Distinct Influences of Urban Villages on Urban Heat Islands: A Case Study in the Pearl River Delta, China

Abstract

Widely scattered urban villages (UVs) and increasingly serious urban heat islands (UHIs) are common urban problems in highly urbanized regions, especially in the developing countries. However, the influences of UVs on UHIs remain little understood. In this study, different methodologies are performed to retrieve land surface temperature (LST) from thermal bands and the nearest object-oriented method with spectral, texture, shape metrics using ZY-3 high-resolution satellite imagery, and road network data are used to extract UVs and other land-use types in the Guangzhou–Foshan (GF) core areas of Pearl River Delta (PRD). Moreover, the relationship between LST and land-use types is then analyzed on the multiple scales. The results show that five land-use types (vegetation, normal construction land (NCL), UVs, water, and unused land) extracted by the object-oriented method were qualified for subsequent analysis because of satisfactory overall accuracy (0.887) and the Kappa coefficient (0.863). In the GF core areas presenting the most outstanding UHI effect across the PRD region, about 60.5% of the total area is covered by the impervious surfaces, including NCL (50.4%) and UVs (10.1%). The average LST of UVs was 1.89–2.97 °C lower than that of NCL. According to the average contribution index of thermal effect and the Pearson’s correlation coefficients, UVs present a relatively lower contribution to UHI and a weaker warming effect than NCL, but possess a higher contribution to UHI and a stronger warming effect than other land-use types, resulting in some slightly lower LST-valleys in the UVs adjacent to the NCL and distinct LST-peaks of UVs close to vegetation and water on the surface temperature profile lines. This work increases our understanding of the relationship between increasingly serious UHIs and widely distributed UVs, and would be valuable for local authorities to monitor and improve urban environment in metropolitan regions.

Urban villages as transfer stations for dengue fever epidemic: A case study in the Guangzhou, China

“…In a word, the present extraction accuracy can meet the requirements for further analysis. Detailed information about the retrieval of land-use types can be found in an earlier study [24].…”

“…A lack of overall planning and scientific management of UVs has resulted in a large number of irregular buildings scattered in urban areas, with subsequent poor sanitation, lack of infrastructure and serious environmental pollution [21, 22]. These characteristics of UVs, combined with their perennial humidity and relatively low temperature [23, 24], provides an ideal living environment for the breeding of Aedes albopictus , the sole vector of dengue transmission in Guangzhou. However, the current quantitative relationship between UVs and DF epidemics has received very little attention.…”

The Deviation between the Field Measurement and ENVI-met Outputs in Winter- A Cases Study in a Traditional Dwelling Settlement of China

“…It is true that the ENVI-met can be a reliable tool for predicting the air temperature in hot summer [24][25][26][27][28][29][30]. Considering the interest of this study, the predication in cold winter is still very necessary, especially in the latest software platform.…”

Neglected Urban Villages in Current Vector Surveillance System: Evidences in Guangzhou, China

“…albopictus, featuring slightly lower land surface temperature than NCL areas, which was suitable for Ae. albopictus breeding and having a large floating population and a high density of low-cost accommodation [39]. Third, the maximum flight distance of Ae.…”