Quantifying urbanization levels on the Tibetan Plateau with high-resolution nighttime light data

The Tibetan Plateau(TP)is undergoing rapid urbanization.To improve urban sustainability and construct eco-logical security barriers,it is essential to quantify the spatial patterns of urbanization level on the TP,but the existing studies on the topic have been limited by the lack of socioeconomic data.This study aims to quantify the urbanization level on the TP in 2018 with Luojia1-01(LJ1-01)high-resolution nighttime light(NTL)data.Specifically,the compounded night light index is used to quantify spatial patterns of urbanization level at mul-tiple scales.The results showed that the TP had a low overall urbanization level with a large internal difference.The urbanization level in the northeast,southeast and south of the TP was relatively high,forming three hotspots centered in Xining City,Lhasa City and Shangri-La City,while the urbanization level in the central and western regions was relatively low.The analysis of influencing factors,based on the random forest model,showed that transportation and topography were the main factors affecting the TP’s spatial patterns of urbanization level.The comparison analysis with socioeconomic statistics and traditional NTL data showed that LJ1-01 NTL data can be used to more effectively quantify the urbanization level since it is more advantageous for reflecting the spatial extent of urban land and describing the spatial structure of socioeconomic activities within urban areas.These advantages are attributed to the high spatial resolution of the data,appropriate imaging time and unaf-fected by saturation phenomena.Thus,the proposed LJ1-01 NTL-based urbanization level measurement method has the potential for wide applications around the world,especially in less-developed regions lacking statistical data.Using this method,we refined the measurement of the TP’s urbanization level in 2018 for multiple scales including the region,basin,prefecture and county levels,which provides basic information for the further urban sustainability research on the TP.

From preference to landscape sustainability:a bibliometric review of landscape preference research from 1968 to 2019

Landscape preference(LP)studies highlight one of the most important issues of human-environment relationship,and their related publications have increased rapidly over the last two decades.However,there is no systematic review with a holistic understanding of this field.here we applied a bibliometric approach to examine the evolution of LP research and identify its status and future prospects.We obtained 7,637 LP research publications from Web of Science core collection from 1968 to 2019 and analyzed the characteristics of publication outputs as well as performances in various countries and institutions.Besides,content keywords analysis was conducted to discover the drivers,focus,motivation,and trends of LP research.We found that 1)publications,subject categories,and active journals increased rapidly since the 2000s;2)the USA,England,and Australia are the leading countries in LP research,while China is starting to have some influence;3)LP research is most closely linked to ecological and environmental studies,being developed by objective drivers,i.e.,interactions with landscape change,and subjective motivations;and 4)LP research is advancing the landscape sustainability science,integrating natural and social science together through ecosystem services.By comprehensively reviewing the evolution and prospect of LP research,we provide insights for further research in this field.

Chinese Built-up Land in Floodplains Moving Closer to Freshwaters

Human proximity to water and its dynamics are important to understanding the socio-hydrological dilemma between using floodplains and avoiding flood risk.However,previous studies have not distinguished between the water proximity of built-up land in floodplains(BLF)and the water proximity of built-up land outside floodplains(BLOF).This article provides a new and spatiotemporal perspective of the BLF water proximities for understanding the changing flood risk in China.The results show that China’s BLFs had an average water proximity of 5.41 km in 2014.Most of the BLFs(62%,25.889103 km2)were located within 3 km of waterbodies.From 1990 to 2014,China’s BLFs increased rapidly by 81%from23.069103 km2 to 41.749103 km2,of which a large portion(57%)was concentrated in water surroundings(≤km),shortening the distance between BLFs and waterbodies by 169 m.The BLF growth concentrated in water surroundings even in areas where BLFs have an overall increasing distance from waterbodies.Both the increases in the BLFs and their proximity to waterbodies can increase flood exposure and exacerbate flood risk.The scientific community and policymakers should pay attention not only to the volume of BLF growth,but also its spatial relationship with waterbodies.