Biomonitoring of Atmospheric Heavy Metal Deposition by Mosses in the Vicinity of Industrial Sites   总被引：2，自引：0，他引：2  

Harald G. Zechmeister  Alarich Riss  Andrea Hanus-Illnar 《Journal of Atmospheric Chemistry》2004,49(1-3):461-477

At four industrial regions, heavy metal concentrations and calculated depositions were investigated by sampling and analysing mosses. In each region, a special spatial pattern of heavy metal concentrations was detected, reflecting the industrial processes. Metals most likely originating from the industrial sites showed an exponential decrease of concentrations and depositions with increasing distance from the pollution source. The exponential deposition pattern was in some cases modified by a series of natural factors, like the main direction of winds or orographic conditions. The distance at which deposition dropped to background values was up to 20 km. Beside the fact that the moss-metho is a useful tool for deposition measurement in the vicinity of stationary sources, some improvements for using this method are discussed, highlighting factors such as a proper calculation of deposition from concentrations, or the better knowledge of correlations between heavy metal concentrations in mosses and effects on human health.  相似文献   

中国畜禽养殖的空间分析及分区研究(英文)   总被引：3，自引：1，他引：2  

付强  诸云强  孔云峰  孙九林 《地理学报(英文版)》2012,22(6):1079-1100

The capacity of livestock breeding in China has increased rapidly since 1949, and the total output of meat, poultry and eggs maintains the world’s top first in recent 20 years. Livestock emissions and pollution is closely associated with its population and spatial distribution. This paper aims to investigate the spatial patterns of livestock and poultry breeding in China. Using statistical yearbook and agricultural survey in 2007, the county-level populations of livestock and poultry are estimated as equivalent standardized pig index (ESP), per cultivated land pig index (PCLP) and per capita pig index (PCP). With the help of spatial data analysis (ESDA) tools in Geoda and ArcGIS software, especially the Moran’s I and LISA statistics, the nationwide global and local clustering trends of the three indicators are examined respectively. The Moran’s I and LISA analysis shows that ESP and PCP are significantly clustering both globally and locally. However, PCLP is clustering locally but not significant globally. Furthermore, the thematic map series (TMS) and related gravity centers curve (GCC) are introduced to explore the spatial patterns of livestock and poultry in China. The indicators are classified into 16 levels, and the GCCs for the three indicators from level 1 to 16 are discussed in detail. For districting purpose, each interval between gravity centers of near levels for all the three indicators is calculated, and the districting types of each indicator are obtained by merging adjacent levels. The districting analysis for the three indicators shows that there exists a potential uniform districting scheme for China’s livestock and poultry breeding. As a result, the China’s livestock and poultry breeding would be classified into eight types: extremely sparse region, sparse region, relatively sparse region, normally sparse region, normal region, relatively concentrated region, concentrated region and highly concentrated region. It is also found that there exists a clear demarcation line between the concentrated and the sparse regions. The line starts from the county boundary between Xin Barag Left Banner and Xin Barag Right Banner, Inner Mongolia Autonomous Region to the west coast of Dongfang County, Hainan Province.  相似文献   

Rural and gender studies: A conceptual comparison     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(3):152-160

The aim of this article is to describe the noticeable similarities in the development of rural research and geography-close gender studies. Both research fields have developed greatly since 1970. Rural research has its roots in geography, while models and theories in gender research emanate from other disciplines. This article primarily treats the development of Nordic research and describes the development and different phases of each research field. The purpose is to draw attention to the parallel routes of development that characterize these fields, although in Swedish research they have not influenced each other much. Rural gender research, an area where the two research fields are interrelated, is the one exception. This focus, mainly developed by feminist geographers, has been largely invisible within the mainstream of both fields and has probably hindered new paths of development. Finally, I describe a route towards the development of a gender research based on the concept of space influenced by both fields of research.  相似文献   

