The effect of land use planning (2006–2020) on construction land growth in China

Land use planning is a comprehensive instrument for managing non-agricultural land growth in China, and the evaluation of its implementation effect on growth control is of great significance for policy improvement. However, little empirical research has been done to estimate its implementation effect at the city level of the whole country. This study aims to evaluate the effectiveness of land use planning on construction land growth control at the city level in China. Taking 288 cities as the research object, an econometrics model was built to estimate the effect based on socioeconomic and land use data from 2006 to 2012. The results show that the implementation of land use planning has a certain effect in curbing the expansion of construction land, and that the incremental amount of construction land decreases by 107,449 ha due to the planning implementation. In addition, the implementation effect of land use planning presented significant differences among cities, which shows that there is a weaker effect in megacities and large cities than in medium-small cities. Besides, the implementation effect of land use planning also shows temporal differences: its effect is better in 2007–2009 than in 2010–2012. Furthermore, considering both planned goals and effectiveness, planning implementation is judged to be able to slow but not fully prevent the rapid expansion of construction land. Finally, to further improve efficiency and success, this research puts forward some suggestions such as improving the existing quota system, delineation of the urban development boundary and integrating the special plan system.     

The investigation of properties of electron transport in AlGaN/GaN heterostructures

Magnetoresistance of two-dimensional electron gas in the triangular quantum well created as a result of polarization effects at AlGaN/GaN heterointerface has been studied. Magnetotransport measurements clearly revealed Shubnikov-de Haas oscillations in both two terminal transmission line model samples and three terminal high electron mobility transistor structures at low temperature. Low value of quantum scattering time was obtained for different structures. Region with negative magnetoresistance was observed at low magnetic field.     

Guangzhou

With a history of more than 2100 years, Guangzhou, despite its glory past, has now experienced a decline in the role as a central city in the region due to the rapid growth of cities in the Pearl River Delta. Guangzhou is also suffering from problems caused by congested inner city and unregulated growth of new development areas. The city’s structure has gradually changed from a compact model to leapfrogged urban sprawl. These problems are aggravated by limited land resource under its direct jurisdiction and the pressure to reposition itself in a regional development context that is more competitive than ever before. To face the challenges ahead, Guangzhou has expanded its administrative boundary recently and has taken a number of planning and infrastructure development initiatives to enhance its competitiveness in the future.     

Spatial Distribution of Atmospheric Boundary Layer SO2 in Monsoon Region of China based on OMI/OMPS

The monsoon has obvious influences on biological migration, cultural formation, regional architectural structure, and changes in meteorological elements, but lacks study on the impact of the PBL SO₂. In this paper, we make a study on the temporal and spatial distribution characteristics of the PBL SO₂ in Chinese monsoon region by OMI SO₂ from 2005 to 2014 and OMPS NMSO₂ from 2015 to 2017 in order to identify the influence of monsoon on PBL SO₂ in different regions. Four typical cities were selected to do correlation analysis, and HYSPLIT model was run for backward Trajectory simulation by the corresponding date of daily SO₂ columns are greater than the monthly average in January 2012. The results show that china’s PBL SO₂ is spatial heterogeneity; the change of winter and summer monsoon has obvious influence on the PBL SO₂, temperature and pressure are the main factors affecting the concentration of the PBL SO₂. Regional meteorological conditions have large differences in the dry and wet deposition, photochemical reaction and wind diffusion of SO₂; the winter airflow has a greater impact on the increase of the SO₂, internal discharge in the Sichuan Basin, and southwesterly airflow which comes from the Indian Peninsula and the Bay of Bengal has a significant effect on the increase of SO₂ in Chongqing. Yinchuan is affected by the airflow that comes from the Mongolian Plateau or the Tianshan Mountains; Tianjin and Hangzhou are influenced by airflow come from the North China Plain or the Mongolian Plateau.     

