Analyzing parcel-level relationships between Luojia 1-01 nighttime light intensity and artificial surface features across Shanghai,China: A comparison with NPP-VIIRS data

Nighttime light (NTL) remote sensing data have been widely used to derive socioeconomic indices at national and regional scales. However, few studies analyzed the factors that may explain NTL variations at a fine scale due to the limited resolution of existing NTL data. As a new generation NTL satellite, Luojia 1-01 provides NTL data with a finer spatial resolution of ∼130 m and can be used to assess the relationship between NTL intensity and artificial surface features on an unprecedented scale. This study represents the first efforts to assess the relationship between Luojia 1-01 NTL intensity and artificial surface features at the parcel level in comparison to the Suomi National Polar-orbiting Partnership-Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) NTL data. Points-of-interest (POIs) and land-use/land-cover (LULC) data were used in random forest (RF) regression models for both Luojia 1-01 and NPP-VIIRS to analyze the feature contribution of artificial surface features to NTL intensity. The results show that luminosity variations in Luojia 1-01 data for different land-use types were more significant than those in NPP-VIIRS data because of the finer spatial resolution and wider measurement range. Seventeen variables extracted from POI and LULC data explained the Luojia 1-01 and NPP-VIIRS NTL intensity, with a good out-of-bag score of 0.62 and 0.76, respectively. Moreover, Luojia 1-01 data had fewer “blooming” phenomena than NPP-VIIRS data, especially for cropland, water body, and rural area. Luojia 1-01 is more suitable for estimating socioeconomic activities and can attain more comprehensive information on human activities, since the feature contribution of POI variables is more sensitive to NTL intensity in the Luojia 1-01 RF regression model than that in the NPP-VIIRS RF regression model.     

1999—2020年长江经济带(江苏段)生态环境变化监测及人类活动驱动分析

协调区域城镇化与生态环境保护之间的关系,是推动我国长江经济带可持续发展的核心问题之一.针对现有研究中,生态环境变化与人类活动驱动之间的响应关系缺少时空对应的数据支持、影响过程不明的问题,本文充分利用多源卫星遥感技术在处理和提取时空信息上的优势,以长江经济带江苏段沿江县区为例,利用1999—2000年、2009—2010...     

中国DMSP-OLS长时间序列夜间灯光遥感数据饱和校正研究

利用夜间灯光数据进行长时期社会经济问题研究时,需要对数据饱和校正,从而得到可信可靠的研究结果。针对不变区域法在长时间序列夜间灯光数据饱和校正时假设不变区域数据不随时间变化以及未区分数据饱和部分和未饱和部分的不足,本文提出首先对数据年际校正,再以NDVI数据为辅助进行饱和校正的方法。年际校正时准确定义了基准区域和基准年份,饱和校正过程中分别对不同城市聚类分区构建校正模型。研究发现,夜间灯光数据包括未饱和部分和饱和部分,饱和阈值为30;两部分数据亮度值与相应无饱和数据亮度值的函数关系不同,未饱和部分符合线性模型,饱和部分符合指数模型;区分不同城市聚类分区进行饱和校正十分必要,尤其是大范围区域数据饱和校正;以NDVI足迹数据为辅助,运用指数模型对饱和部分数据校正后,数据值域增大,空间异质性增强,与区域GDP拟合程度改善,很好地消除了由于卫星传感器设置特性产生的饱和效应,得到更好反映人类社会经济活动强度和空间分布特征的长时间序列饱和校正夜间灯光数据。文中得到的年际校正和饱和校正模型可以不做参数调整而直接运用,校正方法适用性较强。     

Remote sensing and social sensing for socioeconomic systems: A comparison study between nighttime lights and location-based social media at the 500 m spatial resolution

With the advent of “social sensing” in the Big Data era, location-based social media (LBSM) data are increasingly used to explore anthropogenic activities and their impacts on the environment. This study converts a typical kind of LBSM data, geo-tagged tweets, into raster images at the 500 m spatial resolution and compares them with the new generation nighttime lights (NTL) image products, the Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) monthly image composites. The results show that the monthly tweet images are significantly correlated with the VIIRS-DNB images at the pixel level. The tweet images have nearly the same ability on estimating electric power consumption and better performance on assessing personal incomes and population than the NTL images. Tweeted areas (i.e. the pixels with at least one posted tweet) are closer to satellite-derived built-up/urban areas than lit areas in NTL imagery, making tweet images an alternative to delimit extents of human activities. Moreover, the monthly tweet images do not show apparent seasonal changes, and the values of tweet images are more stable across different months than VIIRS-DNB monthly image composites. This study explores the potential of LBSM data at relatively fine spatiotemporal resolutions to estimate or map socioeconomic factors as an alternative to NTL images in the United States.     

