Vertical dynamic and thermodynamic characteristics of urban lower boundary layer and its relationship with aerosol concentration over Beijing

By utilizing observational data from a 325 m tower of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS) on March 19-29, 2001 and August 11-25, 2003, a comprehensive study was conducted on the vertical dynamical and thermodynamic characteristics of the urban lower boundary layer (ULBL) and its relationship with aerosol concentration over Beijing. Firstly, a comparative analysis was made on the gradient data (wind, temperature and humidity), ultrasonic data (atmospheric turbulences) and air-quality observations at different tower heights (47, 120 and 280 m). Secondly, a diagnosis was made to reveal the major features of normalized variances of velocity and temperature, turbulence kinetic energy as well as their relationship with aerosol concentrations. Furthermore, the characteristics of the ULBL vertical structure and the TSP concentration/distribution variations during a sand/dust weather process were also analyzed. The outcome of the study showed that under unstable stratification, the normalized variances of velocity (σu/u*, σv/u*, σw/u*) and temperature (σT/T*) at 47 and 120 m heights fit the Monin-Obukhov similarity (MOS) framework and the fitting formulas were given out accordingly. According to the stratification parameter (z′/L), the stable ULBL could be divided into 2 zones. With z′/L<0.1, it was a weakly stable zone and MOS framework was applicable. The other was a highly stable zone with z′/L>0.1 and the normalized velocity variances tended to increase along with higher stability, but it remained constant for normalized temperature variances. At daytime, the near-surface layer includes two heights of 47 and 120 m, while 280 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in Beijing in March 2001 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 320 m reached 913.3 μg/m3 and the particles were transported from the upper to lower ULBL, which was apparently related to the development process of a low-level jet and its concomitant strong sinking motion.     

杭州城区“最具出游力”人群休闲旅游障碍性因素的实证分析

休闲旅游作为一种旅游方式和休闲活动内容越来越受到重视，通过对杭州市“最具出游力”人群调查，运用旅游地理学分析方法发现，影响他们进行休闲旅游的因素最重要的是时间因素、交通因素和学习因素，传统观点中的经济因素地位明显下降；同时分析了不同职业、性别和年龄人员中各因素作用的差异。这种实证性的调查分析方法和结论对于休闲旅游理论和杭州市休闲产业的发展都有一定意义。     

Discharge‐sediment processes of the Zhadang glacier on the Tibetan Plateau measured with a high frequency data acquisition system

In high elevation cold regions of the Tibetan Plateau, suspended sediment transfer from glacier meltwater erosion is one of the important hydrological components. The Zhadang glacier is a typical valley‐type glacier in the Nyainqentanglha Mountains on the Tibetan Plateau. To make frequent and long period records of meltwater runoff and sediment processes in the very high elevation and isolated regions, an automatic system was installed near the glacier snout (5400 m a.s.l) in August 2013, to measure the transient discharge and sediment processes at 5‐min interval, which is shorter than the time span for the water flow to traverse the catchment from the farthest end to the watershed outlet. Diurnal variations of discharge, and suspended sediment concentration (SSC) were recorded at high frequency for the Zhadang glacier, before suspended sediment load (SSL) was computed. Hourly SSC varied from the range of 0.2 kg/m³ to 0.5 kg/m³ (at 8:00–9:00) to the range of 2.0 kg/m³ to 4.0 kg/m³ (at 17:00–18:00). The daily SSL was 32.24 t during the intense ablation period. Hourly SSC was linearly correlated with discharge (r = 0.885**, n = 18, p < 0.01). A digit‐eight hysteresis loop was observed for the sediment transport in the glacier area. Air temperature fluctuations influence discharge, and then result in the sediment variations. The results of this study provide insight into the responses of suspended sediment delivery processes with a high frequency data in the high elevation cold regions. Copyright © 2016 John Wiley & Sons, Ltd.     

Long‐term monitoring of a mercury contaminated estuary (Ria de Aveiro,Portugal): the effect of weather events and management in mercury transport

The main aim of this research was to assess the mercury transport from an estuarine basin with a background of anthropogenic contamination during a spring tidal cycle (year 2009) and compare it with two previous tidal cycles (years 1994 and 1999), as part of a long‐term monitoring program. Results showed that effective mercury transport occurs both in the dissolved and particulate fractions (0.18 and 0.20 kg per tidal cycle, respectively), and despite an overall decrease in environmental contamination, results more than double previous findings on particulate transport in the system. These findings result essentially from changes in the tidal prism (net export of 2 million m³ of water), given that both dissolved and particulate concentrations did not increase over time. Hydrodynamic simulations were performed to evaluate the effect of physical disturbance (dredging) and weather events (increased freshwater flow) in these processes, and results suggest the increased freshwater flow into the system as the main forcing function for the mercury transport increment. These results highlight the importance of long‐term monitoring programs, since despite an overall improvement in local contamination levels, the enhancement of transport processes through hydrological changes increases environmental pressure away from the contamination source. Copyright © 2012 John Wiley & Sons, Ltd.     

