scholarly journals Retrofitting solutions for a campus building to mitigate urban heat island in a hot humid climate

2021 ◽  
Vol 2042 (1) ◽  
pp. 012062
Author(s):  
Vajreshwari Patil ◽  
Maite Bizcarguenaga ◽  
Katherine Lieberknecht ◽  
Juliana Felkner
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Ambient Air ◽  
Cooling Effect ◽  
Heat Island ◽  
Humid Climate ◽  
Temperature Reduction ◽  
Urban Heat ◽  
Hot Humid Climate

Abstract In this study we examine the summer cooling effects of trees and green facades on reducing urban heat island effects. Using ENVI-met model simulations, we investigate the influence of added greenery on the surface and ambient air temperature and its role on air fluctuations in the hot humid climate of Austin, TX, at pedestrian height. Under the specific conditions considered in this model, the results show the combination of trees and green facades has a greater cooling effect. Added greenery to the building mostly impacts the building's surface temperature during the hottest hours of the day, registering a maximum surface temperature reduction of 20.33°C. Simulations also show a maximum overall potential air temperature reduction of 0.54°C, and a maximum potential air temperature cooling effect near the building of 0.91°C. Future research should be conducted to address this study's limitations. Nevertheless, these findings can provide architects, designers, planners, and policymakers with a better understanding of the many benefits trees and green facades have, and provide them with the necessary tools to implement new solutions across sectors and scales to reduce the impacts urban areas have on the environment and provide a better living for all.

scholarly journals Cooling Effect of Different Land Cover Types: A Case Study in Xi’an and Xianyang, China

2021 ◽  
Vol 13 (3) ◽  
pp. 1099
Author(s):  
Yuhe Ma ◽  
Mudan Zhao ◽  
Jianbo Li ◽  
Jian Wang ◽  
Lifa Hu
Keyword(s):  
Land Cover ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Cooling Effect ◽  
Heat Island ◽  
Land Cover Types ◽  
Island Effect ◽  
Urban Heat

One of the climate problems caused by rapid urbanization is the urban heat island effect, which directly threatens the human survival environment. In general, some land cover types, such as vegetation and water, are generally considered to alleviate the urban heat island effect, because these landscapes can significantly reduce the temperature of the surrounding environment, known as the cold island effect. However, this phenomenon varies over different geographical locations, climates, and other environmental factors. Therefore, how to reasonably configure these land cover types with the cooling effect from the perspective of urban planning is a great challenge, and it is necessary to find the regularity of this effect by designing experiments in more cities. In this study, land cover (LC) classification and land surface temperature (LST) of Xi’an, Xianyang and its surrounding areas were obtained by Landsat-8 images. The land types with cooling effect were identified and their ideal configuration was discussed through grid analysis, distance analysis, landscape index analysis and correlation analysis. The results showed that an obvious cooling effect occurred in both woodland and water at different spatial scales. The cooling distance of woodland is 330 m, much more than that of water (180 m), but the land surface temperature around water decreased more than that around the woodland within the cooling distance. In the specific urban planning cases, woodland can be designed with a complex shape, high tree planting density and large planting areas while water bodies with large patch areas to cool the densely built-up areas. The results of this study have utility for researchers, urban planners and urban designers seeking how to efficiently and reasonably rearrange landscapes with cooling effect and in urban land design, which is of great significance to improve urban heat island problem.

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.

scholarly journals Evaluating the Effectiveness of Mitigation Options on Heat Stress for Sydney, Australia

2018 ◽  
Vol 57 (2) ◽  
pp. 209-220 ◽  
Author(s):  
Shaoxiu Ma ◽  
Andy Pitman ◽  
Jiachuan Yang ◽  
Claire Carouge ◽  
Jason P. Evans ◽  
...  
Keyword(s):  
Heat Stress ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Ambient Air ◽  
Mitigation Strategies ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Ambient Air Temperature ◽  
Populations At Risk ◽  
Urban Heat

AbstractGlobal warming, in combination with the urban heat island effect, is increasing the temperature in cities. These changes increase the risk of heat stress for millions of city dwellers. Given the large populations at risk, a variety of mitigation strategies have been proposed to cool cities—including strategies that aim to reduce the ambient air temperature. This paper uses common heat stress metrics to evaluate the performance of several urban heat island mitigation strategies. The authors found that cooling via reducing net radiation or increasing irrigated vegetation in parks or on green roofs did reduce ambient air temperature. However, a lower air temperature did not necessarily lead to less heat stress because both temperature and humidity are important factors in determining human thermal comfort. Specifically, cooling the surface via evaporation through the use of irrigation increased humidity—consequently, the net impact on human comfort of any cooling was negligible. This result suggests that urban cooling strategies must aim to reduce ambient air temperatures without increasing humidity, for example via the deployment of solar panels over roofs or via cool roofs utilizing high albedos, in order to combat human heat stress in the urban environment.

scholarly journals STUDI PULAU PANAS PERKOTAAN DAN KAITANNYA DENGAN PERUBAHAN PARAMETER IKLIM SUHU DAN CURAH HUJAN MENGGUNAKAN CITRA SATELIT LANDSAT TM STUDI KASUS DKI JAKARTA DAN SEKITARNYA

