Bernhard Butzin 《GeoJournal》1991,2(1):11-26

Within a typical process of urbanization several particularities can be noticed in the Helsinki region: The peninsular location does not allow a zonal expansion of the city. It has rather enforced a tight spatial sectoral expansion with specific problems of traffic and land use. The retarded industrialization has led to an unusually fast population increase without control until the 1960s.The rapid growth created a twofold problem: pressure of population versus inadequate housing, small residences versus high rents; consequently selective migration and small size families. The number of jobs rapidly increased and displaced the residential population of the inner city. This resulted in high traffic which neither the few main roads nor the public transport system of central Helsinki could cope with.These problems correspond to the essential tasks of urban planning: the bottle neck in housing construction has to be broken; the growth of jobs in the central city needs to be stopped as well as the displacement of the residential population. Decentralization, especially of the private tertiary and quartary sector may help. A system of central places within the region would diminish the commuting traffic. Transportation may be solved by a concept of growth points and growth axis along the railway lines.This grown concept of Helsinki should be thought over under the now foreseeable conditions of population stagnation.  相似文献   

XFEM,strong discontinuities and second-order work in shear band modeling of saturated porous media     

Ehsan Mikaeili  Bernhard Schrefler 《Acta Geotechnica》2018,13(6):1249-1264

We investigate shear band initiation and propagation in fully saturated porous media by means of a combination of strong discontinuities (discontinuities in the displacement field) and XFEM. As a constitutive behavior of the solid phase, a Drucker–Prager model is used within a framework of non-associated plasticity to account for dilation of the sample. Strong discontinuities circumvent the difficulties which appear when trying to model shear band formation in the context of classical nonlinear continuum mechanics and when trying to resolve them with classical numerical methods like the finite element method. XFEM, on the other hand, is well suited to deal with problems where a discontinuity propagates, without the need of remeshing. The numerical results are confirmed by the application of Hill’s second-order work criterion which allows to evaluate the material point instability not only locally but also for the whole domain.  相似文献   

Enhancing adaptive composite map projections: Wagner transformation between the Lambert azimuthal and the transverse cylindrical equal-area projections   总被引：1，自引：0，他引：1  

Bernhard Jenny  Bojan Šavrič 《制图学和地理信息科学》2018,45(5):456-463

The adaptive composite map projection technique changes the projection to minimize distortion for the geographic area shown on a map. This article improves the transition between the Lambert azimuthal projection and the transverse equal-area cylindrical projection that are used by adaptive composite projections for portrait-format maps. Originally, a transverse Albers conic projection was suggested for transforming between these two projections, resulting in graticules that are not symmetric relative to the central meridian. We propose the alternative transverse Wagner transformation between the two projections and provide equations and parameters for the transition. The suggested technique results in a graticule that is symmetric relative to the central meridian, and a map transformation that is visually continuous with changing map scale.  相似文献   

Impact of an 0.2 km3 Rock Avalanche on Lake Eibsee (Bavarian Alps,Germany) – Part I: Reconstruction of the paleolake and Effects of the Impact     

Sibylle Knapp  Philipp Mamot  Bernhard Lempe  Michael Krautblatter 《地球表面变化过程与地形》2021,46(1):296-306

Rock avalanches destroy and reshape landscapes in only a few minutes and are among the most hazardous processes on Earth. The surface morphology of rock avalanche deposits and the interaction with the underlying material are crucial for runout properties and reach. Water within the travel path is displaced, producing large impact waves and reducing friction, leading to long runouts. We hypothesize that the 0.2 km³ Holocene Eibsee rock avalanche from Mount Zugspitze in the Bavarian Alps overran and destroyed Paleolake Eibsee and left a unique sedimentological legacy of processes active during the landslide. We captured 9.5 km of electrical resistivity tomography (ERT) profiles across the rock avalanche deposits, with up to 120 m penetration depth and more than 34 000 datum points. The ERT profiles reveal up to ~50 m thick landslide debris, locally covering up to ~30 m of rock debris with entrained fine-grained sediments on top of isolated remnants of decametre-wide paleolake sediments. The ERT profiles allow us to infer processes involved in the interaction of the rock avalanche with bedrock, lake sediments, and morainal sediments, including shearing, bulging, and bulldozing. Complementary data from drilling, a gravel pit exposure, laboratory tests, and geomorphic features were used for ERT calibration. Sediments overrun by the rock avalanche show water-escape structures. Based on all of these datasets, we reconstructed both position and size of the paleolake prior to the catastrophic event. Our reconstruction of the event contributes to process an understanding of the rock avalanche and future modelling and hazard assessment. Here we show how integrated geomorphic, geophysical, and sedimentological approaches can provide detailed insights into the impact of a rock avalanche on a lake. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd  相似文献   

