Impact of Urban Expansion on Rain Island Effect in Jinan City, North China

Abstract

Rapid urbanization leads to changes in urban micro meteorology, such as the urban heat island effect and rain island effect, which eventually brings about urban waterlogging and other problems. In this study, the data of precipitation, temperatures and impervious surfaces with long series and high resolution are used to study the rain island effect in Jinan City, China. MK-Sen’s slope estimator, Pettitt test and Pearson correlation analysis are used to quantitatively analyze the effects of urban expansion on extreme climate indices. The results show that Jinan City has experienced rapid urbanization since the 1978 economic reform, and the impervious surface areas have increased from 311.68 km2 (3.04%) in 1978 to 2389.50 km2 (23.33%) in 2017. Urban expansion has a significant impact on temperature, with large variations in extreme temperature indices over the intensive construction area relative to the sparse construction area, as well as significant positive correlations with impervious surfaces. Jinan City shows a certain degree of rain island effect, which seems to be spatially correlated with the urban heat island effect. The frequency of short-duration precipitation events significantly increases and the intensity of precipitation events generally increases. The magnitude and frequency of extreme precipitation indices in the intensive construction area significantly increases when compared to that in the sparse construction area, and they have a significant correlation with impervious surfaces. The tendency of Jinan City’s precipitation regime center shifts toward the intensive construction area.

Likelihood of Transformation to Green Infrastructure Using Ensemble Machine Learning Techniques in Jinan, China

“…In the south, with high elevation, and southeastern intensive construction parts of Jinan, rainfall is high (68.54 mm/m), whereas the urban center and northwest of Jinan have comparatively low rainfall (60.43 mm/m). A similar rainfall pattern was observed in other studies [46,47], and it is attributed to the local elevation and urbanization of Jinan. AQI values are high in the urban center compared to the rest of the city (Figure 2).…”

Understanding the Links between LULC Changes and SUHI in Cities: Insights from Two-Decadal Studies (2001–2020)

“…Additionally, because of UHIs, urban rain islands can form, resulting in greater precipitation during the flood season in flood-prone places and leading to waterlogging at a regional scale [20]. In Jinan City, for instance, it has been proven that the URI effect is spatially correlated with that of the UHI, resulting in an increased frequency and severity of short-duration precipitation episodes [21]. During the rainy season, areas with intensive construction receive more rain.…”

Dynamic monitoring and analysis of factors influencing ecological environment quality in northern Anhui, China, based on the Google Earth Engine

“…However, these indices only evaluate one aspect of the environment and often reflect one-sided ecological conditions. For example, the normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) are used to reflect the growth status of plants in many study areas 18 – 20 , as well as the distribution of urbanized land 21 , 22 , while the land surface temperature (LST) has been used to study the effects of the urban thermal environment 23 – 25 . To cope with these challenges, Xu proposed a remote sensing ecological index (RSEI) that integrates the four indicators of greenness, dryness, humidity, and heat and extracts a single variable that can represent multiple variables without artificially setting the weight 26 .…”