Geoenvironmental appraisal in a developing urban area

The area between Endada and Bhimunipatnam, an urban expansion of the Visakhapatnam Metrocomplex Region, Andhra Pradesh, India, is mainly underlain by the Eastern Ghats of Precambrian age. Geomorphologic units delineated are denudational, colluvial, fluvial and coastal plains. Geoenvironmental appraisal has been made with respect to the geomorphologic units. Geoenvironmental hazards include soil and rock characteristics, drainage conditions, structural features, slope stability, gully erosion, beach erosion, sea spray, depth to water table and groundwater quality, which impart considerable restraints on the urbanization of the area. Effective land use management measures are suggested to avoid the adverse impacts on the area for sustainable development.     

Development of a parameterization for simulating the urban temperature hazard using satellite observations in climate model

Urban surface temperature is hazardously higher than surrounding regions (so-called urban heat island effect UHI). Accurately simulating urbanization-induced temperature hazard is critical for realistically representing urban regions in the land surface-atmosphere climate system. However, inclusion of urban landscapes in regional or global climate models has been overlooked due to the coarse spatial resolution of these models as well as the lack of observations for urban physical properties. Recently, National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) observations illustrate important urban physical properties, including skin temperature, surface albedo, surface emissivity, and leaf area index, It is possible to identify the unique urban features globally and thus simulate global urban processes. An urban scheme is designed to represent the urban-modified physical parameters (albedo, emissivity, land cover, roughness length, thermal and hydraulic properties) and to include new, unique physical processes that exist in urban regions. The urban scheme is coupled with National Center for Atmospheric Research (NCAR) Community Land Model Version 2 (CLM2) and single column coupled NCAR Community Atmosphere Model CAM2/CLM2 to assess the mechanisms responsible for UHI. There are two-steps in our model development. First, satellite observations of albedo, emissivity, LAI, and in situ observed thermal properties are updated in CLM2 to represent the first-order urban effects. Second, new terms representing the urban anthropogenic heat flux, storage heat flux, and roughness length are calculated in the model. Model simulations suggest that human activity-induced surface temperature hazard results in overlying atmosphere instability and convective rainfall, which may enhance the possibility of urban flood hazard.

中国历史耕地变化及其对自然环境的影响*

农业开发已经直接或间接地影响并正在影响自然环境的许多方面,中国农业开发历史悠久,对自然环境造成的影响广泛而强烈,对认识人类活动导致的全球与区域环境变化具有代表性。文中总结了近年来基于考古和历史文献记录的中国历史耕地变化定量重建和耕地开发环境影响的研究成果。主要结论包括: (1)中国在历史耕地变化重建方面具有独特的优势,主要数据源包括田亩、税赋、人口等与耕地数量相关的数值记录,考古遗址点、聚落、路网、行政建制等与农业活动相关的信息,有关土地开发和农业生产的描述性记录等三大类。 (2)对全国尺度的耕地面积推断始于春秋战国时期,过去1000年以来已重建了省(路)域的垦殖率,过去300年基于历史记录重建的东北、华北等区域垦殖率的分辨率已到县,在重建基础上利用分配模型获得的过去300年格网化垦殖率的分辨率可达10 km×10 km甚至1 km×1 km。相比于当前广泛使用的国际数据集,这些区域定量重建结果更为准确。(3)历史时期中国耕地的3次大规模扩张分别主要出现在西汉、两宋和清中叶,与此相对应,植被破坏和水土流失从北方地区扩展到南方地区,从平原低地扩展到低山丘陵、深山地区;过去300年耕地变化导致了碳排放的增加和可辨识的区域气候变化。未来中国的历史耕地变化重建及其对环境影响研究,应与国际过去土地利用/覆盖研究衔接,研究重点为延长历史耕地重建时限、提高重建单元的空间分辨率和改进耕地格网化分配模型。     

