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841.
The Florida State University (FSU) multimodel superensemble forecast is evaluated against several other operational weather models for the Southeast Asia region. The superensemble technique has demonstrated its exceptional skills in forecasting precipitation, motion and mass fields compared to either individual global operational or ensemble mean forecasts. The motion field investigation for the season of 2001 reveals that the superensemble forecasts are closer to the observed data compared to the other global member operational models through its low systematic errors at the 850 hPa level. The FSU multimodel superensemble forecasts exhibit the lowest root mean square errors (RSMEs), the highest correlation against the best observed data and the lowest systematic errors compared to the other operational model members. These forecasts have the potential to provide better daily weather predictions over the Southeast Asia region, particularly during the early northeast monsoon that often causes heavy rainfall in the equatorial part of the Southeast Asia region. 相似文献
842.
Towards a method for postcolonial development geography? Possibilities and challenges 总被引:2,自引:0,他引:2
In this paper we explore the contours of a 'method' for postcolonial development geography, which makes it possible to imagine another 'world-picturing'. We suggest three steps towards such a method. First, we propose that a postcolonial method involves thinking about why we are doing research in the south in the first place; how we come to and produce our questions; and how we analyze and represent our findings based on our subject positionings. Second, that we need to recognize theorization as an inherent part of method, rethink how we currently theorize and reconfigure our methods of theorization to address wider political aims. Problematizing theorization helps challenge the universalism of Eurocentric theories, thus enabling development geography to move towards more decolonized versions and visions. Finally, that this must be accompanied by firmer recognition of our multiple investments – personal, institutional and geopolitical – and how they frame the possibilities for change. These are some possible steps that we think can reconfigure the 'scholarly track' that postcolonial development geographers traverse. 相似文献
843.
844.
Nassima Atmaoui Nina Kukowski Bernhard Stöckhert Diethard König 《International Journal of Earth Sciences》2006,95(2):225-238
Typical pull-apart structures were created in scaled clay experiments with a pure strike-slip geometry (Riedel type experiments). A clay slab represents the sedimentary cover above a strike-slip fault in the rigid basement. At an early stage of the development of the deformation zone, synthetic shear fractures (Riedel shears) within the clay slab display dilatational behaviour. With increasing basal displacement the Riedel shears rotate and open further, developing into long, narrow and deep troughs. The shear displacement and the low angle with the prescribed principal basal fault set them apart from tension gashes. At a more evolved stage, synthetic segments (Y-shears) parallel to the basal principal fault develop and accommodate progressive strike-slip deformation. The Y-shears connect the tips of adjacent troughs developed from the earlier Riedel shears, resulting in the typical rhomb-shaped structures characteristic for pull-apart basins. The Strait of Sicily rift zone, with major strike-slip systems being active from the Miocene to the Present, comprises pull-apart basins at different length scales, for which the structural record suggests development by a mechanism similar to that observed in our experiments. 相似文献
845.
Potential of High-Resolution Satellite Data in the Context of Vulnerability of Buildings 总被引:1,自引:2,他引:1
High-resolution space-borne remote sensing data are investigated for their potential to extract relevant parameters for a
vulnerability analysis of buildings in European countries. For an evaluation of large earthquake scenarios, the number of
parameters in models for vulnerability is reduced to a minimum of relevant information such as the type of building (age,
material, number of storeys) and the geological and spatial context. Building-related parameters can be derived from remote
sensing data either directly (e.g. height) or indirectly based on the recognition of the urban structure type in which the
buildings are located. With the potential of a fully- or semi-automatic inventory of the buildings and their parameters, high-resolution
satellite data and techniques for their processing are a useful supporting tool for the assessment of vulnerability. 相似文献
846.
The computation of electromagnetic (EM) fields, for 1-D layered earth model, requires evaluation of Hankel Transform (HT)
of the EM kernel function. The digital filtering is the most widely used technique to evaluate HT integrals. However, it has
some obvious shortcomings. We present an alternative scheme, based on an orthonormal exponential approximation of the kernel
function, for evaluating HT integrals. This approximation of the kernel function was chosen because the analytical solution
of HT of an exponential function is readily available in literature. This expansion reduces the integral to a simple algebraic
sum. The implementation of such a scheme requires that the weights and the exponents of the exponential function be estimated.
The exponents were estimated through a guided search algorithm while the weights were obtained using Marquardt matrix inversion
method. The algorithm was tested on analytical HT pairs available in literature. The results are compared with those obtained
using the digital filtering technique with Anderson filters. The field curves for four types (A-, K-, H-and Q-type) of 3-layer
earth models are generated using the present scheme and compared with the corresponding curves obtained using the Anderson
sc heme. It is concluded that the present scheme is more accurate than the Anderson scheme 相似文献
847.
The authors identify and describe the following global forces of nature driving the Earth’s climate: (1) solar radiation as a dominant external energy supplier to the Earth, (2) outgassing as a major supplier of gases to the World Ocean and the atmosphere, and, possibly, (3) microbial activities generating and consuming atmospheric gases at the interface of lithosphere and atmosphere. The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth’s climate. Quantitative comparison of the scope and extent of the forces of nature and anthropogenic influences on the Earth’s climate is especially important at the time of broad-scale public debates on current global warming. The writers show that the human-induced climatic changes are negligible. 相似文献
848.
Palestinian suicide terrorism has been a key feature in the latest phase of the Israeli–Palestinian conflict. During the past decade, and particularly since September 2000, there has been a substantial increase in the use of this type of warfare. Recent studies suggest that, contrary to common belief, suicide terrorism is highly rational and driven by strategic considerations. This article explores the rationality of Palestinian suicide terrorism from a geographical perspective. It is argued that suicide terrorism works along two parallel paths: rationality and randomness. It complies with geographical fundamentals, and target selection is highly rational, subject to spatial considerations such as distance, agglomeration, and accessibility. As the permeability to Israel became more difficult, suicide bombers and their organizers had to adopt more flexible practices which emphasized other spatial considerations. Timing is of importance both for strategic and tactical reasoning. Obstructing negotiations and peace talks has been a salient objective, but the exact timing of suicide bombings has been influenced by tactical considerations, which aim at maximizing casualties. 相似文献
849.
杨庄截潜工程趾板段建基面以下为弱风化白云岩和含燧石条带白云岩,透水性较强,造成库水漏失严重.为解决建基面以下基岩渗漏问题,采用趾板段帷幕灌浆封堵基岩裂隙而形成防渗帷幕,以减少库水漏失.通过趾板段帷幕灌浆达到封堵基岩裂隙的目的,满足工程设计的防渗要求. 相似文献
850.
模糊理论在公路边坡稳定性分析中的应用 总被引:7,自引:0,他引:7
边坡工程是一个复杂的系统工程。边坡的稳定与否直接关系到其防护工作的程度。因此,如何有效、合理地判断边坡的稳定性对整个工程的经济与社会效益极为重要。影响边坡稳定的因素众多,判断其稳定与否应考虑各因素的综合效果。论文运用模糊理论中的多因素综合评判模型对某高速公路边坡的稳定性进行研究。通过全面考虑影响因素,建立相应的评判因素集及单因素评判矩阵,运用专家评判法和判断矩阵法确定出各因素的权重。最后通过多层次模糊评判得到该边坡的稳定性评判结果。研究证明,该法在边坡稳定性分析评判中是切实可行的。 相似文献