Abstract
Acceleration of urbanization has brought about a series of problems, which include irreversible changes to urban surfaces and continuous increases in land surface temperatures (LSTs). In this context, analysis of the driving factors and spatial heterogeneity of urban LST is of considerable importance for mitigating urban heat island effects and promoting healthy and comfortable urban living environments. This study explored the relationship between the spatial characteristics and driving factors of the LST by using a geographically weighted regression (GWR) model to analyze multisource data from the Xigang District of Dalian City. The results showed that the urban heat island effect in Xigang District is significant, with LSTs generally above 28°C at the end of August, mostly concentrated in the range of 38–40°C. The highest LST values were detected in northern port and harbor areas; the lowest LST values occurred in mountainous forest areas. The global Moran’s I value was 0.994, which was indicative of a very high positive correlation, and local Moran’s I values formed H-H and L-L type clusters concentrated in the northern harbor area and southern mountainous area, respectively. Finally, the GWR model could reflect the spatial heterogeneity of the relationships between LST and its driving factors well. Among these, in terms of natural physical factors, digital elevation model, normalized difference vegetation index, and modified normalized difference water index data were found to be negatively correlated with LSTs in most cases; in the social dimension, the point-of-interest number and building-coverage ratio were generally positively correlated with LSTs.
Highlights
Since the initiation of China’s economic reforms in the 1970s, the country has experienced rapid urbanization and numerous economic leaps, which have been accompanied by a surge in population growth, shortages of resources and space for living and commercial production, large-scale conversion of vegetation cover into impervious surfaces, and reductions in ecological space. e intensification of human activities and the consequential increase in industrial and residential energy consumption have led to the emergence of the urban heat island (UHI) effect and a decline in the quality of the thermal environment [1]
It was evident that the UHI effect was significant in the study area, and the overall land surface temperatures (LSTs) rose gradually from the south to the north, with the highest LST values occurring close to the harbor and the lowest LST values occurring in mountain forest areas. e LST was generally above 28°C; only 0.20% of the LST values fell below 28°C. e proportions were all between 10% and 20% in the range greater than 40 and that at 28–40°C divided into 2degree increments. e majority of LST values fell within the range of 38–40°C and covered an area of 4,86.18 hectares, accounting for 19.10% of the land in Xigang District, and the
Based on the absolute values of the coefficients, it was found that, in terms of natural factors, the normalized difference vegetation index (NDVI) had the strongest effect on LST in the study area, followed by the modified normalized difference water index (MNDWI); the digital elevation model (DEM) had the weakest effect
Summary
Since the initiation of China’s economic reforms in the 1970s, the country has experienced rapid urbanization and numerous economic leaps, which have been accompanied by a surge in population growth, shortages of resources and space for living and commercial production, large-scale conversion of vegetation cover into impervious surfaces, and reductions in ecological space. e intensification of human activities and the consequential increase in industrial and residential energy consumption have led to the emergence of the urban heat island (UHI) effect and a decline in the quality of the thermal environment [1]. Studies on the driving factors of LST generally focus on meteorological characteristics, landscape features, remote sensing spectral information, land use types, and urban morphology [19, 20]. Climatic factors such as wind speed, precipitation, sunshine duration, and climate all have an impact on LST, but these are not the root cause of the UHI effect. Ese studies have proposed that changes in land cover are the primary factor driving changes in LST and have suggested that urban planning can be used to alleviate the UHI effect [27,28,29]. A multisource data analysis was conducted to investigate the impacts of natural physical and social factors on LST. e relationships between different driving factors and the spatial characteristics and heterogeneity of LST in Xigang District, located in the coastal city of Dalian, were analyzed. is study aims to provide an effective tool for urban planning and environmental management in order to alleviate problematic UHI effects
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