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11.
Hannes Römer Jens Kersten Ralph Kiefl Stefan Plattner Alexander Mager Stefan Voigt 《International journal of geographical information science》2014,28(4):682-699
A critical requirement for an effective and coordinated response by public entities tasked with management, security, and relief during large-scale public events or natural disasters is the availability of current situational information. However, today there is a lack of comprehensive operational systems allowing a near-real-time (NRT) collection, visualization, and provision of situational information for larger areas. In this study a methodological framework is proposed, which allows an NRT extraction and visualization of situational information based on aerial image acquisition. The framework combines digital image analysis using a generic supervised information extraction approach based on statistical modeling with a downstream web-based visualization component realized through an automatic update of web services. Even though being applicable for different scenarios, the workflow will be demonstrated for the specific use-case of a NRT monitoring of open spaces including assembly and parking areas. Compared to other approaches, image analysis results indicate a high robustness and a low demand for computational power sources (7 seconds per image). Due to a high degree of automation, the proposed workflow contributes to a NRT ‘end-to-end’ monitoring system, which was developed within the VABENE (German acronym for ‘traffic management under large-scale public events and disaster conditions’) project covering all parts from the acquisition of raw aerial imagery to the dissemination of information products to end-users. 相似文献
12.
Knowledge about the hydrochemical conditions of deep groundwater is crucial for the design and operation of geothermal facilities. In this study, the hydrochemical heterogeneity of the groundwaters in the Malm aquifer, Germany, is assessed, and reasons for the extraordinarily high H2S concentrations in the central part of the Bavarian Molasse Basin are proposed. Samples were taken at 16 sites, for a total of 37 individual wells, to analyze cations, anions, gas loading and composition. The hydrochemical characteristics of the Malm groundwater in the center of the Molasse Basin are rather heterogeneous. Although the groundwater in the central basin is dominated by meteoric waters, there is a significant infiltration of saline water from higher strata. Care has to be taken in the interpretation of data from geothermal sites, as effects of chemical stimulation of the boreholes may not be fully removed before the final analyses. The distribution of H2S in the gas phase is correlated to the gas loading of the water which increases in the central basin. Temperatures, isotopic data and the sulfur mass balance indicate that H2S in the central basin is related to thermochemical sulfate reduction (south of Munich) and bacterial sulfate reduction (north of Munich). 相似文献
13.
Sedimentology,three‐dimensional geobody reconstruction and carbon dioxide origin of Pleistocene travertine deposits in the Ballık area (south‐west Turkey)
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14.
The magnetic fields of celestial bodies are usually supposed to be due to a ‘hydromagnetic dynamo’. This term refers to a number of rather speculative processes which are supposed to take place in the liquid core of a celestial body. In this paper we shall follow another approach which is more closely connected with hydromagnetic processes well-known from the laboratory, and hence basically less speculative. The paper should be regarded as part of a general program to connect cosmical phenomena with phenomena studied in the laboratory. As has been demonstrated by laboratory experiments, a poloidal magnetic field may be increased by the transfer of energy from a toroidal magnetic field through kink instability of the current system. This mechanism can be applied to the fluid core of a celestial body. Any differential rotation will produce a toroidal field from an existing poloidal field, and the kink instability will feed toroidal energy back to the poloidal field, and hence amplify it. In the Earth-Moon system the tidal braking of the Earth's mantle acts to produce a differential angular velocity between core and mantle. The braking will be transferred to the core by hydromagnetic forces which at the same time give rise to a strong magnetic field. The strength of the field will be determined by the rate of tidal braking. It is suggested that the magnetization of lunar rocks from the period ?4 to ?3 Gyears derives from the Earth's magnetic field. As the interior of the Moon immediately after accretion probably was too cool to be melted, the Moon could not produce a magnetic field by hydromagnetic effects in its core. The observed lunar magnetization could be produced by such an amplified Earth field even if the Moon never came closer than 10 or 20 Earth's radii. This hypothesis might be checked by magnetic measurements on the Earth during the same period. 相似文献
15.