Modeling the spatiotemporal dynamics of electric power consumption in Mainland China using saturation-corrected DMSP/OLS nighttime stable light data

Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption (EPC) is crucial for the effective utilization of electric power in China. The Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) nighttime stable light (NSL) data have good potential for estimating EPC effectively at large scales. However, saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation. We developed a new method to correct the saturated lighted pixels, using the SPOT VEGETATION (SPOT/VGT) 10-day synthesis product (S10) normalized difference vegetation index (NDVI) data and then modeled the spatiotemporal dynamics of EPC in Mainland China from 2000 to 2008. The results demonstrated the reliability of our approach with an average R value of 0.93 (P<0.001) and an average relative error of ?28.92%. EPC in Mainland China showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008. EPC in Mainland China also showed clear regional variation. Northern coastal China and eastern coastal China consumed 37.61% of the total EPC in Mainland China, with only 25.96% of the population and 6.11% of the area.     

Global mapping of urban built-up areas of year 2014 by combining MODIS multispectral data with VIIRS nighttime light data

An improved methodology for the extraction and mapping of urban built-up areas at a global scale is presented in this study. The Moderate Resolution Imaging Spectroradiometer (MODIS)-based multispectral data were combined with the Visible Infrared Imager Radiometer Suite (VIIRS)-based nighttime light (NTL) data for robust extraction and mapping of urban built-up areas. The MODIS-based newly proposed Urban Built-up Index (UBI) was combined with NTL data, and the resulting Enhanced UBI (EUBI) was used as a single master image for global extraction of urban built-up areas. Due to higher variation of the EUBI with respect to geographical regions, a region-specific threshold approach was used to extract urban built-up areas. This research provided 500-m-resolution global urban built-up map of year 2014. The resulted map was compared with three existing moderate-resolution global maps and one high-resolution map in the United States. The comparative analysis demonstrated finer details of the urban built-up cover estimated by the resultant map.     

Electricity consumption patterns within cities: application of a data-driven settlement characterization method

ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.     

基于DMSP-OLS和珞珈一号夜光遥感影像的粤港澳大湾区城市空间格局演变

夜光遥感影像数据可有效反映城市空间格局变化。本文基于1992—2012年的DSMP-OLS夜光遥感影像和2018年的珞珈一号遥感影像,利用分层阈值法提取粤港澳大湾区内各城市建成区;通过计算平均灯光强度、平均灯光增长速率、城市建成区面积、城市建成区增长速率、城市重心、城市重心偏移距离等一系列指数,揭示区内各城市的空间格局演变过程。研究结果表明:①1992—2018年,粤港澳大湾区的城市规模大幅增长,沿珠江口两侧形成了以澳门、广州、深圳和香港为核心的倒“U”形城市群,并呈辐射状向周边扩张。②以珠江口为界,粤港澳大湾区东部各个城市的发展水平整体高于西部各个城市,广州、深圳、香港等核心城市发展水平明显高于江门、肇庆、惠州等外围城市。③1992—2018年,粤港澳大湾区建成区的增长速率由小变大,最后逐渐趋于稳定,2002—2007年是城市扩张最迅猛时期。④1992—2018年,粤港澳大湾区的各城市重心迁移方式表现为3种类型:持续向区域中心迁移;持续向相邻城市邻接区迁移;持续向海洋方向迁移。大部分城市的重心迁移方向呈“震荡”特征。     

Assessment with satellite data of the urban heat island effects in Asian mega cities

