不同季节的北京市GPS可降水量与PM_(2.5)/PM_(10)的比较研究

通过北京市2013年的PM2.5/PM10资料与GPS可降水量资料比较发现,在秋冬春季节,PM2.5/PM10与GPS可降水量呈明显的正相关性,相关系数大于0.5,在个别时段达到了0.89,而这一相关性在降水较多的夏季并不明显;水汽含量的上升是秋冬春季节雾霾天气过程发生的重要因素。     

A Meta-analysis of No-tillage Effects on Greenhouse Gas Emissions from Wheat-based Rotation Cropping Agroecosystem in China

Globally, agricultural soils are considered as one of the most important sources of greenhouse gas(GHG) emissions. No-tillage(NT), one of the most admired ways of climate-smart agriculture, has been deemed to have co-benefit to mitigation of GHG emissions and sustainability for crop yield, however, the effect of NT on GHG emissions is controversial. This study analyzed the overall effects of NT on GHG emissions, as well as the moderators that significantly influenced the overall effects, of the ...     

Spatio-temporal Evolution of Urban Expansion Based on a Novel Adjusted Index and GEE: A Case Study of Central Plains Urban Agglomeration,China

It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of urban agglomerations. In this study, a novel vegetation-building-nighttime light-adjusted index(VBNAI) was established for rapid and effective mapping of urban construction land(UCL) in Central Plains Urban Agglomeration(CPUA), China during 2000–2020 based on Google Earth Engine(GEE)...     

基于Spearman秩相关系数的PWV与PM2.5相关性研究

在讨论大气可降水量(PWV)与细颗粒物(PM 2.5)之间的相关性时,传统方法未能很好地顾及连续数据中包含的非雾霾天气信息的影响,为此本文提出2个数据选取标准——时间标准和空气质量指数(AQI)等级标准,用于获取雾霾期间对应的PWV和PM 2.5序列。为解决数据筛选后不连续的问题,引入一种非参数性质的Spearman秩相关系数ρ,在北京市2014~2016年雾霾多发期,分析不同AQI等级对应时段的非连续等距的PWV和PM 2.5序列的相关性可知,筛选后3 a的ρ在第1、4季度的均值分别为0.6613和0.6280,整体均值为0.6447,表明雾霾天气下PWV和PM 2.5序列具有单调正向的相关性,而传统分析方法(未筛选)下两者的相关系数均较小,表明在对数据进行选取后的分析结果更具针对性和准确性。     

Understanding the Relationship Between Shrinking Cities and Land Prices: Spatial Pattern,Effectiveness, and Policy Implications

Urban shrinkage has emerged as a widespread phenomenon globally and has a significant impact on land, particularly in terms of land use and price. This study focuses on 2851 county-level cities in China in 2005–2018(excluding Hong Kong, Macao,Taiwan, and ‘no data’ areas in Qinhai-Tibet Plateau) as the fundamental units of analysis. By employing nighttime light(NTL) data to identify shrinking cities, the propensity score matching(PSM) model was used to quantitatively examine the impact of shrinki...     

Microbial Responses of Soil Fertility to Depth of Tillage and Incorporation of Straw in a Haplic Chernozem in Northeast China

Straw is widely incorporated into soil worldwide, but most studies have concentrated on the effects of straw mulching or incorporation with topsoil. To determine the effect of depth of straw incorporation on bacterial and fungal communities, we established a field experiment in a region in Northeast China with Haplic Chernozems using four treatments: conventional tillage(CT, tillage to a depth of 15 cm with no straw incorporation), straw incorporation with conventional tillage(SCT, tillage to a ...     

2000—2020年哈-长城市群建设用地扩张分析

本文基于Landsat-5TM和Landsat-8OLI遥感影像,利用支持向量机分类方法提取2000、2005、2010、2015、2020年5个时期的哈-长城市群建设用地信息,选取扩张速度、扩张强度、弹性系数等参数探讨哈-长城市群20年来建设用地扩张进程在时间维度上的变化特征.研究结果表明:2000―2020年哈-长城市群建设用地增加了15956.58km2,扩张速度先慢后快,整体扩张强度呈上升趋势;2015―2020年是扩张速度最快且扩张强度最大的时间段,扩张速度达到13.15％,扩张系数达到0.59,属于中速扩张阶段;哈-长城市群建设用地在扩张过程中弹性系数超出了合理值1.12,呈现不合理的态势,土地集约利用化程度不高,人地关系整体不协调.     

