Understanding Urban Expansion on the Tibetan Plateau over the Past Half Century Based on Remote Sensing: The Case of Xining City, China

Abstract

The Tibetan Plateau (TP) is an important area that affects global sustainable development. Quantifying spatiotemporal patterns of urbanization is crucial for maintaining the sustainability on the TP. This study took Xining City, the largest city on the TP, as an example to understand the urban expansion in this region in the past 50 years. We combined the high-resolution spy satellite data and China’s long-term urban land dataset (CULD) to quantify the urban expansion of Xining City. The object-oriented random forest classification was performed to extract urban land from spy satellite data in 1969, and the inter-annual correction was used to combine urban land information from 1969 to 2017. We found that the proposed approach can accurately quantify the urban expansion of Xining City over the past half century with an overall accuracy of 91% and a kappa coefficient of 0.86. Such high accuracy benefits from the fine resolution of spy satellite data and the consistency of CULD. We also found that Xining City experienced accelerated and fragmented urban sprawl to higher altitude areas, as a result of socioeconomic development and topographical limitations. The acceleration of urban expansion was more obvious, and the urban landscape fragmentation was more serious at high altitude areas. Such urban expansion encroached on cropland and grassland, and caused increased risks of landslides and other geological disasters. Therefore, Xining City urgently needs to promote the development of compact cities to control urban sprawl at higher altitude areas and provide a reference for improving urban sustainability across the TP. In this study, we analyzed the urban expansion of Xining city from 1969 to 2017, and provided a reliable way to understand the long-term spatiotemporal urbanization based on remote sensing, which has the potential for wide applications. In addition, the extracted urban information can help to improve the urban sustainability of Xining City and the entire TP.

Using CORONA Imagery to Study Land Use and Land Cover Change—A Review of Applications

“…For example, Shalaby et al [55] studied the directions of urban expansion and confirmed that the high spatial resolution of declassified images was sufficient to accurately map initial morphologic features. Pan et al [70] monitored the urban expansion of Xining City in China and confirmed the capability of CORONA and its resolution to quantify urban expansion.…”

Spatiotemporal variation and periodic evolution characteristics of groundwater in the Xining area of China, eastern Qinghai–Tibet Plateau

“…With the implementation of the great development strategy of Qinghai Province in China, Xining, which is the capital city of Qinghai Province, has rapidly risen to be the main grain-producing area and industrial base. The city has concentrated 50% of the population and 35% of the economy in the province (Pan et al 2021). Groundwater has become an important resource that cannot be ignored in promoting the sustainable development of Xining area with the continuous increase in city scale and population (Qinghai et al 2018).…”