Medium and short-term channel planform changes on the Rivers Tay and Tummel, Scotland

Channel planform change was analysed using a variety of data-sources for the medium-term (>25 years and <250 years) and short-term (<25 years) on a reach of the Rivers Tay and Tummel, Scotland. Map data were input into a Geographic Information System (GIS) and used to determine planform characteristics and changes in width, braiding index and sinuosity for the study reach between 1755 and 1976. Aerial photographs were utilised to determine the more recent changes that had taken place between 1971 and 1994. The analysis showed that significant changes had occurred over the medium term with a mean reduction in channel width of 34% for this period. These changes are comparable to those found in studies of similar European rivers for this period. Changes determined for the short-term displayed a continuance of this trend at a comparable rate of change. An analysis of flood frequency and magnitude, precipitation and discharge records for both periods does not show an associated decrease and therefore does not reflect the changes in channel planform. Evidence points towards flood embankment construction in the mid-1800s as the initial cause of channel change for the study reach which was later exacerbated by flow regulation. Incision and the subsequent stabilisation of lateral and mid-channel gravel bars by vegetation succession has resulted in an overall increase in the stability of the study reach which has persisted even where the embankments have fallen into disrepair.     

Human–environment interaction in the Baltic Sea

A model based on a Bayesian Belief Network (BBN) has been constructed for the Baltic Sea with the aim of investigating future scenarios of human activities in the region and informing environmental management strategies, such as those developed under a Science and Policy Integration for Coastal Zone Assessment Systems Approach Framework application. This paper describes necessary refinements to take into account historical influences on this relatively enclosed system. BBNs are static models and therefore do not incorporate feedback loops, whereas natural systems clearly display feedback mechanisms. This paper describes the implementation of one step feedback loops into a BBN model in an attempt to partly remove this constraint. Feedback loops within this stochastic model were shown to improve its accuracy. The drivers, both natural and anthropogenic, having greatest impact on the environment are identified. These refinements were made to improve its accuracy in modelling the system and gives insights into the functioning of that system.     

Regionality in Norwegian farmland abandonment: Inferences from production data

Economic subsidies continue to be in focus as potentially important drivers of agricultural change. Their exact functioning as drivers in very complex systems are not all that well analysed or documented however, and their effect e.g. in terms of environmental output are currently being questioned. In the work reported here, we focus on how the regionality of the farming system may influence the potential effect of agricultural subsidies, also in terms of farmland abandonment. We do this through using multiple linear regressions (MLR) and geographically weighted regression (GWR) on the Norwegian database on agricultural production data, combined with farm location data. Our findings demonstrate how the outcome of certain support systems may differ between regions, and how a region may dominate national statistic. We conclude that as subsidies continue to be a key tool in achieving agricultural policy aims, we need a better understanding of how the subsidy systems work. To understand the impact of a change in subsidy it is necessary to consider the local context in which it operates, e.g. demographics, bio-physical resources and feasibility of land rental. Spatial data and techniques such as spatial MLR and GWR are increasingly accessible to policy makers and should be used to provide insight into the local impacts of current policy. However this understanding must also emphasize farmer motivation and decision making and these investigations must be regionally based.     

Systems of provision: Fast fashion and jeans

Using the example of jeans and the fast fashion sector, this critical review explores how systems of provision analysis can be used to understand geographical connections between spaces of production and places of consumption. The study of global commodity chains and production networks has proliferated in economic geography, yet the focus on transactions between places frequently omits to consider the material culture that surrounds processes of making and buying. In contrast, in cultural geography the meanings and transformations associated with ‘following things’ has explored the shifting meanings of commodities as well as personal experiences of shopping with a focus on signifying culture. Ben Fine’s systems of provision approach can offer a more comprehensive analysis. Fine considers how the role of the consumer has emerged as well as the economic processes through which value is established in goods and is an inclusive way of examining the activities that connect consumption and production. Through discussing some of the recent and emerging work on denim jeans this review shows how a systems of provision approach can effectively map a ‘fast fashion’ system and provides a framework that can be applied to other economic geographies.     