Impact of Urban 3D Morphology on Particulate Matter 2.5(PM_(2.5)) Concentrations:Case Study of Beijing,China

Urban particulate matter 2.5(PM_2.5) pollution and public health are closely related, and concerns regarding PM_2.5 are widespread. Of the underlying factors, the urban morphology is the most manageable. Therefore, investigations of the impact of urban three-dimensional(3D) morphology on PM_2.5 concentration have important scientific significance. In this paper, 39 PM_2.5 monitoring sites of Beijing in China were selected with PM_2.5 automatic mo...     

Impact of Industrial Agglomeration on Productivity: Evidence from Iran's Food Industry

This paper aims to examine the effect of agglomeration on firm level productivity in Iran's food manufacturing by employing a firm level dataset during 1986–2015 among firms for four districts. The empirical results show that agglomeration in north districts are key factors in productivity growth. In this work, we apply a spatial Bayes model that uses hierarchical techniques during the three terms. The productivity clustering map is able to capture such patterns as the high productivity area that appears in the south, north districts of Iran. This paper evaluates the effect of agglomeration on firm productivity in Iran's food industries at district level. We find that regional market potential is the strong predictor of productivity; moreover, industrial agglomeration has a productivity-augmenting impact.     

融合GNSS水汽、风速与大气污染物的河北省冬季PM2.5浓度预测研究

为提高PM_2.5浓度预测的时效和精度,本文综合大气污染物、GNSS水汽和风速等观测要素,利用FFT与LSTM神经网络方法构建PM_2.5浓度预测模型,开展未来24 h的PM_2.5浓度预测研究。首先对大气污染物、GNSS水汽和风速等观测要素进行快速傅里叶变换,提取各类要素的公共变化周期,获得最佳公共周期为216 h;然后选取最佳公共周期长度的各类要素作为模型输入,24 h序列的PM_2.5浓度作为模型输出,分别以PM_2.5单要素的RBF神经网络和融合大气污染物、风速、GNSS水汽的LSTM神经网络构建PM_2.5浓度预测模型;最后利用实测PM_2.5浓度序列分别对2种模型开展外部可靠性检验,将RMSE和IA作为评价指标进行模型精度评价。研究结果表明,基于FFT-LSTM的PM_2.5浓度预测模型的RMSE和IA分别为16.22 μg/m³和84.36%,模型预测精度较好,可有效预测未来24 h的PM_2.5浓度,该模型可为大气污染防治部门空气质量预测提供参考。     

Measurement and Scenario Simulation of Effect of Urbanisation on Regional CO2 Emissions Based on UEC-SD Model:A Case Study in Liaoning Province,China

Based on the logical causal relationship and taking Liaoning Province, China, which is the Chinese traditional industrial base and is in the stage of accelerated urbanisation, as a case study, this study builds the ′Urbanisation-Energy Consumption-CO2 Emissions System Dynamics(UEC-SD)′ model using a system dynamics method. The UEC-SD model is applied to analyse the effect of the urbanisation process on the regional energy structure and CO2 emissions, followed by simulation of future production and living energy consumption structure as well as the evolutionary trend of CO2 emissions of three urbanisation scenarios(low speed, intermediate speed and high speed) under the assumed boundary conditions in urban and rural areas of Liaoning Province, China. The results show that the urbanisation process can alter production and the living energy consumption structure and thereby change regional CO2 emissions. An increase in the urbanisation rate in case area will lead to regional CO2 emissions rising in the short term, but when the urbanisation rate approaches 80%, CO2 emissions will reach a peak value and then decrease. Comparison of different urbanisation rates showed that production and living energy consumption exhibit different directions of change and rules in urban and rural areas. The effect of urbanisation on CO2 emissions and energy structure is not direct, and urbanisation can increase the differences in energy and CO2 emissions between urban and rural areas caused by the industrial structure, technical level and other factors.     

