City size and employment dynamics in China: Evidence from recruitment website data

This article explored China's urban employment dynamics with particular focus on the city size effect.Big data derived from the largest recruitment website were used to ex-amine the direct and indirect impacts of city size on employment demand by using mediating and moderating models.We also investigated the roles of the government and location fac-tors which have seldom been considered in literature.Results showed that the concentration degree of new jobs is higher than that of stock employment and population across cities,implying a path dependency mechanism of job creation and employment expansion.Mean-while,numerous job posts in inland central cities are probably a symptom of more even dis-tribution of employment in future China.Econometric models further verified the significant correlation between city size and job creation.Moreover,industrial diversity,fixed asset in-vestment,and spatial location have heterogeneous effects on employment demand in cities of different sizes and different levels of administration.These results can not only deepen our understanding of the crucial role of city size in urban employment growth but also demon-strate the future trend of labor and population geography of China.Policy implications are then proposed for job creation in cities of China and other developing countries.     

新冠疫情期间武汉樱花的情感效应

运用大数据文本挖掘和分析工具,对比新冠疫情期间武汉和非武汉地区居民所发布的微文,探究了武汉樱花在不同居民群体间情感效应的作用机制,研究发现：1）本地居民樱花微文的关注点多而分散,非本地居民的关注点少而集中;2）武汉樱花对不同地区居民情感的影响与疫情发展状况紧密相关;3）武汉樱花在疫情期间对武汉居民具有情感支持效应,对非武汉地区居民具有情感凝聚效应;4）疫情改变人的情感和景观解读背景,并赋予景观新的意义,新的景观意义反作用于居民,构成情感闭合回路。最后提出建议,抗疫恢复工作应多关注居民心理层面的缺失,从居民与城市、景观的情感关系入手,向武汉居民传达城市美好生活理念。     

绿色金融如何影响中国城市环境污染？——以雾霾污染为例

文章将绿色金融纳入环境规制的分析框架,以2016－2019年中国289个地级以上城市雾霾污染为例,使用空间杜宾模型探讨绿色金融、环境规制、产业结构、技术水平对雾霾治理的影响,侧重分析了绿色金融与其他因素的交互作用。结果表明：绿色金融具有空间溢出效应,本地绿色金融可以降低周边地区雾霾污染;绿色金融能够与环境规制协同互补,以优化产业结构、提升技术水平的方式促成雾霾治理。绿色金融的结构效应弱于环境规制,在中部地区并不显著;绿色金融的技术效应强于环境规制,能够激励不同地区技术创新。文章启示,绿色金融与环境规制能够相互增益,应建立区域间绿色金融合作机制,增强绿色金融的普惠性,助力区域产业转型和污染治理。     

“一带一路”建设对沿线国家经济增长的影响效果与中介路径

科学评估“一带一路”建设对沿线国家经济增长的影响效果与中介路径,对理解国际合作模式、推动“一带一路”建设向高质量发展转变具有重要意义。基于2003—2017年“一带一路”沿线64个国家的相关数据,采用固定效应面板模型和中介效应检验程序,实证检验了“一带一路”建设对沿线国家经济增长的总体性影响效果,并分析对外直接投资、进出口贸易、交通运输、就业等中介因素之间的作用关系。研究结果表明：2013—2017年间“一带一路”建设能够显著地促进沿线国家的经济增长,但新建交通基础设施线路长度、中国对外直接投资等对沿线国家GDP增长的直接促进作用并不显著。它主要通过推动中国与沿线国家之间的贸易增长,对沿线国家内部的货物资源流动、人口就业率、就业结构等产生积极影响,进而促进沿线国家的GDP增长。     

青藏高原大尺度地表流体的重力效应特征分析

基于2002~2017年三维大气再分析模型、水文模式及GRACE卫星重力数据,采用负荷格林函数和卫星重力反演方法分析青藏高原大尺度地表流体的重力效应特征。结果表明,青藏高原地区大气扣除季节项前后的重力效应峰对峰变化介于1.9~10.7 μGal和1.1~4.6 μGal,其负荷效应呈现出显著的季节性特征;土壤水和积雪扣除季节项前后的重力效应峰对峰变化介于0.9~9.9 μGal和0.7~8.3 μGal,其负荷效应呈现出显著的季节性和年际变化特征;GRACE时变重力场扣除季节项前后的重力变化峰对峰变化介于4.4~24.1 μGal和3.4~18.3 μGal,考虑观测误差、构造运动和信号泄漏误差的影响,其显著的季节性和年际变化反映了多种地表流体的综合影响。     

Impact of Phenanthrene on Denitrification Activity and Transcription of Related Functional Genes in Estuarine and Marine Sediments

