Corrigendum to “Seasonal food web structures and sympagic-pelagic coupling in the European Arctic revealed by stable isotopes and a two-source food web model” [Progress in Oceanography 71 (2006), 59-87]     

Janne E. Søreide  Haakon Hop  Stig Falk-Petersen 《Progress in Oceanography》2007,73(1):96-98

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Industrial minerals and rocks, aggregates and natural stones in the Nordic countries     

Kurt Johansson Rune B. Larsen Markku J. Lehtinen Lars Persson Mika Raeisaenen Stig A. Schack Pedersen Paer Weihed Nils-Gunnar Wik 《《幕》》2008,31(1):133-139

The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc.
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies.  相似文献   

Trace metals in the Göta river estuary     

Lars-Göran Danielsson  Bertil Magnusson  Stig Westerlund  Kerong Zhang 《Estuarine, Coastal and Shelf Science》1983,17(1):73-85

The concentrations of the trace metals Cd, Cu, Fe, Ni, Pb and Zn in the Göta River estuary have been investigated. The following metal fractions have been determined: acid-leachable, dissolved, labile and particulate.The estuary represents a salt wedge type estuary and is situated in a densely populated region of Sweden. The metal concentrations found for the dissolved fraction is in the range of what can be considered as background levels for freshwater. It is difficult to evaluate any estuarine processes other than conservative mixing for Cd, Cu, Ni and Zn. The dissolved levels in the freshwater end member are Cd, 9–25 ngl^?1; Cu, 1·1–1·4 μgl^?1; Fe, 20–75 μg l^?1: Ni, 0·7–0·9 μg l^?1: Pb 0·09–0·2 μg l^?1; and Zn, 6–7 μg l^?1:The results from the acid-leachable fraction show that at high suspended load the particles sediment in the river mouth. The trace metal levels in this fraction are subject to large variations.  相似文献   

Single frequency processing of Ørsted GPS radio occultation measurements     

Georg Bergeton Larsen  Stig Syndergaard  Per Høeg  Martin Bjært Sørensen 《GPS Solutions》2005,9(2):144-155

The Global Positioning System (GPS) radio occultation measurements obtained using the TurboRogue GPS receiver on the Danish satellite Ørsted have been processed using the single frequency method. Atmospheric profiles of refractivity and temperature are derived and validated against numerical weather prediction data from the European Centre for Medium-Range Weather Forecast (ECMWF). Results from the Ørsted GPS measurement campaign in February 2000 indicate that the single frequency method can provide retrievals with accuracy comparable to that of using two frequencies. From comparisons between measured dry temperature profiles and corresponding dry temperature profiles derived from ECMWF analysis fields, we find a mean difference of less than 0.5 K and a standard deviation of 2–4 K between 500 and 30 hPa in height. Above 30 hPa the impact of the ionosphere becomes more dominant and more difficult to eliminate using the single frequency method, and the results show degraded accuracy when compared to previous analysis results of occultation data from other missions using the dual frequency method. At latitudes less than 40° (denoted low latitudes), the standard deviation is generally smaller than at latitudes higher than 40° (denoted high latitudes). A small temperature bias is observed centered at 200 hPa for low latitudes and at 300 hPa for high latitudes. This indicates that the ECMWF analyses do not adequately resolve the tropopause temperature minimum. In the lowest part of the troposphere an observed warm bias is thought to be due to erroneous tracking of the GPS signal in cases of atmospheric multipath propagation.  相似文献   

2D finite-difference elastic wave modelling including surface topography1     

Stig Hestholm  Bent Ruud 《Geophysical Prospecting》1994,42(5):371-390

A 2D numerical finite-difference algorithm accounting for surface topography is presented. Higher-order, dispersion-bounded, cost-optimized finite-difference operators are used in the interior of the numerical grid, while non-reflecting absorbing boundary conditions are used along the edges. Transformation from a curved to a rectangular grid achieves the modelling of the surface topography. We use free-surface boundary conditions along the surface. In order to obtain complete modelling of the effects of wave propagation, it is important to account for the surface topography, otherwise near-surface effects, such as scattering, are not modelled adequately. Even if other properties of the medium, for instance randomization, can improve numerical simulations, inclusion of the surface topography makes them more realistic.  相似文献   

电离层水平不均匀性对无线电掩星资料反演的影响   总被引：2，自引：4，他引：2       下载免费PDF全文

张训械  曾桢  胡雄  Per Hoeg  G.B.Larsen  B.S.Martin  C.R.Jakob 《地球物理学报》2002,45(Z1):24-29

