Estimating traveler populations at airport and cruise terminals for population distribution and dynamics     

Warren C. Jochem  Kelly Sims  Edward A. Bright  Marie L. Urban  Amy N. Rose  Phillip R. Coleman  Budhendra L. Bhaduri 《Natural Hazards》2013,68(3):1325-1342

In recent years, uses of high-resolution population distribution databases are increasing steadily for environmental, socioeconomic, public health, and disaster-related research and operations. With the development of daytime population distribution, temporal resolution of such databases has been improved. However, the lack of incorporation of transitional population, namely business and leisure travelers, leaves a significant population unaccounted for within the critical infrastructure networks, such as at transportation hubs. This paper presents two general methodologies for estimating passenger populations in airport and cruise port terminals at a high temporal resolution which can be incorporated into existing population distribution models. The methodologies are geographically scalable and are based on, and demonstrate how, two different transportation hubs with disparate temporal population dynamics can be modeled utilizing publicly available databases including novel data sources of flight activity from the Internet which are updated in near-real time. The airport population estimation model shows great potential for rapid implementation for a large collection of airports on a national scale, and the results suggest reasonable accuracy in the estimated passenger traffic. By incorporating population dynamics at high temporal resolutions into population distribution models, we hope to improve the estimates of populations exposed to or at risk to disasters, thereby improving emergency planning and response, and leading to more informed policy decisions.  相似文献   

Toward a physically plausible upper bound of sea-level rise projections   总被引：3，自引：1，他引：2  

Ryan L. Sriver  Nathan M. Urban  Roman Olson  Klaus Keller 《Climatic change》2012,115(3-4):893-902

Anthropogenic sea-level rise (SLR) causes considerable risks. Designing a sound SLR risk-management strategy requires careful consideration of decision-relevant uncertainties such as the reasonable upper bound of future SLR. The recent Intergovernmental Panel on Climate Change’s (IPCC) Fourth Assessment reported a likely upper SLR bound in the year 2100 near 0.6 m (meter). More recent studies considering semi-empirical modeling approaches and kinematic constraints on glacial melting suggest a reasonable 2100 SLR upper bound of approximately 2 m. These recent studies have broken important new ground, but they largely neglect uncertainties surrounding thermal expansion (thermosteric SLR) and/or observational constraints on ocean heat uptake. Here we quantify the effects of key parametric uncertainties and observational constraints on thermosteric SLR projections using an Earth system model with a dynamic three-dimensional ocean, which provides a mechanistic representation of deep ocean processes and heat uptake. Considering these effects nearly doubles the contribution of thermosteric SLR compared to previous estimates and increases the reasonable upper bound of 2100 SLR projections by 0.25 m. As an illustrative example of the effect of overconfidence, we show how neglecting thermosteric uncertainty in projections of the SLR upper bound can considerably bias risk analysis and hence the design of adaptation strategies. For conditions close to the Port of Los Angeles, the 0.25 m increase in the reasonable upper bound can result in a flooding-risk increase by roughly three orders of magnitude. Results provide evidence that relatively minor underestimation of the upper bound of projected SLR can lead to major downward biases of future flooding risks.  相似文献   

长白山地区全新世泥炭剖面地球化学特征及其古环境意义   总被引：4，自引：0，他引：4       下载免费PDF全文

赵红艳  王升忠  李鸿凯 《古地理学报》2004,6(3):355-362

长白山地区是中国泥炭分布集中地区之一。本文选择长白山地区典型的泥炭剖面--大桥剖面,探讨其沉积物常量元素和微量元素的垂直分布规律及其对全新世气候变化的指示作用,并与该区另一代表剖面--金川泥炭剖面进行对比。结果表明,泥炭中常量元素含量最大值出现在195 cm,向上、向下都减少,铁含量与灰分、容重在剖面上的变化规律基本一致,说明它主要来源于灰分;由于泥炭和砂土的基本性质,如容重、灰分、pH值有很大的区别,泥炭层微量元素大于下部砂土的含量,亚表层微量元素含量最高,这与灰分、纤维含量正好相反,与pH值剖面变化一致;沉积物容重、灰分、pH值、Ca/ Mg以及元素的富集因子、泥炭中总碳含量在剖面上的变化,显示很强的一致性,据此反映该区经历了早11880～7600aBP)、中(7 600～480aBP)、晚(2480～0aBP)全新世三个环境阶段,其结论与前人通过孢粉、同位素手段分析得到的金川泥炭剖面环境变迁规律相同,从而说明它们可以作为研究环境变迁的敏感指标。  相似文献   

Multidisciplinary characterization of the middle Holocene eolian deposits of the Elsa River basin (central Italy)   总被引：1，自引：0，他引：1  

E.A.C. Costantini  S. Priori  B. Urban  A. Hilgers  D. Sauer  G. Protano  L. Trombino  D. Hülle  F. Nannoni 《Quaternary International》2009,209(1-2):107