国内外城市生态网络建设经验及对上海的启示

城市基本生态网络的实施是一项艰巨的任务,必须在行政、经济、技术等多方面进行保障,并在政策方面有所创新,才能激发政府、开发商、业主及其他利益相关者等对实施生态空间的积极性。本文搜集和分析了国内外生态城市建设、生态控制线实施等相关案例以及生态补偿机制的研究和实践,提出了对上海市实施生态控制线的建议。     

黄土丘陵小流域生态用水试验研究--气候和土地利用变化的影响

为探讨黄土高原地区的生态恢复,以半干旱黄土丘陵区安家沟小流域的气象、土壤水分、地形图和土地利用图(1982年和2002年)为源信息,分析了不同植被类型的蒸散量和生态用水量、流域生态用水量及其与气候和土地利用变化的关系。研究结果表明:(1)流域土地利用结构从1982-2002年间变化较大,农地(特别是梯田)增加较快,乔木林地急剧减少,主要表现为毁林、开荒和造田;(2)研究区内各种植被/土地利用类型的蒸散量和生态用水都极大地受控于气候(特别是降雨量)的影响,其年际差异较大;(3)不同植被/土地利用类型间的蒸散量和生态用水差异明显,在各个年份乔灌林的生态用水量均大于农作物和自然草地的蒸散量和生态用水量,但生态用水的差异程度小于蒸散量的差异程度;(4)以自然草地(即荒草地)为标准,农作物的蒸散量和自然草地接近,但乔灌林地的蒸散量和生态用水量均远高于自然草地,难于实现土壤水分平衡;(5)流域土地利用结构的变化(主要是强耗水植被的减少)减小了流域生态用水量,增强了流域的水分平衡能力。     

河南粮食主产区土地生态文明建设评价指标体系构建研究

土地生态文明是生态文明建设的重要组成部分,评价指标体系构建是土地生态文明的基础和关键,也是土地生态学的重要研究内容。对土地生态文明的内涵进行了界定和分析,借鉴相关研究成果并结合河南粮食主产区实际状况,构建了以土地数量、土地质量、土地生态、土地利用制度等4项为准则层、13项指标层和30项元指标组成的土地生态文明建设综合评价指标体系,为粮食主产区土地生态文明乃至国家生态文明建设提供理论依据。     

Accumulation and sources of heavy metals in urban topsoils: a case study from the city of Xuzhou, China

The knowledge of the variability, the anthropogenic versus natural origin and corresponding environmental risk for potentially harmful elements in urban topsoils is of importance to assess human impact. The aims of the present study were: (1) to assess the distribution of heavy metals (Sn, Li, Ga, Ba, Fe, Mn, Co, Be, Ti, Al, Hg, Cr, Sb, As, Bi, Pd, Pt, Au, Ni, Cd, Zn, Cu, Pb, Se, Mo, Sc and Ag) in urban environment; (2) to discriminate natural and anthropogenic contributions; and (3) to identify possible sources of pollution. Multivariate statistic approaches (principal component analysis and cluster analysis) were adopted for data treatment, allowing the identification of three main factors controlling the heavy metal variability in Xuzhou urban topsoils. Results demonstrate that Hg, Cr, Sb, As, Bi, Pd, Pt, Au, Ni, Cd, Br, Zn, Cu, S, Pb, Se, Mo, Sc and Ag could be inferred to be tracers of anthropogenic pollution, whereas Al, Ti, Ga, Li, V, Co, Pt, Mn and Be were interpreted to be mainly inherited from parent materials. Iron, Ba, Sn, Pd and Br were interpreted to be affected by mixed sources.     

