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。

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。

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。

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。

我国城市夜间文旅消费集聚区网络口碑空间格局及影响因素分析

夜间文旅消费集聚区已成为点亮城市夜间经济的重要载体,提升其消费体验是推动集聚区高质量发展、释放经济潜力的有效途径。该文基于省级以上夜间文旅消费集聚区与携程旅行平台点评数据,结合最近邻指数和核密度分析探究集聚区及其网络口碑的空间分布特征,并进一步利用地理探测器探讨各城市夜间文旅消费集聚区网络口碑的影响因素。结果表明:①我国夜间文旅消费集聚区集中分布在胡焕庸线东南半壁,不同类型夜间文旅消费集聚区具有空间差异性;②夜间文旅消费集聚区网络口碑整体较好,呈“两极多核”分布态势,高值区基本分布在胡焕庸线以东的“钻石菱形”区域,而核心区及次核心区多位于我国“T”形开发轴带区域;③社会消费品零售总额、第三产业增加值及常住人口等社会经济因子对城市夜间文旅消费集聚区网络口碑影响较大,其中社会消费品零售总额是影响集聚区网络口碑的主导因子,并与百度搜索指数成为主导交互因子。为此,在城市夜间文旅消费集聚区建设及开发过程中应合理培育和布局夜间经济增长极,提升消费满意度,推动形成高质量夜间文旅消费集聚区。

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。

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。

中国城市集群与城市空间演化

城市集群是随着城市间交通时间不断缩短、市场一体化程度不断提高而出现的空间现象。本文以2008—2020年243个外围城市为研究对象,使用全球卫星夜间灯光和交通时间的匹配数据集,构建城市集群和城市空间演化的量化指标,实证分析外围城市集群对其空间演化的影响及作用机制。研究发现外围城市集群显著加速了其内部空间集中化。进一步,本文使用清代城市历史地理数据构建工具变量讨论模型内生性,并开展系列稳健性和异质性分析,证实了结论的稳健性。机制分析表明,在双“核心–外围”关系并存的空间中,外围城市集群增强了其核心区劳动力和企业的集聚效应,且该效应会随着核心区主导能力的增强而增强。本文将城市空间演化方面的研究视角拓展至双“核心–外围”空间尺度,研究结论可为理解我国城市空间演化、促进区域协调发展提供新的思路和参考。

中国夜间文旅消费集聚区空间格局及影响机理

夜间文旅消费集聚区是推进文旅融合高质量发展的典型示范,对引领文旅产业发展、释放夜间消费潜力具有重要意义。采用GIS空间分析、地理探测器等方法探究中国夜间文旅消费集聚区空间格局及影响机理。结果表明:(1)夜间文旅消费集聚区呈现“东密西疏、南多北少”的集聚型分布态势,“环城、亲水、傍景”布局特征明显,“一主、两副、多微核”的空间形态显著。(2)夜间文旅消费集聚区分布的空间正相关性明显,呈现“东热西冷”圈层式递减的空间分异格局。(3)类型结构上,遗址遗迹类分布在历史文化悠久地区,风土民俗类集聚在少数民族地区,产业主题类空间分布广泛,风景名胜类分布较为均衡,文旅商综合类主要分布在经济发达地区。(4)地形、河流和气候是影响夜间文旅消费集聚区分布的基础要素,人口素质、客运能力、产业发展和政策支持是影响其分布的关键因素。

基于时序NPP-VIIRS夜间灯光和土地利用数据的福州市GDP时空分布研究

基于时序NPP-VIIRS夜间灯光、社会经济统计等数据,构建GDP空间化模型,并结合空间分辨率为30 m×30 m的土地利用数据对模型进行修正,研究2013—2020年福州市经济空间差异性及演变趋势。结果表明:(1)利用土地利用数据对GDP空间化模型进行修正以提高单元网格精度和效度的方法是可行的,对较小尺度的经济空间分析具有意义。(2)将土地利用数据对应的各产业产值用于对GDP空间化模型修正,能够进一步提升单元网格的模拟精度。(3)从共时性比对来看,福州市的经济空间呈现东部GDP较高,西部和北部GDP以低值为主、高值零星分布的格局。从历时性来看,自2015年起,福州市GDP高值区域的扩张与GDP总值的增长速度明显提高,2018年后整体出现略微下降趋势。

粤港澳大湾区夜间经济发展现状与能级提升研究

夜间经济常被认为只是夜间消费而未获得更全面的重视。本研究在历史回顾和实践经验总结的基础上,将夜间经济定义为在夜间进行的生产、消费、分配、交换等多种经济活动的总称,认为夜间经济活动的目的是在新经济、社会和环境等因素之间取得平衡和可持续性。研究强调,在中国经济致力于高质量发展、新旧动能转换的历史时期,拓展包含夜间生产在内的夜间经济对城市和区域发展具有重要意义。改革开放之初,今天的粤港澳大湾区城市在夜间经济实践上曾先行一步;时至今日,粤港澳大湾区仍是中国夜间经济发展的领头羊。本研究归纳分析粤港澳大湾区夜间生产的催生动力、夜间消费的空间布局和业态供给现状,进而提出粤港澳大湾区夜间经济发展能级提升的方向与路径。