The origin and evolution of the Earth-Moon system is studied by comparing it to the satellite systems of other planets. The normal structure of a system of secondary bodies orbiting around a central body depends essentially on the mass of the central body. The Earth with a mass intermediate between Uranus and Mars should have a normal satellite system that consists of about half a dozen satellites each with a mass of a fraction of a percent of the lunar mass. Hence, the Moon is not likely to have been generated in the environment of the Earth by a normal accretion process as is claimed by some authors.Capture of satellites is quite a common process as shown by the fact that there are six satellites in the solar system which, because they are retrograde, must have been captured. There is little doubt that the Moon is also a captured satellite, but its capture orbit and tidal evolution are still incompletely understood.The Earth and the Moon are likely to have been formed from planetesimals accreting in particle swarms in Kepler orbits (jet streams). This process leads to the formation of a cool lunar interior with an outer layer accreted at increasingly higher temperatures. The primeval Earth should similarly have formed with a cool inner core surrounded in this case by a very strongly heated outer core and with a mantle accreted slowly and with a low average temperature but with intense transient heating at each individual impact site. 相似文献
16.
Els Hannes Diana Kusumastuti Maikel León Espinosa Davy Janssens Koen Vanhoof Geert Wets 《Journal of Geographical Systems》2012,14(2):143-165
In this paper, the “mental map” concept is positioned with regard to individual travel behaviour to start with. Based on Ogden and Richards’ triangle of
meaning (The meaning of meaning: a study of the influence of language upon thought and of the science of symbolism. International
library of psychology, philosophy and scientific method. Routledge and Kegan Paul, London, 1966) distinct thoughts, referents and symbols originating from different scientific disciplines are identified and explained
in order to clear up the notion’s fuzziness. Next, the use of this concept in two major areas of research relevant to travel
demand modelling is indicated and discussed in detail: spatial cognition and decision-making. The relevance of these constructs
to understand and model individual travel behaviour is explained and current research efforts to implement these concepts
in travel demand models are addressed. Furthermore, these mental map notions are specified in two types of computational models,
i.e. a Bayesian Inference Network (BIN) and a Fuzzy Cognitive Map (FCM). Both models are explained, and a numerical and a
real-life example are provided. Both approaches yield a detailed quantitative representation of the mental map of decision-making
problems in travel behaviour. 相似文献
17.
Ülo Suursaar Tarmo Kall Holger Steffen Hannes Tnisson 《Boreas: An International Journal of Quaternary Research》2019,48(4):913-928
Recent LiDAR surveys have revealed that on postglacially uplifting coasts of Estonia rhythmic coastal landforms (beach ridge sequences and foredune plains) occur to a considerable extent. We studied four of them to reveal age and periodicity in these multiple ridge systems and discussed their genesis in the Subatlantic (semi‐continental) conditions of the Baltic Sea area. Using recent models of Fennoscandian uplift due to glacial isostatic adjustment (GIA), we constructed Holocene apparent sea level curves for the study sites at Õngu, Mänspe, Haldi and Keibu; converted distance–height shore profiles into time series (including corrections on shore profile non‐linearity and variations in GIA‐eustasy balance); and analysed the patterns using spectral analysis. It was suggested that due to non‐tidal conditions, relatively low‐energy hydrodynamic forcing and small aeolian contribution, the ridges mark ancient shorelines. They are relatively modest in height (mostly 0.2–1 m), form regular and extensive (up to 150 ridges) patterns, and date back to ~9000 years before present. We studied <5‐ka‐old sections. The mean ridge spacing varied, depending also on coastal slope, between 21 and 39 m. Both simple counting and spectral analysis involved some specific limitations, yet the estimates for typical spacing were alike, at 32 (±5) years. The regular nature of the low‐ridge patterns originated from relative sea level lowering and gradual sediment accretion/erosion. However, the progradation was rather uplift‐ than accretion‐driven and the stepwise process in ridge formation was probably not autocyclic. It was governed or modulated by quasi‐periodic 25–40 year cyclicity in local wave forcing, relative sea level variations and wind conditions. Being most likely connected to the North Atlantic Oscillation, the quasi‐regular, decadal‐scale, similarly phased variations may magnify each other's effect on the westerly exposed coasts of Estonia. Additionally, some other (e.g. event‐driven) mechanisms may also be present. 相似文献
18.
