青藏高原对我国乃至亚洲生态安全具有重要的屏障作用。近年来，青藏高原正在经历的快速城镇化进程对区域脆弱的生态环境造成了威胁。但受青藏高原相关数据匮乏的限制，关于该地区的城镇化及光污染的研究相对缺乏。近期发布的长时间序列和高分辨率夜间灯光数据为揭示青藏高原城镇化进程及光污染影响提供了新的途径。因此，本文的研究目标是基于夜间灯光数据量化青藏高原城镇化水平和光污染的动态变化。主要工作包括以下三个方面。

（1）揭示了青藏2018年城镇化水平空间格局。基于珞珈一号高分辨率夜间灯光数据在流域、地级行政区和县级行政区尺度上计算了表征综合城镇化水平的复合夜间灯光指数。根据计算结果在县级尺度上进行了城镇化水平热点分析，识别出青藏高原重点城镇化地区。最后，探讨了珞珈一号夜间灯光数据在量化青藏高原城镇化水平方面的优势和城镇化水平空间格局的影响因素。

（2）量化了青藏高原1992-2018年城镇化水平动态变化。基于1992-2018年长时间序列夜间灯光数据集逐年计算了青藏高原的城镇化水平，并在流域、省级行政区、地级行政区和县级行政区尺度等多个尺度上分析了青藏高原1992-2018年的城镇化水平变化过程。最后，分析了青藏高原不同时间段城镇化水平的影响因素。

（3）分析了青藏高原1992-2018年光污染范围变化过程。基于长时间序列夜间灯光数据集分析了青藏高原1992-2018年光污染面积的变化，并分别在生态区、国家重点生态功能区、国家级自然保护区和国家公园等多个尺度上量化了光污染的影响。最后，对青藏高原1992-2018年光污染进行了归因分析并分析了光污染对自然生境和野生动物的影响。

本文的主要发现包括以下三个方面。

（1）青藏高原2018年整体城镇化水平偏低，区域内部城镇化水平差异较大，且存在显著的空间集聚特征，主要形成了以西宁市、拉萨市和香格里拉市为核心的三大高城镇化水平热点区。青藏高原城镇化水平空间格局主要受到交通和地形的影响。

（2）青藏高原1992-2018年的总体城镇化水平呈持续增长趋势。青藏高原内部城镇化发展存在显著的空间差异，东南部城镇化发展较快，西北部发较慢。青藏高原城镇化水平发展过程主要受到交通和地形的影响，且交通对城镇化水平的影响随着时间变化逐渐增强。

（3）青藏高原1992-2018年光污染范围呈指数型增长，光污染的影响主要集中在青藏高原的东沿和雅鲁藏布江谷地等局部地区。拉鲁湿地国家级自然保护区持续受到光污染的严重威胁。青藏高原光污染范围增长主要归因于城镇化进程中的道路建设。从光污染对自然生境的影响来看，青藏高原草地受光污染影响最大，占光污染扩展总面积的51.87%。从光污染对野生动物的影响来看，青藏高原1992-2018年受光污染影响的物种数量及其栖息地面积逐渐增加。

       本文的主要创新点分为以下三个方面：（1）数据上，本研究基于高分辨夜间灯光数据和长时间序列夜间灯光数据度量了青藏高原全域的城镇化水平，有效弥补了区域社会经济统计数据的不足。（2）通过在多个时空尺度上量化青藏高原的城镇化水平，识别出了区域高城镇化水平的热点地区和城镇化水平高速发展地区。（3）揭示了青藏高原的光污染现状，弥补了青藏高原相关研究的缺失。

       本研究表明青藏高原城镇化水平呈加速上升趋势，这一过程已经造成了光污染范围呈指数型增长，对区域自然生境和生物多样性构成了严重威胁。为了维持和改善青藏高原的生态安全屏障功能，建议高度重视该地区的城镇化发展及其生态环境效应，应根据资源环境承载力科学合理地确定区域城镇人口规模，严格按照国家和区域规划标准确定城镇土地规模，促进紧凑城镇发展。还需进一步优化交通网络布局和城镇化布局，加强城镇周边生态环境的保护与恢复，通过合理布置光源严格限制光源强度等措施减少光污染，促进区域可持续发展。

The Tibetan Plateau (TP) plays an important role as a barrier for the ecological security of China and even Asia. In recent years, rapid urbanization on the TP has posed a threat to the fragile ecological environment. However, due to the lack of data on the TP, the research on urbanization and light pollution (LP) in this region are relatively lacking. The recently released long time series nighttime light (NTL) data GHNTL (Harmonization of DMSP and VIIRS nighttime light data from 1992-2018 at the global scale) and high-resolution NTL data LJ1-01 (Luojia1-01) provide a new way to reveal the urbanization process and the impact of LP on the TP. Therefore, the objective of this study is to quantify the urbanization level and light pollution on the TP. The contents of the dissertation are as follows.

