Coupling coordination analysis of urbanization and eco-environment in Yanqi Basin based on multi-source remote sensing data

Highlights

• Tiangong-2 WIS was used as a single source of RSEI inputs in 2018.

• Calculated nighttime light index to describe urbanization development.

• Relationship between urbanization and environment was investigated in Yanqin Basin.

Abstract

While multi-source remote sensing technology has the advantage of accurate and objective quantification, an understanding of the coupling and coordination between regional urbanization and ecological environment is the basis for achieving regional sustainable development. This paper builds the Remote Sensing Ecological Index (RSEI) based on Landsat data and Tiangong-2 WIS, using multi-source remote sensing data to comprehensively evaluate the coupling and coordination relationship between urbanization and ecological environment with a coupling coordination degree model in China's typical arid area of Yanqin Basin during 2000–2018. The results show the RSEI index has a certain rationality and superiority in assessing the ecological environment. In 2000–2018, the ecological environment of the Yanqi Basin was optimized, the RSEI index increased by 23.06%, and the overall ecological environment was at a good level (0.6–0.8). At the same time, the urbanization level of each town had been significantly improved in Yanqi Basin. Through the urban center of gravity transfer model, it was found that direction of urban development shifted to the southwest direction by 7.49 km, which is basically consistent with the position of poor ecological environment. Finally the current urbanization and ecological environment coupling relationship in urban areas of Yanqi Basin was found to exhibit a sluggish rate of urbanization with a moderate imbalance between urbanization with ecological environment. Therefore, when making decisions for planning the regional economic development, the concept of ecological relationships should be integrated to effectively protect and achieve a healthy and sustainable development of the region.

Introduction

The rapid urbanization process has become one of the most prominent features of Chinese social development since the 20th century (Li, 2019a). Adding the growing challenge to optimize the ecological environment (Naveh, 1994), how to harmonize the two the relationship has become an important strategic issue (Yao, 2019). The connection between urbanization and ecological environment is a complex interaction and coupling. Urbanization stresses ecological environment and ecological environment restricts urbanization (Wang et al., 2014a, Wang et al., 2014b). Studies on coordinated development of urbanization and eco-environment has attracted extensive attention and research from many scholars. Liu et al. (2019) proposed an analytical framework to illustrate the coupling mechanism of urbanization and ecological environment from a multidimensional perspective, “Coupled Human and Natural Cube (CHNC).” This perspective expanded the analytical dimension of human-earth system coupling research. Fang et al. (2017) based on the complex coupling relationship between urbanization and ecological environment in urban agglomerations and it systematically analyzed the basic theoretical framework of interactive coupling effect between urbanization and ecological environment in mega-urban agglomerations.

With the rapid development of remote sensing technology, remote sensing data is becoming more and more diversified. Among the remote sensing technology, the domestic data satellite Tiangong-2 WIS is the first to achieve three spectrums on a single instrument. Although Tiangong-2 WIS was an effective data source for scholars in scientific research in various fields (Peng et al., 2019, Mu et al., 2019, Cong et al., 2019, Xing and Meng, 2019), its application potential in RSEI (Guan et al., 2018, Hu and Xu, 2019, Li et al., 2019b) has not been explored. In addition, many scholars have confirmed that night-light data, used to extract the urban area (Sritarapipat, 2017) and measure the urbanization level (Kamarajugedda et al., 2017, Xu et al., 2014), has certain advantages in terms of urbanization and urban expansion. Therefore, this paper uses multi-source remote sensing data to quantitatively understand the coupling and coordination relationship between urbanization and eco-environment.

The experimental area studied, Yanqi Basin, is a typical arid area in northwestern China and is situated in the Silk Road Economic Belt. How to protect eco-environment in the process of urbanization, to make full use of the ecological service function, and to achieve coordinated economic and ecological development have become important issues facing the Yanqi Basin. Meanwhile, studies on long-term and comprehensive ecological environment evaluation of Yanqi Basin are extremely scarce, and there are few studies on the coupling degree of urbanization and ecological environment development. In view of these issues, this research uses DMSP/OLS, NPP/VIIRS night light data to establish a nighttime light index that characterizes urbanization, and uses images from Landsat TM in 2000 and Tiangong-2 WIS in 2018 to explore the characteristics of spatial differentiation for ecological quality in environment as indicated in the Remote Sensing Ecological Index (RSEI). In addition, with the help of Coupling Coordination Degree Model (CCDM), the research quantitatively measures the coupling degree of urbanization and ecological environment development in Yanqi Basin from 2000 to 2018, in order to provide scientific and effective decision support for the coordinated development of urbanization and ecological environment in the study area. The study of the environmental coupling relationship also provides a new exploration idea for urbanization and ecology.