Spatiotemporal dynamics of land development intensity and summertime extreme surface urban heat island effect in Greater Shanghai (1990-2017)

Author(s):  
Hao Zhang ◽  
Xiao-yan Dai

<p>Greater Shanghai, one of China’s top megacities, is susceptible to extreme heat events during the summer. This study investigated the spatiotemporal dynamics of land development intensity and its influence on summertime extreme surface urban heat island (SUHI) effect in Greater Shanghai, during 1990 and 2017. Driven by the robust economic development and population growth, the formation of Greater Shanghai has dramatically changed from a traditionally compact city to an explosively urbanizing region in 1990–2017. The results revealed an overall increase in regional LDI of Greater Shanghai in the loss of cropland and water bodies. Simultaneously, the intensified SUHI effect was measured by the increasing relative SUHI intensity (from 1.81℃ in 1990 to 3.16℃ in 2017) and magnitude (from 306.80 km<sup>2</sup> in 1990 to 1570.56 km<sup>2</sup> in 2017). The urban-rural gradient analysis based on centric buffers and the representative transects further revealed the spatiotemporal heterogeneity of LDI and its linkage with the evolutionary pattern of the SUHI effect. As indicated, the areal extent of downtown Shanghai within the 0–15 km buffer increased by 201.70 km<sup>2</sup> in 1990–2017. However, its stably decreasing trends in LDI and associated SUHI effect were observed across the study period. In contrast, the urban periphery and exurban area, which attracted huge investment to develop the infrastructure required for population resettlement and the industrial restructure, experienced a dramatic increase in 1660.57km<sup>2</sup> of newly developed land. Concurrently, the remarkably increases in LDI and associated SUHI effect the urban periphery and exurban area were notable. Finally, focusing on the overall alarming situation of the summertime SUHI effect in Greater Shanghai, policy implications, and practical suggestions towards sustainable land development and UHI mitigation were discussed.   </p>

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1678 ◽  
Author(s):  
Yan-jun Guo ◽  
Jie-jie Han ◽  
Xi Zhao ◽  
Xiao-yan Dai ◽  
Hao Zhang

In this study, 167 land parcels of downtown Shanghai, China, were used to investigate the relationship between parcel-level land use/land cover (LULC) components and associated summertime intra-surface urban heat island (SUHI) effect, and further analyze the potential of mitigating summertime intra-SUHI effect through the optimized LULC components, by integrating a thermal sharpening method combining the Landsat-8 thermal band 10 data and high-resolution Quickbird image, statistical analysis, and nonlinear programming with constraints. The results show the remarkable variations in intra-surface urban heat island (SUHI) effect, which was measured with the mean parcel-level blackbody sensible heat flux in kW per ha (Mean_pc_BBF). Through measuring the relative importance of each specific predictor in terms of their contributions to changing Mean_pc_BBF, the influence of parcel-level LULC components on excess surface flux of heat energy to the atmosphere was estimated using the partial least square regression (PLSR) model. Analysis of the present and optimized parcel-level LULC components and their contribution to the associated Mean_pc_BBF were comparable between land parcels with varying sizes. Furthermore, focusing on the gap between the present and ideally optimized area proportions of parcel-level LULC components towards minimizing the Mean_pc_BBF, the uncertainties arising from the datasets and methods, as well as the implications for sustainable land development and mitigating the UHI effect were discussed.


2020 ◽  
Vol 9 (10) ◽  
pp. 568
Author(s):  
Ying-ying Li ◽  
Yu Liu ◽  
Manjula Ranagalage ◽  
Hao Zhang ◽  
Rui Zhou

In this study, a retrospective analysis of the relationship between the land use/land cover (LULC) change and associated surface urban heat island (SUHI) effect in fast-growing Greater Hefei between 1995 and 2016 was performed. Our results reveal the heterogeneous patterns of LULC change. The concentric buffer-based urban–rural gradient analysis reveals that most of the newly emerging developed land occurred within downtown Hefei. In contrast, in three suburban municipality/county jurisdictions, the overall area change in the non-developed land was much lower, but the net increase in developed land is remarkable. Meanwhile, the spatiotemporal patterns of SUHI are in good agreement with that of the developed land, as evidenced by the notable increase in SUHI intensity (SUHII) levels and SUHI spatial extent (SUHISE) in response to the rapid urban expansion, particularly along transportation corridors. In addition, partial least square regression (PLSR) models indicate that the buffer-based predictors/independent variables are significantly related to the responses (SUHII and SUHISE), explaining approximately 61.3% of the variance in the SUHII and 79.8% of the variance in the SUHISE, respectively. Furthermore, the relative strength of the independent variables in determining the relationship was quantitatively examined. The findings of this study provide clear evidence for decision making for sustainable land development and mitigation of the SUHI effect.


2021 ◽  
pp. 117802
Author(s):  
Ahmed M. El Kenawy ◽  
Juan I. Lopez-Moreno ◽  
Matthew F. McCabe ◽  
Fernando Domínguez-Castro ◽  
Dhais Peña-Angulo ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Angel Hsu ◽  
Glenn Sheriff ◽  
Tirthankar Chakraborty ◽  
Diego Manya

AbstractUrban heat stress poses a major risk to public health. Case studies of individual cities suggest that heat exposure, like other environmental stressors, may be unequally distributed across income groups. There is little evidence, however, as to whether such disparities are pervasive. We combine surface urban heat island (SUHI) data, a proxy for isolating the urban contribution to additional heat exposure in built environments, with census tract-level demographic data to answer these questions for summer days, when heat exposure is likely to be at a maximum. We find that the average person of color lives in a census tract with higher SUHI intensity than non-Hispanic whites in all but 6 of the 175 largest urbanized areas in the continental United States. A similar pattern emerges for people living in households below the poverty line relative to those at more than two times the poverty line.


2018 ◽  
Vol 56 (4) ◽  
pp. 576-604 ◽  
Author(s):  
Qihao Weng ◽  
Mohammad Karimi Firozjaei ◽  
Amir Sedighi ◽  
Majid Kiavarz ◽  
Seyed Kazem Alavipanah

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