(1) Revealing the spatial pattern of urbanization level on TP in 2018. Based on LJ1-01 high-resolution NTL data, the compounded night light index (CNLI) reflecting the comprehensive urbanization level was calculated at the at multiple scales (i.e., basin-level, prefecture-level and county-level). Then, according to CNLI, the hotspots of urbanization level were analyzed at the county level to identify the key urbanization areas on the TP. Finally, the advantages of LJ1-01 NTL data to quantify the TP’s urbanization level and the factors affecting the spatial patterns of urbanization level in the region were discussed.

(2) Quantifying the dynamic change of urbanization level on the TP during 1992-2018. Based on the GHNTL long time series data, the urbanization level on the TP from 1992 to 2018 was calculated by CNLI, and the change process of CNLI from 1992 to 2018 was analyzed at several scales, such as basin-level, prefecture-level and county-level. Finally, the influencing factors of urbanization level in different periods on the TP were analyzed.

(3) Analyzing the change process of LP range on the TP during 1992-2018. Based on the GHNTL dataset, the change of LP area over the TP from 1992 to 2018 was analyzed, and the effects of LP was quantified at multiple scales, including ecological zones, national key ecological function zones, national nature reserves and national parks. Finally, the attribution analysis of LP on the TP from 1992 to 2018 was carried out and the effects of LP on natural habitats and wildlife were analyzed.

The results are as follows.

(1) The TP’s urbanization level was relatively low in 2018, with urbanization levels varying greatly across the region with significant spatial agglomeration. The TP had three hotspots with high level of urbanization: Xining, Lhasa and Shangri-La. The spatial pattern of the TP’s urbanization was mainly affected by transportation and topography.

(2) The overall urbanization level on the TP showed a continuous growth trend from 1992 to 2018. The speed of urbanization development on the TP had obvious spatial heterogeneity, with the southeast developing faster and the northwest developing slower. The development process of the urbanization level on the TP was mainly affected by topography and transportation, and the influence of transportation on the urbanization level gradually increased with time.

(3) The extent of LP on the TP increased exponentially from 1992 to 2018, and the impact of LP was mainly concentrated in the eastern edge of the TP and the Brahmaputra Valley. The Lalu Wetland National Nature Reserve was continuously threatened by LP during 1992-2018. The increasing scope of LP on the TP is mainly attributed to the road construction in the process of urbanization. In terms of the impact of LP on natural habitats of the TP, the grassland was the most affected by LP, accounting for 51.87% of the total expanded area of LP. From the perspective of the effects of LP on wildlife, the number of species affected by LP and their habitat area increased gradually from 1992 to 2018 on the TP.

The main innovation points of this paper are as follows: (1) In terms of data, this study measures the urbanization level of the whole region of the TP based on high-resolution NTL data and long time series NTL data, effectively making up for the deficiency of regional social and economic statistical data. (2) By quantifying the urbanization level on the TP at multiple spatiotemporal scales, hot spots with high urbanization level and areas with rapid urbanization development are identified. (3) This paper reveals the present situation of LP in the TP, which makes up for the lack of the related research on the TP.

This study shows that the urbanization level on the Qinghai-Tibet Plateau is accelerating, and this process has caused an exponential increase in the range of light pollution, which poses a serious threat to the regional natural habitat and biodiversity. In order to maintain and improve the function of the TP as an ecological security barrier, it is suggested to attach great importance to the urbanization development and its ecological and environmental effects in this region. The size of urban population should be determined scientifically and reasonably according to the carrying capacity of resources and environment, and the size of urban land should be determined in strict accordance with national and regional planning standards, so as to promote the development of compact cities and towns. The size of urban population should be determined scientifically and rationally according to the carrying capacity of resources and environment. At the same time, the size of urban land should be determined in strict accordance with the national and regional planning standards to promote the development of compact cities and towns. It is also necessary to further optimize the layout of traffic network and urbanization, strengthen the protection and restoration of the ecological environment around cities and towns, and reduce light pollution by rationally placing light sources and strictly limiting the intensity of light sources, so as to promote the sustainable development of the region.