Identifying drivers of urban landuse changes in the Wenchuan earthquake- affected area by using night-time light data

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken areas.However,spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation data.This research,leveraging night-time light remote sensing imagery and land cover data,conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone areas.It introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these regions.To validate the proposed methods,the 2008 Wenchuan earthquake-affected area in China was selected as a representative study area.The results indicated that the average Digital Number(DN)values in socio-economically impacted areas showed a trend of rising,falling,and then rising again after the earthquake.DN values in three types of damaged areas including Type Ⅱ,Type Ⅲ,and Type Ⅳ exceeded pre-earthquake levels.The analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake,whereas factors such as slope,elevation,lithology,and faults had a stronger influence on urban land expansion after the earthquake.It can be seen that,in view of the differences in the natural conditions of regions for post-disaster reconstruction,the local government need to actively adjust and adapt to urban spatial planning,so as to leverage the scale effect of large-scale inputs of funds,facilities,human resources and other factors after the disaster,thus enhancing resilience and recovery efficiency in response to disaster impacts.

Spatio-temporal variation and propagation direction of coal fire in Jharia Coalfield,India by satellite-based multi-temporal night-time land surface temperature imaging

In this paper,the spatio-temporal variation and propagation direction of coal fire were studied in the Jharia Coalfield(JCF),India during 2006–2015 through satellite-based night-time land surface temperature(LST)imaging.The LST was retrieved from Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)night-time thermal-infrared data by a robust split-window algorithm based on scene-specific regression coefficients,band-specific hybrid emissivity,and night-time atmospheric transmittance.The LST-profile-based coal fire detection algorithm was formulated through statistical analysis of the LST values along multiple transects across diverse coal fire locations in the JCF in order to compute date-specific threshold temperatures for separating thermally-anomalous and background pixels.This algorithm efficiently separates surface fire,subsurface fire,and thermally-anomalous transitional pixels.During the observation period,it was noticed that the coal fire area increased significantly,which resulted from new coal fire at many places owing to extensive opencast-mining operations.It was observed that the fire propagation occurred primarily along the dip direction of the coal seams.At places,lateral-propagation of limited spatial extent was also observed along the strike direction possibly due to spatial continuity of the coal seams along strike.Moreover,the opencast-mining activities carried out during 2009–2015 and the structurally weak planes facilitated the fire propagation.

Significant Shift of Ambient Night-Time Air Temperature during Rice Growing Season in Major US Rice States

Heat stress studies in rice (Oryza sativa sp.) under extreme weather scenarios generally use constant temperatures to influence the crop responses without relation to actual weather changes. These heat stress studies may have limited implications for future crop yields because elevated temperatures are not based on local temperature fluctuations. This study investigated the night-time air temperature pattern and assessed the status and reliability of available weather station data in four major rice growing states;Arkansas (AR), California (CA), Louisiana (LA) and Texas (TX) using four public weather station databases. Hourly and daily night-time air temperatures from 20:00 to 06:00 were obtained from 1940 to 2018 during the rice growing period. During the 67-year period, a significant increase of 1.12°C and 0.53°C in seasonal night air temperature occurred in CA and AR (P ≤ 0.001) while LA and TX showed minimal to no increase in night air temperature. Across all rice states and years, night air temperature fluctuations ranged between ±0.2°C and ±4°C with the greatest occurred in CA (2.9°C) and AR (4.5°C). Mean night-time air temperature across all states ranged from 22.6°C to 29.5°C with a rate of increase of 0.01°C to 0.02°C per year since 1941. Due to a relatively smaller spatial dataset (from 1941-2018), trend analyses for AR, TX and LA showed modest bias with root mean square errors (RMSE) of 0.5°C to 1.1°C of absolute mean temperature across all locations. Results in this study showed seasonal night-time air temperature change occurred in some major US rice producing states during the last 67-years. This study highlights the need for more weather stations near agricultural farms to reliably derive actual temperature patterns in the rice growing regions.