The hierarchy of cities in Internet news media and Internet search: Some insights from China

Applying a novel approach based on the vast city-related information in the Internet, this paper probes into the hierarchy of Chinese cities in virtual space by developing a theoretical analysis framework and analyzing the amount of coverage that a city received in the Internet news media (attribute data) and the distance decay effect in Internet search of a city from other cities (relational data). We used the Baidu Media Index and Search Index of city names in China to capture the amount of yearly city exposure in the Internet news media and how often cities have been searched by Internet users in other cities, respectively. Our results show that the extent of Internet news coverage of a city is highly related to that city's real-world characteristics including its administrative status, economic development, tourist resources, and its distance to/from Beijing. Besides, the distance decay coefficients in the Internet search of cities vary widely and the effects are mediated by the city's amount of coverage in the Internet news media, job opportunities and transport functions. There is evidence to suggest that the hierarchy of cities in virtual space has been heavily shaped by specific social, economic, and political factors.     

Idealizing Brazilian cities: Their master plans from 1960 through 2015

This article discusses the Brazilian city through the perspective of its written idealisation, both in the format of Master Plans and their resulting legislations. The analysis reflects ideas expressed by local society, legislators and urban planners, recognizing that a myriad of intermediate agents play specific roles and confirming the main features in the way the city is understood. The discussion is based on a selection of 26 Master Plans for the ten largest cities in Brazil between 1960 and 2015. This timeframe reveals distinct phases constructed with different priorities and ways of idealising Brazilian cities and, by extension, those on the Latin American continent. The study suggests an increase in legal complexity, expansion of municipal responsibilities and the maintenance of physical-territorial priorities as the main instruments of urban management. Many of the themes observed in the selected Plans also indicate an overlapping symbiosis between the comprehensive Master Plans themselves and the laws for urban land use they encompass. The impressive expansion of responsibilities adopted by local governments, as well as holistic aspirations, has made achievement of the ideal city more difficult than ever. Efforts to democratise urban land access and appropriate use have gained importance in the composition of the ideal city; however, the access of the low-income population to proper land and basic infrastructure and services still relies on controversial and structural changes. Analysis of the desired city – here considered as the idealised city – during the selected period reveals a strategic absence of emergent features and points to both optimistic and pessimistic approaches.     

基于HJ-1CCD影像的呼伦贝尔草原区MODIS/FPAR产品验证与分析

植物吸收性光合有效辐射分量(FPAR)是描述植被结构以及与之相关的物质与能量交换过程的基本生理变量。选取内蒙古呼伦贝尔谢尔塔拉镇针茅和羊草草甸草原为研究对象,利用2013年5次地面实测实验,通过HJ-I CCD高分辨率卫星影像建立统计模型,从而实现对该研究区MODIS/FPAR产品的验证与分析。1km HJ/FPAR"真值"与MODIS/FPAR产品值的变化趋势基本一致,并且二者具有较好的一致性,R2达到了0.6762。MODIS/FPAR产品能够很好地反映呼伦贝尔草甸草原在整个生长季的长势及物候变化,这是因为研究区样地尺度上HJ/FPAR和MODIS/FPAR产品值不但变化趋势相一致,而且相关系数R2高达0.9148。无论在同尺度(1km)还是整个研究区尺度,MODIS/FPAR均有一定的高估现象。研究结果对了解和进一步使用该地区的MODIS/FPAR产品具有重要的指导意义。     

HJ-1B热红外通道星上定标精度检验与敏感性分析

利用内蒙古达里湖定标与真实性检验场地的星地同步观测数据,通过辐射传输模型计算大气廓线高度、大气气体含量、水表参数和观测角度等因子的不确定性对HJ-1B热红外通道（B08）星上定标精度的影响,分析星上定标对各观测因子误差的敏感性。结果表明,回归星上黑体常温点293K和高温点328K得到的HJ-1B B08星上定标,在285.5K点的定标精度在0.84K以内,从定标角度来说,满足陆表温度反演1.0K以内对定标精度的要求,而较难满足水表温度反演0.3K以内对定标精度的要求;星上定标更适用于洁净、干燥大气和高温、高比辐射率地物目标的定标。