Natural hazards in Nordic Countries   总被引：1，自引：0，他引：1  

Farrokh Nadim Stig AsbjФrn Schack Pedersen Philipp Schmidt-Thome Freysteinn Sigmundsson Mats Engdahl 《《幕》》2008,31(1):176-184

Compared to many areas of the world, the human losses caused by natural hazards are smaller in Nordic countries. This is mainly due to the low population density in the exposed areas. However, the economic losses are significant and the geohazards picture varies among the countries. The predominant natural hazards in Nordic countries are floods, landslides, and, with the exception of Denmark, snow avalanche. Volcanoes and earthquakes are major geohazards in Iceland, and parts of Norway are susceptible to seismic activity. Slidetriggered tsunamis also represent a threat to parts of the coastal areas of Nordic countries and Greenland.  相似文献   

Avoidance response of sediment living amphipods to zinc pyrithione as a measure of sediment toxicity     

Eriksson Wiklund AK  Börjesson T  Wiklund SJ 《Marine pollution bulletin》2006,52(1):96-99

An avoidance test was developed using non-cultured individuals of the sediment dwelling amphipod Monoporeia affinis. As test substance we used zinc pyrithione, an antifouling agent and a common shampoo ingredient. The toxicity to Daphnia and fish is well known but sediment toxicity of this very hydrophobic compound is less known. The preference of juvenile M. affinis was tested in jars, each including 12 petri dishes. In each replicate, half of the petri dishes contained sediment mixed with six concentrations ranging from 0 to 10microg zinc pyrithione per L sediment and half of the petri dishes contained the corresponding sediment-substance mixture plus an extra food addition. The amphipods significantly avoided petri dishes with the three highest concentrations of zinc pyrithione and the calculated EC(50) was 9.65microgL(-1) sediment. No difference in mortality was observed between concentrations. Using the avoidance behaviour in sediment toxicity testing is a simple and cost-effective screening for toxicants.  相似文献   

2D surface topography boundary conditions in seismic wave modelling     

Bent Ruud  Stig Hestholm 《Geophysical Prospecting》2001,49(4):445-460

New formulations of boundary conditions at an arbitrary two-dimensional (2D) free-surface topography are derived. The top of a curved grid represents the free-surface topography while the grid's interior represents the physical medium. The velocity–stress version of the viscoelastic wave equations is assumed to be valid in this grid. However, the rectangular grid version attained by grid transformation is used to model wave propagation in this work in order to achieve the numerical discretization. We show the detailed solution of the particle velocities at the free surface resulting from discretizing the boundary conditions by second-order finite-differences (FDs). The resulting system of equations is spatially unconditionally stable. The FD order is gradually increased with depth up to eighth order inside the medium. Staggered grids are used in both space and time, and the second-order leap-frog and Crank–Nicholson methods are used for time-stepping. We simulate point sources at the surface of a homogeneous medium with a plane free surface containing a hill and a trench. Applying parameters representing exploration surveys, we present examples with a randomly realized surface topography generated by a 1D von Kármán function of order 1. Viscoelastic simulations are presented using this surface with a homogeneous medium and with a layered, randomized medium realization, all generating significant scattering.  相似文献   

Lipids and trophic linkages in harp seal (Phoca groenlandica) from the eastern Barents Sea   总被引：2，自引：0，他引：2  

Stig Falk-Petersen  Tore Haug  Kjell T. Nilssen  Anette Wold  Trine M. Dahl 《Polar research》2004,23(1):43-50

Fatty acid profiles and lipid biomarkers from 20 harp seals were used to investigate the foraging ecology of harp seals and the transfer of energy through the Franz Josef Land-Novaya Zemlya food chain. High levels of the Calanus fatty acid trophic markers (FATMs) 20:1(n-9) (mean 14.6%) and 22:1(n-11) (mean 6.5%), together with the typical dinoflagellate FATMs 22:6(n-3) (mean 6.5%) and C18PUFA (mean 5.5%), were found in blubber samples. Based on the analyses of the fatty acid profiles separated by principal component analysis, we confirmed the importance of polar cod ( Boreogadus saida ) and the pelagic amphipod Themisto libellula in the diet of harp seal. The high levels of 22:6(n-3), C18PUFA and C20 and C22 FATMs show that the harp seal lipids mainly originate from dinoflagellates consumed by Calanus copepods.  相似文献   

The Baltica–lapetus passive margin dyke complex in the Sarektjåkkå Nappe,northern Swedish Caledonides     

Olaf M. Svenningsen 《Geological Journal》1994,29(4):323-354

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Composite memory variable velocity–stress viscoelastic modelling     