This study focuses on using remote sensing for comparative assessment of surface urban heat island (UHI) in 18 mega cities in both temperate and tropical climate regions. Least-clouded day- and night-scenes of TERRA/MODIS acquired between 2001 and 2003 were selected to generate land-surface temperature (LST) maps. Spatial patterns of UHIs for each city were examined over its diurnal cycle and seasonal variations. A Gaussian approximation was applied in order to quantify spatial extents and magnitude of individual UHIs for inter-city comparison. To reveal relationship of UHIs with surface properties, UHI patterns were analyzed in association with urban vegetation covers and surface energy fluxes derived from high-resolution Landsat ETM+ data. This study provides a generalized picture on the UHI phenomena in the Asian region and the findings can be used to guide further study integrating satellite high-resolution thermal data with land-surface modeling and meso-scale climatic modeling in order to understand impacts of urbanization on local climate in Asia.     

武汉城镇化与热岛效应的定量研究

针对目前城市化进程加快对城市增温和城市热岛效应的促进作用尚不十分明确的问题,提出基于遥感技术的城镇化与热岛效应数量关系的构建。结果表明,1987-2013年间,武汉市中城镇化水平(50%~80%ISA)面积增加了14.5倍,高城镇化水平(80%~100%ISA)面积增加了2.8倍,城镇化范围沿着武汉市主城区和主要干道不断扩张;不透水面值与地表温度表现出明显正相关,不透水面值平均增加1%,可使地表温度增温0.06℃~0.19℃,城镇化水平对武汉城市热岛效应作用明显。研究结果为探讨城市热岛效应的缓解对策提供了基础,对合理规划和管理城市化意义重大。     

Spatialization of electricity consumption of China using saturation-corrected DMSP-OLS data

Electricity is one of the most important components in energy consumption, which is directly related to economic growth, CO₂ emission and global warming. This research intends to estimate spatial distribution of electricity consumption in China, the largest developing country, and analyze the temporal and spatial change of electricity consumption during 1994–2009. The spatial modeling is based on the total electricity consumption of each province and DMSP (Defense Meteorological Satellite Program) – Operational Line-scan System (OLS) data, the latter provides the nighttime light information corresponding to electricity consumption, GDP and population. A simple method was developed to correct the saturated pixels with digital number of 63 in non-radiance-corrected DMSP-OLS data, using cities’ GDP data. The spatial electricity consumption maps were produced during 1994–2009, and they were validated by the electricity consumption records of 101 cities. Finally, the spatial–temporal changes of electricity consumption were analyzed. The results of this research can help to understand the regional discrepancy, especially rural and urban areas of China, of electricity consumption and economic development.     

深圳市土地覆盖格局空间变化研究

以深圳市为研究对象,利用遥感影像和空间分析方法,研究了深圳市土地覆盖格局的梯度变化特征:各个土地覆盖类型的斑块形状指数沿梯度区呈先增大后减少的趋势,在城区内其值较低,城乡结合区其值较高;城区的斑块密度与边缘密度较小,聚集度较高,越靠近城乡结合处,斑块的密度越大.分析土地覆盖类型斑块平均形状指数和斑块聚集度的变化,可看出人为活动的干扰由市中心向郊区呈增强的趋势.     

Spatial microsimulation modeling for residential energy demand of England in an uncertain future

High quality infrastructure is crucial to economic success and the sustainability of society. Infrastructures for services, such as transport, energy, and water supply, also have long lead times, and therefore require effective long-term planning. In this paper, we report on work undertaken as part of the UK Infrastructure Transitions Research Consortium to construct long-term models of demographic change which can help to inform infrastructure planning for transport, energy, and water as well as IT and waste. A set of demographic microsimulation models (MSM), which are spatially disaggregate to the geography of UK Local Authorities, provides a high level of detail for understanding the drivers of changing patterns of demand. However, although robust forecasting models are required to support projections based on the notion of ‘predict-and-provide,’ the potential for behavioral adaptation is also an important consideration in this context. In this paper, we therefore establish a framework for linkage of a MSM of household composition, with behavior relating to the consumption of energy. We will investigate variations in household energy consumption within and between different household groups. An appropriate range of household types will be defined through the application of decision trees to consumption data from a detailed survey produced by the UK Department of Energy and Climate Change. From this, analysis conclusions will be drawn about the impact of changing demographics at both household and individual level, and about the potential effect of behavioral adjustments for different household groups.     