Brixenbach research catchment: Quantification of runoff process proportions in a small Alpine catchment depending on soil moisture states and precipitation characteristics     

Gertraud Meißl  Clemens Geitner  Andreas Batliner  Klaus Klebinder  Bernhard Kohl  Gerhard Markart 《水文研究》2021,35(6):e14186

The Brixenbach valley is a small Alpine torrent catchment (9.2 km², 820–1950 m a.s.l., 47.45°, 12.26°) in Tyrol, Austria. Intensive hydrological research in the catchment since more than 12 years, including a hydrogeological survey, pedological and land use mapping, measurements of precipitation, runoff, soil moisture and infiltration as well as the conduction of rainfall simulations, has contributed to understand the hydrological response of the catchment, its subcatchments and specific sites. The paper presents a synthesis of the research in form of runoff process maps for different soil moisture states and precipitation characteristics, derived with the aid of a newly developed Soil-hydrological model. These maps clearly visualize the differing runoff reaction of different subcatchments. The pasture dominated areas produce high surface flow rates during short precipitation events (1 h, 86 mm) with high rainfall intensity, whilst the forested areas often develop shallow subsurface flow. Dry preconditions lead to a slight reduction of surface flow, long rainfall events (24 h, 170 mm) to a dominance of deep subsurface flow and percolation.  相似文献   

A compromise aspect-adaptive cylindrical projection for world maps     

Bernhard Jenny  Bojan Šavrič  Tom Patterson 《International journal of geographical information science》2013,27(6):935-952

There are two problems with current cylindrical projections for world maps. First, existing cylindrical map projections have a static height-to-width aspect ratio and do not automatically adjust their aspect ratio in order to optimally use available canvas space. Second, many of the commonly used cylindrical compromise projections show areas and shapes at higher latitudes with considerable distortion. This article introduces a new compromise cylindrical map projection that adjusts the distribution of parallels to the aspect ratio of a canvas. The goal of designing this projection was to show land masses at central latitudes with a visually balanced appearance similar to how they appear on a globe. The projection was constructed using a visual design procedure where a series of graphically optimized projections was defined for a select number of aspect ratios. The visually designed projections were approximated by polynomial expressions that define a cylindrical projection for any height-to-width ratio between 0.3:1 and 1:1. The resulting equations for converting spherical to Cartesian coordinates require a small number of coefficients and are fast to execute. The presented aspect-adaptive cylindrical projection is well suited for digital maps embedded in web pages with responsive web design, as well as GIS applications where the size of the map canvas is unknown a priori. We highlight the projection with a height-to-width ratio of 0.6:1, which we call the Compact Miller projection because it is inspired by the Miller Cylindrical projection. Unlike the Miller Cylindrical projection, the Compact Miller projection has a smaller height-to-width ratio and shows the world with less areal distortion at higher latitudes. A user study with 448 participants verified that the Compact Miller – together with the Plate Carrée projection – is the most preferred cylindrical compromise projection.  相似文献   

煤系有机质多阶段成气的分子碳同位素表征及其对高过成熟干酪根生气潜力评价的启示     

孙永革  杨中威  Bernhard CRAMER 《地球化学》2013,42(2)

采用开放体系在线程序升温裂解-色谱-碳同位素比值质谱技术(PY/GC-IRMS)考察了煤系有机质热演化过程中甲烷瞬时生成速率与碳同位素组成特征,提出煤系有机质不同热演化进程甲烷生成的四个阶段:生油窗阶段、主生气阶段、晚期生气阶段(芳环侧链断裂)、开环-缩聚作用阶段.以一级反应动力学为基础,采用高斯分布算法,计算了各阶段甲烷产出的动力学参数.研究结果对煤成气资源量的正确评价,特别是近年来有机质高演化阶段成气潜力的评价具有重要指示意义.  相似文献   

