Evaluating the influencing factors of urbanization in the Xinjiang Uygur Autonomous Region over the past 27 years based on VIIRS-DNB and DMSP/OLS nightlight imageries

Abstract

The Xinjiang Uygur Autonomous Region is the core economic area of the "Silk Road Economic Belt". The urbanization of this region plays a highly important role in economic and cultural communications between China, Central Asia and Europe. However, the influencing factors of urbanization in this region remain unclear. In this study, we presented a new modified thresholding method to extract the urban built-up areas from two nightlight remote sensing data sources, i.e., the DMSP/OLS and VIIRS/DNB nightlight imageries. Then, geographical detectors and hierarchical partitioning analysis were used to test the influences of anthropogenic and geographic environmental factors on urbanization. Our results showed that the relative error between the actual and the extracted urban built-up areas calculated using our method ranged from-0.30 to 0.27 in two biggest sample cities (Urumqi and Karamay) over the last 27 years. These errors were lower than those calculated by using the traditional method (-0.66 � relative error �-0.11). The expansion of urban built-up areas was greater in the northern regions than the southern regions of Xinjiang, as well as was greater in large cities than small and medium-sized cities. The influence of anthropogenic factors on urbanization has continually decreased over the past 27 years, while the influence of geographical environmental factors has increased. Among all influencing factors, fixed asset investment, topographic position index and per capita possession of water resources have the high contributions on urbanization, accounting for 18.75%, 15.62% and 14.18% of the variance of urbanization, respectively. Here, we provided a new method for studying urbanization by using remote sensing data. Our results are helpful for understand the driving factors of urbanization, and they provide guidance for the sustainable economic development of the Xinjiang Uygur Autonomous Region.

Variability in plant trace element uptake across different crops, soil contamination levels and soil properties in the Xinjiang Uygur Autonomous Region of northwest China

“…These showed that although most of soils were contaminated by trace elements, the pollution status does not reach harmful levels to human health. In fact, compared with other industrial developed areas in China, trace element contents in farmland soils of Xinjiang was low 1 , 7 , 21 , 29 . For example, Zn, Pb, Cr and Cd contents in farmland soils of Beijing were 81.8, 18.5, 75.7 and 0.18 mg·kg −1 , respectively 6 .…”

“…Xinjiang is located in an economically underdeveloped region in the inland northwest, China, the lower industrial and traffic conditions introduced less trace elements into the farmland soils compared with the central and eastern China 3 , 41 . In addition, most of cultivation periods in Xinjiang farmland were shorter than 30 years as major land development along with population migration was carried out after 1980s 29 , 42 . The shorter cultivation periods also resulted in fewer trace elements into farmland soils.…”

“…It has a typical continental climate, with an annual sunshine duration of 2600–3400 h, and the average monthly temperature ranges from − 20 °C to 33 °C. The average annual precipitation of this region is about 170 mm 28 , 29 . Xinjiang is the most important region for producing grain and fruits in China, with about 6.13 × 10 4 km 2 of farmland, accounting for 3.88% of the total area of China’s farmland, and has been planted with over 30 different kinds of crops 28 .…”

Prevalence and risk factors for myopia and high myopia: A cross‐sectional study among Han and Uyghur students in Xinjiang, China

“…However, the prevalence of high myopia for students living in northern Xinjiang was lower than that in southern Xinjiang. Due to the higher level of economic development and education in northern Xinjiang, students living in this region may have greater pressure related to studying and lower levels of outdoor activities than those living in southern Xinjiang, which may result in a higher prevalence of myopia 18,24 …”

Spatio-Temporal Evolution and Driving Mechanism of Urbanization in Small Cities: Case Study from Guangxi

“…The urbanization development level varies greatly between provinces in China, representing the spatial differentiation under the comprehensive effect of many factors such as economy, society, politics, and ecology within the region. However, Li [102] conducted an exploratory study on this using GeoDetector based on the night light data. He analyzed the factors affecting urbanization development in Xinjiang and pointed out that the influence of human factors is weakening, while the influence of geographical environment factors is slowly increasing, with fixed assets investment, topography index, per capita water resources, and other indicators making more contributions.…”