Global geospatial data from Earth observation: status and issues 总被引:1,自引:0,他引:1
ABSTRACTData covering the whole of the surface of the Earth in a homogeneous and reliable manner has been accumulating over many years. This type of data became available from meteorological satellites from the 1960s and from Earth-observing satellites at a small scale from the early 1970s but has gradually accumulated at larger scales up to the present day when we now have data covering many environmental themes at large scales. These data have been used to generate information which is presented in the form of global data sets. This paper will give a brief introduction to the development of Earth observation and to the organisations and sensors which collect data and produce global geospatial data sets. Means of accessing global data sets will set out the types of data available that will be covered. Digital elevation models are discussed in a separate section because of their importance in georeferencing image data as well as their application to analysis of thematic data. The paper will also examine issues of availability, accuracy, validation and reliability and will look at future challenges. 相似文献
19.
Summary The Austrian city of Graz at the south-eastern edge of the Alps frequently experiences wintertime stagnations during anticyclonic
flow conditions, leading to high local concentrations of primary pollutants. This paper investigates the dominant three-dimensional
local flow structures in the Graz region during a representative January stagnation period in 1998 using data obtained from
a field experiment that supplemented the routine meteorological network with an array of sodars and tethersondes and a meteorological
tower. Important modifications to the temperature and wind fields over Graz and its surroundings are attributed to both topographical
and urban effects. The main modifications to the along-valley wind system in the Mur valley that runs through Graz from north
to south are caused by near-surface temperature field differences between a warmer north and a cooler south part of the city
and the regular development of a nighttime down-valley low-level jet and its upward lifting when crossing the city centre.
Received October 8, 1998 Revised December 2, 1998 相似文献
20.
Central European Cenozoic plume volcanism with OIB characteristics and indications of a lower mantle source 总被引:6,自引:0,他引:6
Average concentrations of incompatible elements and isotopes of radiogenic Sr, Nd and Pb in a 350 km long belt of Central
European volcanics (CECV) resemble those in OIB in general and in OIB from the N Atlantic in particular. This similarity allows
to infer comparable sources for CECV and OIB which might have been located in the lower mantle according to seismic tomography
and chemistry, with the latter unlike a MORB source. The incompatible element contribution of lower mantle origin can be modelled
from primitive mantle minus continental crust and upper mantle inventories. Alkali basaltic magmas from the modelled source
are close in composition to CECV and OIB. The continental crust contains almost half of the silicate Earth's content of Rb,
K, Pb, Ba, Th and U, which were mobilized to a major extent through dehydration of subducted ocean crust. Related losses from
the lower mantle had to be replaced by deep subductions of oceanic lithosphere recognized from their isotopic imprint. From
a balance based on Nd isotopes it can be concluded that average CECV contains 60% matter from residual primitive mantle and
40% from deeply subducted lithosphere (including some young upper mantle materials). Plume products from separate CECV regions
developed, within 45 Ma, from rather depleted to more primitive isotopic signatures. Four periods of volcanism from Eocene
to late Quaternary time are explained as four pulses of an almost stationary ultrafast plume uprise as modelled by Larsen
and Yuen (1997). Magma production has increased from the first to the third pulse with the peak during Miocene time in the
Vogelsberg region. The final pulse produced the Quaternary Eifel volcanoes. Tectonism from the Alpine orogen has probably
triggered the synchronous volcanism of CECV, Massif Central etc. The European lithospheric plate has moved under the control
of the opening Atlantic almost in an eastern direction with a velocity of 1 cm per year and has shifted extinct volcanoes
off their source channels.
Received: 10 July 1998 / Accepted: 10 February 1999 相似文献