Correlation between magnetic susceptibility and heavy metals in urban topsoil: a case study from the city of Xuzhou, China

Anthropogenic influence, mainly due to urban and industrial activities and traffic exhaust, may affect urban topsoil via atmospheric contamination and solid waste. Magnetic susceptibility measurements were conducted on 21 urban topsoil samples from the city of Xuzhou, China. High intensities of magnetic susceptibility were detected in the majority of the samples. SEM analysis shows that magnetic minerals are in the form of spherules and mainly due to anthropogenic inputs. The heavy metals Pb, Cu, Zn, Se, Sc, Mo, Fe, and Bi show strong correlations with magnetic susceptibility, and Ag, Ba, Cd, Ni, Cr, Sb, and Sn, on the other hand, show a weak correlation with magnetic susceptibility. Whereas, of these metals studied, only Hg has no significant correlation with the susceptibility. The Tomlinson pollution load index (PLI) also shows significant correlation with the susceptibility (χ). The present study shows that magnetic susceptibility is a fast, inexpensive, and non-destructive method for the detection and mapping of contaminated soils.     

Simulation of seismic-prospecting random noise in the desert by a Brownian-motion-based parametric modeling algorithm

Random noise has a negative impact on seismic-prospecting record processing. An important step to improve the methods aimed at the attenuation of random noise is to scientifically characterize the properties of the noise. Numerical modeling is useful to understand the nature of the random noise. In this study, we present a Brownian-motion-based parametric modeling algorithm for the simulation of seismic-prospecting random noise in the desert. The optimal Hurst exponent required to implement the method can be determined by comparing the spectral properties related to the noise data and the simulated results. The data used to analyze the properties of the noise were acquired in the Tarim Basin (Northwest of China). We verify the performance of the modeling algorithm by comparing the results obtained after the simulation with the real noise data in both the time domain and the spatio-temporal domain. The experimental results thus obtained prove the accuracy and efficiency of the proposed modeling algorithm. This study can be used as a basis to investigate the seismic-prospecting random noise characteristics and thus contribute to its mitigation.     

斜向挤压构造的物理模拟及其对焉耆盆地构造解释

针对焉耆盆地的实际构造问题,设计了刚性边界基底均匀收缩斜向挤压砂箱实验模型。实验结果表明,斜向挤压情况下,挤压带边界方向和挤压方向对构造线走向起控制作用,其中边界方向的控制作用更加显著。斜向挤压作用与压扭作用不完全等同,斜向挤压虽然也有走滑分量,但被均匀地分布在整个变形区域,故不一定形成具明显走滑特征的断层。笔者认为,对于焉耆盆地这类构造的形成,用斜向挤压作用可以得到更好的解释。     

栾川矿集区地学大数据挖掘和三维/四维建模的资源-环境联合预测与定量评价

21世纪地球科学的"第四范式"与第四工业时代以及5G+智能通信为矿业开发与环境防护的关联研究提供了新契机.以地球动力学背景、成矿过程、定量评价"三位一体"的地学理论为基础,以栾川矿集区为例,运用地学大数据(多维多尺度的地质、地球物理、地球化学、高光谱与高分辨率遥感(多时相)以及实时矿业等数据)的深层次人工智能挖掘和三维...     

数值模拟在岩溶塌陷预警系统建设中的应用 ——以临沂市城区岩溶塌陷为例

岩溶塌陷是近年来频发的主要地质灾害类型之一,其发生、发展主要受岩溶水不合理开采所致,水位是影响岩溶塌陷的重要因素.文章以临沂市城区岩溶塌陷为例,探讨在建立完善的监测网络基础上,通过水文地质模型模拟城区一带的岩溶塌陷区水位的变化趋势,预测分析可行的地下水开采方案,建立起完整的岩溶塌陷动力预警系统,为减少或避免岩溶塌陷的发生提供了科学依据,也为同类地质灾害的监测、预警、预防提供了借鉴模式.     