飞机增雨作业物理检验方法探究及个例分析

人工增雨效果的物理检验为评估人工影响天气的效果提供物理依据,因此越来越受到关注,文章根据2009年5月1日在河北张家口的一次积层混合云降水过程的飞机人工增雨作业探测资料,尝试了从不同高度上寻找对比区,来进行作业效果的物理检验。结果表明：利用反证法思路,发现温度在-10℃时,FSSP 100ER量程1（测量范围为2~47 μm）测量的云粒子中并不全是液相的,也有一定量冰相云粒子存在;而且不同高度粒子浓度急速增大的时刻与冰相云粒子陡增的时刻是趋于一致的,观测的实际结果基本符合冷云催化原理;降雨区域面积是扩大的,某种程度上讲,作业收到了一定的效果。     

京津冀地区GNSS ZTD时序分析及对厄尔尼诺事件的响应

京津冀地区夏季暴雨频发,水汽是影响暴雨形成的关键要素之一.本文利用中国大陆构造环境监测网络（CMONOC）京津冀地区GNSS（全球导航卫星系统）观测资料,开展GNSS天顶对流层总延迟（ZTD）时序分析及对厄尔尼诺事件的响应研究.利用快速傅里叶变换与小波变换方法从频域和时域开展GNSS ZTD时序分析,并对GNSS ZTD不同周期时序与东部型指数（I_EP）、中部型指数（I_CP）进行比较,分析I_EP、I_CP对GNSS ZTD周期变化的影响.研究发现：GNSS ZTD异常时段与厄尔尼诺事件存在对应关系.东部型指数（I_EP）与GNSS ZTD呈正相关;中部型指数（I_CP）与GNSS ZTD呈显著负相关.在东部型厄尔尼诺事件的影响下,GNSS ZTD的季节性周期增大,月周期和半月周期减小;在中部型厄尔尼诺事件的影响下,GNSS ZTD的季节性周期、月周期、半月周期都减小.研究结果可为掌握区域GNSS ZTD预测变化规律提供参考,并为利用水汽感知厄尔尼诺事件提供可行性基础.     

Violence Change and Cohort Trajectories: Baltimore Neighborhoods, 1990-20001

Whereas the relationship between poverty and violence is incontrovertible in the American city, demographic relationships at the neighborhood level are relatively poorly understood. Patterns of violence and population change are examined at the census tract level in Baltimore, Maryland across the decade from 1990 to 2000. Aggravated assault and homicide are combined and used as a composite indicator of serious violence. Population data are examined for selected tracts representative of anomalous outliers experiencing population decline but increased violence. The data are broken down into five-year cohorts represented graphically at their beginning (1990) and end (2000) points. The analysis indicates that some neighborhoods have experienced collapse of youthful cohorts. Normally, a decline in youthful population would predict a reduction in crime, but this analysis suggests that at the neighborhood scale criminogenic processes may affect neighborhoods somewhat independently of their demographic attributes. Most notably, population decline at the neighborhood level may be accompanied by crime increase, contrary to macrolevel theoretical expectation.     

Positional accuracy and measurement error in digital databases of land use: an empirical study

This paper discusses the issues of positional accuracy and measurement error in the context of a large empirical study of landscape change in England and Wales. The epsilon band model of digitizing accuracy is used to make estimates of the levels of positional uncertainty and measurement error that is due to digitizing polygon outlines. The degree of error expected had the same polygons been captured in raster format is then determined. These results prompt a general discussion of the nature of error in spatial databases.     

辽河滩海西部海南—仙鹤地区古地貌特征及其控砂作用

基于三维地震和测井资料分析,以层序地层分析和古地貌恢复技术相结合,根据地层剥蚀状况,将层序界面分为洼陷带内的平行不整合面、凹陷边缘超覆带的角度不整合面、旋转断块顶部的角度不整合面和潜山顶部强烈剥蚀不整合面4种类型,针对不同的界面类型采用不同的剥蚀地层恢复方法,重建了辽河滩海海南—仙鹤地区关键构造期古地貌形态。研究发现海南—仙鹤地区发育下切谷、陡坡断裂坡折带、古凸起等多种古地貌单元,古地貌整体呈现沟、梁斜列,下切沟谷和陡坡断裂坡折带发育,物源面积大、物源方向与海南断层斜交等特点。古地貌对物源体系、层序构成和砂体分布具有明显控制作用,具有"大沟对大扇,小沟对小扇"、砂体平面上分布受断层坡折控制、纵向分布受体系域控制等特点。     

A New Data Processing Strategy for Huge GNSS Global Networks

In Global Positioning System (GPS) data analyses, large networks are usually divided into sub-networks to solve the conflict between increasing amounts of data and limited computer resources, although an integrated analysis would provide better results. This conflict becomes even more critical with the increasing number of stations, and low-Earth-orbiting satellites and the Galileo system coming into operation. The major reason is that a huge number of ambiguity parameters are kept in the normal equation for sequential integer ambiguity fixing. In this paper, the problem is solved by a special procedure of parameter elimination for both real-valued and ambiguity-fixed solutions, based on an adapted ambiguity-fixing approach where the covariance-matrix of ambiguity parameters is not required anymore. It is demonstrated that, with the new strategy, the required memory can be reduced to one-tenth and the computation time to at least one-third compared to the existing methods, and huge GPS networks with several hundred stations can be processed efficiently on a personal computer.