Laboratory technique for measurement of spectral induced polarization response of soil sampies1     

Heikki Vanhala  Heikki Soininen 《Geophysical Prospecting》1995,43(5):655-676

Laboratory measurements of soil samples are necessary to assess the effect of mineralogy, grain size distribution, moisture content, and electrolyte composition on the resistivity spectrum of soil material. Laboratory results are also required for the interpretation of field data. Induced polarization phenomena in glacial soils are poorly understood and so far no convenient laboratory techniques are available for its measurement. Coarse grain size and the need to measure unsaturated samples and to monitor the homogeneity of the sample require a sample holder–electrode construction that differs from those presented in Clay mineral Studies. This study presents a spectral induced polarization laboratory system that is suitable for measuring fine- and coarse-grained and both saturated and unsaturated soil samples. The noise caused by the electrode–electrolyte interface is studied in detail. It is shown that easy-to-use platinum or acid-free steel potential electrodes are convenient over a broad frequency band ranging from 0.016Hz up to more than 1000 Hz. The laboratory experiments and comparisons between laboratory and field results also indicate that sampling and sample packing procedures have only a minor influence on the phase spectrum of glacial soils.  相似文献   

Heavy metals and high pup mortality in the Saimaa ringed seal population in eastern Finland     

Heikki Hyvärinen  Tero Sipilä 《Marine pollution bulletin》1984,15(9):335-337

Hair nickel, mercury, cadmium, lead and chromium concentrations were measured from still-born ringed seal pups and from other ringed seal groups from Lake Saimaa in Finland. Nickel concentration was significantly higher in the hair samples of still-born pups as compared to live-born pups and to adult seals. There was assumed to be some connection between the stillbirth of the pups and nickel concentration of the hair. Mercury concentration of the natal hair of pups was significantly higher than the mercury concentration of the first adult hair but no clear connection between stillbirth and mercury pollution was observed. No differences were observed in cadmium, lead and chromium concentrations of the hair of still-born and other ringed seal groups.  相似文献   

Spherical cap harmonic analysis applied to the Scandinavian geomagnetic field 1985.0     

Heikki Nevanlinna  Joumi Rynö  Gerry V. Haines  Kjell Borg 《Ocean Dynamics》1988,41(3-6):177-186

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GHG mitigation of agricultural peatlands requires coherent policies   总被引：1，自引：0，他引：1  

Kristiina Regina  Arif Budiman  Mogens H. Greve  Arne Grønlund  Åsa Kasimir  Heikki Lehtonen 《Climate Policy》2016,16(4):522-541

As soon as peat soil is drained for agricultural production, the peat starts to degrade, which causes emissions to the atmosphere. In countries with large peatland areas, the GHG mitigation potential related to management of these soils is often estimated as the highest amongst the measures available in agriculture. Although the facts are well known, the policies leading to diminished emissions are often difficult to implement. We have analysed the reasons why the mitigation potential is not fully utilized and what could be done better in national implementation of climate policies. Four cases are used to illustrate the necessary steps to reach mitigation targets: determining the amount and properties of peat soils, estimating the potential, costs and feasibility of the mitigation measures, and selecting and implementing the best measures. A common feature for all of the cases was that national and international climate policies have increased the public interest in GHG emissions from peat soils and increased the pressure for mitigation. Basically the same factors restrict the implementation of mitigation measures in all countries with significant peat soil areas. The most important of these is lack of policy coherence, e.g. ignoring climate policies when planning land use or agricultural policies. We conclude that GHG mitigation is achieved only if other policies, especially national regulations and strategies, are in line with climate policies.

Policy relevance

Agricultural peat soils could be used to help reach GHG mitigation goals in many countries, but the full potential of mitigation of peat soils is not used. Although peatland cultivation inevitably leads to loss of the whole peat layer and high emissions, there are few incentives or regulation to effectively minimize these losses. This article discusses the possibilities to reduce GHG emissions from agricultural peat soils, with specific emphasis on the barriers of implementing mitigation measures nationally. The lessons learned from the selected cases emphasize the role of all policy makers and their cooperation in planning coherent policies for achieving the goals determined by climate policies.  相似文献   

Guest Editorial - "Geoanalysis 2003"     

Jean Kane  Lea Hmlinen  Heikki Niskavaara  Michael Ramsey  Harry Sandstrom 《Geostandards and Geoanalytical Research》2004,28(2):191-192

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Geochemical Baselines of Nickel and Chromium in Various Surficial Materials in the Barents Region, NW Russia and Finland     