Satellite imaging coral reef resilience at regional scale. A case-study from Saudi Arabia     

Rowlands G  Purkis S  Riegl B  Metsamaa L  Bruckner A  Renaud P 《Marine pollution bulletin》2012,64(6):1222-1237

We propose a framework for spatially estimating a proxy for coral reef resilience using remote sensing. Data spanning large areas of coral reef habitat were obtained using the commercial QuickBird satellite, and freely available imagery (NASA, Google Earth). Principles of coral reef ecology, field observation, and remote observations, were combined to devise mapped indices. These capture important and accessible components of coral reef resilience. Indices are divided between factors known to stress corals, and factors incorporating properties of the reef landscape that resist stress or promote coral growth. The first-basis for a remote sensed resilience index (RSRI), an estimate of expected reef resilience, is proposed. Developed for the Red Sea, the framework of our analysis is flexible and with minimal adaptation, could be extended to other reef regions. We aim to stimulate discussion as to use of remote sensing to do more than simply deliver habitat maps of coral reefs.  相似文献   

Monitoring 25 years of land cover change dynamics in Africa: A sample based remote sensing approach   总被引：3，自引：1，他引：2  

Andreas Bernhard Brink  Hugh Douglas Eva   《Applied geography (Sevenoaks, England)》2009,29(4):501-512

The study examines the changes in sub-Saharan's natural land cover resources for a 25 year period. We assess these changes in four broad land cover classes – forests, natural non-forest vegetation, agriculture and barren – by using high spatial resolution Earth observing satellites. Two sets of sample images, one ‘historical’ targeted at 1975 and a second ‘recent’ targeted at the year 2000, have been selected through a stratified random sampling technique over the study area, targeting a sampling rate of 1% in each of the strata. The results, presented at eco-region level and aggregated at sub-Saharan level, show a 57% increase in agriculture area at the expense of natural vegetation which has itself decreased by 21% over the period, with nearly 5 million hectares forest and non-forest natural vegetation lost per year. The impacts of these changes on the environment on one site and on the socio-economy on the other site are discussed and possible pressures on human well being are highlighted.  相似文献   

Variation of colour patterns in larval Hydropsyche (Trichoptera): Implications for species identifications and the phylogeny of the genus     

Bernhard Statzner  Nathalie Mondy 《Limnologica》2009,39(2):177-183

Larvae of the lotic caddisfly genus Hydropsyche may occur in densities of thousands to several tens of thousands of individuals/m² across continents and running water types. Therefore, stream ecologists frequently face the task of identifying larvae of this genus. Early keys to larval Hydropsyche of Asia, Europe and North America often used the relatively complicated frontoclypeal colour pattern for species discrimination, whereas equivocal views about the variation of this pattern limited its use in recent keys. Has each species of a given species group a different (although intraspecifically variable) basic pattern of lighter spots on the darker frontoclypeus, or have all species of a group the same basic colour pattern that varies more or less intraspecifically? An answer to this question has obvious implications for the identification of the species as well as for the phylogeny of the genus, so we examined the variation of this colour pattern across ∼11,000 specimens of 10 Hydropsyche species from the Loire River (France).All 10 species had the same basic colour pattern on the frontoclypeus (six contrasting light patches on a dark background) that varied intraspecifically across a certain range of colour contrasts. Comparing other sources illustrating the frontoclypeus of Hydropsyche larvae provided more support for the idea that six contrasting light patches on the frontoclypeus is the typical basic colour pattern that varies within almost all European species; males of these species have a simple phallus form. Two European and many North American species of the genus (from the Ceratopsyche group) have a different basic colour pattern of seven light patches on the frontoclypeus that varies also intraspecifically; males of these species have a complicated phallus form.If the variation of such colour patterns in co-existing populations of several species is known, the relative contrast differences among the individual patches on the frontoclypeus and the form of the individual patches can provide valuable information for rapid species identification. Analysis of this variation may also contribute to phylogenetic studies of the genus Hydropsyche and other hydropsychids.  相似文献