A proposal for a consistent parametrization of earth models     

Thomas Forbriger  Wolfgang Friederich 《Geophysical Journal International》2005,162(2):425-430

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THE BEIJING AREA MESOSCALE NWP SYSTEM AND ITS APPLICATION   总被引：2，自引：0，他引：2       下载免费PDF全文

WANG Yingchun  WANG Jianjie  CUI Bo  LU Duanjun  YU Wei  GUO Xiaorong  CHEN Dehui 《Acta Meteorologica Sinica》2000,14(2):233-246

Significant progress has been made on the development of mesoscale numerical weather prediction(NWP)system for Beijing area,as a joint project of the National Meteorological Center(NMC)andthe Beijing Meteorological Bureau(BMB).On the basis of the non-hydrostatic mesoscale model PSU/NCAR MM5,a mesoscale NWP system for Beijing area(BJ-MM5V.1)has been developed on thecomputer IBM/SP2 MPP with 24 nodes at NMC.As a two-way nested grid model two grids arechosen with 45 and 15km grid length respectively,and 23 levels in the vertical.It takes 2 hours and20 minutes to make a 36h forecast,which satisfies the time requirement for the operational use.Inaddition to the routine data received from GTS at NMC,the enhanced observations over Beijingregion are used for the objective analyses.This system was put into semi-operational use during thesummer of 1997 to test its performance.The forecast products,hourly rainfalls and all of themeteorological elements needed,are provided to the forecasters at BMB for use.It is identified fromthe test results that the system is robust and has pretty good ability to forecast the spatial andtemporal distribution of the precipitation for the local heavy rainfalls.  相似文献   

流体饱和多孔介质波动方程的有限元解法   总被引：19，自引：6，他引：13       下载免费PDF全文

邵秀民  蓝志凌 《地球物理学报》2000,43(2):264-278

讨论了流体饱和多孔介质中波传播问题的有限元解法,首先在Ｂｉｏｔ理论的基础 上,概述了数学问题的提法,然后提出了一种新型简便的人工边界上的无反射边界条件,同时 给出了有人工边界时流体饱和多孔介质波动方程的有限元计算公式．数值试验的结果表明, 本文提出的无反射边界条件和数值方法均很有效．  相似文献   

Modeling the effects of nonlinear equilibrium sorption on the transport of solute plumes in saturated heterogeneous porous media     

A. Abulaban  J. L. Nieber 《Advances in water resources》2000,23(8)

Transport of sorbing solutes in 2D steady and heterogeneous flow fields is modeled using a particle tracking random walk technique. The solute is injected as an instantaneous pulse over a finite area. Cases of linear and Freundlich sorption isotherms are considered. Local pore velocity and mechanical dispersion are used to describe the solute transport mechanisms at the local scale. This paper addresses the impact of the degree of heterogeneity and correlation lengths of the log-hydraulic conductivity field as well as negative correlation between the log-hydraulic conductivity field and the log-sorption affinity field on the behavior of the plume of a sorbing chemical. Behavior of the plume is quantified in terms of longitudinal spatial moments: center-of-mass displacement, variance, 95% range, and skewness. The range appears to be a better measure of the spread in the plumes with Freundlich sorption because of plume asymmetry. It has been found that the range varied linearly with the travelled distance, regardless of the sorption isotherm. This linear relationship is important for extrapolation of results to predict behavior beyond simulated times and distances. It was observed that the flow domain heterogeneity slightly enhanced the spreading of nonlinearly sorbing solutes in comparison to that which occurred for the homogeneous flow domain, whereas the spreading enhancement in the case of linear sorption was much more pronounced. In the case of Freundlich sorption, this enhancement led to further deceleration of the solute plume movement as a result of increased retardation coefficients produced by smaller concentrations. It was also observed that, except for plumes with linear sorption, correlation between the hydraulic conductivity and the sorption affinity fields had minimal effect on the spatial moments of solute plumes with nonlinear sorption.  相似文献   

