentive was effective to reduction of air temperature by decreasing of surface temperature of pavement compare to other pavements. This is showed that water-retentive pavement can be contributed to mitigation of urban heat island.

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>

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