近60年洞庭湖泊形态与水沙过程的互动响应   总被引：2，自引：0，他引：2  

尹辉  杨波  蒋忠诚  曾发明  彭鹏  李景保 《地理研究》2012,31(3):471-483

以历史文献、图件及1951～2009年长系水沙等资料为依据,对比分析洞庭湖形态与水沙过程的互动响应,结果表明:由于湖泊形态与水沙过程存在着相互作用的关系,近60年间,水沙过程以多种形式改变湖泊形态特征值,如湖盆结构破碎、解体,水深变浅以及湖面﹑湖容依次减少1840km²及130×10⁸m³;同时湖泊形态特征值改变也引起水沙特性变异,在1951～2002年间湖盆蓄水量呈明显的增减波动,但同流量下汛期水位普遍抬高1.2～1.90m,西﹑南﹑东洞庭湖水位变幅依次增大1.61m、1.39m和1.35m,各主要水文站前5位最高洪水位排序的年份均出现在湖面积(容积)历史最低值,泥沙淤积率为70%以上;2003年6月三峡水库蓄水及"退田还湖"后,高、中水位下湖盆调蓄量有所减少,城陵矶丰、枯水位分别降低1.12m及0.35m,西湖区与东南湖区的泥沙输出比均呈增大趋势,泥沙淤积率减至35.9%。其互动响应机制,可概化为泥沙淤积循环→湖盆结构破碎、解体,湖面湖容缩小→水沙特性异变→改变湖泊形态→水沙特性变异的互动响应动态演进模式。  相似文献   

长治高温气候特征及分析预报     

王正旺  杨艳平  程玉斌  刘颖  宋凯  江渊  薛博 《山西气象》2012,(2):12-15,34

通过对长治市1977年-2004年6月-8月出现≥35℃的高温天气的地理分布特征、时间和强度等统计研究,给出了高温天气的气候背景。从500hPa高空形势分析,归纳出造成高温天气的四种主要环流形势（两槽一脊型、纬向环流型、大陆暖高型、副高控制型）;分析了风、云、降水等气象要素与高温天气的内在联系。通过850hPa高温预报指标站的选取及数值预报产品的统计分析,给出了高温天气的综合性预报模型。  相似文献   

河北省霾时空分布特征分析   总被引：17，自引：3，他引：14  

魏文秀 《气象》2010,36(3):77-82

利用河北省142个气象台站的霾资料,对1971—2007年河北霾的时空分布特征进行了统计分析,发现河北霾出现频数具有明显的地域性和月际分布特征。山麓地区霾平均出现频数最高,明显高于其两侧的平原和山地,山地霾频数最小。霾频数的月际分布特征是12月或1月最多,8月或9月最少。利用2004—2007年500 hPa高度和海平面气压实况资料,通过分析对比,统计归纳出河北地区霾日500 hPa的环流形势有纬向型、两槽一脊型、均值场型、一脊一槽型和两脊一槽型5种。分析结果表明,霾的出现与天气形势有关,霾频数大小与空气污染程度和地形联系密切。这些结果对于了解河北霾的生成机制和预报具有重要意义。  相似文献   

东亚季风系统的时空变化及其对我国气候异常影响的最近研究进展   总被引：24，自引：3，他引：21  

黄荣辉  顾雷  陈际龙 《大气科学》2008,32(4):691-719

本文回顾了关于东亚季风系统的时空变化及其对我国气候异常影响的最近研究进展。许多研究说明,东亚季风系统无论风场的垂直结构、年循环或是水汽输送和降水特征都明显不同于南亚和北澳季风系统,它是亚澳季风系统中一个相对独立的季风系统。并且,研究结果表明了东亚季风系统有明显的时空变化:其中夏季风系统在年际时间尺度上存在着一个准两年周期振荡和具有极向三极子异常的空间分布特征,并从20世纪70年代中后期起至今发生了明显变弱的年代际变化,这个变化在华北尤其显著;而东亚冬季风在年际时间尺度上存在一个准四年周期振荡,从20世纪80年代中后期起也发生了明显变弱的年代际变化,它引起了我国的持续暖冬。进一步的研究还揭示了东亚季风系统的变异是与海–陆–气耦合系统变异及其相互作用密切相关,因而,东亚季风系统可以看成是一个大气–海洋–陆地的耦合气候系统,即称之为东亚季风气候系统。此外,本文还从上述东亚季风气候系统的年际和年代际变异提出了长江流域严重洪涝灾害发生的气候学概念模型和华北持续干旱的气候背景。  相似文献   