Coping strategies in rural areas of the Buzau Sub–Carpathians     

Nicolae Muica  David Turnock  Veselina Urucu 《GeoJournal》2000,50(2-3):157-172

This paper focuses on the Sub–Carpathian region which has traditionally maintained a large rural population and is today suffering acute economic and social stress. During the present transition phase the rural population is struggling to survive by combining elements of the modern and traditional economies and research has been undertaken to clarify a range of household strategies. After profiling the communes of the Buzau Carpathians the problem is tackled at two levels on the basis of questionnaire work carried out during 1998–1999. First there is a general overview to outline conditions in Patarlagele commune, including some local contrasts between settlements on main transport axis along the Buzau valley and those in the hills and side valleys. Second there is a consideration of in-depth profiles of specific households in villages in the wider area including Panatau as well as Patarlagele commune. It remains to be seen to what extent the district will be able to safeguard its social capital when growth resumes in large towns especially Brasov and Buzau with which Patarlagele has the best contacts. It is also an open question how far the remoter settlements will retain a viable population, assuming that the services remain relatively poor while disadvantage persists with regard to both employment opportunities and physical security. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Social Cohesion; Is it sufficient? Migrant communities in two disadvantaged neighborhoods in Istanbul     

Hürriyet G. Ögdül 《GeoJournal》2000,51(4):321-328

Planners assume that old neighbourhoods have an atmosphere in which social relations can easily flourish. They also regard the strong social ties within a neighborhood as the guarantee for the success of housing rehabilitation. This article argues that existence of social cohesion in a neighbourhood is not necessarily an advantage in a process of modernisation and rehabilitation. In some cases the community may constitute a closed `island' especially in places where communities have historically inherited an hierarchical character. The article is based on a recent research project dealing with urban communities in inner city areas of Istanbul, especially those containing migrant populations which seemingly have strong community ties. The historical background of the community from the Ottoman period is examined in the first part of the article. The roots of the community as a territorial administrative unit (mahalle) and its modification in contemporary migrant communities are analysed. The second part of the article presents the results of two case studies. One of the case studies is a social housing district where the migrant community is mixed and social relations with the rest of the city are relatively well developed. The other case study area is an historical district where strong social ties create an introverted character of the community in spite of its central location. The result of the study reveals that urban `communities' in a city like Istanbul have both negative and positive aspects. Primarily it is important to assess and understand the degree of `opennes' of the community to the outer world. In any action to be taken planners should look not only inside the community, but also at its 'outer' relations.  相似文献   

Anchored locally – Linked globally. Transnational social movement organizations in a (seemingly) borderless world*     

Dietrich Soyez 《GeoJournal》2000,52(1):7-16

Dial locally -act globally: this slogan seems to appropriately reflect, under prevailing conditions of globalization and disembeddedness, the seemingly unrestrained possibilities of a variety of actors to influence events - without being present - anywhere on the planet. While focusing on a broadly conceived group of transnational social movement organizations - from non-governmental organizations to loosely linked transnational advocacy networks - the aim of this paper is to give evidence of the fact that geography - and all manner of borders - still matters even for these actors. Despite being linked with the world, they continue to act from deeply embedded local contexts, very often not triggering true transnational interaction but much more limited translocal encounters. In doing so, however, they literally cause collisions between different worlds while not only modifying existing but also constructing new spaces.September 1984 – first week of my field-work on Cape Breton Island, Nova Scotia, eastern Canada. A teacher at the local high school had agreed to make the first contacts with environmental groups, who were opposed to the use of pesticides by a Swedish forest products company. In return, he asked me to give two geography lessons on Germany to his class.After the lessons the 15-year-old pupils asked questions. One of the first of these was what I did with my family on a free weekend. Without long consideration, I answered: ``We often go for a walk in the forest with our children'. The pupils doubled up laughing in response, and the geography teacher was obviously also amused.A few days later I understood the reason for this reaction, when I saw typical forest land in Nova Scotia for the first time. Forests of an age which in Germany would be airy timber forests, which could be walked through even away from paths, were here largely inpenetrable thickets with numerous trunks per square meter not much thicker than an arm. Nobody could `go for a walk' here...This episode serves as a background to the issues that will be discussed, and I will return to it in my conclusion. It supports a central aspect, which is often neglected in many discussions about globalization: geography matters.  相似文献   