Night-time Rise in Rat Pineal N-Acetyltransferase due to Carbaryl Administration Is Reduced by Propranolol Treatment

The purpose of the present study was to examine the effects of administration of sublethal doses of carbaryl on nighttime rat pineal melatonin synthesis in the presence and absence of propranolol, a β-adrenergic receptor antagonist. Two groups of adult male albino rats were administered orally N-methyl-l-naphthylcarbamate (carbaryl) (8. 33mg/kg BW daily in corn oil) for six successive days; another two groups received corn oil only.On the last day of carbaryl treatment, half of the animals received an intraperitoneal injection of propranolol (20 mg/kg body weight, one hour before lights off). The other two groups were given a saline injection. Four hours after darkness onset, pineal N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) activities as well as pineal concentrations of 5-hydroxytryptophan (5HTP), serotonin (5HT),5-hydroxyindole acetic acid (5HIAA) and pineal and serum melatonin levels were measured. Nocturnal NAT activity was increased due to carbaryl administration but the pesticide was ineffective in stimulating NAT activity in rats treated with propranolol.Pineal 5HT was decreased due to carbaryl administration but 5HTP and 5HIAA levels were unaffected. Pineal and serum melatonin levels were decreased due to propranolol treatment. The results indicate that carbaryl may influence pineal NAT activity by a mechanism that involves β-adrenergic neural transmission.

Dialect Diversity,Factor Agglomeration and City Size:Empirical Test Based on Satellite Night-Time Light Data

Since the reform and opening up program was initiated in 1978,China’s urbanization has made rapid progress,but urban development remains unbalanced and insufficient.From the perspective of social and cultural diversity,this paper explores the impact of dialect diversity on city size.Dialect diversity impedes the expansion of cities by causing a trust segmentation and impeding cross-regional factor flow and the factor agglomeration effect.Based on the regional dialect diversity indicator and the NPP-VIIRS city night-time light index of 2016,this paper offers an empirical study of the impact of dialect diversity on city size.Econometric results indicate that dialect diversity has a significantly negative impact on city size.On average,an increase of each dialect sub-category leads to a decrease in city size estimated by the night-time light index by 4.55%.Robustness test and causality identification reveal that the estimated results of this paper have a robust causal relationship.Further empirical research indicates that dialect diversity affects the expansion of city size by inhibiting the flow and agglomeration of labor,capital and technology factors.Our research suggests that the development of diverse and inclusive modern cities needs to balance the costs and benefits of cultural diversity and uniformity,break through cultural barriers,remove cultural prejudices,raise the level of social trust,and give play to the complementary effect of cultural diversity.

Electromagnetic response function for the semi-annual variations estimated by the single-station method using the night-time values of the geomagnetic fields

The geomagnetic night-time values were used to estimate the electromagnetic response function Q1 for half-year period. If the spatial structure of the source field can be described by the approximation, one can estimate the Q1 value using the single-station Z/H method. This technique enables us to carry out regional deep gcomagnetic sounding by the method. The data used for analyses are geomagnetic night-time values for about, typically, 26 years from 5 good-quality stations and for several years from 34 stations distributed over the globe. The results indicate that the night-time values yield more reliable response estimates for half-year period compared to the usual estimates obtained from daily means. It implies that the approximation for the night-time fields holds good for the half-year period, but the daily means are not suitable for estimating the response function of the semi-annual variations by using the single-station method. Source field analyses for daily means data and night-time means data have also been carried out in this paper.

Estimation and comparison of night-time OH levels in the UK urban atmosphere using two different analysis methods

Night-time OH levels have been determined for UK urban surface environments using two methods, the decay and steady state approximation methods. Measurement data from the UK National Environmental Technology Centre archive for four urban sites （Bristol, Harwell, London Eltham and Edinburgh） over the time period of 1996 to 2000 have been used in this study. Three reactive alkenes, namely isoprene, 1,3-butadiene and trans-2-pentene were chosen for the calculation of OH levels by the decay method. Hourly measurements of NO, NO〉 03, CO and 20 VOCs were used to determine night-time OH level using the steady state approximation method. Our results showed that the night-time OH levels were in the range of 1 × 10^3-1× 10^6 molecules/cm3 at these four urbap sites in the UK. The application of a t-test of these analyses indicated that except Bristol, there was no significant difference between the OH levels found from the decay and steady state approximation methods. Night-time levels of the OH radical appeared to peak in summer and spring time tracking the night-time 03 levels which also passed through a maximum at this time.

Use of solar PV inverters during night-time for voltage regulation and stability of the utility grid

Photovoltaic(PV)inverters are vital components for future smart grids.Although the popularity of PV-generator installations is high,their effective performance remains low.Certain inverters are designed to operate in volt-ampere reactive(VAR)mode during the night.Yet,this approach is ineffective due to the consumption of active power from the grid(as internal losses)and the regulation necessity of the direct-current(DC)bus.This paper will demonstrate the operation of a PV inverter in reactive power-injection mode when solar energy is unavailable.The primary focus is on the design of the inverter controller with respect to the synchronous rotating frame control method.The proposed novel method enables an inverter to inject the required level of reactive power to regulate the voltage levels of the utility grid within specified limits.In the process,the inverter does not absorb active power from the grid for its internal operation.The presented model has the ability to inject≤2 kVAR of reactive power at zero power factor without absorbing active power from the grid.Simulation and hardware models of the inverter were developed and tested for different reactive loads in which the hardware model represented the real-world application.The reactive power injection of the two models ran at zero power factor and produced the expected outcomes for their corresponding independent reactive loads.Henceforth,it was evident that the proposed method can enhance the efficiency of an inverter and ensure the stability of the utility grid to which it is connected.