基于多时相遥感的鄂尔多斯市不透水面变化分析

不透水面作为城市发展和生态环境的重要评估因子,在保障生态环境健康和城市可持续发展中具有重大意义。本文以鄂尔多斯为研究区,通过融合多时相Landsat和夜间灯光数据,提取1990—2019年的不透水面信息,并利用重心分析法、标准差椭圆理论和景观指数理论分析时空演变规律。研究结果表明:①1990—2019年鄂尔多斯市不透水面经历了快速扩张;东北部不透水面覆盖度高于西南部;不透水面的扩张模式总体上表现为“向外扩张-向内加密”。②东北部扩张速度减缓,西南部扩张速度增快。③不透水面扩张的方向性减弱;不透水面扩张的方向有由“东北-西南”向“东-西”转变的趋势。④斑块数量及边缘斑块破碎度增加,城市与郊区的连通性增强,城市有向周边郊区扩张的趋势。本文研究对于进一步了解城市生态环境健康与城市可持续发展的相关关系具有一定的参考价值。     

Urbanization effects on vegetation cover in major African cities during 2001-2017

Urbanization effects on vegetation cover (VC) have been analyzed in many regions. However, little attention has been paid to Africa, which has undergone rapid urbanization in recent decades. In this study, MODIS land cover and enhanced vegetation index (EVI) data were used to examine urbanization effects on VC in 59 large cities in Africa during 2001–2017. The ΔEVI (urban EVI minus rural EVI) was used to represent urbanization effects on VC. Major findings include: (1) for 59 cities averaged, annual ΔEVI averaged from 2015 to 2017 was -0.116. Negative annual ΔEVI (i.e. urban EVI lower than rural) were observed in 56 of 59 cities. (2) For 59 cities averaged, urban area increased 17.9% from 2001 (262.8 km²) to 2016 (309.8 km²). (3) Annual ΔEVI decreased significantly (p<0.05) in 44 of 59 cities for the period 2001–2017, and annual average area of urbanization effects on VC increased significantly in 40 of 59 cities. For 59 cities averaged, the percentage of urban area with significant decreasing trends of annual ΔEVI was 60.0%. Spatially, cities near the Gulf of Guinea showed more significant decreasing ΔEVI than cities in other regions. In addition, the trends and spatial distributions of urbanization effects on VC differed little by seasons. These results suggested that urbanization and its effects on VC in Africa should arouse more attentions.     

Spatiotemporal analysis of vegetation variability and its relationship with climate change in China

This paper investigated spatiotemporal dynamic pattern of vegetation, climate factor, and their complex relationships from seasonal to inter-annual scale in China during the period 1982–1998 through wavelet transform method based on GIMMS data-sets. First, most vegetation canopies demonstrated obvious seasonality, increasing with latitudinal gradient. Second, obvious dynamic trends were observed in both vegetation and climate change, especially the positive trends. Over 70% areas were observed with obvious vegetation greening up, with vegetation degradation principally in the Pearl River Delta, Yangtze River Delta, and desert. Overall warming trend was observed across the whole country (>98% area), stronger in Northern China. Although over half of area (58.2%) obtained increasing rainfall trend, around a quarter of area (24.5%), especially the Central China and most northern portion of China, exhibited significantly negative rainfall trend. Third, significantly positive normalized difference vegetation index (NDVI)–climate relationship was generally observed on the de-noised time series in most vegetated regions, corresponding to their synchronous stronger seasonal pattern. Finally, at inter-annual level, the NDVI–climate relationship differed with climatic regions and their long-term trends: in humid regions, positive coefficients were observed except in regions with vegetation degradation; in arid, semiarid, and semihumid regions, positive relationships would be examined on the condition that increasing rainfall could compensate the increasing water requirement along with increasing temperature. This study provided valuable insights into the long-term vegetation–climate relationship in China with consideration of their spatiotemporal variability and overall trend in the global change process.     