Social Mix and the `Balanced Community' in British housing policy – a tale of two epochs     

Ian Cole  Barry Goodchild 《GeoJournal》2000,51(4):351-360

In Britain, concepts of `social mix' and the `balanced community' provide an example of how policy discourses have adapted to changing conceptions of the role of the state in public provision, forms of social division and inequality, and housing market transformations. The recent development of a policy agenda by the Labour government in Britain devised to promote more socially balanced neighbourhoods is not new, and its lineage may be traced back to the origins of housing and urban policy. However, the manner in which this objective has been framed and the intervention it has provoked have varied considerably over time. One is struck more by the episodic and discontinuous nature of the application of mix and balance in British policy than any sense of a coherent set of strategies pursued through changing times. This paper contrasts the place of social mix and balance in the discourses of the immediate post-war period in Britain with the renewed emphasis on such ideas in the policies of the New Labour government elected in 1997. In the first period, the claims of social mix were infused with the language of national reconstruction and the post-war settlement and the development of universal state provision. More recently, interest in social balance has arisen partly as a response to increased management difficulties and the process of `residualisation' in social housing and partly in response to new concepts of the underclass, social exclusion and social capital. The promotion of social mix and balance in contemporary policy has been shaped by notions of the underclass, social exclusion and the development of social capital in poorer communities. Policy intervention is overtly premised on the assumption that more mixed communities will promote more positive social interaction for residents, despite the lack of evidence for this claim. In practice, much of the discourse has now taken on a stronger sense of discipline and control in order to manage social housing estates. The meaning of social balance remains confused, however, and the achievement of this objective through policy intervention is likely to remain fraught with problems.  相似文献   

A preliminary assessment of social risk in Romania   总被引：1，自引：0，他引：1  

Liliana Guran  David Turnock 《GeoJournal》2000,50(2-3):139-150

Social risk is seen as endemic in the postmodern world of 'glocalisation', especially in cities competing for a place in the global economy while simultaneously seeking to contain tensions between a kaleidoscopic mix of urban interests and life styles. Transition economies in Eastern Europe are very much at risk, especially in southeastern Europe where a general decline in living standards heightens tension as large cities are threatened with heavy unemployment. Several indicators of social risk are examined at the county level in Romania, but it is evident that while there are some close correlations between unemployment on the one hand and labour unrest, divorce and criminality on the other this is not always the case. Some counties have remained stable despite high unemployment while others manifest high social risk with below-average unemployment. Further research is needed to assess risk on a regional basis more accurately, but it is clear that the electorate will continue to vent its anger on incumbent governments when necessary restructuring does not immediately attract new investment and job creation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Socioeconomic transformation in rural Romania through the eyes of experts: Demographic and social issues     

Wilfried Heller 《GeoJournal》2000,50(2-3):151-155

There is no standard model of transformation for post- socialist countries and each country encounters specific problems rooted in the geographical characteristics of the areas concerned. The human resources are of the greatest importance because it really matters how people (especially the decision-makers) perceive system change and continually reformulate their expectations and strategies; so investigations into the views of people caught up in the transformation can provide a deeper understanding of the background to structural change. Working the national, regional level and local levels in Romania, experts were asked to consider the advantages and disadvantages arising out of the transformation, the most important problems and constraints for future rural development and the policies needed. The paper examines the responses on demographic and social issues. It emerges the most detailed responses were supplied by local-level representatives while respondents at the regional level steered a middle course between the need to address local problems and the prime importance of stimulating the Romanian economy so as to generate resources for welfare programmes (with the latter issue the overriding concern of interviewees at national level). There was general agreement on the importance of foreign investment and European integration for economic development, with local actors taking only small steps in line with the existing opportunities. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献