大兴安岭阿尔山天池沉积物中正构烷烃记录揭示的全新世古气候变化

我国东北地区地处东亚季风北缘,在高、低纬过程的共同影响下,区域气候和环境变化较为复杂。文章选取大兴安岭中段的阿尔山天池长2.5m的全新世以来的湖泊沉积岩芯（ACL17C）作为研究对象,对源于植物叶蜡的正构烷烃及相关代用指标进行分析,结果表明阿尔山天池自10.0cal. ka B.P.以来,正构烷烃浓度所代表的湖泊及流域的生产力逐渐增强,并在5.0~3.0cal. ka B.P.期间达到峰值,结合其他指标推测该阶段湖泊水位较高,有机物输入稳定,沉积速率较慢,气候温暖湿润,可能是全新世气候适宜期;2.3~1.5cal. ka B.P.期间,正构烷烃浓度下降,沉积物颗粒变粗,指示湖泊水位突降,藻类含量上升,植被状况较差,可能发生了区域性的气候变干事件;1.5cal. ka B.P.之后,相关指标显示植被状况转好,湖泊水位上升。通过对比大、小兴安岭及附近区域的植被及气候演化结果,表明该区域全新世气候适宜期可能发生在中、晚全新世,与其他地区记录的早、中全新世适宜期存在显著差异。

     

构造应力环境对浅成岩体成矿系统的制约:从安庆月山岩体冷却过程动力学计算模拟结果分析

为探讨构造应力环境对浅成岩体成矿系统的制约,以安庆地区的月山岩体及其所形成的安庆铜矿床为例,在传统地质调查研究的基础上,通过假设不同的力学边界条件进行岩体冷却过程动力学的计算模拟实验研究。计算结果显示,在没有构造应力作用时,在岩体的接触带上不可能形成有利成矿定位的局部汇流扩容空间,挤压和拉伸作用都能够在岩体接触带形成局部汇流扩容空间,但二者的空间分布规律有着极大的差别,只有拉伸构造应力作用下的动力学计算模拟实验能在已发现矿体部位形成汇流扩容空间,表明构造应力环境对成矿定位的汇流空间的制约以及拉伸构造应力作用对月山岩体成矿的重要贡献。在拉伸构造应力和无构造应力作用时,接触带上的流体压力都是随着变形的进程而趋降低的,只有在挤压构造应力作用下,流体压力才会有一个超压的过程,流体超压是形成斑岩型矿床的重要机制。可见挤压环境才是一种有利于斑岩型矿床成矿的构造环境,铜陵-安庆地区缺乏与矽卡岩矿床相对应的斑岩型矿床主要原因之一是成矿时处于一种拉伸的构造应力作用环境。     

正断层三维生长和连接过程研究：以南海北部陆丰凹陷为例

正断层生长和侧向连接是最基本的三维地质构造问题，深入剖析其三维时 空演化过程对理解沉积盆地内正断层系统的形成与演化至关重要。 南海扩张时间和影响范围一直是国内外地学界研究的热点问题之一。南海北部珠江口盆地陆丰凹陷发育大量正断层，并覆盖有高精度二维地震反射剖面，成为研究上述问题的理想地区之一。本研究以陆丰凹陷为研究对象，开展三维构造解析和建模研究，为正断层系统三维时 空演化过程提供一个实例。研究结果表明：陆丰凹陷主控断层F1的生长和连接过程主要分三个阶段：晚白垩世—早古新世，两条断层分别形成并以孤立断层模式分别向两侧生长；早古新世—早渐新世，断层发生侧向连接作用合并为F1断层，连接处发育侧断坡；晚渐新世—中中新世，F1断层继续向两侧生长。基于F1断层定量分析（生长指数和断距），发现F1断层活动强度表现为先增加然后突然降低，其转折时间对应于T60界面，~23 Ma，较好地对应了西北次海盆扩张终止时间，说明南海北部扩张已经影响到陆丰凹陷。结合前人对珠江口盆地构造变形和演化研究，初步认为南海北部扩张波及的范围已跨过陆丰凹陷向大陆方向继续延伸，其北部边界可能对应于华南大陆南缘的滨海断裂带。本研究可为正断层系统三维生长过程研究提供案例，同时为南海扩张过程研究提供基础数据支撑。