福建省植被NPP时空格局及其驱动力分析

以福建省为研究区,以中等分辨率MODIS NDVI遥感数据、气象数据及其他辅助数据为数据源,基于植被净初级生产力(net primary productivity,NPP)光能利用率估算模型——CASA,定量研究了该区域历史序列(2001—2012年)NPP时空变化格局,探索其主要影响因素。结果表明:2001—2012年该区域NPP总体呈现下降趋势,2003年和2005年为历年变化下降率最大的两年;该区域NPP时空分布特征明显,在空间上表现为由南向北递减的空间分布格局,且沿海经济发达区域NPP普遍较低;时间上表现为春秋两季具有相同的空间分布,夏季具有最高的NPP,占全年NPP的56%,冬季平均NPP在120gC·m~(-2)·a~(-1)以下;降水和温度与NPP的线性相关性较小,且线性相关性随空间位置的不同而有所差异;福建省NPP对气候因子的响应随空间位置的变化而变化,在不同的区域,其主要的胁迫因子不同,NPP总体受到辐射量的驱动因素要比其他胁迫因子强。     

Delineation and classification of rural–urban fringe using geospatial technique and onboard DMSP–Operational Linescan System

This study aims to analyse the processes and patterns of peri-urbanization using diurnal earth observation data-sets from onboard DMSP–Operational Linescan System. In this study, multiple correlation, simple and conditional linear regression are used to find out the degree of relationship and spatial behavioural pattern of the factors responsible for the urbanization. All the factors are standardized using the Analytical Hierarchy Process (AHP) coupled fuzzy membership functions. AHP is used to derive the weighting of the factors to produce the urbanity index. In total three functional zones – urban, rural and urban shadow are generated based on factor standardization and spatial contiguity index. Urban fringe is sharing ≥ 60% of Urbanity Index followed by rural fringe (39.50–60% of urbanity index) and urban shadow <39.50% of urbanity index. Shape index indicates that the city is going through unplanned development following cross to star shape growth.     

城市热岛空间格局及其变化的图形信息特征分析

热岛效应是城市化进程中产生的特有环境问题。基于Landsat TM/ETM+（1989、2001、2007、2013年）遥感影像完成哈尔滨地面亮温定量反演、标准化和等级划分等处理,并分析城市热岛空间分布特征和时空演变规律。基于地学信息图谱理论,定量分析24 a间热岛效应图谱信息变化特征,探究城市热岛格局的时空演变进程和形成机制,揭示城市化进程与热岛效应之间的响应关系。结果表明,随着哈尔滨城市化进程加速,4级热岛效应呈递增趋势,面积比例分别为4.36%、5.69%、6.29%和7.12%,主要分布在道外区和铁路沿线地带;植被和水体区域的地面温度较低,其边缘温度更低;反复变化型面积最大,后期变化型面积最小,面积比例分别为33.30%和7.30%。地学信息图谱分析可为城市热岛效应随城市化演变趋势提供准确、丰富的信息,对全面分析城市热岛的形成和发展具有重要的意义。     

TM/ETM+/LDCM Images for Studying Land Surface Temperature (LST) Interplay with Impervious Surfaces Changes over Time Within the Douala Metropolis,Cameroon

Douala, the most important metropolis of Cameroon, is a sub-Saharan wet coastal environment of which the anarchic urbanization is a socio-economic and environmental problem, significantly influencing the local climate. In this study, three Landsat images from 1986 (TM), 2007 (ETM+) and 2016 (LDCM), were utilized to investigate the effect of this urbanization on the increasing land surface temperature (LST) between these dates. Thus, the urban indices (UI), determined from the Landsat Visible and NIR channels were used to identify impervious areas (Urban Fabric and bare soil) of urban area. It has been shown from the UI images that, impervious areas have been increased from 1986 to 2016. The LST images derived have a continual expansion of zones and points of heat throughout these dates. The correlation analysis of LST and UI, at the pixel-scale, indicated the positive relationship between these parameters, which could show a real impact of urbanization on the increasing temperature in the area. These correlations are fairly low in 1986 (maximum R-square value is about 0.35) and in 2007 (maximum R-square value is about 0.44. In 2016, a high positive correlation (maximum R-square value is about 0.77) confirm that, the impervious areas strengthen the temperature and the Urban Heat Island effect in Douala urban zone. Overall, the earth observation images and the geographic information system techniques were effective approaches for aiming at environment monitoring and analyzing urban growth patterns and evaluating their impacts on urban climates.