In temperate regions, eolian deposits of different natures are often pedogenically-altered and mixed with underlying sediments. The research reported in this paper identifies for the first time the presence of eolian deposits in soils of central Tuscany and investigates the characteristics and origin. Five relict, polycyclic paleosol profiles were studied. P1 was situated in a natural dust trap, a doline on top of an isolated limestone hill; P2 and P3 were both situated on a limestone plateau, and P4 and P5 on a mid- and foot slope on schist. The profiles were sampled for routine analyses, iron forms, heavy minerals, major and trace elements, and pollen, spores and non-pollen palynomorphs. Undisturbed samples were taken for micromorphological and SEM analyses. Nine soil horizons were sampled for OSL dating. Eolian deposits were dominant or abundant in the first layers of P1, P2 and P3. OSL age determinations of soil horizons deriving from eolian parent material were middle Holocene. Chemical and heavy mineral analyses indicated different possible sources, including bare slopes, alluvial fans and wide channels, coming from the nearby streams that drain the Middle Tuscany ridge and the Mounts of Chianti; marginal contribution of volcanic ashes was only found in P1.The research demonstrated that wind soil erosion accompanied water erosion and colluvial deposition during the middle Holocene in the Elsa River basin. Pollen spectra, in particular, indicated that soil degradation occurred in an environment showing signs of incipient desertification, resulting from an increase of aridity in a land already strongly influenced by humans. Although central Italy is currently considered to be only marginally affected by wind soil erosion, a climate change, which would imply increased arid conditions, could trigger a new cycle of slope denudation, wind erosion and loess deposition.  相似文献   

Ice-wedge casts and relict polygonal patterns in Scandinavia     

Harald Svensson 《第四纪科学杂志》1988,3(1):57-67

Ice-wedge casts in Scandinavia frequently occur in three regions: (a) southwestern Jutland (outside the limit of the Weichselian glaciation); (b) southwestern Sweden; and (c) northernmost Norway. The latter two areas are both early deglaciated regions. Characteristics of casts in vertical sections are discussed with reference to the host and infilling material. Aerial photographs provide an effective tool for detecting relict ice-wedge polygons (crop marks, micromorphology). Experience from present-day permafrost regions with active ice-wedge formation helps to explain the palaeoclimatic significance of the relict polygons. Attempts to establish the ages of formation are discussed from a methodological point of view.  相似文献   

Meltwater Discharge to the Skagerrak–Kattegat from the Baltic Ice Lake during the Younger Dryas Interval     

Hui Jiang  Nils-Olof Svensson  Svante Björck 《Quaternary Research》1998,49(3):264-270

Diatom data from the Skagerrak–Kattegat show that large amounts of meltwater were discharged into the Kattegat–Skagerrak from the Baltic Ice Lake during the Younger Dryas interval. Strong meltwater discharge greatly freshened surface-water salinity in the Kattegat and areas along the Swedish west coast and possibly changed the directions of sea-surface salinity gradients from north–south to east–west or northwest–southeast. It resulted in a markedly stratified water column in salinity in the Kattegat, which complicates the environmental interpretation based on different types of microfossils. The meltwater influence on the large area of the Skagerrak during the Younger Dryas was, however, restricted along the Norwegian coast where it flowed into the Norwegian Sea.  相似文献   

P–SVmultimode summation differential seismograms for layered structures     

Z. J. Du  A. Michelini  G. F. Panza  & L. Urban 《Geophysical Journal International》1998,134(3):747-756

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The identification of Feix and Nixi in the solar corona     

Svensson  L. Å.  Ekberg  J. O.  Edlén  B. 《Solar physics》1974,34(1):173-179

The levels of the configuration 3s ²3 _p ⁵3d of Fe ix have been experimentally determined from their combinations with 3s3 _p ⁶3d ³ D in the region 300–400 Å. Wavelengths can now be accurately predicted for all transitions within 3s ²3 _p 53^d, and eight of these can be identified with coronal lines from 2042 to 4585 Å. Also, identifications of solar lines from 171 to 245 Å with electric-dipole and magnetic-quadrupole transitions to the ground state, 3s ²3p ^{6 1} S, are confirmed and extended. Solar identifications with corresponding transitions in Ni xi, both within 3s ²3 _p ⁵3d and to the ground state, are proposed on the basis of a short extrapolation.  相似文献   

Temporal changes and spatial variation of soil oxygen consumption, nitrification and denitrification rates in a tidal salt marsh of the Lagoon of Venice, Italy   总被引：4，自引：0，他引：4  

P. G. Eriksson  J. M. Svensson  G. M. Carrer 《Estuarine, Coastal and Shelf Science》2003,58(4):861-871

The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh creeks and in areas covered by the dominant vegetation, Limonium serotinum. In May, cores were also collected in areas with vegetation dominated by Juncus maritimus and Halimione portulacoides. In laboratory incubations at in situ temperature in the dark, flux rates of oxygen and DIN were monitored in the overlying water of the intact cores. ¹⁵N-nitrate was added to the overlying water and nitrification and denitrification were measured using isotope-dilution and -pairing techniques. The results show that highest soil oxygen consumption coincided with the highest water temperature in June and July. The highest denitrification rates were recorded in spring and autumn coinciding with the highest nitrate concentrations. Soil oxygen consumption and nitrification rates differed between sampling sites, but denitrification rates were similar among the different vegetation types. The highest rates were recorded in areas covered with L. serotinum. Burrowing soil macrofauna enhanced oxygen consumption, nitrification and denitrification in April and May. The data presented in this study indicate high temporal as well as spatial variations in the flux of oxygen and DIN, and nitrogen transformations in the tidal salt marshes of the Venice lagoon during the growth season. The results identify the salt marshes of the Venice lagoon as being metabolically very active ecosystems with a high capacity to process nitrogen.  相似文献   

A Bayesian machine learning model for estimating building occupancy from open source data     

Robert Stewart  Marie Urban  Samantha Duchscherer  Jason Kaufman  April Morton  Gautam Thakur  Jesse Piburn  Jessica Moehl 《Natural Hazards》2016,81(3):1929-1956

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