地理国情普查外业调查与核查探讨

地理国情普查主要是查清我国地形地貌、地表覆盖等自然和人文地理要素的现状和空间分布情况,建立普查成果数据库,为开展常态化的国情监测奠定基础。正确理解吉林省地理国情普查技术设计和作业指导书,以及国情普查的内容与指标,进行外业核查与遥感影像解译样本采集工作,为最终形成地理国情要素数据、地表覆盖分类数据和遥感影像解译样本数据库奠定基础。     

基于GIS的城镇建设用地发展适宜性评价——以常州市金坛区为例

为更加深入地了解村镇尺度城镇建设用地发展适宜性情况,提高土地利用综合效益,本文以常州市金坛区遥感影像数据和土地利用现状数据为基础,采用层次分析法和GIS空间分析技术,选择自然、区位、生态和土地转换适宜度四大类10个指标,建立了适用于平原地区的具有区域代表性的城镇建设用地发展适宜性评价指标体系,分析了金坛区城镇发展适宜区分布与空间自相关特征。研究结果能为城市规划、土地规划等提供依据,尤其在城镇建设用地发展布局上具有重要的现实意义。     

Late‐glacial to Holocene depositional architecture of the Ombrone palaeovalley system (Southern Tuscany,Italy): Sea‐level,climate and local control in valley‐fill variability

The Ombrone palaeovalley was incised during the last glacial sea‐level fall and was infilled during the subsequent Late‐glacial to Holocene transgression. A detailed sedimentological and stratigraphic study of two cores along the palaeovalley axis led to reconstruction of the post‐Last Glacial Maximum valley‐fill history. Stratigraphic correlations show remarkable similarity in the Late‐glacial to early‐Holocene succession, but discrepancy in the Holocene portion of the valley fill. Above the palaeovalley floor, about 60 m below sea‐level, Late‐glacial sedimentation is recorded by an unusually thick alluvial succession dated back to ca 18 cal kyr bp . The Holocene onset was followed by the retrogradational shift from alluvial to coastal facies. In seaward core OM1, the transition from inner to outer estuarine environments marks the maximum deepening of the system. By comparison, in landward core OM2, the emplacement of estuarine conditions was interrupted by renewed continental sedimentation. Swamp to lacustrine facies, stratigraphically equivalent to the fully estuarine facies of core OM1, represent the proximal expression of the maximum flooding zone. This succession reflects location in a confined segment of the valley, just landward of the confluence with a tributary valley. It is likely that sudden sediment input from the tributary produced a topographic threshold, damming the main valley course and isolating its landward segment from the sea. The seaward portion of the Ombrone palaeovalley presents the typical estuarine backfilling succession of allogenically controlled incised valleys. In contrast, in the landward portion of the system, local dynamics completely overwhelmed the sea‐level signal, following marine ingression. This study highlights the complexity of palaeovalley systems, where local morphologies, changes in catchment areas, drainage systems and tributary valleys may produce facies patterns significantly different from the general stratigraphic organization depicted by traditional sequence‐stratigraphic models.     

渝东南下古生界页岩构造裂缝形成及分布控制因素

天然裂缝对页岩气储集和渗流有重要影响,但目前对页岩构造裂缝研究不够深入。本文通过露头、岩心裂缝观察和分析,探讨了渝东南下古生界页岩构造裂缝类型、形成机理及分布控制因素。基于裂缝特征及力学成因,将剪切裂缝分为高角度剪切裂缝、倾斜滑脱裂缝和水平滑脱裂缝。倾斜滑脱裂缝是在上覆岩层重力和水平构造应力共同作用下沿应力集中的软弱面发生剪切滑动形成,水平滑脱裂缝是在构造挤压应力作用条件下主要沿页理面方向的剪切或层间滑动形成;页理发育程度及岩层曲率是控制水平滑脱裂缝形成的关键因素,岩石矿物组成、构造作用及岩层厚度是控制其它类型构造裂缝形成和分布的主要因素,页岩岩石力学层的划分需要根据裂缝特征、岩性变化特征、岩石力学参数及沉积界面等综合确定,岩层厚度与层间构造裂缝密度呈负相关关系。     

豫西偃龙煤田深部铝土矿地质特征及矿床成因

偃龙煤田深部铝土矿区位于豫西铝土矿成矿区嵩箕铝土矿成矿小区,是豫西铝土矿成矿区的重要组成部分。区内铝土矿赋存于上石炭统本溪组中上部,下伏具有岩溶特征的寒武—奥陶纪灰岩,沉积相为滨岸泻湖泥岩相区,属海相沉积的一水硬铝石岩溶型矿床,矿体主要填充在岩溶作用形成的负地形之中。本文系统阐述了矿区的含矿岩系、矿床地质及矿石质量特征等,研究了本区铝土矿的成矿地质条件、矿床的展布规律和富集规律,对矿床成因及控矿因素进行了分析,指出铝土矿床分布在坳陷区边部及隆起区的过渡带,铝土矿的厚度和品质与本溪组厚度有着明显的正相关关系,预测深部仍有较好的成矿远景。     

一种简化的暴雨灾害风险及影响评估方法和应用研究 ——以京津冀“7·21”暴雨事件为例

文章综合考虑中国区域范围内降雨时空分布特征以及地理地貌等特征,将全国降雨区划分为4大类,在此基础上,得出不同降雨类区暴雨致灾因子的强度等级评定方法;同时,研究确定了与暴雨灾害密切相关的地形高程、高程标准差、河网密度、土壤类型等环境脆弱性影响要素,并对各类要素分别进行了分级评定;将各类环境脆弱性影响要素结合暴雨致灾因子要素,运用加权求和方法建立了暴雨灾害综合风险评估模型;并结合GIS技术,将城市、农村人口分布情况、用地等数据叠加到风险分布格局中,最终分析得出不同风险等级下影响的城市和农村人口数量、土地面积等内容。该评估模型相较于以往其他暴雨风险评估模型,其适用范围更广,可以适用于全国范围内的任意区域暴雨灾害风险评估;实时评估业务能力更强,将该模型结合降雨实况资料或预报资料可以对全国任意区域降雨灾害综合风险进行事后、跟踪评估或预评估;评估对象更有针对性,结合GIS技术,可以针对得出的风险分布结果分别给出不同风险等级范围内的承灾体受影响的定量评估结果。