Reijo Salminen  Igor Bogatyrev  Victor Chekushin  Sergey P. Glavatskikh  Virgilija Gregorauskiene  Heikki Niskavaara  Lubov Selenok  Markku Tenhola  Olga Tomilina 《Geostandards and Geoanalytical Research》2004,28(2):333-341

The geochemical baselines of nickel and chromium were studied from the data produced by the Barents Ecogeochemistry project, a large international regional geochemical mapping exercise. The project surveyed major and trace element distributions in stream water, organic and mineralogically-modified soil horizons, and terrestrial moss in the northwestern part of Russia and in Finland. Other materials were collected during the pilot phase and later from thirty special sites. The results on respective materials by XRF, ICP-MS and ICP-AES showed that both geological and anthropogenic factors have an influence on the geochemical baseline concentrations of Ni and Cr in organic soil and stream water. The main explanation of the observed distribution patterns in terrestrial moss is human activity, but geological factors can also affect the baselines. The variation of geochemical baselines in the mineral-rich soil horizon depends only on variations in bedrock. The mineralogy of samples mainly controls the leachability properties of soil samples.  相似文献   

Pollen-stratigraphical evidence of Holocene hydrological change in northern Fennoscandia supported by independent isotopic data     

Heikki Seppä  Dan Hammarlund 《Journal of Paleolimnology》2000,24(1):69-79

Pollen records from 21 sites were used to reconstruct Holocene hydrological changes in northern Fennoscandia. The inferred dominance of maritime-type Betula-forests from c. 9600 BP onwards indicate an oceanic climate in the region during the early Holocene, with high amounts of precipitation and low seasonal contrasts. This interpretation is supported by oxygen isotope records obtained on lacustrine carbonates from Abisko, northern Sweden. Enrichment of ¹⁸O during the early Holocene suggests enhanced zonal circulation and a pronounced influence of Atlantic air-masses in northern Sweden. The pattern of Pinus expansion in the area was time-transgressive, ranging from 9200-8000 BP in the extreme north-east to 7900-5500 BP in the western and south-western parts of the region. The replacement of Betula-forests by Pinus-forests indicates a climatic change towards drier summers and increased seasonality. At Abisko, a close correlation between regional Pinus expansion and depletion of ¹⁸O in lacustrine carbonates suggests that the expansion of Pinus was triggered by a gradual attenuation of the influence of westerlies. Thus, in large-scale palaeohydrological terms, the early expansion of Pinus in the north-easternmost parts of Fennoscandia as compared to the successively later expansion in the west and south-west may reflect a gradually decreasing influence of Atlantic air-masses in northern Fennoscandia during the early and mid Holocene.  相似文献   

N-body model for M51 – I. Multiple encounter versus single passage?     

Heikki Salo  Eija Laurikainen 《Monthly notices of the Royal Astronomical Society》2000,319(2):377-392

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Holocene temperature trends in the extratropical Northern Hemisphere based on inter‐model comparisons          下载免费PDF全文

Yurui Zhang  Hans Renssen  Heikki Seppä  Paul J. Valdes 《第四纪科学杂志》2018,33(4):464-476

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The Holocene thermal maximum and late-Holocene cooling in the tundra of NE European Russia     

J. Sakari Salonen  Heikki Sepp  Minna Vliranta  Vivienne J. Jones  Angela Self  Maija Heikkil  Seija Kultti  Handong Yang 《Quaternary Research》2011,75(3):501-511

To investigate the Holocene climate and treeline dynamics in the European Russian Arctic, we analysed sediment pollen, conifer stomata, and plant macrofossils from Lake Kharinei, a tundra lake near the treeline in the Pechora area. We present quantitative summer temperature reconstructions from Lake Kharinei and Lake Tumbulovaty, a previously studied lake in the same region, using a pollen–climate transfer function based on a new calibration set from northern European Russia. Our records suggest that the early-Holocene summer temperatures from 11,500 cal yr BP onwards were already slightly higher than at present, followed by a stable Holocene Thermal Maximum (HTM) at 8000–3500 cal yr BP when summer temperatures in the tundra were ca. 3°C above present-day values. A Picea forest surrounded Lake Kharinei during the HTM, reaching 150 km north of the present taiga limit. The HTM ended with a temperature drop at 3500–2500 cal yr BP associated with permafrost initiation in the region. Mixed spruce forest began to disappear around Lake Kharinei at ca. 3500 cal yr BP, with the last tree macrofossils recorded at ca. 2500 cal yr BP, suggesting that the present wide tundra zone in the Pechora region formed during the last ca. 3500 yr.  相似文献