Different responses of arbuscular mycorrhizal fungal community to day-time and night-time warming in a semiarid steppe

Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.

不同风格驾驶员眼动特性分析——夜间快速路分流区

为提高驾驶员在夜间快速路分流区换道的安全性,以不同风格的驾驶员为研究对象,分析不同风格驾驶员换道时眼动参数的变化规律。首先在前人研究基础上自编夜间快速路驾驶风格量表,对量表进行信度和Pearson相关系数法的效度检验;然后通过主成分分析法对问卷调查法得出的结果进行分析,得出驾驶风格综合得分量化模型,并使用K均值聚类分析法划分驾驶风格;最后基于眼动仪进行实车试验,获取三种风格驾驶员换道的眼动数据。试验结果表明:谨慎型、一般型、激进型驾驶员对于后视镜平均注视次数占比为48%、27%、25%;对左右两侧的平均累计注视时间占比是31%、25%、19%;平均瞳孔面积占比为56.3%、27.6%、16.1%。试验结果可以为提高驾驶员换道的行车安全性研究提供一定的数据支持。

企业数字化转型与城市经济活力——基于夜间灯光数据的混频回归

以2013—2021年中国沪深A股上市公司为样本,以夜间灯光数据衡量城市经济活力,实证检验企业数字化转型对城市经济活力的影响。研究发现,企业数字化转型对城市经济活力有显著的正向影响,在控制了内生性与稳健性后结论仍然成立,而促进就业、专业化分工与生产效率是其作用渠道,媒体关注度与数字普惠金融是具有正向影响的作用机制。异质性分析发现,高市场集中度的企业数字化转型对城市经济活力的边际影响更强,数字化转型对高城镇化率的城市经济活力的边际影响更强。结合宏观地级市与微观企业数据进行混频回归,丰富了企业数字化转型与城市经济活力的相关研究,在当前“从微观视角研究宏观问题”与“基于宏观背景研究微观问题”的大背景下具有重要的理论与实践意义,有助于政府、企业等相关主体认识到数字化转型的经济后果以及城市经济发展的影响因素,从而更好地实施数字化转型以及促进经济高质量发展。

区域夜间经济发展的理论逻辑与提升路径:以成渝地区双城经济圈为例

本文构建了包括供给需求逻辑、政市关系逻辑、空间布局逻辑、竞合优势逻辑在内的区域夜间经济理论分析框架。据此分析,成渝双城经济圈夜间经济市场需求旺盛、供给亮点纷呈,多地高度重视、政策密集出台,初步形成双城引领、多点开花的空间格局,具有一定的竞合优势,但也存在业态供给亟待丰富创新、政府作用未充分发挥,空间布局缺乏系统规划,竞合优势有待增强等问题。成渝双城经济圈夜间经济能级提升可从四个层面着手:完善市场体系,进一步形成供需适配的市场供给格局;优化营商环境,展现更加积极的政府作为;优化空间布局,推动形成经济圈夜间经济新地理;立足资源禀赋,塑造区域夜间经济竞合新优势。

基于数据库和客观方法对夜间雾化增强图像的感知质量评估

为提高夜间雾化图像的质量,对夜间雾化增强图像的主客观质量评估进行探索.首先构建夜间雾化增强图像质量评估数据库并进行主观分析,然后提出一种基于夜间成像特性的无参考图像质量评估方法.新方法在辉光图像上提取光散射和颜色特征,再在增强图像上提取雾密度和纹理特征.结果表明,新方法性能优于现有其他先进的无参考图像质量评估方法.