The effects of phenanthrene(Phe)on the denitrification activity and denitrifying genes(narG,nirS and nosZ)were evaluated by dose-response experiments in sediments of Dagu River Estuary(DRE)and Jiaozhou Bay(JZB).The results showed that potential denitrification activity(PDA),N2O,NO3−and NO2−reduction rates of both areas were inhibited with an increase of Phe concentrations.The PDA,N2O,NO3−and NO2−reduction rates of both areas was highest and lowest in the control(DRE:0.453,0.427,7.439 and 3.222mgNkg−1 h−1,JZB:0.592,0.555,8.470 and 3.793mgNkg−1 h−1)and highest Phe amended treatments(DRE:0.069,0.001,4.486,and 1.563 mgNkg−1 h−1;JZB:0.114,0.024,5.527 and 2.200 mgNkg−1 h−1).The inhibition rate of PDA was highest,follow by NO2−reduction and then NO3−reduction.Moreover,with the increasing of Phe concentrations,total bacteria count and the abundance of denitrifying genes were decreased.And N2O accumulation was promoted with the addition of Phe for both areas.Based on the comparison of EC50 values,denitrifiers harboring three genes were more sensitive to Phe than PDA,and denitrifiers harboring nirS gene were more sensitive,followed by nosZ gene,and then narG gene.Furthermore,according to correlation analysis,the relative abundance of denitrifying genes was much more positively correlated with PDA,NO3−and NO2−reduction than total bacteria count.In addition,the denitrification activity and total bacteria count in JZB were more inhibited than that of DRE.This study is useful for understanding the impact of Phe pollution on denitrification in estuary and marine sediments,with profound implications for the management of aquatic ecosystems regarding eutrophication(N-removal)and greenhouse effect.     

地基微波辐射计遥感人工触发闪电的观测研究

为了深入研究雷电产生的微波热辐射特征,从2016年初夏开始利用地基微波辐射计在中国气象局雷电野外科学实验基地开展了连续4年的观测实验,根据雷电热效应的特征,制定了观测方案,并为地基微波辐射计设置了“引雷观测模式”。结果表明,地基微波辐射计具有对雷电热效应产生响应的能力。2017—2019年,辐射计一共成功捕获了30次人工触发闪电,观测效率逐年增长,平均为71.4 %;微波亮温脉冲幅度的最大值约125 K。结合其中28次触发事件的雷电流数据,分析了亮温脉冲幅度和雷电流积分量之间的相关性,并发现了最大亮温脉冲幅度与总电流作用积分之间可能存在指数关系。根据亮温观测数据估算了雷电热效应的持续时间,平均约0.5 s,其中25次触发事件的雷电流热效应持续时间与雷电流持续时间变化较为一致,相关系数约0.73。     

闽西南地区一次高架雷暴中尺度特征分析

利用常规观测资料、ERA5再分析资料、闪电定位仪资料、福建龙岩双偏振多普勒天气雷达资料,分析了2020年春季闽西南地区的一次强对流过程。结果表明,此次过程发生在地面锋线北侧冷区内,属于典型的高架雷暴过程,产生的灾害性天气包括冰雹、短时强降水、高山站雷雨大风。500 hPa冷平流、850 hPa暖湿平流、925 hPa闽西南地区的假相当位温高能舌为高架雷暴的发生发展提供了有利的环境条件。探空显示逆温层深厚且逆温层顶温度高,暖湿气流沿着锋面被强迫抬升,至逆温层之上饱和假相当位温随高度递减,存在显著的条件不稳定,对流得到快速发展。雷达分析表明,本次高架雷暴冰雹回波自低层快速倾斜向上发展,具有发展快、强度强、降雹时间长的特征。其双偏振参数演变特征与基于地面抬升的雷暴基本一致,降雹阶段表现为CC谷、Z_DR接近零、K_DP小于零。降雹前回波单体中存在强Z_DR和K_DP柱,可以作为冰雹预报的参考,提前量达到半小时。     

测绘行业教育培训现状分析

深入实施人才强测战略,扎实推进测绘地理信息事业改革创新发展,加强测绘地理信息行业职工教育培训工作,成为促进测绘地理信息事业全面发展的关键点。本文以黑龙江省为例分析了测绘地理信息行业职工培训的现状及存在的问题,并提出了建议与对策。     

沙漠地区无人机影像连接点提取

提出了一种纹理自适应的影像连接点提取方法,有针对性地解决沙漠地区无人机影像对比度低、相似性强、纹理信息不均衡,经常会造成连接点过少甚至提取、匹配失败的突出问题。该方法利用影像金字塔进行粗匹配,建立影像之间近似单应变换关系;通过对原始影像分块计算灰度共生矩阵的熵来评估影像纹理指标,并据此实现特征点的自适应提取与匹配。实验表明,该方法能够得到数量较多、分布均匀、可靠性强的同名点。