Stig Hestholm 《Geophysical Journal International》2002,148(1):153-162

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Deterministic decomposition of pitch-and-roll buoy measurements     

Stig E. Sand 《Coastal Engineering》1984,8(3):243-263

Wave-gauge arrays, current meters and pitch-and-roll buoys are widely used for the recording of directional properties of ocean waves. For the determination of directional spectra the traditional stochastic procedure usually includes the selection of a parameterized spreading function. The present theory, which is illustrated below for a pitch-and-roll buoy, decomposes the information into frequencies, amplitudes, directions, and also phases. Furthermore, this procedure requires no assumption of any function describing the expected form of the directional spread. The theory of this deterministic decomposition is described and compared to the traditional stochastic principles. Only for reasons of this comparison and presentation, the deterministically obtained directional distributions are fitted to normal distributions.Measurements taken by pitch-and-roll buoys and by current meter/wave gauge are presented and discussed. The remarkable tendency in the variation of the directional spread as a function of frequency is found for two quite different locations. To quantify the directional spread obtained from the deterministic method normal distributions are fitted, and the mean values and variances are plotted and discussed.  相似文献   

Short-term variations in trace metal concentrations in the baltic     

Lars-Göran Danielsson  Stig Westerlund 《Marine Chemistry》1984,15(3):273-277

Baltic surface water was sampled at a fixed position at intervals of a few hours. The trace metal concentrations were measured by graphite furnace AAS after extraction. The mean concentrations found were (ng l^?1): Cd, 30 ± 2.7; Cu, 800 ± 48; Fe, 358 ± 165; Ni, 820 ± 49; Pb, 16 ± 4.5; Zn, 900 ± 160. The variability in the trace metal concentrations is of the same order of magnitude as the precision of the method. Thus, no spatial variations in trace metal concentrations were found.  相似文献   

The national atlases of Finland     

Stig Jaatinen Dr. 《GeoJournal》1982,6(3):201-208

The first edition of Atlas of Finland was published in 1899, and since then four more editions have appeared, the fifth started in 1977. The two first editions (the second appeared in 1910) were published in order to define the identity of the nation during a time of Russian political opression and a nationalistic awakening. During the same period, in 1901 J. Gebhard published a social-statistical atlas of Finland, likewise a work of scholarly pioneering. The third edition of Atlas of Finland appeared in 1925, here the geographical analysis was much enhanced thanks to the editorial work of J.G. Granö. At this time Finland was still predominately an agrarian state, however, when the forth edition of the Finnish national atlas was published in 1960, the wind of change had set in. Prof. Leo Aario was the leader of this edition, where the deep changes after WW II were documentated,3also the beginning of the rapi d industrialization of the country.The fifth edition is published in separate thematic folios of some 25 pages each. The first folio on Forestry was published in 1977, and so far 4 folios have appeared of a total of 25. In each folio the graphic material and the text are integrated. There will be some 1 500 statistical maps, most of them on the scale of 1:8 mill., about 10 maps on the scale of 1:1 mill. will be included. The editorial work is organized in connection with the National Board of Survey of Finland, which has also the responsibility for the printing and marketing of the atlas. The fifth edition should be finished in 1986. At the same time the work on the next edition should be on its way.  相似文献   

Seasonal and spatial changes in the zooplankton community of Kongsfjorden, Svalbard   总被引：1，自引：0，他引：1  

Wojciech Walkusz  Slawek Kwasniewski  Stig Falk-Petersen  Haakon Hop  Vigdis Tverberg  Piotr Wieczorek  & Jan Marcin Weslawski 《Polar research》2009,28(2):254-281

Seasonal changes in the zooplankton composition of the glacially influenced Kongsfjorden, Svalbard (79°N, 12°E), and its adjacent shelf were studied in 2002. Samples were collected in the spring, summer and autumn in stratified hauls (according to hydrographic characteristics), by means of a 0.180-mm Multi Plankton Sampler. A strong front between the open sea and the fjord waters was observed during the spring, preventing water mass exchange, but was not observed later in the season. The considerable seasonal changes in zooplankton abundance were related to the seasonal variation in hydrographical regime. The total zooplankton abundance during the spring (40–2010 individuals m⁻³) was much lower than in the summer and autumn (410–10 560 individuals m⁻³). The main factors shaping the zooplankton community in the fjord include: the presence of a local front, advection, the flow pattern and the decreasing depth of the basin in the inner fjord. Presumably these factors regulate the gross pattern of zooplankton density and distribution, and override the importance of biological processes. This study increased our understanding of seasonal processes in fjords, particularly with regard to the strong seasonal variability in the Arctic.  相似文献