美国公共图书馆夜间服务实践调研及启示

文章选取美国排名前25的公共图书馆作为研究对象,对美国公共图书馆夜间服务实践展开网络调研,从服务群体、服务空间和读者活动三方面分析了美国公共图书馆的夜间服务现状及服务特点。基于研究结果阐述了对我国公共图书馆夜间服务高质量发展的启示:创新思维,积极策划服务项目;细分受众,精准把控用户需求;吸引社会力量,加强跨界融合;深挖地域特色文化,打造夜间经济文化IP。

文旅商联动视角下城市夜间经济高质量发展策略——以盐城市为例

文旅商联动是以文塑旅、以旅兴商、以商彰文的过程,而基于文旅商联动促进城市夜间经济高质量发展,可进一步增强城市文旅发展动能、拓展文旅消费空间、推进文旅品牌升级。以盐城市为例,针对其夜间经济发展存在的问题,从文化、旅游、商业与城市深度融合的视角,探索文旅商联动背景下城市夜间经济高质量发展的模式,并提出以文化为主线的重规划、延业态、铸品牌、强营销、优营商等策略。

基于多源遥感数据的鬼城现象分析方法

遥感技术对于城市化进程监测,把握人与自然和谐共生等方面起着至关重要的作用。为进一步推动遥感技术在城市专题研究中的深入应用,本文提出一种基于多源遥感数据的鬼城现象分析方法,将美国军事气象卫星(DMSP)夜间灯光数据和Landsat遥感影像数据进行特征融合与优势互补,在此基础上建立支持向量机(SVM)监督分类中的样本精炼与迭代分类机制,并将获得的城市建成区精细化结果,引入至现有鬼城指数(GCI),以分析“鬼城现象”发生区域的时空分布特征。为了测试该方法,本文选取广西壮族自治区各下辖市作为试验区域,分析2008—2015年“鬼城现象”,从可视化效果和精度两个方面验证本文方法的有效性。实验结果表明,所提出的方法相比传统SVM监督分类方法可以获得更优的鬼城现场时空分布特征。

基于网络评论分析的重庆夜间文旅集聚区提升对策研究

重庆中心城区拥有洪崖洞、磁器口等11处国家级夜间文旅消费集聚区,“夜间旅游”撑起了重庆都市旅游的半壁江山。本文采用网络文本分析的方法,通过归纳游客差评、还原消费情景,发现重庆夜间文旅消费集聚区存在产品同质化、产品低质化和消费快餐化的现象,其未来发展亟须解决名实不副和表里不一的问题。

吕梁山两次夜间暴雨的边界层特征及能量来源与转换

利用常规观测、NCEP/NCAR 1°×1°再分析、FY-2E卫星数据等资料,对分别由β-中尺度持续拉长状对流系统(MβECS)和中尺度对流复合体(MCC)造成的两次吕梁山夜间暴雨过程进行数值模拟和粒子后向轨迹追踪,结果表明:过程1受边界层南风急流和西南气流影响,山西西部低空急流偏西分量和晋中盆地边界层西南气流的增强是对流不稳定能量重建的重要因子。过程2则受边界层南风和东风急流作用,南风急流被显著抬升到对流层中高层,形成含有冰晶层的中高层云系,东风急流则供应低空水汽。两次过程边界层(0.8-1.2 km)粒子携带的水汽均明显超过低层(1.5-3 km),是夜间短时强降水所需水汽的最大贡献者。700 hPa及以上非绝热作用产生扰动有效位能,之后向扰动动能的转化是两次过程中短时强降水发生所需能量的主要来源。

新质生产力视角下长三角夜间经济一体化发展探析

随着新质生产力的发展,夜间经济作为城市经济的重要组成部分,对于推动长三角一体化发展具有重要意义。本文从长三角城市夜间经济的历史嬗变出发,剖析长三角夜间经济的发展现状,提出以新质生产力引领长三角夜间经济的创新发展策略。挖掘城市夜间经济的潜力,可以有效促进区域经济的均衡发展,升级城市产业,提高城市韧性,为长三角地区的高质量发展提供新的动能。

广西北部湾经济区城市群空间扩展研究——基于夜间灯光数据

以2013年、2017年、2021年3期夜间灯光数据作为数据源,借助GIS技术提取规定阈值的灯光分布区域表征城市建成区范围,通过城市空间扩展强度指数、扩展速度、紧凑度、标准差椭圆等方法分析广西北部湾经济区城市群空间扩展特征、扩展格局,并借助灰色关联分析法探究城市群空间格局变化的驱动机制。结果表明:(1)从空间扩展特征看,广西北部湾城市群空间以外延式扩展为主,整体紧凑度偏低,外围轮廓紧凑性较差。(2)从空间扩展格局看,城市群空间逐步形成南宁—北海—钦州—防城港城镇发展轴,崇左、玉林作为重要节点城市同步扩展,初步形成协同发展格局。(3)城市群空间分布格局由“北—南”向“西北—东南”,最后向“东—西”方向逐步演变,标准差椭圆面积缩小,重心整体向西北方向(南宁)移动。(4)从驱动机制看,影响城市群空间扩展的主导因素是以地区生产总值为代表的经济发展。