2012 ◽  
Vol 13 (1) ◽  
pp. 19 ◽  
Author(s):  
Halda Aditya Belgaman ◽  
Sri Lestari ◽  
Hilda Lestiana
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Urban Areas ◽  
Satellite Image ◽  
Heat Island ◽  
Surrounding Area ◽  
Urban Heat ◽  
Climate Parameter ◽  
Landsat Satellite

Pulau panas adalah suatu fenomena dimana suhu udara di suatu daerah lebih tinggi daripada suhu udara terbuka di sekitarnya. Daerah urban (perkotaan) sering mempunyai suhu lebih tinggi 1-6 derajat Celsius dibandingkan daerah sekitarnya (daerah pinggiran/ rural). Fenomena inilah yang dikenal sebagai ”Pulau Panas perkotaan” atau ”Urban Heat Island” (UHI). Penelitian ini bertujuan untuk mengetahui pengaruh fenomena pulau panas perkotaan terhadap parameter iklim terutama suhu dan curah hujan di daerahJakarta dan sekitarnya. Data yang digunakan pada tugas akhir ini adalah data curah hujan dan temperatur udara harian pada 5 stasiun pengamatan iklim, periode Januari 1991 – Desember 2001 sebagai data permukaan. Citra satelit Landsat 7 ETM+ path / row 122/064 akuisisi tanggal 15/07/2001 band 5,4,2 digunakan untuk menganalisis tutupan lahan dan band 6 digunakan untuk distribusi temperatur permukaan. Hasil menunjukkan nilai temperatur permukaan Kota Jakarta dan sekitarnya berada antara 15.07˚C hingga 33.28˚C. Lokasi pulau panas perkotaan terdapat di daerah Jakarta pusat dan Jakarta utara, dengan perbedaan temperatur sebesar 3˚C dibandingkan dengan daerah sekitarnya.Tutupan lahan yang terdapat di lokasi tersebut merupakan lahan terbangun yang terdiri dari bangunan perumahan, perkantoran, dan jalan raya. Perhitungan nilai korelasi Spearman antara data temperatur udara dari lima stasiun pengamatan dengan nilai piksel temperatur permukaan memperlihatkan adanya korelasi positif antara dua variabel tersebut yang ditunjukkan oleh indeks korelasi sebesar 0.6.Dengan persamaan regresi diperoleh citra temperatur permukaan di seluruh daerah pengamatan yang hasilnya menggambarkan bahwa lokasi pulau panas perkotaan sangat berpengaruh terhadap distribusi temperatur udara di atasnya.Heat island was a phenomenon where the temperature of air in one region higher than the temperature of the open air around it. Urban areas often had the temperature higher 1-6 Celsius when compared the area of surrounding area (the area of outskirts/rural). This phenomenon that was known as ”Pulau Panas Perkotaan” or ”Urban Heat Island” (UHI). This Research aimed to knowing influence of the heat islands of urban areas to climate parameter especially the temperature and the rainfall in the Jakarta and surrounding area. Data used in this research was rainfall data and daily air temperaturefrom 5 climate observation stations, within time period from January 1991 to December 2001 as the surface data. The Landsat satellite image 7 ETM+ path/row 122/064 acquisition date 15/07/2001, band 5, 4, 2 was used to analyze the cover of land and the band 6 was used for the distribution of surface temperature was based on the pixels value.Results showed the value of surface temperature in Jakarta and surrounding area was between 15.07˚C through to 33.28˚C. Location of heat island were in the centre Jakarta and north Jakarta, with the difference of the temperature as big as 3˚C with thesurrounding area. The land cover in this location were the housing building, the office complex, and the highway. Calculation of Spearman correlation value between the air temperature and surface temperature showed the existence of the positive correlation between two variables that it was demonstrated by the correlation index 0.6. From the regression equation we get the interpolated air temperature in Jakarta area.

scholarly journals The Trend Inconsistency between Land Surface Temperature and Near Surface Air Temperature in Assessing Urban Heat Island Effects

2020 ◽  
Vol 12 (8) ◽  
pp. 1271 ◽  
Author(s):  
Tao Sun ◽  
Ranhao Sun ◽  
Liding Chen
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Temporal Trends ◽  
Surface Air Temperature ◽  
Heat Island ◽  
Near Surface ◽  
Urban Heat

The credible urban heat island (UHI) trend is crucial for assessing the effects of urbanization on climate. Land surface temperature (LST) and near surface air temperature (SAT) have been extensively used to obtain UHI intensities. However, the consistency of UHI trend between LST and SAT has rarely been discussed. This paper quantified the temporal stability and trend consistency between Moderate Resolution Imaging Spectroradiometer (MODIS) LST and in situ SAT. Linear regressions, temporal trends and coefficients of variations (CV) were analyzed based on the yearly mean, maximum and minimum temperatures. The findings in this study were: (1) Good statistical consistency (R2 = 0.794) and the same trends were found only in mean temperature between LST-UHI and SAT-UHI. There are 54% of cities that showed opposite temporal trends between LST-UHI and SAT-UHI for minimum temperature while the percentage was 38% for maximum temperature. (2) The high discrepancies in temporal trends were observed for all cities, which indicated the inadequacy of LST for obtaining reliable UHI trends especially when using the maximum and minimum temperatures. (3) The larger uncertainties of LST-UHI were probably due to high inter-annual fluctuations of LST. The topography was the predominant factor that affected the UHI variations for both LST and SAT. Therefore, we suggested that SAT should be combined with LST to ensure the dependable temporal series of UHI. This paper provided references for understanding the UHI effects on various surfaces.