Spatio-temporal Evolution Characteristics and Driving Forces of Winter Urban Heat Island: A Case Study of Rapid Urbanization Area of Fuzhou City,China

Under the influence of anthropogenic and climate change, the problems caused by urban heat island(UHI) has become increasingly prominent. In order to promote urban sustainable development and improve the quality of human settlements, it is significant for exploring the evolution characteristics of urban thermal environment and analyzing its driving forces. Taking the Landsat series images as the basic data sources, the winter land surface temperature(LST) of the rapid urbanization area of Fuzhou...     

东营凹陷孔一段“红-灰”岩层旋回沉积记录:以王家岗地区王46井为例

渤海湾盆地东营凹陷始新统孔店组一段(孔一段)发育了垂向叠置的“红-灰”组合岩层,并呈现出一定的旋回沉积特征。为了深入了解该地层的沉积过程及其对古气候变化的响应,研究以东营凹陷王家岗地区重点探井王46井为例,基于年代地层格架的约束,利用岩心、录井和自然伽马测井曲线对孔一段进行了旋回沉积记录的研究,揭示了地层的旋回沉积过程。红层响应于洪水漫湖产生的漫湖泥和漫湖砂滩,而灰绿色韵律层属于间歇性湿润期的浅湖砂滩沉积,二者在垂向上突变接触。伽马曲线的连续小波分析和频谱分析表明该地层的沉积过程受控于米兰科维奇天文旋回的偏心率和岁差周期,造成的旋回地层厚度分别为39.4 m和6.9 m。通过对125 ka的偏心率周期进行带通滤波,建立了孔一段的“浮动”天文年代标尺。孔一段共记录了33个偏心率周期,判定的沉积时限约为4.13 Ma,地层的视平均沉积速率在0.236~0.408 m/ka之间变化。偏心率和岁差旋回对地层沉积的控制表现为偏心率为极大值时,间歇性湖泊沉积频繁发生,反之则以洪水漫湖沉积为主,同时岁差的极小值对应了间歇性湖泊沉积,反之则主要发生了洪水漫湖沉积。      

安徽庐江龙桥铁矿床金云母40Ar/39Ar定年:矿床成因的年代学证据

龙桥铁矿床是安徽庐枞盆地中的重要矿床,铁矿体主要赋存在中三叠统东马鞍山组。采集龙桥铁矿井下-355m中段
矽卡岩矿体中与磁铁矿共生的金云母进行了40Ar/39Ar同位素年代学测试,得到坪年龄(147.13±1.45)Ma,代表了磁铁矿的形成
时代。本区在中三叠世沉积了一套富含铁质的矿胚层;晚侏罗世-早白垩世,由于东部岩石圈伸展及郯庐断裂走滑热事件的影
响,深部的成矿物质和热液开始上升并叠加改造含铁沉积矿胚层,热液叠加改造成矿作用从147Ma或更早就已经开始,此后矿床
经历了区域火山喷发和正长岩体侵入等多次热事件的持续叠加改造成矿作用。龙桥铁矿矿床成因为沉积—热液叠加改造型。      

古地貌恢复及其对重力流沉积砂体的控制作用: 以鄂尔多斯盆地三叠系延长组长73亚段为例

鄂尔多斯盆地三叠系延长组长7₃亚段沉积体系和砂体成因类型及展布特征受湖盆底部形态控制明显,不同地区砂体类型、成因及空间展布各异。根据岩心、钻井、测井等资料运用印模法与沉积学方法精确地恢复了鄂尔多斯盆地三叠系延长组长7₃亚段的古地貌,并对微古地貌单元进行精细刻画,在此基础上分析了古地貌对盆地延长组长7₃亚段沉积体系和砂体成因类型及展布特征的控制作用。研究表明:长7₃期古地貌整体呈东缓西陡的不对称坳陷形态,明确了研究区发育高地、坡折带、湖底深洼（凹）、湖底平原、湖底古隆、湖底古脊和古沟道7个微古地貌单元。研究区延长组长7₃亚段重力流沉积体系受古地貌控制较明显,从湖盆边缘至湖盆中心依次发育三角洲前缘沉积、沟道型重力流沉积、半深湖-深湖沉积,从坡折带至湖盆中央,重力流沉积类型逐渐从砂质碎屑流沉积转换为浊流沉积。古地貌形态控制着研究区延长组长7₃亚段重力流砂体的整体展布,而高地、坡折带及古沟道等微古地貌单元则进一步控制重力流砂体的物源方向、成因类型、运输方向、横向连通性及展布形态等。