电离层水平不均匀结构是引起掩星资料反演的主要误差源.本文模拟不均匀结构对无线电掩星资料反演的影响.首先利用3-D全球射线追踪技术进行了模拟.结果指出:电离层电子密度20%的变化可能引起GPS的时延增加约12m.其次,将90%的掩星时延对应的路径长度,定义为电离层掩星测量的水平分辨率,其值为1200-2000 km.最后,计算了不同纬度电离层当地正午、子夜和日出时的电离层水平不对称指数.它表明:低纬夏季日出时,不对称指数达-78%,反演结果可能有较大误差.  相似文献   

Rg observations from four continents: inverse- and forward-modelling experiments     

B. O. Ruud  E. S. Husebye  S. O. Hestholm 《Geophysical Journal International》1993,114(3):465-472

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One hundred years of hydrographic measurements in the Baltic Sea   总被引：1，自引：0，他引：1  

Stig Fonselius  Jorge Valderrama   《Journal of Sea Research》2003,49(4):229

The first measurements of salinity of the deep water in the open Baltic Sea were made in the last decades of the 1800s. At a Scandinavian science meeting in Copenhagen in 1892, Professor Otto Pettersson from Sweden suggested that regular measurements of hydrographic parameters should be carried out at some important deep stations in the Baltic Sea. His suggestion was adopted and since that time we have rather complete hydrographical data from the Bornholm Deep, the Gotland Deep, and the Landsort Deep and from some stations in the Gulf of Bothnia. The measurements were interrupted in the Baltic Proper during the two World Wars. At the beginning only salinity, temperature and dissolved oxygen were measured and one or two expeditions were carried out annually, mostly in summer. In the 1920s also alkalinity and pH were occasionally measured and total carbonate was calculated. A few nutrient measurements were also carried out. After World War II we find results from four or more expeditions every year and intercalibration of methods was arranged. Results of temperature, salinity and dissolved oxygen measurements from the Bornholm Deep, the Gotland Deep, the Landsort Deep and salinity measurements from three stations in the Gulf of Bothnia, covering the whole 20th century are presented and discussed. The salinity distribution and the variations between oxygen and hydrogen sulphide periods in the deep water of the Gotland Deep and the Landsort Deep are demonstrated. Series of phosphate and nitrate distribution in the Gotland Deep are shown from the 1950s to the present and the effects of the stagnant conditions are briefly discussed. Two large inflows of highly saline water, the first during the First World War and the second in 1951, are demonstrated. The 20th century minimum salinity of the bottom water in the Baltic Proper in 1992 is discussed.  相似文献   

Little auks (Alle alle) breeding in a High Arctic fjord system: bimodal foraging strategies as a response to poor food quality?     

Harald Steen  Daniel Vogedes  Fredrik Broms  Stig Falk-Petersen  & Jørgen Berge 《Polar research》2007,26(2):118-125

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Stable carbon‐isotope record of shallow‐marine evaporative epicratonic basin carbonates,Ordovician Williston Basin,North America          下载免费PDF全文

Antun Husinec  Stig M. Bergström 《Sedimentology》2015,62(1):314-349

Secular variations in stable carbon‐isotope values of marine carbonates are used widely to correlate successions that lack high‐resolution index fossils. Various environmental processes, however, commonly may affect and alter the primary marine carbon‐isotope signal in shallow epicratonic basins. This study focuses on the marine carbon‐isotope record from the carbonate–evaporite succession of the upper Katian (Upper Ordovician) Red River Formation of the shallow epicratonic Williston Basin, USA. It documents the carbon‐isotope signal between the two major Ordovician positive shifts in δ¹³C, the early Katian Guttenberg and the Hirnantian excursions. Eight δ¹³C stages are identified based on positive excursions, shifts from positive to negative values and relatively uniform δ¹³C_carb values. A correlation between carbon‐isotope trends and the relative sea‐level changes based on gross facies stacking patterns shows no clear relation. Based on the available biostratigraphy and δ¹³C trends, the studied Williston Basin curves are tied to the isotope curves from the North American Midcontinent, Québec (Anticosti Island) and Estonia, which confirm the Late Katian age (Aphelognathus divergens Conodont Zone) of the upper Red River Formation. The differences in the δ¹³C overall trend and absolute values, coupled with the petrographic and cathodoluminescence evidence, suggest that the carbon‐isotope record has been affected by the syndepositional environmental processes in the shallow and periodically isolated Williston Basin, and stabilized by later burial diagenesis under reducing conditions and the presence of isotopically more negative fluids.  相似文献