Urban Heat Island Intensity in Chiang Mai City Using Mobile Surveying Approach

2014 ◽  
Vol 931-932 ◽  
pp. 605-613
Author(s):  
Pisut Sangnum ◽  
Niti Kammuang-Lue ◽  
P. Sakulchangsatjatai ◽  
P. Terdtoon
Keyword(s):  
Population Density ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Ambient Air ◽  
Urban Heat Island Intensity ◽  
Traffic Density ◽  
Heat Island ◽  
Chiang Mai ◽  
Ambient Air Temperature ◽  
Urban Heat

This research aims to evaluate on Urban Heat Island Intensity in Chiang Mai city and to study effects of population density, building density and traffic density on ambient air temperature. The ambient air temperature was measured by thermocouples at a constant altitude of 2 m above the road. The surveyed routes were divided to urban routes and rural routes. The Urban Heat Island Intensity (UHII) was calculated from an average ambient air temperature difference between urban and rural areas. Experimental investigations were carried out in 2 periods, which were a day time (12.30-02.30 pm) and a night time (10.00 pm-00.00 am) on Monday, Wednesday, and Sunday in summer time (March-May, 2013). The results show that the UHII in Chiang Mai city in a day time is +1.1 °C and in a night time is +1.3 °C. Moreover, the population density, building density and traffic density were found to have significant effects on ambient air temperature, especially the population density and building density have direct effect on ambient air temperature. However, the traffic density has direct effect on ambient air temperature only in a day time.

scholarly journals RELATIONSHIPS BETWEEN LAND USE/LAND COVER AND LAND SURFACE TEMPERATURE IN TABRIZ FROM 2000 TO 2017

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 1041-1044
Author(s):  
A. Tahooni ◽  
A. A. Kakroodi
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Impervious Surface ◽  
Bare Soil ◽  
Heat Island ◽  
Land Use Land Cover ◽  
Urban Heat

Abstract. Urban Heat Island (UHI) refers to the development of higher urban temperatures of an urban area compared to the temperatures of surrounding suburban and rural areas. Highly reflective urban materials to solar radiation present a significantly lower surface temperature and contribute to reducing the sensible heat released in the atmosphere and mitigating the urban heat island. Many studies of the UHI effect have been based on Land Surface Temperature (LST) measurements from remote sensors. The remotely sensed UHI has been termed the surface urban heat island (SUHI) effect. This study examines Tabriz city land use/land cover (LULC) and LST changes using Landsat satellite images between 2000 and 2017. Maximum likelihood classification and single channel methods were used for LULC classification and LST retrieval respectively. Results show that impervious surface has increased 13.79% and bare soil area has decreased 16.2%. The results also revealed bare soil class LST after a constant trend become increasing. It also revealed the impervious surface LST has a decreasing trend between 2000 and 2011 and has a little change. Using materials that have low absorption and high reflectance decrease the effect of heat island considerably.

scholarly journals A High-Resolution Monitoring Approach of Canopy Urban Heat Island using Random Forest Model and Multi-platform Observations

2021 ◽  
Author(s):  
Shihan Chen ◽  
Yuanjian Yang ◽  
Fei Deng ◽  
Yanhao Zhang ◽  
Duanyang Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Random Forest ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Model Framework ◽  
Rapid Urbanization ◽  
Urban Heat ◽  
The City

Abstract. Due to rapid urbanization and intense human activities, the urban heat island (UHI) effect has become a more concerning climatic and environmental issue. A high spatial resolution canopy UHI monitoring method would help better understand the urban thermal environment. Taking the city of Nanjing in China as an example, we propose a method for evaluating canopy UHI intensity (CUHII) at high resolution by using remote sensing data and machine learning with a Random Forest (RF) model. Firstly, the observed environmental parameters [e.g., surface albedo, land use/land cover, impervious surface, and anthropogenic heat flux (AHF)] around densely distributed meteorological stations were extracted from satellite images. These parameters were used as independent variables to construct an RF model for predicting air temperature. The correlation coefficient between the predicted and observed air temperature in the test set was 0.73, and the average root-mean-square error was 0.72 °C. Then, the spatial distribution of CUHII was evaluated at 30-m resolution based on the output of the RF model. We found that wind speed was negatively correlated with CUHII, and wind direction was strongly correlated with the CUHII offset direction. The CUHII reduced with the distance to the city center, due to the de-creasing proportion of built-up areas and reduced AHF in the same direction. The RF model framework developed for real-time monitoring and assessment of high-resolution CUHII provides scientific support for studying the changes and causes of CUHII, as well as the spatial pattern of urban thermal environments.

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