基于神经网络的印度洋长鳍金枪鱼(Thunnus alalunga)时空分布与海洋环境关系研究     

程懿麒  张俊波  汪金涛  雷林 《海洋与湖沼》2021,52(4):960-970

长鳍金枪鱼(Thunnusalalunga)是主要的经济性金枪鱼鱼种之一,其空间分布与环境因子存在着密切联系。利用2012—2019年印度洋长鳍金枪鱼生产数据和海洋环境数据,包括海表面温度(sea surface temperature, SST)、叶绿素浓度(chlorophyll a, chl a)和海表面盐度(sea surface salinity, SSS)构建印度洋长鳍金枪鱼时空分布神经网络模型。以空间(经度,纬度)、环境因子(SST, chl a, SSS)为解释变量,局部渔获量为因变量,变化隐含层节点数,构建了18个BP空间分布模型,并采用10×10交叉验证模型稳定性,以均方误差(meansquareerror,MSE)、平均相对方差(averagerelativevariance,ARV)以及拟合优度(R~2)作为不同模型精度与稳定性的评判标准,最终选取5-18-1(隐含层节点18)模型为最佳模型,其平均MSE值为0.02232,平均ARV值为0.511。利用最优模型预测结果与同期实际捕捞产量进行叠加对比发现两者具有一致性。环境因子敏感性分析表明海表温度显著影响印度洋长鳍金枪鱼渔场分布,其贡献率达到0.2。印度洋长鳍金枪鱼高精度BP神经网络时空分布模型为其资源的可持续开发与动态管理提供了一种新思路。  相似文献   

Leveraging parallel spatio-temporal computing for crime analysis in large datasets: analyzing trends in near-repeat phenomenon of crime in cities     

Jayakrishnan Ajayakumar  Eric Shook 《International journal of geographical information science》2020,34(9):1683-1707

ABSTRACT

Crime often clusters in space and time. Near-repeat patterns improve understanding of crime communicability and their space–time interactions. Near-repeat analysis requires extensive computing resources for the assessment of statistical significance of space–time interactions. A computationally intensive Monte Carlo simulation-based approach is used to evaluate the statistical significance of the space-time patterns underlying near-repeat events. Currently available software for identifying near-repeat patterns is not scalable for large crime datasets. In this paper, we show how parallel spatial programming can help to leverage spatio-temporal simulation-based analysis in large datasets. A parallel near-repeat calculator was developed and a set of experiments were conducted to compare the newly developed software with an existing implementation, assess the performance gain due to parallel computation, test the scalability of the software to handle large crime datasets and assess the utility of the new software for real-world crime data analysis. Our experimental results suggest that, efficiently designed parallel algorithms that leverage high-performance computing along with performance optimization techniques could be used to develop software that are scalable with large datasets and could provide solutions for computationally intensive statistical simulation-based approaches in crime analysis.  相似文献   

Spatial variability in specific discharge and streamwater chemistry during low flows: Results from snapshot sampling campaigns in eleven Swiss catchments     

Marius G. Floriancic  Benjamin M. C. Fischer  Peter Molnar  James W. Kirchner  Ilja H.J. van Meerveld 《水文研究》2019,33(22):2847-2866

Catchments consist of distinct landforms that affect the storage and release of subsurface water. Certain landforms may be the main contributors to streamflow during extended dry periods, and these may vary for different catchments in a given region. We present a unique dataset from snapshot field campaigns during low‐flow conditions in 11 catchments across Switzerland to illustrate this. The catchments differed in size (10 to 110 km²), varied from predominantly agricultural lowlands to Alpine areas, and covered a range of physical characteristics. During each snapshot campaign, we jointly measured streamflow and collected water samples for the analysis of major ions and stable water isotopes. For every sampling location (basin), we determined several landscape characteristics from national geo‐datasets, including drainage area, elevation, slope, flowpath length, dominant land use, and geological and geomorphological characteristics, such as the lithology and fraction of quaternary deposits. The results demonstrate very large spatial variability in specific low‐flow discharge and water chemistry: Neighboring sampling locations could differ significantly in their specific discharge, isotopic composition, and ion concentrations, indicating that different sources contribute to streamflow during extended dry periods. However, none of the landscape characteristics that we analysed could explain the spatial variability in specific discharge or streamwater chemistry in multiple catchments. This suggests that local features determine the spatial differences in discharge and water chemistry during low‐flow conditions and that this variability cannot be assessed a priori from available geodata and statistical relations to landscape characteristics. The results furthermore suggest that measurements at the catchment outlet during low‐flow conditions do not reflect the heterogeneity of the different source areas in the catchment that contribute to streamflow.  相似文献